Maya 2010 Getting Started

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Autodesk® Maya® 2010 Software
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Contents

Chapter 1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
About the Getting Started lessons . . . . . . . . . . . . . . . . . . . . . 2
Before you begin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Installing Maya . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Conventions used in the lessons . . . . . . . . . . . . . . . . . . . . . . 4
Using the lesson files . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Using the Maya Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Additional learning resources . . . . . . . . . . . . . . . . . . . . . . . 10
Restoring default user settings . . . . . . . . . . . . . . . . . . . . . . 11

Chapter 2 Maya Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Preparing for the lessons . . . . . . . . . . . . . . . . . . . . . . . . . 14
Lesson 1: The Maya user interface . . . . . . . . . . . . . . . . . . . . 15
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Starting Maya . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
The Maya interface . . . . . . . . . . . . . . . . . . . . . . . . . 16
Copying and setting the Maya project . . . . . . . . . . . . . . . 25
Saving your work . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Exiting Maya . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Beyond the lesson . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Lesson 2: Creating, manipulating, and viewing objects . . . . . . . . . 29

iii

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Creating a new scene . . . . . . . . . . . . . . . . . . . . . . . . 30
Primitive objects . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
The Toolbox: Layout shortcuts . . . . . . . . . . . . . . . . . . . 32
The Toolbox: Transformation tools . . . . . . . . . . . . . . . . . 34
The Channel Box . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Duplicating objects . . . . . . . . . . . . . . . . . . . . . . . . . 39
Save your work . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Lesson 3: Viewing the Maya 3D scene . . . . . . . . . . . . . . . . . . 42
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Camera tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Workflow overview . . . . . . . . . . . . . . . . . . . . . . . . . 46
Viewing objects in shaded mode . . . . . . . . . . . . . . . . . . 51
Grouping objects . . . . . . . . . . . . . . . . . . . . . . . . . . 52
The Hypergraph . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Selection modes and masks . . . . . . . . . . . . . . . . . . . . . 56
Pivot points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Save your work . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Lesson 4: Components and attributes . . . . . . . . . . . . . . . . . . 60
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Template display . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
The Attribute Editor . . . . . . . . . . . . . . . . . . . . . . . . . 65
Surface materials . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Save your work . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Chapter 3 Polygonal Modeling . . . . . . . . . . . . . . . . . . . . . . . . 71
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Preparing for the lesson . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Lesson 1: Modeling a polygonal mesh . . . . . . . . . . . . . . . . . . 73
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Setting modeling preferences . . . . . . . . . . . . . . . . . . . . 74
Using 2D reference images . . . . . . . . . . . . . . . . . . . . . 75
Creating a polygon primitive . . . . . . . . . . . . . . . . . . . . 78
Modeling in shaded mode . . . . . . . . . . . . . . . . . . . . . 80
Model symmetry . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Selecting components by painting . . . . . . . . . . . . . . . . . 83
Selecting edge loops . . . . . . . . . . . . . . . . . . . . . . . . . 84
Editing components in the orthographic views . . . . . . . . . . 86
Editing components in the perspective view . . . . . . . . . . . . 93
Drawing a polygon . . . . . . . . . . . . . . . . . . . . . . . . . 95
Extruding polygon components . . . . . . . . . . . . . . . . . . 97
Bridging between edges . . . . . . . . . . . . . . . . . . . . . . 102

iv | Contents

Adding polygons to a mesh . . . . . . . . . . . . . . . . . . . . 105
Splitting polygon faces . . . . . . . . . . . . . . . . . . . . . . . 107
Terminating edge loops . . . . . . . . . . . . . . . . . . . . . . 115
Deleting construction history . . . . . . . . . . . . . . . . . . . 117
Mirror copying a mesh . . . . . . . . . . . . . . . . . . . . . . . 119
Working with a smoothed mesh . . . . . . . . . . . . . . . . . . 121
Creasing and hardening edges on a mesh . . . . . . . . . . . . . 123
Beyond the lesson . . . . . . . . . . . . . . . . . . . . . . . . . 129
Lesson 2: Sculpting a polygon mesh . . . . . . . . . . . . . . . . . . . 130
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Open the scene for the lesson . . . . . . . . . . . . . . . . . . . 131
Using Soft Select . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Selecting with Camera based selection . . . . . . . . . . . . . . 135
Sculpting with symmetry . . . . . . . . . . . . . . . . . . . . . 137
Sculpting with Surface based falloff . . . . . . . . . . . . . . . . 141
Selecting with Drag select . . . . . . . . . . . . . . . . . . . . . 143
Adjusting the Seam tolerance . . . . . . . . . . . . . . . . . . . 146

Chapter 4 NURBS Modeling . . . . . . . . . . . . . . . . . . . . . . . . . 149
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Lesson 1: Revolving a curve to create a surface . . . . . . . . . . . . . 150
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Creating a profile curve . . . . . . . . . . . . . . . . . . . . . . 151
Creating a revolve surface . . . . . . . . . . . . . . . . . . . . . 153
Editing a revolve surface . . . . . . . . . . . . . . . . . . . . . . 153
Lesson 2: Sculpting a NURBS surface . . . . . . . . . . . . . . . . . . 156
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Preparing a surface for sculpting . . . . . . . . . . . . . . . . . . 157
Basic sculpting techniques . . . . . . . . . . . . . . . . . . . . . 159
Additional sculpting techniques . . . . . . . . . . . . . . . . . . 162
Sculpting a nose . . . . . . . . . . . . . . . . . . . . . . . . . . 164
Sculpting eye sockets . . . . . . . . . . . . . . . . . . . . . . . 165
Sculpting eyebrows . . . . . . . . . . . . . . . . . . . . . . . . 166
Sculpting a mouth . . . . . . . . . . . . . . . . . . . . . . . . . 167
Sculpting other facial features . . . . . . . . . . . . . . . . . . . 169
Lesson 3: Lofting curves to create a surface . . . . . . . . . . . . . . . 171
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Creating profile curves for a surface . . . . . . . . . . . . . . . . 172
Duplicating curves . . . . . . . . . . . . . . . . . . . . . . . . . 174
Lofting a surface . . . . . . . . . . . . . . . . . . . . . . . . . . 175
Modifying a primitive object . . . . . . . . . . . . . . . . . . . 176
Using the Outliner to parent objects . . . . . . . . . . . . . . . 178

Contents | v


Chapter 5 Subdivision Surfaces . . . . . . . . . . . . . . . . . . . . . . . 181
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Preparing for the lesson . . . . . . . . . . . . . . . . . . . . . . . . . 181
Lesson 1: Modeling a subdivision surface . . . . . . . . . . . . . . . . 182
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
Creating a subdivision surface . . . . . . . . . . . . . . . . . . . 183
Splitting a surface in polygon proxy mode . . . . . . . . . . . . 185
Extruding polygon faces . . . . . . . . . . . . . . . . . . . . . . 187
Deleting polygon faces . . . . . . . . . . . . . . . . . . . . . . . 190
Subdivision surface levels . . . . . . . . . . . . . . . . . . . . . 191
Refining surface components . . . . . . . . . . . . . . . . . . . 193
Creating a crease in a subdivision surface . . . . . . . . . . . . . 195

Chapter 6 Animation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Lesson 1: Keyframes and the Graph Editor . . . . . . . . . . . . . . . 200
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Setting the playback range . . . . . . . . . . . . . . . . . . . . . 201
Setting keyframes . . . . . . . . . . . . . . . . . . . . . . . . . 202
Using the Graph Editor . . . . . . . . . . . . . . . . . . . . . . 205
Changing the timing of an attribute . . . . . . . . . . . . . . . 209
Fine tuning an animation . . . . . . . . . . . . . . . . . . . . . 210
Deleting extra keyframes and static channels . . . . . . . . . . . 212
Using Playblast to playback an animation . . . . . . . . . . . . 213
Lesson 2: Set Driven Key . . . . . . . . . . . . . . . . . . . . . . . . . 215
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Using Set Driven Key to link attributes . . . . . . . . . . . . . . 216
Viewing the results in the Graph Editor . . . . . . . . . . . . . . 219
Lesson 3: Path animation . . . . . . . . . . . . . . . . . . . . . . . . 220
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Animating an object along a motion path . . . . . . . . . . . . 222
Changing the timing of an object along a motion path . . . . . 224
Rotating an object along a motion path . . . . . . . . . . . . . 230
Blending keyframe and motion path animation . . . . . . . . . 231
Using Playblast to playback an animation . . . . . . . . . . . . 237
Lesson 4: Nonlinear animation with Trax . . . . . . . . . . . . . . . . 239

vi | Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
Open the first scene for the lesson . . . . . . . . . . . . . . . . 240
Creating clips with Trax . . . . . . . . . . . . . . . . . . . . . . 242
Changing the position of clips with Trax . . . . . . . . . . . . . 249
Editing the animation of clips . . . . . . . . . . . . . . . . . . . 251
Reusing clips within Trax . . . . . . . . . . . . . . . . . . . . . 253
Soloing and muting tracks . . . . . . . . . . . . . . . . . . . . . 256
Scaling clips within Trax . . . . . . . . . . . . . . . . . . . . . . 257
Open the second scene for the lesson . . . . . . . . . . . . . . . 259
Creating clips from motion capture data . . . . . . . . . . . . . 260
Extending the length of motion capture data . . . . . . . . . . . 261
Redirecting the motion within a clip . . . . . . . . . . . . . . . 266
Lesson 5: Inverse kinematics . . . . . . . . . . . . . . . . . . . . . . . 276
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
Understanding hierarchies . . . . . . . . . . . . . . . . . . . . . 278
Viewing hierarchies using the Hypergraph . . . . . . . . . . . . 279
Creating a skeleton hierarchy . . . . . . . . . . . . . . . . . . . 281
Parenting a model into a skeleton hierarchy . . . . . . . . . . . 285
Applying IK to a skeleton hierarchy . . . . . . . . . . . . . . . . 288
Creating a control object for an IK system . . . . . . . . . . . . 290
Constraining an IK system . . . . . . . . . . . . . . . . . . . . . 294
Limiting the range of motion of an IK system . . . . . . . . . . 298
Simplifying the display of a hierarchy . . . . . . . . . . . . . . . 304
Applying parent constraints on an IK system . . . . . . . . . . . 305
Planning an animation for an IK system . . . . . . . . . . . . . 308
Animating an IK system . . . . . . . . . . . . . . . . . . . . . . 311

Chapter 7 Character Setup . . . . . . . . . . . . . . . . . . . . . . . . . 317
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317
Lesson 1: Skeletons and kinematics . . . . . . . . . . . . . . . . . . . 318
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
Creating joints . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
Adding joints to a skeleton . . . . . . . . . . . . . . . . . . . . 325
Creating a skeleton hierarchy . . . . . . . . . . . . . . . . . . . 327
Forward and inverse kinematics . . . . . . . . . . . . . . . . . . 327
Posing and animating using inverse kinematics . . . . . . . . . 328
Posing and animating using forward kinematics . . . . . . . . . 332
Lesson 2: Smooth skinning . . . . . . . . . . . . . . . . . . . . . . . 333
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

Contents | vii

Smooth binding a skeleton . . . . . . . . . . . . . . . . . . . . 334
Skin weighting and deformations . . . . . . . . . . . . . . . . . 336
Modifying skin weights . . . . . . . . . . . . . . . . . . . . . . 338
Influence objects . . . . . . . . . . . . . . . . . . . . . . . . . . 340
Lesson 3: Cluster and blend shape deformers . . . . . . . . . . . . . . 344
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344
Creating a target object for a blend shape . . . . . . . . . . . . . 345
Creating a cluster deformer on a target object . . . . . . . . . . 346
Editing cluster weights . . . . . . . . . . . . . . . . . . . . . . . 348
Creating a blend shape . . . . . . . . . . . . . . . . . . . . . . 352
Refining deformation effects . . . . . . . . . . . . . . . . . . . 354
Adding target objects to an existing blend shape . . . . . . . . . 355

Chapter 8 Polygon Texturing . . . . . . . . . . . . . . . . . . . . . . . . 361
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
Preparing for the lesson . . . . . . . . . . . . . . . . . . . . . . . . . 362
Lesson 1: UV texture mapping . . . . . . . . . . . . . . . . . . . . . . 363
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
Creating a cracker box model . . . . . . . . . . . . . . . . . . . 364
Applying a texture map to a polygon mesh . . . . . . . . . . . . 365
Viewing UVs in the UV Texture Editor . . . . . . . . . . . . . . 371
Mapping UV texture coordinates . . . . . . . . . . . . . . . . . 375
Working with UVs in the UV Texture Editor . . . . . . . . . . . 379
Lesson 2: UV unfolding . . . . . . . . . . . . . . . . . . . . . . . . . 389
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389
Lesson Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390
Dividing the mesh . . . . . . . . . . . . . . . . . . . . . . . . . 391
Creating a planar mapping . . . . . . . . . . . . . . . . . . . . 395
Unfolding a UV mesh . . . . . . . . . . . . . . . . . . . . . . . 397
Adjusting the checker pattern . . . . . . . . . . . . . . . . . . . 401
Outputting UVs . . . . . . . . . . . . . . . . . . . . . . . . . . 402
Unfolding with constraints . . . . . . . . . . . . . . . . . . . . 404
Sewing UV Edges . . . . . . . . . . . . . . . . . . . . . . . . . . 411
Smoothing/Relaxing a mesh interactively . . . . . . . . . . . . . 416
Fixing problem areas . . . . . . . . . . . . . . . . . . . . . . . . 417
Applying Textures . . . . . . . . . . . . . . . . . . . . . . . . . 423
Lesson 3: Normal mapping . . . . . . . . . . . . . . . . . . . . . . . 428
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429
Creating a Normal Map . . . . . . . . . . . . . . . . . . . . . . 432

viii | Contents

Viewing a normal map . . . . . . . . . . . . . . . . . . . . . . . 435

Chapter 9 Rendering . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
Lesson 1: Rendering a scene . . . . . . . . . . . . . . . . . . . . . . . 439
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
Creating shading materials for objects . . . . . . . . . . . . . . 441
Refining shading materials for objects . . . . . . . . . . . . . . 445
Maya renderers . . . . . . . . . . . . . . . . . . . . . . . . . . . 450
Rendering a single frame using IPR . . . . . . . . . . . . . . . . 452
Rendering using the Maya software renderer . . . . . . . . . . . 457
Batch rendering a sequence of animation frames . . . . . . . . . 459
Viewing a sequence of rendered frames . . . . . . . . . . . . . . 462
Lesson 2: Shading surfaces . . . . . . . . . . . . . . . . . . . . . . . . 465
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465
Assigning a shading material . . . . . . . . . . . . . . . . . . . 467
Modifying surface specularity . . . . . . . . . . . . . . . . . . . 469
Material types . . . . . . . . . . . . . . . . . . . . . . . . . . . 470
Assigning textures . . . . . . . . . . . . . . . . . . . . . . . . . 471
Using the Hypershade editor . . . . . . . . . . . . . . . . . . . 474
Creating a texture within the Hypershade editor . . . . . . . . . 477
Modifying a bump texture . . . . . . . . . . . . . . . . . . . . . 480
Lesson 3: Lights, shadows, and cameras . . . . . . . . . . . . . . . . . 484
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484
Directional lights . . . . . . . . . . . . . . . . . . . . . . . . . . 486
Spotlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488
Editing light attributes . . . . . . . . . . . . . . . . . . . . . . . 491
Shadows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494
Creating additional cameras in a scene . . . . . . . . . . . . . . 496
Animating camera moves . . . . . . . . . . . . . . . . . . . . . 498
Lesson 4: Global Illumination . . . . . . . . . . . . . . . . . . . . . . 501
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
Render the scene using raytracing . . . . . . . . . . . . . . . . . 503
Render the scene using Global Illumination . . . . . . . . . . . 508
Beyond the Lesson . . . . . . . . . . . . . . . . . . . . . . . . . 517
Lesson 5: Caustics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519

Contents | ix

Render the scene using raytracing . . . . . . . . . . . . . . . . . 521
Render the scene using caustics . . . . . . . . . . . . . . . . . . 526

Chapter 10 Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
Lesson 1: Particles, emitters, and fields . . . . . . . . . . . . . . . . . 536
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536
Creating an emitter . . . . . . . . . . . . . . . . . . . . . . . . 537
Creating volume axis fields . . . . . . . . . . . . . . . . . . . . 539
Adjusting the velocity of moving particles . . . . . . . . . . . . 545
Setting the particle render type . . . . . . . . . . . . . . . . . . 545
Adding dynamic attributes . . . . . . . . . . . . . . . . . . . . 546
Adding per particle attributes . . . . . . . . . . . . . . . . . . . 548
Adding color to particles with a color ramp . . . . . . . . . . . 549
Hardware rendering particles . . . . . . . . . . . . . . . . . . . 551
Lesson 2: Rigid bodies and constraints . . . . . . . . . . . . . . . . . 554
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554
Creating hinge constraints . . . . . . . . . . . . . . . . . . . . . 556
Running a dynamics simulation . . . . . . . . . . . . . . . . . . 557
Changing an active rigid body to passive . . . . . . . . . . . . . 558

Chapter 11 Painting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 561
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 561
Lesson 1: Painting in 2D using Paint Effects . . . . . . . . . . . . . . 563
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 563
Painting strokes . . . . . . . . . . . . . . . . . . . . . . . . . . 564
Modifying the default brush settings . . . . . . . . . . . . . . . 566
Modifying the canvas . . . . . . . . . . . . . . . . . . . . . . . 568
Modifying the colors of a preset brush . . . . . . . . . . . . . . 568
Editing strokes with tubes attributes . . . . . . . . . . . . . . . 570
Saving brush settings for future use . . . . . . . . . . . . . . . . 571
Blending brushes . . . . . . . . . . . . . . . . . . . . . . . . . . 572
Smearing, blurring, and erasing paint . . . . . . . . . . . . . . . 573
Lesson 2: Painting in 3D using Paint Effects . . . . . . . . . . . . . . 575
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 575
Preparing for the lessons . . . . . . . . . . . . . . . . . . . . . . 576
Brushes and strokes . . . . . . . . . . . . . . . . . . . . . . . . 577

x | Contents

Rendering Paint Effects strokes . . . . . . . . . . . . . . . . . . 584
Paint Effects on 3D objects . . . . . . . . . . . . . . . . . . . . 589
Creating a surface to paint on . . . . . . . . . . . . . . . . . . . 590
Painting on objects . . . . . . . . . . . . . . . . . . . . . . . . 593
Using turbulence with brush stroke tubes . . . . . . . . . . . . . 595
Using additional preset brushes . . . . . . . . . . . . . . . . . . 596
Mesh brushes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 598
Converting mesh strokes to polygons . . . . . . . . . . . . . . . 600
Modifying a converted polygonal mesh . . . . . . . . . . . . . . 602
Lesson 3: Painting textures on surfaces . . . . . . . . . . . . . . . . . 608
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 608
Preparing for painting . . . . . . . . . . . . . . . . . . . . . . . 609
Painting with an Artisan brush . . . . . . . . . . . . . . . . . . 611
Painting symmetrical strokes . . . . . . . . . . . . . . . . . . . 612
Using Flood All to apply a single color . . . . . . . . . . . . . . 613
Brush shapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613
Painting with a Paint Effects brush . . . . . . . . . . . . . . . . 615
Smearing and blurring . . . . . . . . . . . . . . . . . . . . . . . 617
Painting a bump map texture . . . . . . . . . . . . . . . . . . . 618

Chapter 12 Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625
Lesson 1: Creating a simple expression . . . . . . . . . . . . . . . . . 627
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 627
Creating expressions to control a single attribute . . . . . . . . . 627
Editing expressions . . . . . . . . . . . . . . . . . . . . . . . . 630
Using expressions to control multiple attributes . . . . . . . . . 631
Linking multiple attributes on the same object . . . . . . . . . . 631
Controlling attributes in two objects . . . . . . . . . . . . . . . 632
Lesson 2: Conditional expressions . . . . . . . . . . . . . . . . . . . . 634
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634
Creating a conditional expression . . . . . . . . . . . . . . . . . 634
Other conditional statement options . . . . . . . . . . . . . . . 637
Fixing a problem in an expression . . . . . . . . . . . . . . . . . 639
Using else statements . . . . . . . . . . . . . . . . . . . . . . . 639
Simplifying expressions . . . . . . . . . . . . . . . . . . . . . . 640
Editing expressions to refine an animation . . . . . . . . . . . . 641
Lesson 3: Controlling particle attributes . . . . . . . . . . . . . . . . 643
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643
Creating particle objects . . . . . . . . . . . . . . . . . . . . . . 644

Contents | xi

Using creation expressions to set a constant color . . . . . . . . 645
Using runtime expressions . . . . . . . . . . . . . . . . . . . . . 646
Modifying runtime expressions . . . . . . . . . . . . . . . . . . 648

Chapter 13 Scripting in Maya . . . . . . . . . . . . . . . . . . . . . . . . 651
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 651
Some basic concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . 652
Lesson 1: Commands in MEL . . . . . . . . . . . . . . . . . . . . . . 656
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 656
Entering MEL commands . . . . . . . . . . . . . . . . . . . . . 657
Observing script history . . . . . . . . . . . . . . . . . . . . . . 658
Modifying object attributes . . . . . . . . . . . . . . . . . . . . 661
Editing Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . 664
Lesson 2: Saving scripts to the Shelf . . . . . . . . . . . . . . . . . . . 666
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 666
Setting up the scene . . . . . . . . . . . . . . . . . . . . . . . . 667
Recording the script history . . . . . . . . . . . . . . . . . . . . 668
Compare the rendered images . . . . . . . . . . . . . . . . . . 670
Saving the history as a button . . . . . . . . . . . . . . . . . . . 671
Lesson 3: Using Variables in MEL . . . . . . . . . . . . . . . . . . . . 674
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 674
Setting up the scene . . . . . . . . . . . . . . . . . . . . . . . . 674
Storing scene information . . . . . . . . . . . . . . . . . . . . . 675
Create a row of barrels . . . . . . . . . . . . . . . . . . . . . . . 677
Stacking the row of barrels . . . . . . . . . . . . . . . . . . . . . 678
Using MEL built-in functions to calculate the Y offset . . . . . . 679
Creating dynamics with MEL commands . . . . . . . . . . . . . 681
Lesson 4: User interface creation and procedures . . . . . . . . . . . . 683
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 683
Creating a window . . . . . . . . . . . . . . . . . . . . . . . . . 684
Window naming . . . . . . . . . . . . . . . . . . . . . . . . . . 686
Introduction to procedures . . . . . . . . . . . . . . . . . . . . 689
Loading a script file . . . . . . . . . . . . . . . . . . . . . . . . 691
Linking the user interface . . . . . . . . . . . . . . . . . . . . . 695
Saving the script . . . . . . . . . . . . . . . . . . . . . . . . . . 700
Using the saved script file . . . . . . . . . . . . . . . . . . . . . 701
Lesson 5: Using Python in Maya . . . . . . . . . . . . . . . . . . . . 703
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703
Entering Python commands . . . . . . . . . . . . . . . . . . . . 704
Using flags in Python . . . . . . . . . . . . . . . . . . . . . . . 707

xii | Contents

Using the edit flag in Python . . . . . . . . . . . . . . . . . . . 711
Communicating between Python and MEL . . . . . . . . . . . . 713

Chapter 14 Assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 717
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 717
Lesson 1: Setting up an asset . . . . . . . . . . . . . . . . . . . . . . . 718
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718
Creating a container . . . . . . . . . . . . . . . . . . . . . . . . 719
Publishing attributes . . . . . . . . . . . . . . . . . . . . . . . . 720
Publishing multiple attributes to a single published name . . . . 722
Creating a template . . . . . . . . . . . . . . . . . . . . . . . . 725
Creating Views . . . . . . . . . . . . . . . . . . . . . . . . . . . 727
Assigning a custom icon . . . . . . . . . . . . . . . . . . . . . . 730
Setting Black Box mode . . . . . . . . . . . . . . . . . . . . . . 731
Lesson 2: Using assets in a scene . . . . . . . . . . . . . . . . . . . . . 732
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 732
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 733
Importing assets to dress a scene . . . . . . . . . . . . . . . . . 734
Assigning an existing template to a container . . . . . . . . . . 735
Binding attributes . . . . . . . . . . . . . . . . . . . . . . . . . 738
Swapping assets . . . . . . . . . . . . . . . . . . . . . . . . . . 740
Referencing assets in a scene . . . . . . . . . . . . . . . . . . . . 742
Creating a proxy container . . . . . . . . . . . . . . . . . . . . 745
Modifying a proxy container . . . . . . . . . . . . . . . . . . . 747
Dressing the rest of the scene with assets . . . . . . . . . . . . . 749

Chapter 15 Hair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 753
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 753
About hair simulation . . . . . . . . . . . . . . . . . . . . . . . . . . 755
Lesson 1: Creating a basic hairstyle . . . . . . . . . . . . . . . . . . . 756
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 756
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 757
Creating hair on a surface . . . . . . . . . . . . . . . . . . . . . 758
Styling the hair . . . . . . . . . . . . . . . . . . . . . . . . . . . 762
Setting up hair collisions . . . . . . . . . . . . . . . . . . . . . 767
Rendering the hair . . . . . . . . . . . . . . . . . . . . . . . . . 771
Modifying hair attributes . . . . . . . . . . . . . . . . . . . . . 772
Setting up shadowing on hair . . . . . . . . . . . . . . . . . . . 774

Contents | xiii

Lesson 2: Creating a dynamic non-hair simulation . . . . . . . . . . . 777
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 778
Setting up the curtain scene . . . . . . . . . . . . . . . . . . . . 778
Making the hair collide with another object . . . . . . . . . . . 782
Assigning a Paint Effects brush to the hair . . . . . . . . . . . . 782
Setting up constraints . . . . . . . . . . . . . . . . . . . . . . . 784
Rendering the curtain scene . . . . . . . . . . . . . . . . . . . . 786

Chapter 16 Fluid Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . 789
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789
Lesson 1: Creating a dynamic 2D fluid effect . . . . . . . . . . . . . . 791
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791
Creating a two-dimensional fluid container . . . . . . . . . . . 792
Adding a fluid emitter to a container . . . . . . . . . . . . . . . 792
Changing the behavior of a fluid . . . . . . . . . . . . . . . . . 794
Combining colors in a fluid . . . . . . . . . . . . . . . . . . . . 797
Colliding a fluid with an object . . . . . . . . . . . . . . . . . . 798
Lesson 2: Creating a non-dynamic 3D fluid effect . . . . . . . . . . . 801
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
Creating a 3D fluid container . . . . . . . . . . . . . . . . . . . 801
Adding fluid to a container . . . . . . . . . . . . . . . . . . . . 803
Defining shader attributes for a fluid . . . . . . . . . . . . . . . 803
Texturing the contents of a fluid container . . . . . . . . . . . . 804
Adding self shadowing to texture density . . . . . . . . . . . . . 808
Lesson 3: Creating a dynamic 3D effect . . . . . . . . . . . . . . . . . 810
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 810
Creating a 3D container . . . . . . . . . . . . . . . . . . . . . . 810
Painting Fuel and Density into a container . . . . . . . . . . . . 811
Painting Temperature values into a container . . . . . . . . . . . 816
Adding color to Density and Temperature . . . . . . . . . . . . 817
Lesson 4: Creating an ocean effect . . . . . . . . . . . . . . . . . . . . 819
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 819
Creating an ocean plane and shader . . . . . . . . . . . . . . . 820
Adding a preview plane to an ocean . . . . . . . . . . . . . . . 821
Modifying ocean attributes . . . . . . . . . . . . . . . . . . . . 822
Floating objects . . . . . . . . . . . . . . . . . . . . . . . . . . 825

xiv | Contents

Chapter 17 Fur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 829
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 829
Lesson 1: Assigning a fur description . . . . . . . . . . . . . . . . . . 830
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 830
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 831
Duplicating objects across an axis of symmetry . . . . . . . . . . 831
Renaming surfaces on a model . . . . . . . . . . . . . . . . . . 833
Assigning objects to a reference layer . . . . . . . . . . . . . . . 834
Assigning a fur description preset to a model . . . . . . . . . . . 836
Reversing surface normals . . . . . . . . . . . . . . . . . . . . . 838
Modifying the fur direction . . . . . . . . . . . . . . . . . . . . 840
Painting fur attributes . . . . . . . . . . . . . . . . . . . . . . . 843
Modifying the color of a fur description . . . . . . . . . . . . . 850
Creating a new fur description . . . . . . . . . . . . . . . . . . 851
Lesson 2: Rendering fur . . . . . . . . . . . . . . . . . . . . . . . . . 855
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 855
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 855
Creating lights in a scene . . . . . . . . . . . . . . . . . . . . . 856
Adding fur shadowing attributes to lights . . . . . . . . . . . . . 858
Rendering the scene . . . . . . . . . . . . . . . . . . . . . . . . 860

Chapter 18 nCloth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 863
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 863
Lesson 1: Creating nCloth collisions . . . . . . . . . . . . . . . . . . 865
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 865
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 865
Creating an nCloth object . . . . . . . . . . . . . . . . . . . . . 866
Making an nCloth collide with its environment . . . . . . . . . 868
Adjusting the accuracy of nCloth collisions . . . . . . . . . . . . 870
Lesson 2: Creating nCloth constraints . . . . . . . . . . . . . . . . . 880
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 880
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 880
Constraining an nCloth to a passive object . . . . . . . . . . . . 881
Changing which nCloth points are constrained . . . . . . . . . 886
Making nCloth flap in dynamic wind . . . . . . . . . . . . . . . 892
Lesson 3: Creating nCloth Clothing . . . . . . . . . . . . . . . . . . . 895
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 895
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 896
Making the dress into an nCloth object . . . . . . . . . . . . . . 896

Contents | xv

Making the character wear the dress . . . . . . . . . . . . . . . 897
Caching nCloth to speed up playback . . . . . . . . . . . . . . 898
Adjusting the fit of the dress . . . . . . . . . . . . . . . . . . . . 899
Defining the behavior of nCloth clothing . . . . . . . . . . . . 900
Painting nCloth properties . . . . . . . . . . . . . . . . . . . . 902
Setting the initial state . . . . . . . . . . . . . . . . . . . . . . . 905
Constraining nCloth clothing . . . . . . . . . . . . . . . . . . . 907
Improving the quality of the nCloth simulation . . . . . . . . . 909
Smoothing nCloth clothing . . . . . . . . . . . . . . . . . . . . 912

Chapter 19 nParticles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 915
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 915
Preparing for the tutorials . . . . . . . . . . . . . . . . . . . . . . . . 916
Lesson 1: Creating nParticles . . . . . . . . . . . . . . . . . . . . . . 917
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 917
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 918
Creating an nParticle system . . . . . . . . . . . . . . . . . . . 918
Making nParticles collide with their environment . . . . . . . . 920
Setting Nucleus Space Scale . . . . . . . . . . . . . . . . . . . . 922
Adjusting nParticle size and color . . . . . . . . . . . . . . . . . 923
Adjusting nParticle collision attributes . . . . . . . . . . . . . . 925
Lesson 2: Creating a smoke simulation with nParticles . . . . . . . . . 930
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 930
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 930
Creating an nParticle system . . . . . . . . . . . . . . . . . . . 931
Editing nParticle Lifespan and Radius . . . . . . . . . . . . . . . 935
Adding a Volume Axis field . . . . . . . . . . . . . . . . . . . . 940
Adjusting nParticle velocity . . . . . . . . . . . . . . . . . . . . 942
Adjusting nParticle Shading attributes . . . . . . . . . . . . . . 943
Open the third scene for the lesson . . . . . . . . . . . . . . . . 949
Fine tuning your smoke effect . . . . . . . . . . . . . . . . . . . 949
Lesson 3: Creating a liquid simulation with nParticles . . . . . . . . . 953
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 953
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 954
Creating a Water style nParticle object . . . . . . . . . . . . . . 954
Adjusting Liquid Simulation attributes . . . . . . . . . . . . . . 958
Adding fluidity to the nParticles . . . . . . . . . . . . . . . . . . 960
Convert nParticles to a polygon mesh . . . . . . . . . . . . . . 963
Cache your nParticle simulation . . . . . . . . . . . . . . . . . 967
Adding Motion Streak . . . . . . . . . . . . . . . . . . . . . . . 968

xvi | Contents

Open the third scene for the lesson . . . . . . . . . . . . . . . . 970
Render your liquid simulation . . . . . . . . . . . . . . . . . . . 971
Assigning material shaders . . . . . . . . . . . . . . . . . . . . . 972
Rendering a simulated frame . . . . . . . . . . . . . . . . . . . 974

Chapter 20 Live . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 979
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 979
About Live . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 979
Lesson setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 983
Lesson 1: Track and solve . . . . . . . . . . . . . . . . . . . . . . . . 983
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 983
Tracking preparation . . . . . . . . . . . . . . . . . . . . . . . . 984
Tracking object points in a shot . . . . . . . . . . . . . . . . . . 986
Evaluating the tracking of a point . . . . . . . . . . . . . . . . . 989
Tracking additional points . . . . . . . . . . . . . . . . . . . . 990
Deleting tracking data . . . . . . . . . . . . . . . . . . . . . . . 992
Importing tracking data . . . . . . . . . . . . . . . . . . . . . . 994
Preparing to solve . . . . . . . . . . . . . . . . . . . . . . . . . 994
Solving the shot . . . . . . . . . . . . . . . . . . . . . . . . . . 996
Evaluating a solved solution . . . . . . . . . . . . . . . . . . . 997
Importing additional tracking data . . . . . . . . . . . . . . . . 999
Beyond the lesson . . . . . . . . . . . . . . . . . . . . . . . . 1001
Lesson 2: Solving with survey data . . . . . . . . . . . . . . . . . . . 1002
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 1002
Creating a Distance constraint . . . . . . . . . . . . . . . . . . 1003
Creating a Plane constraint . . . . . . . . . . . . . . . . . . . . 1004
Registering a solution . . . . . . . . . . . . . . . . . . . . . . . 1005
Creating additional Plane constraints . . . . . . . . . . . . . . 1006
Evaluating the solution with imported geometry . . . . . . . . 1008
Beyond the lesson . . . . . . . . . . . . . . . . . . . . . . . . 1010

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1011

Contents | xvii

Overview
1
Introduction
Welcome to Autodesk® Maya®, one of the world’s leading software applications
for 3D digital animation and visual effects. Maya provides a comprehensive
suite of tools for your 3D content creation work ranging from modeling,
animation, and dynamics through to painting and rendering to name but a
few.
With Maya, you can create and edit 3D models in a variety of modeling formats
and animate your models using Maya’s suite of animation tools. Maya also
provides a range of tools to allow you to render your animated 3D scenes to
achieve photo realistic imagery and animated visual effects.
You can create convincing visual simulations using Maya dynamics and
nDynamics tools. Using Maya® Fluid EffectsTM, you can simulate and render
viscous fluids, atmospheric, pyrotechnic, and ocean effects. Maya® nClothTM
lets you create simulations of fabric and clothing, while Maya® nParticlesTM
can be used to simulate a wide range of effects including liquids, clouds, smoke,
spray, and dust. Other Maya dynamic simulation tools include Maya® FurTM,
Maya® HairTM, and Maya® ArtisanTM brush tools.
The Maya software interface is fully customizable for those users who require
the ability to maximize their productivity. Maya allows users to extend their
functionality within Maya by providing access to MELTM (Maya Embedded
Language). With MEL, you can customize the user interface and write scripts
and macros. In addition, a full Application Programmers Interface (API) is
available to enhance the power and functionality of Maya. Maya also provides
a Python-based Maya API for those users wishing to use it.
The content creation power of Maya is provided to users in an integrated software
application that is designed to enhance user productivity and ease of use.

1

This section provides the following information:

■ About the Getting Started lessons–Information about the lessons, where
to begin, and the order in which you should complete the lessons.

■ Before you begin–Prerequisite knowledge and skills you should possess
before beginning the Getting Started with Maya lessons.

■ Installing Maya–Information on installing Maya.

■ Using the lesson files–How to access and use the lesson files for the Getting
Started with Maya lessons.

■ Conventions used in the lessons–Describes the various conventions used
throughout the Getting Started with Maya lessons.

■ Using the Maya Help–Outlines the various help resources provided with
your Maya software.

■ Additional learning resources–Outlines learning resources beyond what is
included with your Maya software.

■ Restoring default user settings–Describes how to reset Maya to its default
settings before you begin the lessons.

About the Getting Started lessons
Getting Started with Maya introduces the different areas of Maya in a set of brief
lessons. The lessons are designed to let you learn these modules at your own
pace.
If you are new to Maya, this guide gets you started on your learning path. If
you are an existing user or are transitioning from another 3D software
application, Getting Started with Maya provides a starting point for
understanding features you haven’t yet had time to learn.
Getting Started with Maya is not meant to replace the documentation that comes
with the Maya software. Only the commands and options used in the lessons
are explained in this manual. You will find the Maya Help provides an excellent
companion reference to the lessons and much more.
Many of the lessons in Getting Started with Maya contain one or more separate
lessons that provide step-by-step instructions for creating or accomplishing
specific tasks within Maya. You can follow the lessons in this guide from start
to finish or complete only the lessons that correspond to your interests and
needs.

2 | Chapter 1 Overview

We recommend that any new Maya user begin by completing the following:

■ Viewing the Essential Skills Movies that are available when you first start
Maya.

■ Completing the Maya Basics lessons (Chapter 2) which introduce many
fundamental concepts and skills related to the Maya user interface.

The version of Getting Started with Maya within the Maya Help also contains
Apple® QuickTime® movies for some of the lessons.

To use the lessons from the Maya Help

1 In Maya, select Help > Tutorials.
The Maya Help window displays the Getting Started with Maya lessons.

2 Click the tutorial you want to work through.
The Maya Help displays the associated lessons for that tutorial.

Before you begin
Before beginning Getting Started with Maya, you should have a working
knowledge of your computer’s operating system. You should know how to
use a mouse, select menus, and enter text and commands from your keyboard.
You should also know how to open and save files, copy files from a DVD to
your hard drive, and be able to navigate your computer operating system’s
file browser.
If you require an overview or review of these techniques, we recommend that
you refer to the documentation that came with your particular computer and
operating system.
If you are new to 3D computer graphics and animation, you might want to
obtain The Art of Maya (ISBN: 978-1-8971-7747-1). It explains many concepts
and techniques that are unique to the world of 3D computer graphics as they
relate to Maya.

Installing Maya
You must have Maya installed and licensed on your computer system to
successfully complete the lessons in this guide. To operate Maya on your
computer you must be running a qualified Microsoft® Windows®, Linux®, or

Before you begin | 3

Apple® Mac OS® X operating system with the recommended minimum
memory and storage requirements. Maya requires a three button mouse to
access its full functionality for menus, commands, and 3D viewing.
For complete instructions on qualified hardware and operating systems, as
well as installation and licensing of the Maya software, please refer to the
Installation and Licensing manual that came with your Maya software or check
the Maya Features and Specification link at http://www.autodesk.com/maya.

Conventions used in the lessons
Some important conventions used throughout Getting Started with Maya are
explained here.
Maya is available for use on a wide range of operating systems. Any differences
between operating systems when operating Maya are identified throughout
this book in the following ways:
(Windows), (Mac OS X), (Linux)
The screen illustrations and examples within Getting Started with Maya vary
among the Windows, Mac OS X, and Linux operating systems. Maya’s interface
is generally consistent across these systems.
When instructed to select a menu within Maya we use the following
convention:

■ Menu > Command (For example, File > New Scene)

When you are instructed to select the option box for a particular menu item
within Maya, we use the following convention:

■ Menu > Command > Option (for example, Create > NURBS Primitives>
Sphere > ).


Using the lesson files
Many of the Getting Started with Maya lessons have accompanying lesson
files that were created for use with the lessons. These files are included in the
GettingStarted directory that was installed with your Maya software and can
be found in the following locations:
(Windows XP and Vista, 32 and 64-bit)
<drive>:Program FilesAutodeskMaya2010GettingStarted

(Mac OS X)
/Applications/Autodesk/maya2010/GettingStarted

(Linux 64-bit)
/usr/autodesk/maya2010-x64/GettingStarted

Before you use the lesson files, you need to copy the GettingStarted directory
to your Maya projects folder. Then, you need to set the GettingStarted folder
as your project directory in Maya. For more information and steps, see Copying
and setting the Maya project on page 25.

Using the Maya Help
Your Maya software application comes with a comprehensive set of
documentation resources.

Essential Skills Movies
The first time you start Maya, the Essential Skills Movies window displays in
Maya. Watch these movies to learn about the skills you need to master when
you first use Maya. The audio for the movies is available in English, French,
German, Italian, Japanese, Korean, and Mandarin.

Using the lesson files | 5

To play the Essential Skills Movies

1 In the Essential Skills Movies window, click the buttons to play a movie.
Your computer launches the necessary multimedia player and your chosen
movie begins to play.

2 Click your multimedia player’s controls to start, stop, and pause the
movie.

To close the Essential Skills Movies window or the multimedia player

1 To close the Essential Skills Movies window, click the close box in the
upper right corner of the window.
If you do not want to have this dialog box automatically display when
you start Maya, turn on the Don’t show this at startup check box.

2 To close the multimedia player, select File > Exit or click the close box in
the upper right corner of the window. (This instruction might vary
depending upon which multimedia player is used)

If you want to watch the movies in the future

➤ In Maya, select Help > Learning Movies.
The Learning Movies window appears.


Maya Help
Your Maya software application comes installed with Maya technical
documentation that assists you in learning the Maya software. The Maya Help
is HTML-based, structured by module, fully searchable, and is displayed using
your computer’s web browser.
The Maya Help is topic based and displays the major functionality categories
for Maya. The Maya Help can assist you in finding reference information about
particular topics, how to perform specific tasks, and MELTM command
references.

To launch the Maya Help

➤ Select Help > Maya Help.
The Maya Help appears in a separate web browser window (depending
on your user preference settings). The left hand pane of the Maya Help
lets you navigate to various Maya topics.

To obtain help on a particular Maya topic

➤ In the Maya Help navigation pane, click the name of the Maya topic you
want information about (for example, Modeling, Animation, Dynamics,
MEL commands, and so on).
The Maya Help displays the associated sub-topics and categories associated
with the name you selected.

Maya Index and search
You can search the Maya Help directly using the index and search capabilities.
With these tools you find the Maya topic you’re looking for by searching the
topic word in an alphabetic list or by directly typing the topic word(s) into
the search field and having the search tool find the documentation entries
associated with it.

To use the Maya Index

1 In Maya, select Help > Maya Help.
The Maya Help appears in a separate window (depending on your user
preferences). The Maya Index button appears at the top of the left
navigation pane.

2 Click the Index button.

Using the Maya Help | 7

The navigation pane updates to display an alphabetic list at the top of
the pane with the first index items listed.

3 Click an item/letter in the alphabetic list.
The information related to that topic appears in the right pane.

To use the Maya Help search

1 Select Help > Maya Help.
The Maya Help appears in a separate window (depending on your user
preferences). The Maya Search button appears at the top of the left
navigation pane.

2 Click the Search button.
The navigation pane updates to display the available search methods and
options. You search a topic by typing in a word(s) that best represent the
information you require.

3 In the text box, type a word that best represents your search topic.
By default, all of the content in the Maya Help is searched. You can
narrow the search results by selecting a specific user guide from the drop
down list below the text box.

4 Click the Search button to begin.
The search results appear in the left navigation pane, in order of relevancy.

5 Click the desired topic from the search results list.
The information related to that entry appears in the right pane of the
Maya Help.

Popup Help
Popup Help provides you with a quick method of identifying a particular tool
or icon in the Maya user interface.


To use Popup Help

➤ Move your mouse cursor over an icon or button.
The name or description of it appears in a popup window directly over
it.

To turn on the Popup Help if it does not appear

1 If you’re operating Maya on a Windows or Linux operating system:
■ Select Window > Settings/Preferences > Preferences.

■ In the Preferences window, click the Help category and set the Tooltips
box to Enable in the Popup Help section so a check mark appears.

■ Click the Save button to close the Preferences window.

2 If you’re operating Maya on a Mac OS X operating system:
■ Select Maya > Preferences.

■ In the Preferences window, click the Help category and click the
Tooltips Enable box in the Popup Help section so a check mark
appears.

■ Click the Save button to close the Preferences window.

Help Line
The Help Line at the bottom of Maya's window shows information about
tools, menus, and objects. Like the Popup help, it displays descriptions when
you move the mouse over icons and menu items. It also displays instructions
when you select a tool. This is useful if you don’t know or forget how to use
a particular tool.

Using the Maya Help | 9

To use the Help Line

➤ Move your mouse cursor over an icon or button.
The icon or button name and instructions about how to use that tool
appear in the Help Line.

Find Menu
The Find Menu feature lets you find the location of a particular menu item.
Find Menu works only on the main menu items.

To find the location of a main menu item

1 Select Help > Find Menu.
The Find a Menu Item window appears.

2 Type the menu item you want to locate in the text field, and press Enter
(Windows and Linux) or Return (Mac OS X).
The possible locations for the main menu item display in the results field
of the Find Menu window.

Additional learning resources
Beyond the Maya Help resources within your Maya software, you can access
the following resources to learn more about Maya or obtain technical
assistance.

The Maya Learning Path
Discover the many learning resources available from Autodesk using the Maya
Learning Path. For more information, see
http://www.autodesk.com/maya-learningpath.


The Maya Web site
The Maya Web site contains a wealth of resources related to your Maya software
and many other related products and services. You can view the Maya Web
site athttp://www.autodesk.com/maya using your web browser.

Autodesk Training
Autodesk provides a range of products and services to help you get the most
from your Maya software. You can purchase additional self-paced learning
materials or attend certified instructor led training courses at Autodesk
sanctioned training facilities. For more information, see
http://www.autodesk.com/maya-training.

Technical Support
Autodesk delivers technical support services for Maya globally through
telephone and email services, as well as online eSupport services. For more
information, click the Support Center link from the Maya Help menu or click
the Services and Support link on the Maya Web site.

Events and Seminars
Autodesk also runs Maya seminars and short format training courses at major
computing events and trade shows. For more information, see
http://www.autodesk.com/maya-events-seminars.

Restoring default user settings
If you have already used Maya or have a prior version of Maya installed, you
should restore the default settings for Maya before you begin the lessons. This
ensures that Maya appears and operates exactly as the lessons describe.
If you are an existing user of Maya we recommend that you save your existing
preferences for later use prior to restoring the default user settings.

To save your existing custom user preferences

1 Ensure Maya is not running.
Each time you exit Maya it saves the configuration of most components
of your user interface so it appears the same when you start it the next
time. It writes the preferences to a directory called prefs. If you rename
the prefs directory, your original preferences will be maintained and Maya
will create a new prefs directory the next time it is run.

Restoring default user settings | 11

2 Rename your existing user preferences file to a different name; for
example, myprefs. The prefs directory path is:
Windows
(Windows XP)
Documents and Settings<username>My Documentsmaya
2010en_USprefs
(Windows XP 64bit)
Documents and Settings<username>My Documentsmaya 2010-
x64en_USprefs
(Windows Vista)
Users<username>Documentsmaya2010en_USprefs
(Windows Vista 64-bit)
Users<username>Documentsmaya2010-x64en_USprefs
Mac OS X
/Users/<username>/Library/Prefer
ences/Autodesk/maya/en_US/2010/prefs
Linux (64-bit)
~<username>/maya/2010-x64/prefs

NOTE If you are running the Japanese version of Maya, change en_US in the
above directory paths to ja_JP.

If you have a previous version of Maya installed, also rename that prefs
directory to a new name such as myprefs. Maya will load older preferences
if they exist from a previous version.

3 Start Maya and begin the Getting Started with Maya lessons.

To restore your custom user preferences after doing the lessons

1 Ensure Maya is not running.

2 Rename the previously changed preferences back to prefs.


Maya Basics
2
Introduction

Critical to learning any software application is some initial understanding of
the basic concepts: how that software’s world works and the fundamental skills
you need to work in that world. If you have never used a three dimensional
(3D) software application before, you may initially find Maya different compared
to 2D applications.
If you are wondering “where do I begin?”, this chapter is the best place to start.
We recommend that you complete the lessons in this chapter so the essential
concepts and skills presented become familiar to you.

13

This chapter covers some of the fundamental concepts and skills for Maya in
four lessons:

■ Lesson 1 The Maya user interface: Introduction on page 15

■ Lesson 2 Creating, manipulating, and viewing objects: Introduction on
page 29

■ Lesson 3 Viewing the Maya 3D scene: Introduction on page 42

■ Lesson 4 Components and attributes: Introduction on page 60

Preparing for the lessons
To ensure the lessons work as described:

■ Ensure Maya is installed and licensed on your computer.
If you have not installed Maya yet, refer to the Installation and Licensing
manual that accompanies your Maya software package. It outlines the
requirements for installing Maya and procedures for installation and
licensing Maya on supported hardware platforms.

■ If you have never started Maya on your computer before, it will start for
the first time using the default preference settings.

■ If you have run Maya before, you should ensure that your Maya user
preferences are reset to their default setting. This ensures that the lessons
appear and work as described.
Refer to Restoring default user settings on page 11 for instructions on
resetting user preferences to the default setting.

■ Unless otherwise indicated, the directions in this chapter for making menu
selections assume you’re working from the Polygons menu set.

NOTE Before you perform the lessons in this book, ensure that the Interactive
Creation option for primitives is turned off by selecting Create > Polygon
Primitives > Interactive Creation and Create > NURBS Primitives > Interactive
Creation. That is, ensure a check mark does not appear beside these menu
items.

14 | Chapter 2 Maya Basics

Lesson 1: The Maya user interface

Introduction
Just as the driver of an automobile is familiar with the dashboard of their
vehicle, it is important for you to become familiar with the Maya “dashboard.”
The Maya user interface refers to everything that the Maya user sees and operates
within Maya. The menus, icons, scene views, windows, and panels comprise
the user interface.
Through the Maya user interface you access the features and operate the tools
and editors that allow you to create, animate, and render your three
dimensional objects, scenes, and effects within Maya.
As you spend time learning and working with Maya, your knowledge of and
familiarity with the user interface will increase until it becomes second nature.
In this lesson you learn how to:

■ Start Maya on your computer.

■ Use the Maya interface so that you can begin to understand where and
how to access the critical tools to get started with Maya.

■ Select the menu and icon sets within Maya.

■ Learn the names of tools related to the icons in Maya.

■ Create a new scene view.

This first lesson contains additional explanations of the tools and concepts
compared to many of the lessons later in this manual. We suggest you take
some time to review these explanations as they lay the foundation for
understanding where things are in Maya.

Starting Maya
To start Maya on Windows

➤ Do one of the following:
■ Double-click the Maya icon on your desktop.

Lesson 1: The Maya user interface | 15

■ From the Windows Start menu, select All Programs > Autodesk >
Autodesk Maya 2010 > Maya 2010.

To start Maya on Mac OS X


■ Click the Maya icon in the Dock.

■ From the Apple Finder menu, select Go > Applications and then browse
for the Maya icon and double-click it to start Maya.

To start Maya on Linux


■ In a shell window, type: maya.

The Maya interface
Now that Maya is running, you first need to understand what you are seeing.
There are a lot of items displayed in the Maya user interface.
The best way to begin is to learn the fundamental tools and then learn
additional tools as you need them. Begin by learning some of the main tools.


The Maya workspace
The Maya workspace is where you conduct most of your work within Maya.
The workspace is the central window where your objects and most editor
panels appear.

The Maya interface | 17

When you start Maya for the first time, the workspace displays by default in
a perspective window, or panel. There are the other components of the default
perspective view panel:

■ The panel is labeled persp at the bottom to indicate that you are viewing
the Maya scene from a perspective camera view.

■ The panel has its own menu bar at the top left corner of the panel. These
menus allow you to access tools and functions related to that specific panel.

■ The grid is displayed with two heavy lines intersecting at the center of the
Maya scene. This central location is called the origin. The origin is the center
of Maya’s 3D world, and with all object’s directional values measured from
this location.


In Maya, like many other 3D applications, the three dimensions are labeled
as the X, Y, and Z axes. The origin is located at X, Y, Z position of 0, 0, 0. The
grid also lies along the X, Z plane. We refer to this as a plane because you might
visualize an imaginary, flat, two-dimensional square laying along this 3D
position.
Maya labels the X, Y, and Z axes with a color scheme: red for X, green for Y,
and blue for Z. Many tools that you use in Maya use this color scheme to
indicate that you are accessing a particular item that relates to X, Y, and Z in
some way.

The axis indicator shows in which direction, X, Y, or Z, you are viewing the
Maya scene. The axis indicator is color coded in the red, green, and blue color
scheme and appears in the lower left corner of a view panel.
This is extremely useful if you are new to 3D, as many of the instructions in
this manual and the Maya Help assume you know where you are viewing the
scene in relation to the X, Y, Z axes.


Main Menu bar
Tools and items are accessible from pull down menus located at the top of
the user interface. In Maya, menus are grouped into menu sets. These menu
sets are accessible from the Main Menu bar.
The Main Menu bar appears at the top of the Maya interface directly below
the Maya title bar and displays the chosen menu set. Each menu set
corresponds to a module within Maya: Animation, Polygons, Surfaces,
Rendering, and Dynamics. Modules are a method for grouping related features
and tools.

You switch between menu sets by choosing the appropriate module from the
menu selector on the Status Line (located directly below the File and Edit
menus). As you switch between menu sets, the right-hand portion of the
menus change, but the left-hand portion remains the same; the left-hand
menus are common menus to all menu sets. The left-hand menus contain
File, Edit, Modify, Create, Display, and Window.

To select a specific menu set

1 On the Status line, select Animation from the drop-down menu.
The Main Menu changes to display the menu set that relates to the
Animation module. In particular, menu titles such as Animate, Deform,
Skeleton, Skin, and so on, appear.

2 Using the menu selector, choose Polygons from the drop-down menu.


The main menu changes to display the menu set for Polygons. Menu
titles such as Select, Mesh, Edit Mesh, and so on, appear.
For now, leave the menu set at Polygons. You will use this set in the next
step.

To create a primitive 3D object from the Polygons menu set

1 Select Create > Polygon Primitives > Interactive Creation and ensure that
a check mark does not appear beside this item.
For this lesson, you won’t use this option.

2 From the Main Menu Bar, select Create > Polygon Primitives > Cube >.
Maya creates a 3D cube primitive object and places it at the center (origin)
of the Maya workspace.

Status Line
The Status Line, located directly below the Main Menu bar, contains a variety
of items, most of which are used while modeling or working with objects
within Maya. Many of the Status Line items are represented by a graphical
icon. The icons save space in the Maya interface and allow for quick access to
tools used most often.
In this lesson, you learn about some of the Status Line areas.

You’ve already learned the first item on the Status line: the Menu Selector
used to select between menu sets.


The second group of circled icons relate to the scene and are used to create,
open, and save your Maya scenes.
The third and fourth group of buttons are used to control how you can select
objects and components of objects. You will learn more about selection of
objects in later lessons.
The fifth group of icons are used to control the Snap Mode for objects and
components. You will begin to use these tools in a later lesson in this chapter.
The last section comprise three buttons that are used to show or hide editors,
including the Attribute Editor, Channel Box, Layer Editor, and Tool Settings.
The default display shows the Channel Box and the Layer Editor. When you
create an object, like the cube for example, information about that object
displays in these editors. You will learn how to use these editors later in this
chapter.

For better organization on the Status Line, all of the icon buttons are broken
into groups that you can expand and collapse, as shown.

Shelf
The Shelf is located directly below the Status line. The Maya Shelf is useful for
storing tools and items that you use frequently or have customized for your
own use. You can keep the tools and items you use most frequently in a
location that provides handy access. Maya has some of the Shelf items
pre-configured for your use.


To create an object using a tool from the Shelf

1 From the Shelf, select the Surfaces tab in order to view the tools located
on that shelf.

2 Select Create > NURBS Primitives > Interactive Creation to ensure that a
check mark does not appear beside the item.
For this lesson, you won’t use this option

3 From the Shelf, select the NURBS sphere icon located at the left end by
clicking on it.
Maya creates a sphere primitive object and places it at the center of the
Maya workspace in the same position as the cube.

TIP You can determine if this is the correct tool prior to choosing it by first
placing your mouse cursor over the icon, the name or description of it appears
in a popup window directly over it.


In your scene view the wireframe outline of the cube you created earlier in
the lesson has changed color to navy blue, and the sphere is displayed in a
bright green color. The sphere is now the selected object and the cube is no
longer selected. In Maya, when the object displays like this, we refer to it as
being selected or active.

Selection of objects and components is a way of indicating to Maya that this
particular item is to be affected by the tool or action you will subsequently
choose. As you work with Maya, you will be selecting and deselecting items
a lot. You will learn how to select and deselect objects later in this chapter.
Some numerical information appears in the Channel Box editor on the right
hand side of the user interface. This information relates to X, Y, and Z,
translation, rotation, and scaling for the active object. The X, Y, and Z Translate
numerical values are currently set to 0. This indicates that the sphere’s location
is at the origin. The Channel Box is useful for viewing and editing this type
of basic information. You will use the Channel Box later in this chapter.


To hide or show the Channel Box

1 To hide the Channel Box, click the Show/Hide Channel Box icon from
the right end of the Status line.
The Channel Box disappears, and the perspective scene view expands
slightly. With the Channel Box hidden, you have more working area in
your scene view.

2 To show the Channel Box, click the Show/Hide Channel Box icon on
the Status line. The Channel Box appears in the scene view.

Copying and setting the Maya project
Before you can save your work, you need to set a project in Maya.
A project is a file directory that stores and organizes all of the files (scenes,
images, materials, textures, etc.) related to a particular scene. In Maya, you
create and work with a variety of file types and formats. The project directory
allows you to keep these different file types in their unique subdirectory
locations within the project directory.
You can create a new project directory by choosing File > Project > New.
Alternatively, you can choose an existing folder to act as the project directory
if you have prepared a folder in advance.
For these lessons, the project directory will be the GettingStarted folder that
we have created for you. Here, you will find all the template files that you
need for the lessons, and you will save your work as you learn. You need to
copy the GettingStarted folder to your Maya projects folder, and then you
need to set the GettingStarted folder as the project directory in Maya.

To copy and set the GettingStarted folder as your Maya project

1 Navigate to the GettingStarted folder that was installed with your Maya
software. The location of this folder depends on the operating system
that you are using.

Copying and setting the Maya project | 25

(Windows XP and Vista, 32 or 64-bit)
<drive>:Program FilesAutodeskMaya2010GettingStarted
(Mac OS X)
/Applications/Autodesk/maya2010/GettingStarted
(Linux 64-bit)
/usr/autodesk/maya2010-x64/GettingStarted

2 Copy the GettingStarted folder.

3 Paste the GettingStarted folder in one of the following locations,
depending on the operating system that you are using:
(Windows XP, 32 or 64-bit)
<drive>:Documents and Settings<username>My Documentsmayapro
jects
(Windows Vista, 32 or 64-bit)
<drive>:Users<username>My Documentsmayaprojects
(Mac OS X)
/Users/<username>/Documents/maya/projects
(Linux 64-bit)
<home directory>/maya/projects

4 In Maya, choose File > Project > Set.

5 Browse for the GettingStarted folder that you pasted in your Maya
projects directory in step 3.

6 Select the folder and click OK.

Saving your work
Make it a habit to save your work often when working on your Maya projects.
In that way, you can always open an earlier version of your work should you
make a mistake.
Maya refers to everything you’ve created in your workspace as the scene. This
includes any objects, lights, cameras and materials associated with your
working session.


To save your Maya scene

1 Select File > Save Scene.
A file browser appears, listing the GettingStarted project directory where
you can save your scene.
If the GettingStarted directory does not appear, you need to copy the
GettingStarted folder and set it as your Maya project. See Copying and
setting the Maya project on page 25.

2 Within the GettingStarted directory, double-click the scenes folder to
open it.

3 Type: Lesson1 in the file name text box.

4 Click Save.
Maya saves your file to the scenes directory within your GettingStarted
project directory. Maya automatically saves the file with a .mb file
extension. The .mb file extension indicates that the scene was saved as a
Maya binary file: the default file type for a Maya scene.

Exiting Maya
Before you exit Maya, ensure you save any work that you want to retrieve and
continue with at a later time.

To exit Maya

➤ Select File > Exit from the main menu.
Maya does one of the two following actions:

■ If you have saved your scene immediately preceding the Exit command,
Maya exits.

■ If you have not recently saved your scene, a message prompt appears on
the screen asking if you want to save your changes. Click either Save, Don’t
Save, or Cancel.

Exiting Maya | 27

Beyond the lesson
In this lesson you began your orientation to Maya by learning:

■ How to start Maya on your computer.

■ The Maya workspace, and how it shows three dimensional space (X, Y, Z).

■ How Maya color-codes items and tools related to X, Y, Z.

■ The location of the main menus for the various modules within Maya.

■ How to create a three-dimensional object from the Polygons menu.

■ The location of the Status Line and how items are displayed as icons.

■ About the Shelf how to create a three dimensional object from the Shelf.

■ How to hide and show the Channel Box and that basic transformation,
scaling, and rotational information for an object can viewed in the Channel
Box.

■ How to save your work.

■ How to exit Maya.

As you proceed through Getting Started with Maya you should be familiar
with the fundamental concepts and skills covered in this first chapter.
If you want to learn more about a particular tool or feature that has been
presented in this lesson, refer to the Maya Help.


Lesson 2: Creating, manipulating, and viewing
objects

Introduction

Using primitive objects to model 3D forms is a great place to continue learning
about Maya. You can create many types of 3D objects using Maya and then
move, scale, and rotate them to create more complex forms in your scene.
In this lesson, you begin to construct a classic temple using the primitive
object creation tools in Maya. The project is not very complex and provides
you with experience in using some of the important object manipulation and
viewing tools.
As you continue to work with Maya, you’ll learn how to visualize more
complex forms using these basic objects. Maya has many advanced tools and
options for modeling complex forms, as you will learn in later chapters.
In this lesson, you learn how to:

■ Create 3D primitive objects.

■ Select objects for manipulation and editing purposes.

■ Move and rotate objects using your mouse.

■ Move, rotate, and scale objects using numeric input.

■ Duplicate objects.

■ Change the viewing panels in Maya using a variety of methods so you can
view your objects from different points of view.

■ Undo actions when you need to undo a particular task or step.

Lesson 2: Creating, manipulating, and viewing objects | 29

Creating a new scene
You begin your temple project by creating a new empty scene.

To create a new scene

1 Start Maya (if it is not already running).
When Maya starts, it automatically creates a new scene.
If Maya was previously running, follow steps 2 and 3.

2 From the main menu, select File > New Scene.
Maya displays the following prompt.

3 Click No.
Maya creates a new scene and delete everything that was in the previous
scene.

Primitive objects
Maya provides many types of primitive types and shapes such cubes, spheres,
cylinders, and planes.

Primitive objects can be used as a starting point for a wide variety of shapes
and forms. The most common workflow when using primitive objects is:

■ Set the construction options for the primitive when you initially create it
so that it appears in the Maya scene roughly in the size and shape that
you require.

■ Move, scale, and rotate the primitive object into its final position either
by direct manipulation (the move, scale, and rotate tools), or by entering
numeric values through an editor.


■ Duplicate the primitive objects to create multiple copies of the original or
create different variations from your original primitive object.

In this section, you construct the base for the temple using a polygonal cylinder
primitive. The octagonal shape is created by modifying the creation options
for the cylinder tool before you create the object. If you did not modify the
cylinder options you would create a round cylinder.

To create a polygonal cylinder for the base

1 Select the Polygons menu set.

NOTE Unless otherwise indicated, the directions in this lesson for making
menu selections assume you’ve already selected the Polygons menu set.
You should also ensure that the Interactive Creation option for primitives is
first turned off by selecting Create > Polygon Primitives > Interactive Creation
to ensure the check mark does not appear beside the item.

2 From the main menu, select Create > Polygon Primitives > Cylinder >
.
An option window appears.

3 In the Polygon Cylinder Options window, select Edit > Reset Settings and
then set the following options:
■ Radius: 10

■ Height: 1

■ Axis divisions: 8

■ Height divisions: 1

■ Cap divisions: 1

■ Axis: Y

4 In the Polygon Cylinder Options window, click Create.
Maya creates a cylinder primitive object that is octagonal in shape and
positioned at the center of the Maya workspace. This cylinder is 20 units
wide by one unit high, and has eight faceted sides.

Primitive objects | 31

NOTE You were instructed to reset the option settings as a precaution in
case they had been set differently. This is a good habit to practice when
working with tool options to avoid getting a result that was different from
what you expected.

The Toolbox: Layout shortcuts
The Toolbox is located on the left hand side of the Maya user interface. It
contains icons that open tools for transforming your objects within Maya
(selection, move, rotate, scale) as well as layout shortcuts for changing the
views and panel layouts.
The Quick Layout buttons shortcuts allow you to select a different panel or
switch to another layout.
You need to finish positioning the cylinder. To do this you need to see the
object from a side view to make sure it is sitting exactly on the ground plane.

To change the panel layout to view the base from a side view

1 From the Toolbox, click the Four View layout shortcut.


The workspace changes to a four-view layout. The perspective view is
located in the top right corner and the other views show the object from
the top, front and side. The layout shortcuts have other options that you
will learn later in this tutorial.

It’s now possible to see the base from the side view, but it would be easier
to determine the position of the base if the side view were enlarged to a
full view.

2 To enlarge the side view, position the mouse cursor in the side view, and
tap the spacebar of your keyboard.
The workspace changes to a single view layout with the side view in an
enlarged view. It is easier to view the position of the base from this side
view. Notice that the base lies slightly above and below the ground plane
(X, Z).

TIP You can position your mouse cursor in any scene view and tap the
spacebar once to toggle the view. If the view is a full panel view, it will change
to a four panel view and vice versa.

The Toolbox: Layout shortcuts | 33

The Toolbox: Transformation tools
You need to move the base slightly upwards in the Y direction so it is
positioned on the X, Z plane. To do this you use the Move transformation
tool located in the Toolbox.
The upper half of the Toolbox contains the tools for transforming objects
(selection, move, rotate, scale) within Maya. When you move your mouse
cursor over any transformation tool icon you see the name of the tool appear
next to the mouse cursor.

The tool’s name also appears in the Help Line at the bottom of the Maya
window. The Help Line has an additional purpose: it displays summary
instructions as you use tools that require several steps.

Selection and de-selection of objects
Before you can transform an object, you must ensure it is selected. You can
select objects by clicking them directly, or by dragging a rectangular bounding
box around some portion of the object to indicate what you want selected.
To deselect an object, you simply click somewhere off of the selected object.


To select the base primitive object in the scene view


■ With your left mouse button, click the object’s wireframe outline in the
scene view.

■ With your left mouse button, drag a bounding box around one corner or
edge of the object’s wireframe.
The object is selected when its wireframe outline color displays in a bright
green color. If it is not selected, its display color is navy blue.

To use the Move Tool to adjust the position of the base

1 Select the Move Tool from the Toolbox.
A move manipulator icon appears over the primitive cylinder in the scene
view.
The Move Tool Manipulator has handles that point in the direction of
the three fundamental axis directions of 3D space: X, Y, Z. The handles
are colored red, green, and blue based on their function related to the X,
Y, Z axes and control the direction of the movement along an axis.
When you click a specific handle, it indicates that the move is constrained
to that particular axis direction.

2 In the side view, drag the green Y manipulator handle to move the
primitive cylinder upwards in the Y direction. Move it upwards enough
so that the bottom of the base cylinder is aligned with the X axis (the
thick dark line of the grid)

The Toolbox: Transformation tools | 35

The base cylinder now needs to be rotated slightly so the front of the base is
parallel to a grid line. Since each facet of the octagon represents 45 degrees of
a circle, you need to rotate the object approximately half of that amount or
22.5 degrees.

To use the Rotate Tool to adjust the position of the base

1 Display all four views by positioning the mouse cursor in the view and
tapping the spacebar of your keyboard.
The four view panel appears.

2 Position the mouse cursor in the top view and tap the spacebar once.
The top view appears in the workspace.

3 With the base cylinder selected, choose the Rotate tool from the Toolbox.
A rotate manipulator icon appears over the primitive cylinder in the scene
view.

The Rotate Tool manipulator consists of three rings (handles), plus a
virtual sphere enclosed by the rings. The colors of the handles correspond
to the X, Y, and Z axes. The handles are colored red, green, and blue based
on their function related to the X, Y, Z axes and control the direction of
the rotation around an axis.

4 In the top view, drag the green Y manipulator ring to rotate the primitive
cylinder so that one of the facets of the base cylinder is aligned with the
grid as shown in the image below.


You are rotating the cylinder around its Y axis.

You may be asking yourself the question “How do I know if I’ve rotated
the base exactly 22.5 degrees?” You can check the accuracy of the rotation
by viewing the Channel Box. Rotate Y should be close to 22.5 degrees.

TIP You can undo and redo the last action you performed. Undo reverses
the last action you performed on a selected object. It also reverses any action
you performed from the Edit Menu.
To undo an action select, Edit > Undo, Redo, Repeat. Maya allows you to
perform multiple undos.

The Channel Box
The Channel Box is an editing panel that provides you access to an object’s
transformation information and much more. It provides information on three
distinct areas for any type of object: The transform node, shape node, and
input node.
Nodes are where information about object types are kept track of within Maya.
Nodes are comprised of attributes. Attributes refer to information related to
what the node is designed to accomplish. In this case, information about the
primitive cylinder’s Y axis rotation is referred to as the Rotate Y attribute. You
will learn more about nodes later in this tutorial.
When you moved and rotated the cylinder primitive using the Move Tool,
you were doing this by your own visual judgement. This will usually be
sufficient for many of your creative applications.
If you need to control the attribute of an object with more accuracy you can
do this by entering the precise values into the appropriate attribute field of
the Channel Box.

The Channel Box | 37

To move and rotate the base using the Channel Box

1 With the base cylinder selected, view the Transformation attributes in
the Channel Box. Specifically, view the values for Translate Y, and Rotate
Y.

2 In the Channel Box, adjust the attribute values so they match the above
image by clicking in the field and entering the correct numerical values.
This accurately positions the base in your Maya scene.
Maya named the cylinder primitive when it was first created. Rename
the cylinder to something more meaningful to your project.

To rename the cylinder primitive using the Channel Box

1 In the Channel Box, click in the field with the name pCylinder1.

2 Rename the primitive object by typing the new name: templeBase and
then pressing Enter.


Duplicating objects
Duplicating an existing object is a useful way to make an exact copy of it
without having to start over. When you duplicate an item the copy takes on
the characteristics of the original. Using the Duplicate Tool you can
additionally apply transformations to the copy (move, rotate, scale).
Return to a four view layout to view what you’ve accomplished to this point.

To change the panel layout to a four view layout

➤ From the Toolbox, click the Four View layout shortcut.
The workspace changes to a four view layout. It is easier to view the work
from this four view layout.
The base for the temple is constructed of two levels and appears stepped.
You duplicate and scale the templeBase object using the duplicate tool.

To duplicate the temple base

1 Display all four views by positioning the mouse cursor in the view and
tapping the spacebar. Then click in the perspective view to display the
base in this view.

2 With templeBase selected, choose Edit > Duplicate Special > from the
main menu.
The Duplicate Special Options window appears.

Duplicating objects | 39

3 In the Duplicate Special Options window, select Edit > Reset Settings and
■ Translate: 0 1.0 0

■ Rotate: 0 0 0

■ Scale: 0.9 1.0 0.9

■ Geometry Type: Copy

■ Group under: Parent

4 In the Duplicate Options window, click Duplicate Special.
Maya creates a duplicate of the templeBase object that is scaled to 0.9 of
the original in the X, Z axes, and is one unit above templeBase. As a result
of the scale operation, the base for the temple now appears stepped.
Maya keeps track of the name of the duplicated object based on the name
of original and renames the duplicated object templeBase1.

Save your work
In the last lesson we recommended that you save your work at regular intervals.
An example of this is when you have just completed a major task such as
constructing the base for the temple. With this strategy, if you ever make a
mistake, you can always open the previously saved version of your work and
begin from there.


1 Select File > Save Scene.
A file browser appears showing the GettingStarted project directory
where you can save your scene.


If you do not see the GettingStarted project directory, you have not yet
copied the GettingStarted folder and set it as your Maya project. For
more information, see Copying and setting the Maya project on page 25.

2 Within the GettingStarted project directory, ensure that you are saving
in the scenes sub-directory.

3 Type Lesson2Base in the file name text box.

4 Click Save.

Beyond the lesson
In this lesson you continued with the fundamental tools and skills to
successfully learn:

■ An overall workflow for constructing forms using primitive objects.

■ Where the primitive object tools are located in the main menu.

■ How to create a primitive object as well as reset and edit its creation
options.

■ How to change between a single view and four view panel layout using
layout shortcuts and by tapping the spacebar of your keyboard.

■ How to select objects by clicking them with your mouse.

■ How to move and rotate objects using the transformation tools in the
Toolbox.

■ That tool manipulators can constrain a transformation to the X, Y, or Z
axes.

■ How to edit an object’s transformation node attributes (move, rotate, scale)
accurately using the Channel Box.

■ How to rename objects using the Channel Box.

■ How to duplicate objects and apply transformations while doing so.

We suggest you additionally practice the following tasks on your own:

■ Creating other primitive object types, with various options so that you
can understand the variations that are possible.

Beyond the lesson | 41

■ Try using the ViewCube™ located in the upper-right corner of the active
scene view to change the camera’s viewing angle in relation to the objects
in the scene.

■ Practice moving, rotating, and scaling objects, and changing between the
various scene views (single perspective, four view, single side, single top
etc.)

Lesson 3: Viewing the Maya 3D scene

Introduction

In the previous lesson you learned how to view your 3D scene by changing
between single and four view layouts. It is important for you to learn how to
change your views in a more interactive manner so that you can: view your
objects close up or far away, select objects more accurately, or view objects
from different angles in your perspective view.

■ Understand the difference between moving objects in the scene and moving
the point of view on the scene.

■ Use the dolly, track, and tumble camera tools to change the view of your
scene in both the orthographic and perspective views.

■ Rotate objects using the transformation tools in the Toolbox.

■ Select objects using a variety of techniques.

■ Group objects together so they can be transformed as a unit.

■ Display objects in both wireframe and shaded modes.


■ Use additional primitive objects and options.

Camera tools
In the lessons so far, when you looked at an object from the top, front, or side
views you have been viewing the scene through an orthographic view.
Orthographic views appear two-dimensional because the object is displayed
using parallel projections of only two axes at a time. (Scooter images courtesy
of The Art of Maya)

When you view the scene through the perspective view, you are viewing the
scene in a three-dimensional manner. The perspective view simulates what
your scene would look like from a camera’s point of view.

In Maya, you view the scene through a set of virtual cameras. These cameras
are either orthographic or perspective in nature. You can adjust how these
cameras view the scene using the Camera Tools.
The three primary methods for manipulating the camera view are dolly, tumble,
and track.

Camera tools | 43

Dolly Tool
The Dolly Tool gets its name from filmmaking where a camera, mounted on
a wheeled tripod, is moved towards or away from the scene. In Maya, dollying
allows you to view the items in your scene either close up or from further
back.

To dolly the perspective view

1 Enlarge the scene view to a single perspective view.

2 Do one of the following:
■ (Windows & Linux) Press the Alt key and drag the mouse to the right
while holding down the right button on your mouse.

■ (Mac OS X) Press the Option key and drag the mouse to the right
while holding down the right button on your mouse.

3 To dolly the camera outwards from the subject in the scene you can
perform the same key and mouse combinations as described above but
drag the mouse to the left.
Dolly works in both the perspective and orthographic views.

TIP If you make an error when adjusting your camera view of the scene, you
can reset the camera to its default home setting.
To reset the camera view for a particular orthographic or perspective view:
From the panel menu, select View > Default Home.


Tumble Tool
The Tumble Tool allows you to tumble or rotate the camera’s view around a
particular center of interest to achieve either a higher or lower vantage point,
or a different side angle.

To tumble the perspective view

➤ Press the Alt key (Windows & Linux) or the Option key (Mac OS X) and
drag the mouse either left or right, or up or down, while holding down
the left button on your mouse.
Tumbling the view revolves the camera around the center of the scene
view, in whichever direction you drag (left, right, up or down). The
Tumble Tool does not work in the orthographic views.

Track Tool
The Track Tool allows you to move the camera up, down, or sideways in
relation to the scene.

Camera tools | 45

To track the perspective view

➤ Press the Alt key (Windows & Linux) or the Option key (Mac OS X) and
drag the mouse in any direction, while holding down the middle button
on your mouse.
The Track Tool works for both orthographic and perspective views.

NOTE Even though the objects appear to move across the screen when
operating any of these camera tools, it is the viewing camera that is actually
moved in relation to the scene, not the objects.

Workflow overview
The columns are made up of multiple primitives that are moved, scaled, and
rotated into position. Once the first column is created, with each component
named and accurately positioned, you will group and duplicate it to create
others.

To create a polygonal cube for the pedestal

1 From the Main Menu, select Create > Polygon Primitives > Cube > .


2 In the Polygon Cube Options window, select Edit > Reset Settings and
■ Width: 1.75

■ Height: 0.6

■ Depth: 1.75

Leave the other options at their default settings.

NOTE If the Polygon Cube Options window does not appear, ensure that
the Interactive Creation option for primitives is turned off by first selecting
Create > Polygon Primitives > Interactive Creation so that a check mark does
not appear beside this menu item.

3 In the Polygon Cube Options window, click Create.
Maya creates a cube primitive and positions it at the origin.

4 In the side view, move the cube upwards (Y axis) so it rests on the top
surface of the temple base.
You can do this using the Move Tool or with the Channel Box. If you
use the Channel Box, enter a Translate Y value of 2.3.
You may find it useful to dolly or tumble the scene view to obtain a better
viewpoint.

5 In the Channel Box, rename the cube columnPedestal.

To create a polygonal cylinder for the shaft

1 From the main menu, select Create > Polygon Primitives > Cylinder >
.

Workflow overview | 47

2 In the Polygon Cylinder Options window, select Edit > Reset Settings and
■ Radius: 0.5

■ Height: 6

■ Axis divisions: 12

Leave the other options at their default settings

3 In the Polygon Cylinder Options window, click Create.
Maya creates the cylinder primitive at the origin.

4 In side view, move the cylinder upwards (Y axis) so it rests on the top
surface of columnPedestal.
You can do this using the Move Tool or with the Channel Box. If you
use the Channel Box, enter a Translate Y value of 5.6.

5 In the Channel Box, rename the cylinder columnShaft.

The capital for the column rests on top of the column and is very similar to
the pedestal. You duplicate the pedestal and position the duplicate at the top
of the column.

To duplicate the pedestal to create the capital

1 With only columnPedestal selected, select Edit > Duplicate Special >
from the main menu.

■ Translate: 0 6.6 0


■ Scale: 0.8 1.0 0.8


3 In the Duplicate Special Options window, click Duplicate Special.
Maya creates a duplicate of the columnPedestal object and moves and
scales it based on the options you set.

NOTE If you positioned the geometry for the column using the Transform
Tools and your mouse, the Y translate values may be incorrect for your
particular model. You may want to continue positioning the objects by visual
reference using your mouse.

Using the duplicate options is an alternate method for positioning and
scaling duplicated objects when you can anticipate its final location.

4 In the Channel Box, rename the duplicated cube columnCapital.

The base for the column rests on top of the pedestal. You will create the base
using one half of a NURBS sphere primitive and then move and rotate it into
position. You will do this by modifying the creation options for the sphere
primitive.

To create a NURBS sphere for the column base

1 Select Create > NURBS Primitives > Sphere > .

2 In the NURBS Sphere Options window, select Edit > Reset Settings and
■ Start Sweep Angle: 0

■ End Sweep Angle: 180

■ Radius: 0.75

Workflow overview | 49

■ Number of Sections: 8

■ Number of Spans: 4


3 In the NURBS Sphere Options window, click Create.
Maya creates a half-sphere primitive at the origin.

The sphere needs to be rotated 90 degrees and then positioned on top of the
pedestal.

To rotate and position the sphere on the pedestal

1 In side view, rotate the sphere so that the dome part is pointing up.
This is accomplished by either of the following methods:
■ Rotating the sphere about the X axis using the Rotate Tool’s
manipulator handle.

■ Using the Channel Box to change the Rotate X value to -90.

2 Move the sphere so it rests on the top surface of columnPedestal (Translate
Y = 2.6, if you have been inputting values into the Channel Box).

3 Using the Scale Tool, scale the sphere along its Z axis (blue manipulator
handle) so that the sphere becomes slightly squashed in appearance.

When you scale an object non-uniformly along one of its axes, you are
scaling it non-proportionally.


4 In the Channel Box, rename the sphere columnBase.

Viewing objects in shaded mode
Up to this point, you have been viewing your objects in the default wireframe
mode. In wireframe mode, objects appear transparent except for the simple
wire outline that indicates their position and general shape. Maya provides
several options for displaying objects in a shaded manner.

Change the display of your scene so that the objects display as shaded objects.

To display the objects in smooth shaded mode

1 Enlarge your perspective view, and dolly and tumble the scene so you
can easily view what you’ve completed so far.

2 From the panel menu, select Shading > Smooth Shade All.
The objects in your scene display in an opaque dark gray color. You can
work with objects in either shaded or unshaded mode for the balance of
this lesson.

Viewing objects in shaded mode | 51

Grouping objects
When you need to move, scale or rotate multiple objects as one unit it is easier
if they have been grouped together so that they transform as one unit.
Many primitive objects in Maya are grouped objects. For example, the NURBS
cube primitive is comprised of 6 flat squares or planes that have been grouped
together as one unit. When the plane objects are grouped together they create
a hierarchy.
A hierarchy is a collection of nodes or objects that are connected together to
form a unit for some purpose. Hierarchies are useful for describing how the
objects within them share similar characteristics or attributes; move, scale,
rotate for example.

To group the objects for the column

1 Select the four objects that comprise the column simultaneously by doing
one of the following:
■ With your left mouse button, shift-click each object in turn until the
four objects are selected in the scene view.

■ With your left mouse button, drag one large bounding box around
the column objects in an orthographic view.

It is important that you do not select any of the templeBase objects as
part of your selection. If you accidentally select any of the base objects,
deselect them.

2 From the main menu, select Edit > Group > .

3 In the Group Options window, select Edit > Reset Settings and then set
the following options:
■ Group Under: Parent

Leave the other options at their default settings

4 In the Group Options window, click Group.
Maya groups the objects together in a hierarchy. You will learn more about
hierarchies in the steps that follow.


The Hypergraph
The Hypergraph is a window that shows how the nodes and their connections
are organized in your scene. You view object hierarchies and dependencies in
the Hypergraph. Use the Hypergraph to view what happens when you group
an object.

To view the Hypergraph

1 From the view menu, select Panels > Layouts > Two Panes Stacked.
The scene view splits into two viewing panels - each has their own separate
view menu. You will set these to view the scene in the upper view and
the Hypergraph in the other.

2 From the lower pane menu, select Panels > Hypergraph Panel >
Hypergraph Hierarchy.
The Hypergraph panel will display below the scene view panel.

3 At the top of the Hypergraph panel, select the Scene Hierarchy icon to
ensure the Hypergraph is displaying the scene hierarchy.

4 In the Hypergraph panel, select View > Frame All.
The Hypergraph displays the hierarchy for all of the objects in the scene.
This approach to viewing the entities in the scene provides a very
graphical approach to viewing all of the various nodes in your scene.

In the Hypergraph, each node is represented as a rectangle labelled with
an icon that denotes the type of information it represents (for example,
surface, shading, and so on). Each node has a unique name assigned to
it when it is first created. When you rename your objects, you are actually
renaming the node associated with that object.

The Hypergraph | 53

Some nodes display with a line connecting them. This denotes that they
are in a hierarchy and have a dependency structure based on how they
were originally grouped.
For the temple’s column objects, the hierarchy displays each of the named
objects under a node labelled group1. Group1 is the parent node for this
hierarchy of objects.
In Maya, when the parent node (sometimes referred to as the root node)
is moved, rotated, or scaled in any way, the child nodes (sometimes
referred to as the leaf nodes) underneath are also affected.
When you select objects at the top level of a hierarchy and move them,
the objects within the hierarchy or group follow.

NOTE This system of nodes, attributes, and hierarchies may initially appear
somewhat complex, but it is one of the most powerful features of Maya. The
node based architecture provides flexibility and power to create complex
models, shaders, and animations.

To rename the parent node in the Hypergraph

1 In the Hypergraph, click on the group1 node so it becomes active.
In the scene view, all of the objects in the column group become selected
as a result of selecting the group at the top (parent) level of the hierarchy.

2 In the Hypergraph, right-click the top node representing group1 and select
Rename from the pop-up menu.
A small text box appears in the node.

3 Enter Column as the new name.

Now that the column is grouped, you need to position it at one corner of the
temple base.

To position the column on the temple base

1 Change the display of objects to wireframe mode by tapping the 4 key
on your keyboard.
This is a keyboard shortcut. Instead of selecting the item from the menu
you can use a single key to implement the command.


TIP Many of the tools and features in Maya can be accessed using keyboard
shortcuts. In Maya, these shortcuts are called Hotkeys. Some Hotkeys are
displayed directly beside the menu item, others are listed in the Hotkey Editor.
For a complete listing of available hotkeys, go to Hotkey editor.

2 In the Hypergraph, select the Column at the top node so that Column
becomes active in the scene view.

3 In the scene view, use the Move Tool to position Column at the front
corner of the temple base as shown below.

With your first column in position, you can now create a copy of the column
and position it on the adjacent corner of the base.

To create a duplicate copy of the column

1 With Column still selected in the Hypergraph, select Edit > Duplicate
Special > from the main menu.

■ Number of Copies: 1


The Hypergraph view updates to show an additional column object in
the scene. The copy also takes on the prefix name of the original group
and is now labelled Column1.
In the scene view it appears that nothing was actually duplicated. When
an object is duplicated without any transformations the copy is positioned

The Hypergraph | 55

in the same position as the original. The two objects are on top of each
other.

You need to move the column into position on the adjacent corner of the
temple base.

To move the duplicate column into position on the base

1 In the Hypergraph, ensure Column1 is selected by clicking on its top node
so it becomes selected in the scene view.

2 In the scene view, use the Move Tool to position Column1 on the adjacent
corner of the temple base as shown below.

3 From the Toolbox, click the Four View layout shortcut.
The workspace changes to a four view layout and the Hypergraph is no
longer displayed.

Selection modes and masks
It isn’t always efficient to have the Hypergraph window open when you want
to select an object at a particular level within its hierarchy. Maya allows you
to select items in different selection modes depending upon your specific
needs.
There are three main types of selection modes: Hierarchy, Object and
Component. You use these modes in order to mask or limit the selection of
other objects in order to select only the types of items you want. When you
use a selection mask you are filtering out or masking items you don’t want to
be chosen as part of the selection.
The icons for the three modes appear on the Status Line.


When you first start Maya, the default selection mode is set to Objects. This
is useful for much of your selection work with Maya, with a few exceptions.
When you want to select items that have been grouped, set the selection mode
to Hierarchy.

TIP If you set the selection mask, it will remain that way until you change it again.
If an item won’t select for you in Maya, you should check the selection mask setting
to see if it is set correctly.

To use the Hierarchy and Combinations selection mask

1 On the Status Line, choose the Select by Hierarchy and Combinations
icon
The Selection Mask icons update to display the three selection choices.

2 On the Status Line, choose the Select by hierarchy icon.

Select by hierarchy ensures that when you select items they are selected
at their parent or root node.

3 In the scene view, shift-click Column and Column1 so they are selected
simultaneously. (Do not be concerned that they highlight in different
colors.)

Pivot points
A pivot point is a specific position in 3D space that is used as a reference for
the transformations of objects. All objects (curves, surfaces, groups) have pivot
points.
When you group objects in Maya, a new node called a parent node is created
for the group of objects. The pivot point for the group’s parent node is placed
at the origin (0, 0, 0). This is useful if you later want to duplicate and rotate
the objects radially (that is, in a circular fashion around the pivot).

Pivot points | 57

To group the two columns

1 Ensure Column and Column1 are selected.

2 From the main menu, select Edit > Group > .

3 In the Group Options window, select Edit > Reset Settings. Set the
following options:
■ Group Under: Parent

4 In the Group Options window, click Group.
Maya groups the objects together in a hierarchy and the pivot point is
positioned at the origin. (When the pivot point is relocated to the origin
the Move Tool manipulator for the selected group appears at the origin.)

With the two columns grouped, you then duplicate the columns with a
rotation option, the groups will duplicate and rotate around the pivot point
at the origin (0, 0, 0).

To duplicate and rotate the group

1 With column group selected, select Edit > Duplicate Special > from
the main menu.

■ Rotate: 0 90 0


The columns are duplicated and rotated by 90 degrees with each copy.


Save your work
Your temple is taking shape! Save your work before proceeding to the next
lesson.


1 To save your Maya scene, select File > Save Scene As.

2 Type Lesson3Columns in the file browser area reserved for file names.

3 Click Save.

Beyond the lesson
In this lesson, you explored additional tools and skills within Maya as you
continued with the construction of the classic temple. In this lesson you
learned how to:

■ Use your mouse to change the view of your scene using the dolly, track,
and tumble camera tools in both the orthographic and perspective views.

■ Rotate objects using the transformation tools in the Toolbox and the
Channel Box.

■ Group objects so they can be transformed as a unit.

■ Display objects in both wire frame and shaded modes.

■ Access the Hypergraph to view nodes and hierarchies. You are also learning
that many tasks in Maya can be completed or approached using multiple
techniques.

■ Rename nodes within the Hypergraph.

■ Select objects in your scene using the Hypergraph.

■ Use the group pivot point to your advantage when duplicating objects.

Before proceeding with the next lesson you may want to review the material
presented in this lesson so you are familiar with the concepts and skills
associated with them. Some suggested tasks you can try on your own include:

■ Practice using the view camera tools (dolly, track, and tumble) so you can
navigate within the scene views efficiently.

Save your work | 59

■ Practice moving and rotating objects, and changing between the various
scene views (single perspective, four view, single side, single top, and so
on).

■ View objects in the Hypergraph so you can understand their relationships
and hierarchy.

Lesson 4: Components and attributes

Introduction
Working with components is an important part of the workflow when working
in Maya. Components describe objects at a more detailed level. As you edit
the components of your classic temple, you will learn more about what is
possible in Maya.

■ Template objects in the scene.

■ Understand the difference between objects and components.

■ Edit objects at their component level.

■ Assign surface material attributes

■ Access the Attribute editor

Template display
When your scene becomes complex, templating the display of some of the
objects in your scene allows you to more easily select only the objects you
want. When you template the display of an object, its wireframe changes to
a gray color. The object(s) can still be seen, but not easily selected. This helps
to prevent you from selecting or modifying it accidentally. You can change
the display of objects to a template and use them as a modeling reference (the
way a grid is used).
You need to change the display of the base and columns to template mode
so that you can more easily work on the temple roof.


To template the base and columns

1 In the side view, with the Selection Mask set to Hierarchy, select all the
objects in your scene.

2 From the main menu, select Display > Object Display > Template.
The selected objects become templated.

For your classic temple, you need to create the entablature using a torus
primitive. An entablature is a structure that lies horizontally upon the columns
of a temple and supports the roof.

To create and position a torus primitive for the entablature

1 From the main menu, select Create > NURBS Primitives > Torus > .

2 In the NURBS Torus Options window, select Edit > Reset Settings and
■ Radius: 8.5

■ Minor Radius: 0.5


3 In the NURBS Torus option window, click Create.

NOTE If the NURBS Primitives Options window does not appear, ensure that
a check mark does not appear beside the Interactive Creation menu item
before selecting Create > NURBS Primitives > Torus > by first selecting
Create > NURBS Primitives > Interactive Creation.

4 In the Channel Box, rename the torus primitive Entablature.

5 Move the entablature vertically in the scene so it rests on top of the
columns (Translate Y = 9.7).

Template display | 61

Components
All objects in Maya have a transform and a shape node. Geometric shapes,
like the primitives in this tutorial, have smaller parts called components. A few
examples of components in Maya are control vertices, faces, and hulls.
Components allow you to work with objects at a finer level and allow you to
edit them in creative ways.
In order to change the shape of the entablature beyond the basic scale
transformations, you need to modify its component information.

To select components of the entablature

1 In the side view, dolly in for a closer view of Entablature.

2 Set the Selection Mode to Component mode.

3 Right-click the wireframe of Entablature and select Control Vertex from
the pop-up menu.


The menu that pops up is a marking menu for quickly selecting operations
relevant to the object where you right-click the mouse. In this case, the
choices pertain to the display of the entablature’s components.
A set of small blue squares appear on Entablature called control vertices.
Control Vertices (CVs) describe the shape of an object based on their
position in space. If you move any combination of these vertices, you
change the shape of the object.

4 Drag a selection box around the top row of vertices so they become
selected.

5 Using the Move Tool, move the vertices up vertically as shown below to
change the shape of Entablature.

6 To cancel the display of the CVs, right-click the wireframe of Entablature
once again and select Object Mode from the pop-up menu.

The roof for the temple rests on top of the entablature. The roof for the temple
is created using one half of a sphere primitive.

To create a roof for the temple

1 Select Create > NURBS Primitives > Sphere > .

2 In the NURBS Sphere Options window, select Edit > Reset Settings and
■ Start Sweep Angle: 0

■ End Sweep Angle: 180

■ Radius: 8.75


Components | 63


In the NURBS Sphere Options window, click Create.

3 Rename the half-sphere templeRoof.

The roof needs to be rotated -90 degrees about the X axis and positioned on
top of the entablature.

To rotate and position the roof on the entablature

1 In side view, rotate the roof so that the dome part is pointing up.

2 Move the roof so it is positioned close to the top edge of Entablature.

3 Scale the roof along its Z axis (blue manipulator handle) so that the sphere
becomes slightly squashed in appearance.

Now that the roof is complete, you can untemplate the templated objects.

To untemplate objects

1 On the Status Line, choose the Select by Hierarchy and Combinations
button.

2 On the Status Line, choose the Select by hierarchy: template button.

Select by hierarchy: template ensures that only templated objects will be
affected by a selection.


3 In the scene view, drag a selection box around all the objects in the scene
so that the templated objects are selected simultaneously.

4 From the main menu, select Display > Object Display > Untemplate.

5 On the Status Line, choose the Select by hierarchy: root button.

The Attribute Editor
The Attribute Editor provides information about the various nodes and
attributes for the objects and materials in your scene. Like the Channel Box,
you can view and edit the basic transform information and many other keyable
attributes. However, the Attribute Editor provides a more detailed display of
all attributes for a selected object.

To view object attributes using the Attribute Editor

1 In the scene view, select templeRoof so it becomes the selected object.

2 To view the Attribute Editor, click the Show/Hide icon on the Status Line.

The Attribute Editor displays the attributes for templeRoof. The various
attributes for the templeRoof object appear under various tabs. Each tab
represents a node.

The Attribute Editor | 65

3 Click the templeRoof tab to see its attributes.
This tab is known as the transform node, because the most important
attributes on this tab control templeRoof’s transformation. Every visible
object in Maya has a transform node, including cameras and lights.

4 Click the templeRoofShape tab to see its attributes.
This tab is called the shape node because the attributes establish the
object’s geometric shape or physical properties when the object is first
created. Most objects have shape nodes, some do not, such as the group
for the column objects. The shape node also includes other types of
attributes, such as object display attributes.

5 Click the makeNurbSphere tab to see its attributes.
This is an input node that includes attributes related to the object’s
construction history. The attributes of an input node are passed to another
node subsequent in the construction history for the object—in this case,
to the templeRoofShape node.

6 The last two nodes are initialShadingGroup and lambert1. If you can’t
see them, click the display arrow.
The initialShadingGroup and lambert1 nodes are default nodes that relate
to the default shading material for an object. Maya uses them to establish
the initial color of objects and other settings related to shading. If you
create your own shading materials for the temple, as you will in the
following steps, these nodes are replaced by the new shading nodes you
create.


Surface materials
The color, shininess, and reflectivity attributes of an object are controlled by
its surface material (sometimes referred to as a shader, or shading material).
Material attributes relate to how the object simulates a natural reaction to
light in Maya’s 3D computer world.
Maya assigns a default shading material to all objects when they are first
created. In this section, you learn how to assign a new material to your objects.

To assign a new material to the temple objects

1 Right-click the wireframe of Entablature and select Object Mode from
the pop-up menu.

This changes the selection mask back to objects so you can select objects
in the scene. It is a shortcut to access this feature.

2 Drag a selection box around all the objects in your scene to select them.

TIP If objects won’t select in the Maya scene, check that your selection mask
is set correctly on the Status Line.

3 From the Status Line, select the Rendering menu set using the menu
selector.
The main menu changes to display the menu set for Rendering.

4 From the main menu, select Lighting/Shading > Assign New Material >
Blinn.
A Blinn shading material is assigned to all the objects in the scene and
the Attribute Editor updates. Blinn shading materials (named after the

Surface materials | 67

inventor of this shading algorithm) provide for high-quality specular
highlights on surfaces.

5 In the Attribute Editor, rename the blinn1 shading material to
templeShader.

With a shading material assigned to all the objects, you need to edit the color
attributes of the templeShader material.

To edit the shading material’s attributes

1 In the Attribute Editor, click in the gray box to the right of the word
Color.

The Color Chooser appears.


2 Click inside the color wheel (hexagon) and drag the pointer to achieve
a sand color.
The exact color is unimportant for this lesson. As you adjust the color
wheel indicator, the temple objects become the same color you select in
the Chooser.

3 Click Accept to close the chooser.
You will learn more about Maya’s shading and texturing capabilities in
future lessons.

4 In the Attribute Editor menu, choose the Selected menu item, and select
templeBase from the list.

The attributes for templeBase display in the Attribute Editor.

5 Click the templeShader node tab to see its attributes.
If you can’t see this tab, click the display arrow to the right of the tabs.
These are the same attributes you edited when you assigned the
templeShader shader to all the objects in the scene. When you first create
an object, you see two default nodes for shading, initialShadingGroup
and lambert1. When you assign a shading material, the two default nodes
are replaced by the attribute node for the assigned shading material.
You will encounter transform, shape, input, and shading nodes
throughout your work with Maya. There are other types of nodes that
you’ll learn about as you continue learning about Maya.

6 Close the Attribute Editor using the Show/Hide icon.

Save your work
You have completed this lesson. Save your work before proceeding.

Save your work | 69


1 Select File > Save Scene As.

2 Type Lesson4Final in the file browser area reserved for file names, and
then click Save.

Beyond the lesson
In this lesson, you completed the construction of the classic temple and learned
how to:

■ Display objects in template mode.

■ Select objects at their component level using selection masks and the right
mouse button.

■ Assign and edit shading materials for your objects in the scene.

■ Access the Attribute editor and view the various node types for objects.

As you proceed through Getting Started with Maya, we assume you are familiar
with the fundamental concepts and skills covered in this first chapter.
Before proceeding to the next chapter you may want to review the material
associated with them. Some suggested tasks you may want to do on your own:

■ Practice construction of additional forms using primitive shapes by creating.
additional details for your temple scene (stairs, roof details, etc.).

■ Learn more about the tools and options that have been presented in this
lesson, by referring to the Maya Help. To view the Maya Help, select Help
> Maya Help.


Polygonal Modeling
3
Introduction

In Maya, modeling refers to the process of creating virtual 3D surfaces for the
characters and objects in the Maya scene. Surfaces are vital for creating a
convincing 3D image.
Modeling is a process requiring keen visual skills and mastery of the modeling
tools. The more accurate you are when modeling your forms in terms of size,
shape, detail, and proportion, the more convincing your final scene will be.
There are three modeling surface types in Maya:

■ Polygons

■ NURBS

■ Subdivision surfaces.

Each surface type has particular characteristics and benefits.

71

Polygon surfaces are a network of three-or-more sided flat surfaces called faces
that get connected together to create a poly mesh. Polygon meshes are
comprised of vertices, faces, and edges.
The wireframe lines on the mesh represent the edges of each face. The regions
bounded by the edges are faces. Where the edges intersect each other is the
location of a point called a vertex.
When a polygon mesh is rendered, its edges can be set to appear hard or
smooth. As a result, polygons can easily represent both flat as well as curved
3D forms. You’ll work with these component types continuously when
modeling with polygons.
Polygonal surfaces have a wide range of applications and are the preferred
surface type for many 3D applications including interactive games and web
development applications.
Polygonal surfaces can be described with the smallest amount of data of all
the 3D surface types, and therefore, can be rendered quickly, delivering
increased speed and interactive performance to the end user in games and
other applications.

Preparing for the lesson
To ensure the lesson works as described, do these steps before beginning:

1 Select File > New Scene.

2 Make sure Construction History (below the menu bar) is on: . (If it
is turned off, the icon has a large X across it).

Unless otherwise noted, the directions in this chapter for making menu
selections assume you’ve already selected the Polygons menu set.

4 Make sure Display > UI Elements > Help Line is turned on.
You will use the Help Line while modeling.

5 If you have not already done so, copy the GettingStarted folder from
its installation location to your projects directory. Then, set the
GettingStarted directory as your Maya project. For more information,
see Copying and setting the Maya project on page 25.

72 | Chapter 3 Polygonal Modeling

6 As you work through this lesson, remember to save your work frequently
and increment the name of the file every so often (filename1, filename2,
and so on).
In this way you’ll have earlier versions of your work to return to should
the need arise.

7 Make sure that Soft Selection is turned off by opening the Tool Settings
Editor with the Select Tool active and unchecking the box marked Soft
Select.

Lesson 1: Modeling a polygonal mesh

Introduction

In this lesson, you model a helmet for an interactive game character, using
polygonal surface modeling techniques.
In this lesson you’ll be introduced to some of the polygon modeling tools
Maya provides by learning how to:

■ Use 2D image planes as a reference for constructing 3D models

■ Use 3D primitives as the basis for creating more complex models

■ Work with the components of a polygon mesh (faces, edges, and vertices)

■ Smooth a polygon mesh

■ Select the faces, edges, and vertices of polygonal meshes

Lesson 1: Modeling a polygonal mesh | 73

■ Create polygon faces by placing vertices

■ Scale and extrude faces on a polygon mesh

■ Move and rotate extruded polygonal meshes

■ Split vertices and subdivide polygonal faces

■ Combine separate meshes into one mesh

■ Bridge between meshes

■ Add faces to an existing mesh

■ Use Snap to Grid

■ Preview a smoothed high resolution version of a polygon mesh

■ Harden and soften polygon edges

Setting modeling preferences
Before you create your polygon model change some of the default settings to
better work through this lesson.

1 Select Window > Settings/Preferences > Preferences.
The Maya user preferences window appears.
In the Categories section of the Preferences window select Polygons.

2 In the Polygon Display settings, set the following:
■ Border Edges: On

■ Edge Width: 4

This displays border edges prominently on polygon meshes. Displaying
border edges distinctively lets you differentiate them from other edges
on your models and troubleshoot issues.

3 In the Categories section of the Preferences window, choose Selection.

4 In the Polygon Selection settings, set the following:
■ Select faces with: Whole face

The Whole face setting lets you select polygon faces by clicking anywhere
on the face (the Center setting requires you to click on the face’s center


dot). In addition, when a face is selected in the scene, the entire face
appears highlighted.

5 Click the Save button to close the settings window.

6 Turn off the Interactive Creation option for primitives: Select Create >
Polygon Primitives > Interactive Creation (no check mark).

Using 2D reference images
You can use front, side, and top views from drawings, sketches, or photographs
to help visualize your 3D model in Maya, much like an architect or engineer
creates their designs from the plan and elevation views of a blueprint.
You can import 2D images into your orthographic camera views as image
planes. An image plane is a 2D object (plane) that places an image file in the
scene view. By default, an image plane only appears in the camera to which
the image plane is connected. Image planes are also used to create backgrounds
and environments when rendering.
When you load an image into an image plane, it appears in your selected
orthographic view at the origin along an axis that is perpendicular to the
selected orthographic view. You can refer to the image in the orthographic
view to define the silhouette and character lines of your model. You can move
the image plane, change its transparency, or turn it off.
For this lesson you load two images we’ve provided for the lesson into image
planes in the front and side orthographic views of your scene. You’ll refer to
them frequently while you model the helmet.

Using 2D reference images | 75

To load reference images into the front and side orthographic views

1 In the Toolbox, click the Four View shortcut from the Layout Shortcuts
bar.
The perspective view is located in the top right corner and the other views
show your scene from the top, front, and side.

2 In the front view panel menu, select View > Image Plane > Import Image.

3 Select the image file named HelmetFront.jpg.
This image can be found in the GettingStarted directory that you set as
your Maya project:
GettingStarted/PolygonModeling/sourceimages

4 In the browser, click the Open button.
HelmetFront.jpg appears in the front view and depicts a drawing of the
helmet.

5 In the side view panel menu, select View > Image Plane > Import Image.

6 Select the image file named HelmetSide.jpg.
This image can be found in the GettingStarted project directory:
GettingStarted/PolygonModeling/sourceimages

7 In the browser, click the Open button.
HelmetSide.jpg appears in the side view.

NOTE The front and side images for this lesson were created so that the two
views are aligned and the height of each image is identical. When you import
them as image planes, they appear at the same scale. These are important
considerations when you construct your own reference images in the future.
Otherwise, your reference images may not align or may be at different scales
between the two orthographic views.

By referring to the image planes in the orthographic views as you work,
you can correlate how a feature in one view, appears in another. While
a top view reference image is useful in many cases, it isn’t critical for this
lesson.
The image planes can be set so they appear partially transparent to allow
you to work with the polygonal components more easily. To do this you’ll
select the front and side orthographic cameras and modify the
transparency of the images.


To modify the transparency of the reference images

1 In the front view panel menu, select View > Select Camera.
The camera for the front orthographic view is selected.

2 Display the Channel Box by clicking the Show/Hide Channel Box icon
on the Status Line.
The Channel Box displays the keyable attributes for the Front
orthographic camera.

3 In the Inputs section, click the ImagePlane1 name to display the attributes
for the image plane.

4 Set the Alpha Gain attribute to a value of 0.25.
The image appears partially transparent.

5 In the side view panel menu, select the camera and change the Alpha
Gain setting for the side view image plane exactly as you changed the
front view image plane.

TIP You can change the Alpha Gain at any time if you want the image planes
to appear more or less transparent.

6 In the perspective view’s panel menu, select Show > Cameras to
temporarily turn off the display of the image planes in the perspective
view.

Using 2D reference images | 77

Creating a polygon primitive
You’ll create the top portion of the helmet mesh from a cube primitive using
the image planes as a reference. Primitive objects are one method for starting
3D meshes because they can be modified to create other forms.

To create a cube primitive for the helmet mesh

1 Ensure you are working in the perspective view.

2 Select Create > Polygon Primitives > Cube > .

3 In the options window, select Edit > Reset Settings, and then set the
following:
■ Width: 14

■ Height: 14

■ Depth: 14

■ Width divisions: 1


■ Depth divisions: 1

4 Click the Create button.
A cube primitive is created at the origin with the dimensions you specified
and one subdivision around the middle. This cube primitive is comprised
of four-sided polygon faces called quads. Quad polygons are used
frequently with 3D character models as they are easily smoothed and
deform well when bound into a skeleton.

You can smooth the cube so it appears more rounded on the corners and
subdivide it into smaller faces using the Smooth feature.


To smooth and subdivide the cube primitive

1 With the cube still selected in the scene view, select Mesh > Smooth >
, and set the following options in the window that appears:
■ Add divisions: Exponentially

■ Division levels: 2

2 Click the Smooth button
The cube primitive is smoothed and is rounded at its corners. The cube
has also been subdivided into smaller faces.

The polygon faces are still four-sided even though their shape and position
have been modified by the smooth operation.

NOTE If the top, domed portion of the smoothed cube doesn’t roughly
match the helmet sketches as indicated in the image below, scale the cube
with the Scale Tool to make it match.

Creating a polygon primitive | 79

To rename the polygon mesh

➤ With the cube still selected, rename the cube primitive using the Channel
Box from pCube1 to helmetmesh.

Modeling in shaded mode
Modeling a polygon mesh in shaded mode gives you a better sense of the 3D
volume that the model occupies as well as how any surface details appear.
You can control the shading of an object separately in each view. For example,
you can display the object as shaded in the perspective view only, and set the
orthographic views to display objects in wireframe mode. You can also set the
display settings to show both a shaded and wireframe display simultaneously.

To display the helmet mesh in Wireframe on Shaded mode

1 In the perspective view, right-click on the helmet mesh and select Object
Mode from the marking menu that appears.
This changes the selection mode to Objects.

2 Select the helmet mesh.

3 In the perspective view, select Shading > Smooth Shade All from the panel
menu.
The helmet mesh displays in smooth shaded mode.

4 From the panel menu, select Shading > Wireframe on Shaded.


The wireframe appears on the mesh as well as the shading (whether or
not the mesh is selected).

The opacity of the smooth shading in the side and front views prevents you
from seeing the image planes behind the object. X-Ray display mode solves
this problem by making the smooth shaded surface appear semitransparent.

To display the helmet mesh in shaded X-Ray mode

1 With the helmet still selected, choose the following from the side view’s
panel menu:
■ Shading > Smooth Shade All

■ Shading > Wireframe on Shaded

■ Shading > X-Ray.

The helmet mesh updates to a semitransparent shaded display with the
wireframe. You can see the 2D image behind the mesh.

2 Repeat the previous step for the front view as well.

Modeling in shaded mode | 81

After setting the shading for the objects in the various views, you may
wish to adjust the Alpha Gain setting on your image planes to change
their transparency. As you gain experience with Maya, you’ll develop
your own personal preferences for modeling in wireframe or shaded mode
and switching between the various shading modes.

Model symmetry
Whenever you model an object, you should take advantage of any symmetry
that the form provides. It can save you time and effort if you work on only
one half of the model and then later copy it across the model’s axis of
symmetry. The sketch of the helmet is symmetrical along its center line (YZ
plane).

To delete the faces on the left half of the mesh

1 In the top view, right-click on the mesh and select Face from the marking
menu that appears.

2 Drag a bounding box around the faces on the left half of the helmet mesh
to select them.

3 Press the delete key.
The selected faces are deleted.


You now have half as many components in your model. When you near the
completion point of the model, you will copy the finished half across the axis
of symmetry to get the complete model.

Selecting components by painting
You can delete some of the faces that are not needed on the front and lower
section of the helmet mesh using the Paint Selection Tool. This is useful when
you need to select components that are in an irregular region and are not
easily selected using the bounding box.

To select faces for deletion using the Paint Selection Tool

1 In the Toolbox, click the Paint Selection Tool icon.

Selecting components by painting | 83

2 In the side view, right-click the helmet mesh and select Face from the
marking menu that appears.

3 In the side view, paint select the faces that appear along the front and
lower areas of the mesh (see image) by dragging the mouse over the faces.

NOTE The Paint Selection Tool only selects components on the mesh that
face towards the camera.

4 Press the delete key to delete the selected faces.

5 Tumble the perspective view to review your work so far.
The edges that reside along the outside perimeter of a polygon mesh,
called border edges, are displayed with a thicker line than the interior
edges on the mesh. You set this display setting early in the lesson so you
could differentiate this edge type from other edges.

Selecting edge loops
In the top view, the rows of edges immediately above and below the X axis,
and the row to the right of the Z axis are not straight. You’ll want to align the
edges in these rows (referred to as edge loops) by snapping them to the grid
using the Move Tool. An edge loop is a path of polygon edges that are connected
in sequence by their shared vertices. Edge loop selections are very useful when
you model using polygons.


To align edges on the helmet mesh

1 Right-click the mesh and select Edge from the marking menu that appears.
Maya’s component selection mode is set to edges.

2 Double-click one edge in the edge-loop directly below the X axis.
The edge loop is selected.

3 On the Status Line, turn on the Snap to Grids feature by clicking the icon.

Snap to Grids lets you move selected components to the closest grid line
or grid intersection point. When many components are selected, you can
align them to each other via the grid simultaneously.

4 In the Toolbox, double-click the Move Tool to display its tool settings.

5 In the Move Snap Settings, turn off the Retain component spacing setting.

Selecting edge loops | 85

6 In the top view, click-drag the blue arrow on the Move Tool manipulator
downwards a small distance.
The edge loop immediately snaps to a lower grid line. It is not positioned
at the location you want, but all of the edges in the loop you selected are
now aligned to each other.

7 On the Status Line, turn off the Snap to Grids feature by clicking its icon.

8 With the Move Tool still active in the top view, drag the manipulator
arrow upwards a short distance so the edge loop is positioned roughly at
its original location (which should be at the second grid line below the
X axis).

9 Using the steps described above, align the other edge loop that appears
above the X axis and then align the edge loop directly to the right of the
Z axis. (Remember to turn on and off Snap to Grids as required.)
When you have finished, the edge loops nearest the X and Z axes are
aligned. (see image below)

Editing components in the orthographic views
Component selection and transformation is one fundamental method for
editing the shape of a polygon mesh. As you model, you’ll find yourself
frequently examining and then refining the position of the polygon
components (vertices, edges, and faces) while working in the various scene
views so they match the reference images on the image planes.


To manually reposition the vertices on the rear of the helmet

1 Right-click the helmet and select Vertex from the marking menu that
appears.

2 In the side view, select the pair of vertices at the rear lower edge (see
image) by dragging a bounding box around them.

3 In the Toolbox, click the Move Tool.

4 In the side view, click-drag the blue arrow on the Move Tool manipulator
towards the right until the vertices are repositioned so that your helmet
matches the reference sketch on the image plane.

By moving the vertex as well as the vertex adjacent to it along the axis
of symmetry, you ensure that the symmetrical shape of the helmet is
maintained. If you move one vertex independently of the other it may
result in an unwanted bump or valley in the mesh. These types of
anomalies will become more apparent when you copy the completed
half of the mesh across the axis of symmetry.

5 Repeat steps 2 through 4 for the other pairs of vertices on the rear of the
helmet. Ensure that the edge loops appear smooth in relation to each
other.
When you have finished, the back region of the helmet should closely
match the reference image on your image plane.

Editing components in the orthographic views | 87

6 In the side view, select other pairs of vertices along the top and front of
the helmet and move them in a similar fashion so they match the
reference image. Do not reposition the vertices for the top of the face
shield yet.

TIP You can click in the center of the Move Tool manipulator to drag a vertex
selection freely.

Next, you’ll reposition the border edges that lie along the bottom edge of the
mesh. You can select these edge types using the Select Border Edge Tool.

To reposition the lower border edges on the helmet

1 In the side view, select the lowest horizontal edge loop on the helmet by
choosing Select > Select Border Edge Toolfrom the main menu, and then


clicking the first and then the last edge on the loop as indicated in the
image below.

2 Using the Move Tool, drag the selected edge loop downwards until the
left hand vertex roughly matches the lower edge indicated in the reference
sketch.

3 In the side view, select and reposition the remaining vertices individually
on the edge loop using the Move Tool so they match the reference sketch.

NOTE Up to this point in the lesson, you’ve been instructed to reposition
the vertices on the helmet mesh only within the side view (Y, Z plane). Once
you achieve the shape you want in the side view you will then concentrate
on how the model appears when viewed from the front and perspective
views.


To edit the border edges on the upper edge of the face shield

1 From the Select menu, choose Select Border Edge Tool.

2 In the side view, click the first border edge that will be used as the upper
edge of the face shield, then click the last border edge (see image).
The border edges in between are selected.

3 In the Toolbox, select the Rotate Tool by clicking its icon.

4 In the side view, click-drag the rotate manipulator in a clockwise direction
until the border edges are rotated at roughly the same angle as the
corresponding edge in the reference sketch.

5 With the border edges still selected, click the Move Tool again and drag
the green manipulator upwards to match the location of the border edges
in the reference sketch.


6 Reposition the pairs of vertices on the upper front of the helmet to match
the reference sketch.

At this point in the lesson, the outline of your helmet should roughly match
the helmet in the side view reference image. If it doesn’t, review the earlier
steps in this lesson and make any adjustments to your polygonal mesh as
required.
If you view your helmet in the front orthographic view, you’ll notice that the
helmet shows a wider profile from this view than the reference sketch. In the
next steps you’ll correct this using the front and top orthographic views of
the helmet for reference.

To reposition vertices on the side of the helmet to match the sketch

1 Display the front view.


2 In the front view, select the vertices that extend beyond the outline of
the helmet as shown in the reference sketch (see image).

3 In the front view, move these vertices to the left until they match the
widest area of the helmet in the reference sketch (see image).

When you view your helmet from the top orthographic view the region
between the side and rear of the helmet appears a bit flat in relation to the
other areas. To correct this you can move the other vertices in this region
outwards in a similar fashion so the curvature in this area appears fuller and
more rounded. However, viewing only from the orthographic views can be
limiting, and you should also use the perspective view to examine the mesh.


To examine the mesh using the perspective view

1 Enlarge the perspective view.

2 Dolly and tumble the perspective view while you closely examine the
helmet mesh.

As you examine the vertices along any particular edge loop, the vertices on
the mesh should appear to cascade in a smooth gradual fashion to create the
curvature of the mesh with no undesirable spikes or dips.
Ensuring that the mesh appears relatively smooth at various stages throughout
the modeling process will reduce the possibility for issues when you create a
high resolution version of the mesh later on.
If you find areas where one vertex (or more) appears to protrude outwards (or
recedes) on the mesh in relation to neighboring vertices, you can correct these
protruding regions by repositioning the affected vertices in the perspective
view.

Editing components in the perspective view
Repositioning polygon components in the perspective view can be more
challenging when compared to the orthographic views because your frame of
reference changes as you track, dolly, or tumble the 3D view.
By default, the Move Tool lets you reposition components in relation to world
space coordinates. That is, the movement of a component is referenced to a
direction based on the center of the 3D scene and the X, Y, or Z axes.
It is also possible to set the Move Tool to move objects and components based
on other coordinate systems, such as object space and local space.
In addition, you can also move a polygon component in relation to its
surrounding mesh. For example, you can select and move a vertex in a
direction that is perpendicular or normal to its surrounding surface mesh. This
is a useful technique for correcting any protruding vertices on the mesh.

To move a vertex on the mesh in a direction normal to the mesh

1 Dolly and tumble the perspective view while examining the mesh until
you find vertices that protrude outwards from the mesh in an unwanted
fashion.

Editing components in the perspective view | 93

2 In the Toolbox, double-click the Move Tool to display the Move Settings
editor.

3 In the Move Settings editor, in the Move section, turn on the Normal
option.

4 In the perspective view, click the vertex you wish to reposition.
The vertex highlights and the Move manipulator appears to indicate the
three directions of movement that are possible in this mode.

The U and V handles slide the vertex in relation to its associated edges,
while the N handle moves the vertex either away or towards the mesh
depending on the direction you move your mouse.


5 Drag the N handle outwards or inwards depending on what’s required
for that particular vertex. Dolly or tumble the view as required to examine
the mesh after you’ve done this and make any modifications as necessary.

6 Repeat the above steps for any other protruding or receding vertices on
the mesh until you are satisfied that the mesh appears smooth.

7 Before you proceed to the next section, double-click on the Move Tool
and return the Move setting to the default World setting.

If you examine your model in the perspective view your helmet mesh should
now match the reference sketches as they appear in both the front and side
image planes (see image below). The mesh should also have a relatively uniform
distribution of polygon faces on the mesh and the edge loops should flow
smoothly.

Drawing a polygon
To create the lower front region of the helmet (that is, the region that would
protect the mouth and jaw of the wearer) you’ll create a polygon for the cross
section of the lower front region by manually placing vertices using the Create
Polygon Tool (Mesh > Create Polygon Tool).

To place vertices for a polygon

1 In the side view, select Mesh > Create Polygon Tool > .
The Create Polygon Tool settings editor appears.

2 In the tool settings editor, set the following options:
■ Limit the number of points: On

Drawing a polygon | 95

■ Limit points to: 6

These settings specify that a closed polygon face will be created once you
have placed six vertices in the scene.

3 In the side view, place six points for the profile as it appears in cross
section of the lower front region of the helmet (see image below). Ensure
that you place the vertices in a counter-clockwise direction for this step.
The new polygon face is created along the YZ plane (the axis of symmetry
for the model).

4 Press the q key to quit the Create Polygon Tool when the polygon face
is complete.
The new polygon component remains selected in Object Mode.

NOTE If the polygon face doesn’t appear shaded in the side view but does
appear shaded in the perspective view, it means that the polygon face and
the image plane lie on exactly the same plane. You can correct this by moving
the image plane backwards in the side view so it doesn’t lie directly on the
YZ plane, but this step is not critical to the success of the steps that follow.

You’ll extrude this polygon face to create the remainder of the lower front
region of the helmet. Before you can extrude the new face it needs to be
selected in Face mode. You can do this quickly by converting the existing
selection to Faces.

To convert the object selection to face selection

➤ With the face still active in Object Mode, choose Select > Convert
Selection > To Faces.


The selection is converted to a face selection.

TIP You can also press Ctrl + F11 or Ctrl + right-click on the selected object
and choose To Faces > To Faces from the marking menu that appears.

Extruding polygon components
You can create new polygon components from existing ones using the Extrude
feature (Edit Mesh > Extrude). When you extrude a polygon component (for
example, a face, edge, or vertex), you create additional polygon components
from the ones you selected. Using the Extrude feature you will:

■ Create the lower front region of the helmet by extruding the polygon face
you created in the last section of the lesson.

■ Extrude edges around the face shield and along the lower bottom edge.

To extrude the polygon face for the lower front region

1 Enlarge the scene view to a single perspective view.

2 With the polygon face still selected, choose Edit Mesh > Extrude.
The extrude manipulator appears on the selected face.

3 In the perspective view, drag the blue arrow on the manipulator to extrude
a section of mesh out from the face (positive X) a distance of
approximately one half a grid unit (see image).

4 Press the g key to extrude again.

Extruding polygon components | 97

5 Click the large circle that surrounds the manipulator to display the rotate
manipulators and then drag the green circular manipulator to rotate the
angle of the extrusion to match the angle in the reference sketch (see
image) and then drag the arrow manipulator a second time to extrude a
second section of mesh.

TIP As you change the angle of rotation and extrude the mesh you can also
momentarily switch between the move or scale manipulators to fine tune
the position and scale of each section as you extrude it.

6 Press the g key once again and create a third extruded region using the
manipulator to move, rotate, or scale the extruded segment of the mesh
so you position it correctly when compared to the reference sketch (see
image). You may also want to view the extrusion from either the top or
front view to ensure your extrusion doesn’t extend outwards more than
the side region.

7 Save your work.


To delete unwanted faces on the extruded mesh

1 Tumble the perspective view until you can view the inside of the lower
front region (see image below).

2 Select the faces that appear on the inside of the mesh you just extruded,
including the faces on either end of the extrusion.
These faces were required for creating the extruded portions of the lower
region but are not needed beyond this point.

3 Press the Delete key to delete the selected faces.

When you are finished, a gap will exist between the last extruded segment
of the lower region and the helmet mesh.

You’ll combine these separate meshes together and then create a mesh that
bridges between them in the next section of the lesson. To prepare for the


bridge, you need to extrude more edges on the helmet mesh so that the number
of edges match when you create the bridge.

To extrude the bottom edges of the helmet mesh

1 In the perspective view, select the lower edges of the helmet mesh using
Select > Select Border Edge Tool.

2 Select Edit Mesh > Extrude, then drag the blue arrow manipulator in a
direction towards the inside of the helmet to create a row of edges that
are perpendicular to the selected bottom edges. Extrude these edges a
distance that is approximately one grid unit in depth (see image below).

To extrude top and side edges for the face shield

1 In the perspective view, select the upper and side edges on the helmet
mesh using Select > Select Border Edge Tool (see image below).

2 Select Edit Mesh > Extrude and then drag the blue arrow on the extrude
manipulator in a direction towards the inside of the helmet to create
edges that are perpendicular to the top and side edges of the face shield.
Extrude these edges a distance that is approximately one grid unit in
depth (see image below).


To move vertices on the lower front region to match the reference sketch

1 In the perspective view, right-click on the helmet and select vertex mode
to change the selection type to vertices.

2 Select the four vertices on the lower front region of the helmet that are
near the axis of symmetry (see image below) and using the Move Tool,
move the selected vertices upwards by dragging the green arrow on the
Move Tool manipulator so that the lower front region of the helmet
matches the reference sketches as they appear in the various orthographic
views.

3 Adjust any vertices on the lower region that may require minor
repositioning by selecting and moving them as necessary.


Bridging between edges
Next you’ll connect the lower front region to the helmet mesh. You can create
meshes that bridge between one or more border edges of a mesh using the
Bridge feature (Edit Mesh > Bridge).
When using the bridge feature you must ensure that:

■ the edges to be bridged are in the same polygon mesh. That is, you must
combine the two meshes into one using the Combine feature, before you
perform the bridge.

■ you select an equal number of border edges on either side of the region to
be bridged.

To combine the two meshes into one

1 In the perspective view, right-click the mesh and select Object Mode from
the marking menu that appears.

2 Select the helmet mesh, and then shift-select the lower front mesh, so
both meshes are selected.

3 Select Mesh > Combine.
The two meshes are combined into one. When you select either object
now, the other is also selected because they are in the same mesh.

The edge of the mesh on the lower front region of the helmet is comprised
of five edges. The corresponding region on the side region of the helmet only
has three. You can increase the number of edges on the lower side region by


inserting two edge loops across the mesh. Inserting two edge loops in this
region of the mesh also divides the large faces so they better match the size
of the other faces on the rest of the mesh.

To insert edge loops on the side region of the helmet

1 Select Edit Mesh > Insert Edge Loop Tool > .
The Insert Edge Loop Tool settings editor appears.

2 In the tool settings editor, set the following options:
■ Maintain Position: Relative distance from edge

3 In the perspective view, click-drag the edge on the side region of the
helmet near the bottom of the edge as indicated in the image below.
Without releasing the mouse button, drag the mouse upwards about one
third of the distance along the edge and then release the mouse button
to insert the edge loop.

NOTE Click-dragging an edge when using the Relative option inserts an edge
loop that closely matches the existing edge layout on the mesh. That is, the
lower region of the mesh is much wider near the front than at the rear. The
Relative setting adjusts the position of the edge loop locator based on this
topology so is ideal in these situations. When you click-drag using the Relative
option, remember to click near the edge whose layout you want the edge
loop to match.

4 With the Insert Edge Loop Tool still active, click-drag the side region of
the helmet near the top of the same edge and insert a second edge loop
about two thirds of the distance along the edge.

Bridging between edges | 103

5 Press the q key to return to selection mode, and click anywhere off the
mesh to unselect the edges.
Now that you’ve inserted the necessary edges, you can proceed with
creating the bridge.

To bridge between the lower front and side region of the helmet

1 Choose Select > Select Border Edge Tool and then click the border edges
on both the lower front as well as the side region of the mesh where you
want the bridging mesh to be constructed. (You should have five edges
selected on either side).

TIP When you select border edges using the Select Border Edge Tool you
can click on the first and last edge in a series on one side of the bridge and
the tool will select the edges in between.


2 Select Edit Mesh > Bridge > .

3 In the Bridge Options window, set the Divisions to 0, then click the Bridge
button to create the bridge.

4 Press the q key to return to select mode, and click anywhere off the mesh
to unselect the edges.

NOTE If your bridge appears to twist or cross over itself it indicates that the
two meshes have their surface normals mismatched. In this particular case it
likely indicates that you did not create the original profile shape for the lower
front by placing the six vertices in a counter-clockwise direction.
If this occurs you must undo your steps to the point immediately before you
combined the two meshes and then reverse the surface normals on only the
lower front section by selecting it and then selecting Normals > Reverse. You
can then redo the instructions in this section as required.

Adding polygons to a mesh
For the protective face shield on the helmet, you'll create one large multi-sided
polygon using the Append to Polygon Tool and then split it into multiple
four-sided polygons (quads) so that the new polygons match the existing
four-sided topology of the helmet mesh.

To create the face shield using the Append to Polygon Tool

1 Tumble the perspective view so you can see all of the edges surrounding
the area for the face shield.

Adding polygons to a mesh | 105

2 Select Edit Mesh > Append to Polygon Tool > .

3 In the Append to Polygon Tool settings window, set the following:
■ Keep new faces planar: Off

If the planar option is on, the Append to Polygon Tool will not create a
multi-sided polygon as the edges you’ll select do not form a planar region.

4 In the perspective view, click once on the top inner border edge of the
helmet mesh to indicate which mesh you are appending to, and then
click the same edge a second time to begin the append operation (see
image below).

5 Click the bottom edge of the face shield that is opposite the first edge
you just clicked.
A polygon appears that spans the two edges.

6 Continue to click the remaining border edges in a counter-clockwise
direction around the opening for the face shield (see image above) until
you reach the last edge.

7 When you are finished clicking the perimeter border edges for the face
shield, press the q key to quit the tool.
The multi-sided polygon is completed and added to the existing mesh.
Multi-sided polygons are also referred to as n-gons.


Ideally, all faces should be four-sided to match the other faces on the helmet
mesh. In the next section, you'll split the n-gon vertically and horizontally
into several smaller four-sided polygons using the Split Polygon Tool.

Splitting polygon faces
Earlier in the lesson you split the helmet mesh by inserting edge loops across
the mesh. You can split localized areas of a mesh using the Split Polygon Tool.
When using the tool you draw a line across the faces to indicate the location
for the split. You'll begin by vertically splitting the face shield.

To split the face shield vertically

1 Select Edit Mesh > Split Polygon Tool > .
The Split Polygon Tool settings editor appears.

2 Set the following options:
■ Split only from edges: On

■ Use snapping points along the edge: On

■ Snapping tolerance: 100

These settings let you begin and end your split at a location that
corresponds exactly with an edge and lets you snap to the midpoint and
ends of the edge you select. (The number of points setting of 1 ensures
this). These settings will help to ensure that the faces you split align
exactly and that the four-sided topology of the mesh is maintained.

Splitting polygon faces | 107

3 Tumble the camera in the perspective view so you can view both the
upper inner edges of the face shield as well as the lower inner edges.

4 Click-drag the top inner edge of the face shield to indicate the start of
the split (see image below). Drag the mouse to position the vertex until
it stops at the right side of the edge.

5 Click-drag on the lower inner edge of the helmet mesh to indicate the
end of the split (see image). Drag the mouse to the right until the vertex
stops at the right side of the edge.

6 Press the y key to split the face.

7 Press the g key to select the Split Polygon Tool again, and then continue
to split the face shield vertically at the other locations specified in the
image below. Remember to press the y key after each split and then the
g key to select the tool again.
When you are finished the n-gon for the face shield will be split into four
or five new polygons (depending on how you've constructed your mesh).

One polygon on the side of the face shield will still be five-sided. To correct
this, you'll also split the face shield horizontally. Splitting the face shield
horizontally will also let you modify its shape afterwards.


To split the face shield horizontally

1 In the perspective view, with the Split Polygon Tool still active, click-drag
the inner side edge (see image) to indicate the start location for the
horizontal split.

2 In the side view, click-drag the front vertical border edge of the face shield
(this border edge lies on the axis of symmetry) and release the mouse
button at the mid-point along the edge where the vertex naturally snaps
(as if a magnet were attracting it towards that location).

3 Press the y key to split the faces.


NOTE When you split across multiple faces at the same time you only need
to click an edge to indicate the start point for the split and on a second edge
to indicate the end point. The Split Polygon Tool automatically splits the
edges in between.

4 Press the q key to quit the Split Polygon Tool.

In the next steps you'll reposition some of the vertices along the horizontal
split to make the face shield protrude outwards a small amount.

To adjust the shape of the face shield

1 In the side view, select the middle two vertices at the front of the face
shield and use the Move Tool to move the vertices outwards (+Z) a small
amount (see image).

2 In the perspective view, select the remaining middle vertices on the face
shield one at a time and reposition them outwards a small distance using
the Move Tool with the Move Setting option set to Normal.


TIP Tumble the perspective view so you can see the relationship between
the vertices as you move them outwards.

3 Reset the Move Tool's Move Settings to World before continuing to the
next steps.

To create the diagonal grill vents on the lower front of the helmet you’ll insert
edges on the face, reposition some of the vertices, and then extrude some of
the faces.

To insert multiple edges for the diagonal grill vents

1 Select Edit Mesh > Insert Edge Loop Tool > .

2 In the Insert Edge Loop Tool Options window, set the following:
■ Multiple Edge Loops: On

■ Number of edge loops: 4

■ Auto Complete: Off

These settings let you insert four evenly spaced edges on the face where
you want the grill vents to appear.

3 In the perspective view, click the border edge of the face where the grill
vents will appear and then click the edge directly opposite that border
edge (see image).


4 Press the y key to complete the edge loop insertion

5 Click off the mesh to deselect the edges.

6 Press the q key to exit the tool and return to selection mode.

To make the grill vents appear diagonally you’ll select the vertices on the right
side and then slide them downwards using the Move Tool.

To move vertices along an edge using the Move Tool

1 Right-click the helmet mesh and change the selection mode to Vertex.

2 Select the vertices on the right side of the grill feature (see image below).

3 Double-click the Move Tool icon to display the Move Tool’s settings
editor.

4 In the Move Tools’ settings editor, click the Set to Edge button.
The vertices appear unselected temporarily. The Move Tool expects you
to select an edge it will reference for the axis of movement.

5 Click an edge that is on the same line of the edges as the vertices you
selected.
The Move Tool manipulator appears and is aligned to the edge you
selected. The vertices appear selected again indicating that the Move Tool
is now set to move those vertices along the axis defined by the edge you
selected.


6 Drag the red arrow on the Move manipulator downwards to move the
vertices so that the shape of the faces for the grill are more diagonal (see
image).

NOTE Make sure you do not move the vertices so that the lowest vertex
touches the corner vertices or you’ll create an edge that has zero length.

7 Click off the mesh to deselect the vertices.

8 Before proceeding to the next section, double-click the Move Tool and
reset the tool settings by clicking the Reset Tool button.

To make the grill vents three-dimensional, you’ll extrude some of the thin
diagonal faces inwards.

To extrude the faces for the grill feature

1 Right-click the helmet mesh and change the selection mode to Face.

2 Beginning at the bottom of the grill feature, shift-select the two diagonal
faces as indicated in the image below.


3 Select Edit Mesh > Extrude.
The Extrude manipulator appears.

4 Drag the blue arrow on the Extrude manipulator towards the helmet a
short distance to create the two recessed vents for the grill.

5 Press the q key to quit the Extrude feature.


6 Shift-select the two side faces on the grill vents that lie on the axis of
symmetry and delete them (see image below). These faces will not be
required when you create the opposite half of the helmet.

7 Save your work before proceeding to the next section.

Terminating edge loops
When you inserted the edges for the grill vents the adjacent face was changed
from four-sided to eight-sided as a result of the splitting that occurred along
the shared edge.
This situation can easily occur when you are splitting polygons in a localized
region of a mesh, and should be anticipated if maintaining four-sided polygons
is a constraint for your polygon models.
When this occurs you’ll need to find a way to gradually divide the n-gons
into four-sided regions by terminating the edge loops. Terminating edge loops
is when you split a multi-sided n-gon gradually into multiple four-sided
polygons.
When you do this, a single vertex may have five or more shared edges coming
out of it as a result. This process lets you create regions on a mesh that have
more detail while maintaining a particular mesh type—four-sided polygons
in this case.

Terminating edge loops | 115

To manually split the multi-sided polygon into three four-sided polygons

1 Select Edit Mesh > Split Polygon Tool.

2 In the perspective view, click-drag on the top side edge of the top grill
vent. Drag your mouse so the vertex is positioned at the bottom of the
edge (see image).

3 Click-drag on the top edge of the multi-sided polygon and slide the vertex
to the right end of the edge (see image).

The region above the split edge appears like a polygon but is actually
four-sided because of the edges on the grill vent.

5 Split the side edge on the bottom grill vent in a similar fashion by
click-dragging your mouse so the vertex is positioned at the top of the
edge (see image below).


6 Click-drag the bottom edge of the multi-sided polygon and slide the
vertex to the right end of the edge (see image).

Your multi-sided face is now split into three four-sided faces, maintaining
the overall quad topology on the helmet mesh.

8 Press the q key to exit the Split Polygon Tool.

Deleting construction history
Maya keeps track of the options, attribute settings, and transformations made
to an object via its construction history. Construction history is useful when
you’re working on a surface and want to edit an attribute from an earlier stage
of the model’s development.
The simplest way to access the construction history for an object is via its
various input nodes in the Channel Box or via the Attribute Editor. Selecting
an input node displays the attributes associated with that particular
modification to the object. You then edit the attributes on that node as
required and the surface updates.
For example, the input nodes for the helmet mesh include: polyCreateFace,
polyCube, polyExtrudeFace, polySmoothFace, polyMoveVertex, polyUnite,
and so on. You can associate the steps in creating the helmet mesh with nodes
that are related to a particular stage of its construction history.

Deleting construction history | 117

As you near the completion of a model, these construction history nodes are
not required. If your production work entails having another person texture
or animate the model, you’ll want to delete these history nodes from the
objects in your scene altogether so another user doesn’t accidentally change
your work.
Deleting the construction history is usually done only when a model is
completed to a particular milestone stage and the next major phase of
production with it needs to occur. For example, skinning, animating, texturing,
and so on.

To delete the construction history on the helmet mesh

1 Right-click the mesh and change the selection mode to Object, and select
the helmet mesh.

2 Display the Channel Box if it isn’t already, and notice the list of history
nodes that appear in the Inputs section.

3 Select Edit > Delete by Type > History.
The construction history is deleted on the helmet mesh. Notice the list
of items under Inputs has only one item remaining—the polySurfaceShape
node.



Mirror copying a mesh
Once you’ve finalized one half of your polygon model (and deleted its
construction history) you’ll want to create the opposite half by copying it
across the axis of symmetry so you have the complete model. You can produce
a mirrored copy of a polygon mesh using Mirror Geometry (Mesh > Mirror
Geometry).
Before copying one half across the axis of symmetry, you should check that
all of the border edges lie along the axis of symmetry. If any edges do not lie
along this axis, the original half will be copied based on the vertices that create
the widest point and a gap between the two halves may result.

To ensure that the border vertices lie along the axis of symmetry

1 Enlarge the front view so you can view the vertices that lie along the axis
of symmetry.
If any vertices on the mesh protrude across the Y axis, you’ll need to snap
these to the Y axis using the Move Tool in combination with the Snap
to grids feature.

NOTE Any vertices that protrude across the Y axis likely occurred as a result
of an earlier extrude operation. Because the extrude feature extrudes
components based on the face normal, a few vertices may have moved across
the axis of symmetry.

2 In the front view, select all of the vertices that should lie along the axis
of symmetry (Y axis) using a bounding box selection.

3 On the Status Line, turn on Snap to Grids.

4 In the Toolbox, double-click the Move Tool to display its tool settings
and ensure that the Retain component spacing setting is turned off.

5 In the front view, click-drag the red arrow on the Move Tool manipulator
to the right a small distance.
The vertices immediately snap to the grid line to the right. They initially
will not be positioned at the location you want, but you’ll notice that all
of the vertices you selected are now aligned to each other.

6 Drag the manipulator towards the left until the vertices snap to the Y
axis.

Mirror copying a mesh | 119

7 On the Status Line, turn off Snap to Grids.

8 Click off the mesh to unselect the vertices.

To mirror copy the polygon mesh

1 Right-click the mesh, change the selection mode to Object, and then
select the helmet mesh.

2 Select Mesh > Mirror Geometry > , set the following options, and then
click the Mirror button.
■ Mirror Direction: -X

■ Merge with original: On

■ Merge vertices: On

The mesh is copied along -X to create the opposite half of the model.
The two meshes are combined into one and vertices are merged so they
become shared.



At this point, the low resolution version of the helmet model is complete. In
the next section you’ll preview how the model appears at a higher resolution
using the subdiv proxy feature.

Working with a smoothed mesh
Depending on the intended use of your polygonal model, you may want a
low resolution version, a high resolution version, or both. In Maya, its easy
to increase the resolution of a model using the Smooth feature (Mesh >
Smooth).
In addition, you can preview a higher resolution version of the mesh using
either Smooth Mesh Preview or the Proxy > Subdiv Proxy feature. You can
then view and edit the low resolution and high resolution smoothed version
of the mesh separately or simultaneously.
Smooth Mesh Preview lets you quickly preview how your mesh will appear
when smoothed.
The Subdiv Proxy feature links the original and the high resolution smoothed
versions via construction history, you can make changes to the low resolution
version and immediately see the effect on the high resolution smoothed
version.
In this lesson, you’ll use Subdiv Proxy to work with your smoothed mesh.

Working with a smoothed mesh | 121

To create a high resolution smoothed model using Subdiv Proxy

1 Right-click the mesh, change the selection mode to Object, and then
select the helmet mesh.

2 Select Proxy > Subdiv Proxy > , and set the following:
■ Division Levels: 2

■ Mirror Behavior: None

■ Subdiv Proxy Shader: Keep

3 Click the Smooth button.
A higher resolution, smoothed copy of the helmet mesh is created in the
same position as the original mesh. It is possible to see the two versions
in this position (and you can toggle the display to show either or both)
but in this lesson you’ll select the high resolution version and move it
slightly to the left.

NOTE The two versions of the model are also grouped into the same node
hierarchy when the Subdiv Proxy operation is performed.

4 Select both the low and high resolution versions of the mesh in Object
Mode.


5 Press the ‘ key (located to the left of the 1 key) to toggle the display
between the low and high resolution versions.
Toggling the display between the two versions is useful when you want
to view one or the other.

6 Press the ~ key to toggle the display so that both are visible again.

NOTE The Toggle Proxy Display (‘) and the Both Proxy and Subdiv Display
(~) display items are also available from within the Proxy menu.

7 Select only the smoothed version of the mesh in Object Mode and move
it to the left about 25 units (X = -25).
As you edit the low resolution version of the helmet mesh you’ll see the
resulting updates on the smoothed version beside it.

Creasing and hardening edges on a mesh
You can crease or harden the edges on your polygon meshes. Hardening or
creasing the edges sets how the mesh transitions between faces enhancing
the realism of your model.
When you harden an edge on a polygon mesh, you change the direction of
the normals associated with the shared edge, which in turn affects the shading
along those edges. When you crease an edge of a mesh that has an associated
subdiv proxy, the edges on the smoothed high resolution version are creased
by physically modifying the polygon smoothing surrounding those edges.

Creasing and hardening edges on a mesh | 123

In this lesson, you’ll try both methods on your helmet mesh.

To display hard and soft edges on a mesh

1 Right-click the low resolution mesh, set the selection type to Object Mode,
and then select the helmet mesh.

2 Select Soft/Hard Edges.
The wireframe mesh on the helmet updates to display both dashed and
solid lines. The dashed lines indicate edges that are set to display as soft
shaded. The solid lines indicate edges that are set to display as hard
shaded. The reason some of the edges are hard and some are soft relates
to the particular settings for some polygon tools.

To soften the edges on the mesh

➤ With the low resolution version of the helmet still selected, select Normals
> Soften Edge.

All of the edges on the helmet mesh are set to be shaded in a softened fashion.
The wireframe mesh updates to display as dashed lines indicating that all of
the edges are set to be soft shaded. You may not notice any immediate effect
on the smoothed high resolution version, but its important that you perform
this step before you proceed to harden specific edges on this model.


To harden the edges surrounding the face shield

1 Right-click the low resolution mesh and set the selection mode to Edge.

2 Select the inner edges that surround the perimeter of the face shield (see
image below).

TIP You can quickly select the inner edges surrounding the perimeter of the
face shield using the Select Edge Loop Tool. You may need to double-click
in a couple of areas to complete the selection.

3 Select Normals > Harden Edge.
The selected edges are hardened on the low resolution mesh.


Notice that the same edges on the smoothed high resolution version of
the helmet are unchanged. For edges to display sharp on the smoothed
version, you must turn on the Keep Hard Edge attribute.

To turn on the Keep Hard Edge attribute

1 In the perspective view, select only the smoothed high resolution version
of the helmet mesh.

2 In the Channel Box, in the Inputs section, click the listed proxy to display
its attributes.

3 Set the Keep Hard Edge attribute to On.
The sharper transition between the face shield and the rest of the helmet
now appears on the smoothed high resolution version.

4 Select all of the edges for the grill vents and harden them as well.


To crease edges on the mesh

1 Select the lower outer edges on the face shield (see image).

2 Select Edit Mesh > Crease Tool.

3 In the scene view, press the middle mouse button then drag the mouse
to the right to add a crease to the selected edges.
A thick line appears on both the low resolution model and the high
resolution version to indicate that a crease has been applied. Notice on
the high resolution version that the related edges have become sharper
in appearance, but not as sharp as if they were hardened using the Harden
Edge feature.


4 Save your work.

NOTE You can toggle the creased edge display (thick lines) by selecting
Crease Edges.

Your model is now complete. Depending on your requirements you can delete
the construction history on both the low resolution and high resolution
versions.
Refine any regions on the helmet as required to gain more experience with
the tools presented in this lesson.
If you need to work with either version of the model separately you can
ungroup the two meshes by selecting the top node of their hierarchy in the


Hypergraph window (Window > Hypergraph: Hierarchy) and selecting Edit >
Ungroup.

Beyond the lesson
In this lesson you learned some basic techniques of polygonal modeling:

■ You can create complex polygonal models with surprisingly few techniques.

■ Starting from a primitive surface such as a cube, you can smooth, scale,
move, extrude, split, and rotate components of the primitive to create a
low resolution version of the model you want to create.

■ You must frequently adjust vertices to fine-tune the shape, and finally
smooth the edges between faces where desired in order to produce the
final version of your model.

■ Another method for previewing a smoothed version of the mesh before it
is smoothed is via Smooth Mesh Preview. Press the 2 or 3 key while the
mesh is selected to preview it in a smoothed state. Press the 1 key to return
it to the unsmoothed state.

Polygonal modeling has many timesaving features not covered in this lesson:

■ For example, Boolean operations (union, difference, and intersection) are
a common way to create a new object from the interaction of two existing
objects.

■ If you’re planning to use your polygonal surfaces where the poly count is
constrained, such as with interactive games, Maya has a number of tools
for minimizing the number of polygonal faces of an object such as the
Reduce Tool. Fewer faces means simpler geometry. This is critical when
fewer polygons means increased interactive performance with games
applications. You can view the polygon count on your mesh by selecting
the mesh and then choosing Poly Count.

■ Maya also has a category of tools called Deformers. Deformers let you bend,
twist, and scale your objects by enveloping the object in a cage-like
manipulator called a lattice deformer that you can manipulate.

■ The NURBS chapter in this guide describes how to use the Sculpt Geometry
Tool to modify a surface by pushing, pulling, and smoothing a surface
without first selecting vertices. Though the lesson shows how to shape a
NURBS surface, you can apply many of the same techniques when sculpting
polygonal surfaces.


■ You can also modify a polygon mesh using the Soft Modification Tool
which lets you smoothly modify a group of vertices on a mesh.


Lesson 2: Sculpting a polygon mesh

Introduction

In this lesson you alter an existing polygonal head model into a goblin by
sculpting the mesh with the transformation tools.
In this lesson you’ll be introduced to some of the polygon modeling options
Maya provides by learning how to:

■ Use reflection to perform symmetrical transformations to your model

■ Use Soft Select to transform components with falloff

■ Modify the falloff area and shape

■ Create a custom falloff shape


■ Select components using Marquee select and Drag select

■ Use Camera based selection to limit the components you select

■ Use the Split Edge Tool to separate edge rings

Open the scene for the lesson
In this lesson, you’ll work with a scene that we created for your use. The scene
contains a human head. In the remainder of the lesson, you’ll alter this into
a goblin head.

To open the scene

1 Make sure you’ve done the steps in Preparing for the lesson on page 72.

2 Open the scene file named Poly_head.mb.
This file can be found in the Getting Started directory that you set as
your Maya project:
Getting Started/PolygonModeling/Poly_head.mb
The scene contains a human head in a visible layer with a hat and glasses
on hidden layers.

Using Soft Select
You can use Soft Select to select components with falloff on a polygon or
NURBS surface. Falloff is an area around the selected components that is
affected by a transformation according to a weighting. Transforming
components with falloff allows you to perform a smooth transformation over
multiple components without having to adjust each component individually.
For this lesson you use Soft Select to make a number of adjustments to the
head model, starting with the nose.

To stretch the nose

1 Select the Move Tool by clicking the icon on the Toolbox.

2 Right-click the head model and select Vertex from the marking menu.
The vertices appear on the mesh.

3 Select a vertex on the tip of the nose.

Open the scene for the lesson | 131

4 Press the ‘b’ key.
A circular colored area appears around the selected vertex.

This colored area represents the falloff. Yellow represents areas of low
falloff while black represents areas of high falloff. Areas with low falloff
are affected more by transformations to selected components than areas
of high falloff.


Next you need to adjust the Falloff radius.

5 Hold the b key and drag the left mouse button left or right.
The falloff area grows and shrinks as you move the mouse. Adjust the
size so that it encompasses as much of the nose as possible without
touching the face.

6 Drag the z axis manipulator away from the face.
As you drag the vertex away, the rest of the nose is smoothly stretched
with it.

Using Soft Select | 133

7 Select the Rotate Tool from the toolbox and, using the z axis manipulator,
rotate the vertex down approximately 45 degrees.

8 Select the Move Tool again and drag the y axis (it appears yellow when
selected and green when unselected) manipulator down.
This creates a bend in the nose.


9 Turn off Soft Select by pressing the b key on your keyboard.

Selecting with Camera based selection
When selecting components on a model you often only want to select the
components you can see and not the components behind them. You can use
Camera based selection to limit your marquee select to only what the camera
can see.

To pull out the chin

1 Double-click the Select Tool icon in the toolbox.
The Tool Settings editor appears.

2 In the Common Selection Options section, underneath Marquee, turn
on Camera based selection.

3 Right-click the head and select Vertex from the marking menu.

Selecting with Camera based selection | 135

4 While looking at the front of the head, select the five vertices on the
same vertex loop at the front of the chin by holding the left mouse button
at one corner of them dragging a marquee selection over them.
Only the five vertices in the front are selected.

5 Turn on Soft Select by pressing the ‘b’ key on your keyboard.
A colored falloff appears on the surface of the face.

6 Hold the ‘b’ key on your keyboard and drag the the left mouse button
left or right to adjust the Falloff radius so that it encompasses only the
chin.

7 Select the Move Tool and drag the chin down and away from the face so
that it becomes longer and more angular.


Now you have a longer chin without affecting any of the geometry on the
neck, which may have occurred accidentally if Camera based selection had
been off.

Sculpting with symmetry
To give the head a more goblin-like appearance, you need to make the cheeks
and eyebrows more boney. However, to do this, you need to adjust both cheeks
equally. You can do this with the transformation tools’ Reflection settings.

To modify both cheeks simultaneously

1 Double-click the Move Tool in the Toolbox.

2 In the Reflection section, turn on Reflection and set the Reflection axis
to X.


Sculpting with symmetry | 137

4 With the camera positioned in front of the head, select a set of vertices
on the left cheek.
A colored falloff appears on both cheeks.

5 Pull the x axis manipulator to the left so that the cheeks are pulled closer
together.
Both cheeks are transformed identically and appear more boney.


Now you can adjust the eyebrows to make the goblin angrier.

To rotate the eyebrows

1 Press the ‘b’ key on your keyboard to disable Soft Select.

2 Click the outermost vertex on the left eyebrow.

3 Shift + double-click the innermost vertex on the left eyebrow.
All the vertices on the same loop are selected between and including the
two vertices.

Sculpting with symmetry | 139

NOTE The selection of vertices on the other side of the reflection seam do
not appear complete after this step. This is normal and is rectified in step 4.

4 Press the ‘b’ key on your keyboard to enable Soft Select.

5 Hold the ‘b’ key on your keyboard and drag the mouse left and right to
adjust the Falloff radius so that it only affects the eyebrow.

6 Double-click the Rotate Tool from the Toolbox.

7 Drag the Z (dark blue) rotate manipulator in the scene to rotate the
eyebrows inward.


Sculpting with Surface based falloff
The default setting in Maya uses a spherical volume to determine what
components are contained in the Falloff radius. However, sometimes you need
the Falloff radius to follow the contours of the surface. To do this, you must
use Surface based falloff.

To make the ears pointy

1 Double-click the Move Tool in the Toolbox.

2 In the Soft Selection section, set the Falloff mode to Surface.

3 Tumble the model so that you have a clear view of the left ear.


5 Select a vertex on the tip of the ear.

Sculpting with Surface based falloff | 141

6 Hold the ‘b’ key on your keyboard and drag the mouse left or right to
adjust the Falloff radius so that it encompasses the top half of the ear.

7 Use the manipulators to pull the ear until it’s pointed.

Surface based falloff ensures that only the ear is affected by your
transformation. If you were using Volume based falloff, parts of the head
would also be moved along with the ear.


8 Select the Scale Tool and scale the ears along the x axis so they become
thinner.

9 Select the Move Tool again and pull the pointy end of the ears away from
the head.

Selecting with Drag select
In addition to marquee selecting sets of components, you can also select them
by dragging over them with the mouse. This is similar to the way that the
Paint Selection Tool works.

To make the eyes sockets more pronounced

1 Double-click the Select Tool in the Toolbox.

2 In the Common Selection Options section, turn on Drag.
The mouse cursor turns into a brush cursor.

3 Beneath the Drag option, turn on Camera based selection.


Selecting with Drag select | 143


5 On one side of the mesh, drag the mouse around the eye socket, beneath
the eyebrow until you’ve covered a small area around the eye.
You may find it easier to temporarily disable Soft Select to get a better
view of what you are selecting. You can quickly toggle Soft Select on and
off by pressing the ‘b’ key on your keyboard.

6 With Soft Select on, hold the ‘b’ key and drag the mouse to resize the
falloff area so it covers only the eye sockets.

7 Select the Move Tool in the Toolbox and pull the z axis manipulator
toward the head.


The eye sockets are pulled in so that both the eyebrow line, bridge of the
nose, and cheeks are better accented.

8 Press the b key to turn Soft Select off.

9 Right-click the head and select Object Mode from the marking menu.

10 Select the two eyes and move them back along the z axis so they fit into
the eye sockets again.

Selecting with Drag select | 145

11 Set the selection mode back to Marquee.

Adjusting the Seam tolerance
You can use the seam tolerance to fatten the nose at the end.


2 Select a vertex on the left side of the tip of the nose.

3 Press the ‘b’ key to turn Soft Select on.

4 Hold the ‘b’ key and move the mouse left or right to resize the Falloff
radius so it only encompasses the tip of the nose.

5 Select the Move Tool by double-clicking it in the Toolbox.

6 In the Tool Settings Editor, in the Reflection Settings section, click the
Reset button.

7 Set the Seam Tolerance to 5.
The Seam Tolerance controls the falloff around the seam. By increasing
the number, you ensure that the vertices at the tip of the nose spread
evenly.

8 Move the vertex away from the reflection line along the x axis to widen
the end of the nose.

Now you can unhide the hat layer to finish off the goblin.


To unhide the hat

➤ Open the Channel Box and click the first empty box in the hat layer.

Beyond the lesson
In this lesson, you learned how to:

■ Activate Soft Select and adjust the Falloff radius.

■ Transform components with Soft Selection.

■ Use Camera based selection.

■ Select components using reflection.

■ Use both surface based and volume based falloff.

■ Use Drag select.

■ Adjust the Seam tolerance.


There are some additional Soft Selection options which are not described in
this lesson:

■ You can change the shape of the falloff curve in the Soft Selection tool
settings either by adjusting the Falloff curve graph or by selecting any of
the Curve presets below it.

You can also save a custom Falloff curve to the Curve presets. For more
information, see Change the shape of the falloff area.


NURBS Modeling
4
Introduction
NURBS (Non-Uniform Rational B-splines) use a method of mathematically
describing curves and surfaces that are well suited to 3D applications. NURBS
are characterized by the smooth organic forms they produce.
NURBS surfaces can be quickly modeled and edited using a variety of techniques.
NURBS surfaces are created using one or more NURBS curves that define the
profile of the shape that you want for a surface, and then using a specific
construction method to create the finished surface.
NURBS curves and surfaces have many applications and are the preferred surface
type for industrial and automotive designers where smooth forms with minimal
data are required to define a particular form. NURBS curves are ideal for defining
a smooth motion path for an animated object. With NURBS, a surface can be
modeled and then converted to a poly mesh.
In this chapter, you will learn some basic techniques for working with NURBS
curves and surfaces in Maya. This chapter includes these lessons:

■ Lesson 1 Revolving a curve to create a surface: Introduction on page 150

■ Lesson 2 Sculpting a NURBS surface: Introduction on page 156

■ Lesson 3 Lofting curves to create a surface: Introduction on page 171

To ensure the lessons work as described, do these steps before beginning:

1 Select File > New Scene to create a new scene before starting each lesson.

149

2 Make sure the Construction History icon (below the menu bar) is on:

. (If it is turned off, it has a large X across it.)


4 Select the Surfaces menu set. Unless otherwise noted, the directions in
this chapter for making menu selections assume you’ve already selected
the Surfaces menu set.

Creation option for primitives is turned off by selecting Create > NURBS
Primitives > Interactive Creation. That is, ensure a check mark does not appear
beside the menu item.

5 Make sure that Soft Selection is turned off by opening the Attribute Editor
with the Select Tool active and unchecking the box marked Soft Select.

Lesson 1: Revolving a curve to create a surface

Introduction

A simple technique for creating NURBS surfaces is to create a curve for the
profile of your desired form and then create a surface using one of the various
NURBS surfacing tools available in Maya. In this lesson, you create an egg
holder using NURBS curves and the Revolve Tool.

150 | Chapter 4 NURBS Modeling


■ Create a NURBS curve using the control vertices (CV) creation technique.

■ Use the grid for visual reference when modeling.

■ Determine the start and end points for a NURBS curve and its direction.

■ Create a revolved NURBS surface using the Revolve tool.

■ Change the display shading smoothness for a NURBS surface.

■ Edit a NURBS surface by editing its initial profile curve when it is linked
to the surface by construction history.

Creating a profile curve
Revolve is a common modeling technique similar to shaping a vase on a
spinning potter’s wheel. You must first create a profile curve in an orthographic
view and use the Revolve Tool to create a surface.

To create a profile curve

1 Make sure you’ve done the steps in Preparing for the lessons on page 149.

2 Select Panels > Layouts > Four Panes so you can see multiple views of the
scene.

3 Select Create > CV Curve Tool.
This is the most commonly used tool for drawing curves.

Creating a profile curve | 151

4 In the front view, click the numbered positions as shown in the figure.
Make sure the first and last positions are on the grid’s Y-axis (the thickest
vertical line of the front view’s grid).
Also, click three times in the same spot for positions 9, 10, and 11. This
is necessary to create a sharp point or corner in the curve.
To change the position of the most recent point clicked, you can
middle-mouse drag it.

5 (Windows and Linux) After you click position 13, press Enter to complete
the curve’s creation.
(Mac OS X) Press Return to complete the curve’s creation.
The points you clicked in the scene view become the control vertices
(CVs) of the completed curve. CVs are points you manipulate to alter the
shape of a curve (or surface). These points often lie away from the curve.
It takes a little practice to be able to predict exactly where a curve will be
positioned when you click CV positions with the CV Curve Tool. Once
you’ve learned the technique, you’ll be able to create and edit curves with
graceful symmetry. By default, you must click at least four points to create
a curve with the CV Curve Tool.
For some advanced operations in Maya, you need to know the meaning
of the start of a curve and the curve direction. The start of a curve is the first
CV you create when you draw the curve. It is indicated by a small hollow


box at the first CV, visible as you create the curve. Curve direction is
shown on the second CV after the start of the curve, indicated by a small
u icon as you create the curve.

Creating a revolve surface
With the Revolve surface tool, a curve is rotated about an axis to create a
surface. The user can define the axis of revolution.

To create a revolve surface

1 With the curve selected, select Surfaces > Revolve. This creates the egg
holder surface from the revolved profile curve. Examine the results in
the perspective view.
Maya does not delete the profile curve. In a subsequent step, you’ll edit
the profile curve to alter the shape of the surface.

2 Select the surface and rename it Eggholder in the Channel Box.

3 With the pointer in the perspective view, press 5 (for Shading > Smooth
Shade All).
This displays the egg holder as a shaded surface rather than a wireframe
in the perspective view.
Press 1, 2, and 3 to switch between the different degrees of display
smoothness. (These hotkeys correspond to the menu items under Display
> NURBS menu item (Rough/Medium/Fine).
The finer the smoothness, the greater the impact is on interactive
performance when you work with complex models.
The smoothness display only affects the scene view. Rendered images
display with high quality smoothness regardless of this setting.

Editing a revolve surface
After you create a surface from a revolved curve, you can reshape the original
creation curve to reshape the surface. This is possible because Maya’s
Construction History feature was turned on before you did the revolve
operation.
Selecting the original creation curve can be challenging when it is situated
amongst other existing curves and surfaces. The Outliner is an editor that is

Creating a revolve surface | 153

useful for quickly examining the structure and components of a scene. The
Outliner is also useful for selecting objects in situations like this.

To edit a surface with construction history

1 Select In the main menu bar:.
The Outliner appears and displays a list of the items in the scene.

2 In the Outliner, select the curve you revolved (curve1) by clicking on its
name in the list.
The curve becomes highlighted in the scene views.

3 In the front view, right-click and select Control Vertex from the marking
menu.
The CVs for the curve appear.

4 Select and move one or more CVs to adjust the curve shape as desired.
If you have trouble selecting one of the CVs in the front view, select it
in the perspective view after dollying and tumbling the camera as
necessary.
This modifies the shape of the egg holder because it is linked to the shape
of the curve by its construction history.


5 If desired, save the scene for future review.

6 Close the Outliner window.

Beyond the lesson
In this lesson you were introduced to a few basic techniques related to NURBS
modeling:

■ Revolving a curve is the easiest way to create surfaces with radially
symmetrical forms— wheels, vases, glasses, pillars, and so on.

■ NURBS surfaces are webs of interconnected curves. The creation curves are
used to create and subsequently modify the surfaces if required.

■ Proficiency at drawing and editing curves is an important part of NURBS
modeling.

■ The grid is a useful aid for constructing and modifying curves.

Some additional points you should know are:

■ You cannot render curves, so your work with them is always an adjunct
to creating and editing surfaces.

■ Besides moving a curve’s CVs to alter its shape, you can cut, attach, extend,
close, and smooth curves.

■ After you create a surface from a revolved curve, you can edit the surface
at a component level by moving CVs or scaling groups of CVs on that
surface to customize the shape of the surface. (You will need to turn off
construction history in order to do this.)


Lesson 2: Sculpting a NURBS surface

Introduction

In addition to creating NURBS surfaces using curves, you can edit and sculpt
surfaces and primitive objects in Maya using the Sculpt Geometry Tool.
The Sculpt Geometry Tool allows you to interactively push or pull on the
surface regions to create areas that are embossed or in relief in relation to the
surface.
In this lesson, you learn some of the basic concepts of these tools by sculpting
a cartoon face and head from a NURBS primitive sphere using the Sculpt
Geometry Tool.
In this lesson you learn:

■ Basic sculpting operations (push, pull, smooth, relax and erase) with the
Sculpt Geometry Tool.

■ How the density of isoparametric lines affects the surface detail possible
when sculpting.

■ How to increase the surface subdivisions on a NURBS surface to aid with
surface sculpting.

■ How to change the brush radius for the Sculpt Geometry Tool.

■ How Opacity and Max Displacement affect the sculpting operations.

■ How to import geometry from a pre-existing file into your current scene.


Preparing a surface for sculpting
Because a head is roughly spherical, you can create a primitive sphere as a
quick starting point for creating a head and face.

To prepare a sphere for sculpting


2 Select Create > NURBS Primitives > Sphere > . In the options window,
select Edit > Reset Settings, enter the following values, then click the
Create button:
■ Radius: 6



The Radius sets the sphere’s size in grid units. A value of 6 creates a sphere
big enough to use the grid for size comparison.
The Number of Sections sets the number of vertical curves, called isoparms,
for the sphere. Isoparms show the outline of the surface shape. The more
isoparms a surface has, the more CVs it has. (By default, CVs are not
displayed.) More CVs means better precision as you edit a surface. The
Number of Spans sets the number of horizontal isoparms.
The drawback to having too many CVs is that you’ll have a harder time
making smooth shape changes to broad regions. Lots of CVs also means
slower processing time as you work with the surface. It’s best to make
surfaces with as few CVs as necessary.
We chose 30 Sections and Spans for this lesson because experience has
shown that this allows adequate facial subtlety without slowing Maya
operation on a workstation of modest processing power.

Preparing a surface for sculpting | 157

NOTE In wireframe display mode, if you select Display > NURBS > Fine or
Medium, more isoparms appear than there are actual spans and sections.
The surface is visually displayed with extra precision, but the extra isoparms
have no CVs and cannot be edited.

3 Name the sphere Egghead.

4 Rotate the sphere 90 degrees on its side (Rotate Z: 90). This positions the
sphere’s CVs well for modeling a simple head and face. You’ll learn why
later in this lesson.

5 To give Egghead an oval shape, set the ScaleX for the sphere to 1.3 or so.
Optionally, you can move Egghead above the grid so the grid doesn’t
interfere with your view of Egghead. Also, position the perspective view
so the Z-axis of the View Axis points toward you.

Modifying the surface material for easier viewing
Because you will do subtle surface modeling in this lesson, it’s helpful to
display Egghead with bright highlights so you can clearly see the effects of
the changes you make. In the next steps, you’ll assign a Blinn material to
Egghead to give its surface bright highlights. The steps have no explanations,
as the shading subject matter is the focus of a later lesson.

To assign a Blinn surface material

1 With Egghead selected, press 5 to display the surface with smooth shading.

2 Right-click Egghead and select Assign New Material > Blinn.
The Attribute Editor will immediately be displayed for the Blinn material.

3 Drag the Color attribute slider roughly 3/4 of the way to the right, set
Eccentricity to 0, and close the window.


Basic sculpting techniques
In the next steps, you’ll become familiar with features of the Sculpt Geometry
Tool. With this tool, you use your mouse or stylus to push, pull, or smooth a
surface’s shape without selecting or displaying CVs. After you practice sculpting
the surface, you’ll erase your practice strokes then begin sculpting Egghead’s
features.

To practice sculpting using basic sculpting operations

1 With Egghead selected, select Edit NURBS > Sculpt Geometry Tool >
. In the Tool Settings window, click Reset Tool, and make sure the Sculpt
parameters are displayed.
In the Sculpt Parameters section, there are four operations for sculpting
a surface. Each affects the region of the surface where you drag (stroke)
your mouse or stylus relative to the surface normals:

■ The Push operation depresses the surface in the region of the stroke.

■ The Pull operation raises the surface in the region of the stroke.

■ The Smooth operation diminishes bumps or ridges where you drag.

Smoothing works by averaging the position of all features within the
brush radius with all other nearby features.
■ The Relax operation paints over bumps to relax most of the out of
place surface features.

Basic sculpting techniques | 159

Unlike smoothing, Relax works by only averaging the largest surface
anomalies so that the overall shape is maintained.
■ The Erase operation eliminates the effects of the other four operations.

The Erase operation works up to the last time you saved the scene or
clicked the Update button to the right of Erase Surface.

2 Experiment with each of the five operations on the surface. Don’t be
concerned with the results. Just become familiar with the response to
your mouse strokes.
By default, Push and Pull strokes deform the surface in a direction normal
(perpendicular) to the surface. To create the resulting deformation more
accurately, use Push and Pull strokes in a front, side, or top view while
examining the results in a separate perspective view. Tumble the
perspective view regularly for the best visual feedback.
When you position the mouse pointer on the surface, it changes to a red
sculpt icon that shows an abbreviation for the name of the operation
you are performing. For instance, Ps stands for Push.
The red icon also displays the radius of the region affected by the stroke.
The Radius(U) value changes the radius.

3 Select the Erase operation and click the Flood button. This erases all your
changes.

4 Select the Pull operation and enter a Radius(U) of 0.25, then drag between
a pair of horizontal isoparms without crossing either.
This has no effect because the stroke radius didn’t make contact with the
CVs of either isoparm. Regardless of which operation you use, only CVs
are affected by the strokes.

5 Change the Radius(U) to 2 and repeat the prior strokes.


The strokes alter the surface because the radius overlaps the CVs. As this
example shows, you need to make sure the radius is big enough to
influence the desired CVs. It’s common to change the radius many times
during a sculpting session.
If you prefer to affect a small region without increasing the radius, you
can add CVs to the region by inserting more isoparms. You’ll do this later
in the lesson.

6 Flood-erase the changes to the surface as you did previously.

7 Select the Pull operation with a Radius(U) of 0.5. Drag along a vertical
isoparm. For comparison, drag along a horizontal isoparm.

The vertical stroke creates a thinner ridge than the horizontal stroke
because the density of vertical isoparms is greater. The number of
underlying CVs and their positioning affects the outcome of your strokes.

TIP You can alternatively adjust the radius of the Sculpt Geometry Tool using
a Hotkey. Move the tool over the object, press and hold the b Hotkey and
drag left or right. The circle on the object with numerical radius value
represents the size of your tool. Stroke on the object to try out a new size.

Basic sculpting techniques | 161

8 Flood-erase the changes to the surface as you did previously.

9 Rotate the camera view so the X axis of the View Axis points toward you.
Draw a vertical Pull stroke again.

As your stroke nears the center of Egghead, a kink occurs. It’s challenging
to alter a surface symmetrically in a region where many isoparms converge
at a single point, called a pole. Always consider the position of isoparms
as you sculpt a surface. In general, sculpt where isoparms are evenly,
regularly distributed.

10 Erase all changes again, then reposition the camera view so the Z-axis of
the View Axis points toward you.

TIP If the Sculpt Geometry Tool is selected but not the surface you want to
work on, right-click the surface and select Select from the marking menu.

Additional sculpting techniques
Now that you’ve learned the basic features, you’ll learn other useful techniques
before starting to model the facial features.

To practice additional sculpting techniques

1 In the Sculpt Parameter section of the Sculpt Geometry Tool, set Maxs
Displacement to 2.


2 Draw a vertical Pull stroke.

3 Change the Max Displacement to 1.

4 Draw another vertical stroke nearby.
The Max Displacement sets the maximum distance the surface’s CVs are
pushed (or pulled) with a single stroke.

5 Erase the changes to the surface.

6 Set Max Displacement to 2.

7 Draw a vertical Pull stroke.

8 Set the Opacity from the default value of 1 to a value of 0.2.

9 Draw another vertical stroke nearby.
One ridge is higher than the other. The Opacity value scales the influence
of Max Displacement. For example, with an Opacity of 0.2, each stroke
has only roughly 0.2 times the effect of the Max Displacement setting.
It’s generally best to use a low Opacity value as you Push or Pull. You can
increase the deformation gradually with multiple strokes.
If you want to affect only a small region of a surface, use your mouse to
click rather than stroke the region. If the Radius(U) and Opacity of the
brush is small, you might need to click the nearest intersection point of
two isoparms.

10 With Opacity set to 1, erase all changes to the surface again.

Additional sculpting techniques | 163

TIP Consider using an electronic tablet with pen stylus. A pen stylus is more
natural for stroking surface changes as it feels like a pen. With a stylus, you
can set an option that causes the Radius or Opacity to vary with stylus
pressure. For example, you can have heavy strokes create a bigger Radius
than light strokes.
To do this, display the Stroke tab of the Sculpt Geometry Tool. For Stylus
Pressure, select Opacity, Radius, or Both. Radius is a common choice. If you
select Radius, the Radius(U) value on the Sculpt tab sets the maximum radius,
while Radius(L) is the minimum. Explore various settings.
If you use a mouse, set the Stylus Pressure to None. The Radius(U) sets a fixed
radius. Radius(L) is ignored.

Sculpting a nose
Now you’ll begin sculpting Egghead’s face, starting with a simple nose.

To sculpt a nose for the character

1 Position the perspective view so the Z-axis of the View Axis points toward
you.

2 Reset the Sculpt Geometry tool.

3 Select the Pull operation and set the following options:
Radius(U): 1Opacity: 0.2

4 Select the Gaussian brush profile setting so your strokes have a soft, faded
edge:

5 Above the midpoint of Egghead, stroke vertically downward from the
top of the nose to the tip—about the distance between two horizontal
isoparms (see the following illustration). Use several strokes to build up
the bridge of the nose. Create nostrils by stroking horizontally to the
right of the tip of the nose a few times, then to the left of the tip a few
times.


To build up a small area, position the stroke icon there and click the
mouse rather than drag. Tumble the view to examine your results after
each stroke or click.

If the strokes create a bumpy surface, turn on the Smooth operation and
click Flood once or twice to smooth all strokes on the surface. Because
Opacity is 0.2, the Smooth operation is subtle. Alternatively, you can
smooth a selected region by stroking just that area. It’s common to smooth
a surface regularly while using pull and push strokes.
Because there are relatively few isoparms in the nose area, you can only
create a simple nose that’s broad and rounded. If you want to create
sharper features, for instance, depressed nostrils or sharp ridges, you’ll
need to insert isoparms in the nose region. Sculpting a mouth on page
167 describes how to insert isoparms.

Sculpting eye sockets
Eye sockets provide an inset and backdrop for eyes.

To sculpt eye sockets for the character

1 Select the Push operation.

2 Leave other settings the same as for the nose.

3 To make a pair of identical eye sockets, display the Stroke settings in the
Tool Settings window and turn on Reflection.

4 Set the Reflection Axis to X and then position the sculpt icon on Egghead.
A pair of identical Push icons appears on Egghead.

5 Adjust the positioning as desired for the eye sockets. Click the mouse
many times in the desired location.

Sculpting eye sockets | 165

NOTE If the Reflection setting does not push or pull in the same direction
on either side of a NURBS surface you can adjust the Reference Vector to alter
the direction of these operations. In the Sculpt Parameters section select UV
Vector and turn on Enable UV Vector Adjustment. Click and drag the mouse
left or right to adjust the direction of the U and V reference vectors.

Sculpting eyebrows
Eyebrows help define how stern or pleasant a face appears.

To sculpt eyebrows for the character

1 Select the Pull operation. Use the same option settings as for the eye
sockets, including Reflection.

2 Position the sculpt icons above the eyes and draw horizontal strokes. If
necessary, click positions where you need to build up the eyebrows.
Smooth the eyebrows as necessary.


Sculpting a mouth
With the 30 Sections and 30 Spans specified for the original sphere in this
lesson, the large space between isoparms in the mouth region makes it
impossible to create a subtle shape for the lips.

To overcome this problem, you must insert isoparms in the mouth region
before sculpting.

To insert additional isoparms

1 Right-click Egghead and select Isoparm from the marking menu.

2 From the Toolbox, choose the Select Tool.

3 Click the horizontal isoparm below the nose and shift-click the next two
below it so they become yellow.

Sculpting a mouth | 167

4 Select Edit NURBS > Insert Isoparms > . In the options window, turn
on Between Selections, enter a value of 2 for # Isoparms to Insert, then
click Insert.

This inserts two extra isoparms between each pair of selected isoparms,
for a total of four extra isoparms. This provides enough CVs to create
subtlety in the mouth.
You might want to add vertical isoparms at the lips in a similar way. The
extra isoparms would also be useful if you were to later enhance the shape
of the nose. Insert isoparms only where needed. More isoparms means
slower processing speed.
In any case, do not change the number of isoparms by editing the original
number of Sections and Spans in the makeNurbSphere history node. This
will reshape your sculpted surface undesirably.

To sculpt a mouth for the character

1 Select the Sculpt Geometry Tool again.

2 Select the Push operation. Enter 0.2 for Radius(U). In the Stroke tab, make
sure Reflection is turned on.

3 Starting at the center of the area appropriate for the indentation between
the lips, stroke outward from the center. It’s best to start the stroke with
the dual icons on top of one another (in other words, only one icon is
displayed).

4 Select the Pull operation and set the Radius(U) to 0.3. Using a similar
technique as for the prior step, stroke the upper lip. Repeat for the lower
lip.


NOTE It might be easier to push or pull the lips with the Ref. Vector set to
Z Axis. This moves the region you stroke in the world Z-Axis direction. The
default Normal setting moves the region in a direction normal (perpendicular)
to the surface. Because the normal direction on a lip might be up, down, or
straight out, depending on the part of the lip you stroke, there’s more
possibility of undesired results when you use the Normal setting.

Sculpting other facial features
You can now optionally add other facial features. Consider these tips:

■ For facial features such as the chin, cheeks, and forehead, use a Radius(U)
larger than 1 and start with a Maximum Displacement between 0.5 and
1.

■ Insert isoparms wherever you want to add extra detail with the Sculpt
Geometry Tool.

■ To create eyeballs for the sockets, create a sphere and scale it as necessary
to fit the socket. You might want to increase the eyeball’s Scale X value to
make it oblong. To duplicate the eyeball, and make a mirrored copy of the
original you’ll first need to set the pivot point for the eyeball to be at the
origin 0, 0, 0 using the following steps. With the sphere selected, press the
Insert (Windows and Linux) or Home (Mac OS X) key so that the sphere’s
pivot point is displayed. Next move the pivot point to the origin using the
X hotkey so that the pivot snaps to the grid at 0, 0, 0. Select Insert (Home)
to turn off the pivot point display. Finally, use Edit > Duplicate Special >
and set the Scale setting to -1, 1, 1. This makes the new eyeball a
mirrored duplicate of the original on the opposite side of Egghead’s face.
Position the eyeballs in the sockets. Parent the eyeballs to Egghead.

Sculpting other facial features | 169

■ To create simple, unadorned ears, you can create, scale, and squash a
sphere. Create ridges and valleys by pulling CVs or by using the Sculpt
Geometry Tool. Duplicate the ear by first setting its pivot point to the
origin and with the Scale option set to -1, 1, 1. Parent the ears to Egghead.

To import existing models into your scene:

1 If you saved the Eggholder scene in the prior lesson, you can import the
egg holder into this Egghead scene, then position Egghead into the egg
holder.
To import the egg holder into the Egghead scene, use File > Import and
select the name of the scene that contains Eggholder.
Importing a scene imports all objects from that scene.

2 Increase (or decrease) the scale of the egg holder (or Egghead) as necessary
for a snug fit.

Beyond the lesson
In this lesson you were introduced to a few basic techniques related to sculpting
surfaces:

■ The Sculpt Geometry Tool is indispensable for quickly shaping a variety
of surfaces. As you do your own projects, pay special attention to the
position and density of isoparms before you begin sculpting.

■ Isoparms converge at a single point (the pole). Pole regions of a primitive
or surface are hard to sculpt so it’s best to avoid using the Sculpt Geometry
Tool there. For example, when you created the original sphere in this
lesson, you rotated it 90 degrees around its Z-axis. Because of the rotation,
ears for the head would need to be modeled via a different technique (for
example, you could model a pair of ears and parent them to the head).


■ The density and orientation of isoparms on a surface affects the results
with the Sculpt Geometry Tool. As you gain NURBS modeling experience,
you’ll learn how to use the density and orientation of isoparms to your
advantage.

■ Primitive objects are useful objects for sculpting in many cases. After you
create a primitive, you typically sculpt, scale, trim, or otherwise alter the
object into a more complex shape. Though most primitives are surfaces
rather than curves, they still derive their shape from curves.

In general, a sphere makes a convenient foundation for creating a simple
head, but it’s not ideal if you plan to animate an expressive, talking head.
Many 3D artists start with a cylinder or a lofted surface. The procedures
for doing this are more complex than starting with a sphere and are beyond
the scope of this lesson.

Lesson 3: Lofting curves to create a surface

Introduction

Lesson 3: Lofting curves to create a surface | 171

Another method for creating NURBS surfaces is to loft a series of curves that
define the cross section of your desired surface form. Lofting a surface works
like stretching a skin over each of the cross sections to create the final surface.
In this lesson, you learn additional NURBS surfacing techniques by using the
Loft tool to create the body of a salt shaker. You will also create the cap for
the salt shaker by modifying the shape of a primitive sphere.

■ Modify the outline of a circle primitive by editing the position of its CVs.

■ Use the magnet snap feature.

■ Loft cross section curves to create a NURBS surface using the Loft tool.

■ Edit the form of an existing primitive object by moving its CVs.

■ Parent one object to another using the Outliner.

Creating profile curves for a surface
You begin the lesson by creating a pair of profile curves. You then create
several copies of these curves to form the skeletal contours of the salt shaker’s
surface.

To create profile curves for the salt shaker’s body


2 Select Create > NURBS Primitives > Circle > . In the options window,
select Edit > Reset Settings, enter the following values, then click the
Apply button:
■ Radius: 4


The Radius sets the size of the circle in grid units. A value of 4 creates a
circle with enough size so that you can use the grid for convenient size
comparison.
The Number of Sections sets the number of CVs in the circle. By using
24 CVs, you can create a circle with the subtle contours required in this
lesson. Display the CVs of the circle to see the 24 CVs.


A circle is a curve that loops back on itself. The CVs work the same way
as for any other curve. The more CVs you create for a curve or surface,
the more detail you can give its shape.
The drawback to using many CVs is that you’ll have a harder time making
smooth shape changes to broad regions. Also, more CVs means slower
processing time as you work with the curve. It’s best to make curves with
as few CVs as necessary. With experience, you’ll learn how many CVs to
use in a situation.

3 Create another circle, this time with these options:
■ Radius: 2


This creates a smaller circle inside the first circle as shown below.

4 Change the scene view so you can see the circles from the top view.

5 Right-click the inner circle and select Control Vertex from the marking
menu. Repeat for the outer circle.

6 Turn on Snap to Points (below the menu bar).

7 As shown in the following figure, move CVs from the outer circle to the
corresponding inner circle positions. As you drag a CV near its destination,
the Snap to Points mode causes the CV to jump to the exact CV position.

Creating profile curves for a surface | 173

8 Turn off Snap to Points. Turn off the display of CVs for both circles by
right-clicking on the circles and selecting Object Mode from the marking
menu.

Duplicating curves
In the next steps, you’ll create several copies of the previously created circles
(also called curves) to form the skeletal contours of the salt shaker’s surface.

To duplicate curves for the lofted surface

1 Right-click the outer curve and choose Select from the marking menu.

2 Select Edit > Duplicate Special > . In the options window, select Edit
> Reset Settings, enter the following values, then click Duplicate Special:

■ Translate: 0 3 0

■ Scale: 0.93 1 0.93



This creates four copies of the original curve, each translated three units
above the last, and each scaled smaller than the last.

3 Select the inner circle and then move it to 0, 13, 0 by entering these
translate values in the Channel Box. Increase its Scale attributes to 1.33,
1.33, 1.33..

4 Use Edit > Duplicate Special > with the following options:

■ Scale: 1.05 1 1.05


This creates three copies of the circle, each translated two units above
the last, and each bigger than the last.

Lofting a surface
You’ve created a total of nine curves. In the next steps, you loft these curves
into a surface that matches the contours of their perimeters. Above the
midpoint of the surface, the shape will change from a flower-shaped perimeter
to a circular perimeter.

To loft a surface for the salt shaker’s body

1 Starting from the bottom circle, and working towards the top, shift-select
all the circles, one at a time.
The order of selection is important when shift-selecting for a loft
operation. You must start with the bottom flower-shaped circle and end
with the top circular-shaped circle. Alternatively, you can drag a selection
box around the circles. The surface to be lofted will be based on the
selection order of the curves.

Lofting a surface | 175

2 Select Surfaces > Loft.
This creates the salt shaker’s body.

3 Name the surface shakerBody.

4 Press 5 to display the view with smooth shading.

NOTE Many of the surface creation tools also have the option of creating
polygon or subdivision surface versions of a surface with the same input
curves. You do this by setting the appropriate Output Geometry option for
that particular surface tool.

Modifying a primitive object
To create a simple cap for the salt shaker, you’ll create a sphere, alter its shape,
and position it above the body.

To create and modify a sphere for the salt shaker’s cap

1 Select Create > NURBS Primitives > Sphere > . In the options window,
select Edit > Reset Settings, and click the Create button. Maya puts the
sphere at the origin, its display currently obstructed by the salt shaker
body.

2 Name the sphere Cap.

3 Move the cap to the top of the body.


4 Scale the cap size so that its diameter fits snugly at the top of the body.

5 Adjust the cap’s position as desired.

6 In a side view, make sure that the cap is displayed as a wireframe.

7 Right-click on the Cap and choose Control Vertex from the marking
menu.

8 Select the top row of CVs and drag them down until the top of the cap
is flattened:

Check that the bottom half of the cap isn’t poking through the visible
surface of the body. You can scale the bottom CVs inward to avoid this
problem.

Modifying a primitive object | 177

Using the Outliner to parent objects
The Outliner is an editor that is useful for quickly examining the structure
and components of a scene. You can use the Outliner to quickly parent objects
to create an object hierarchy.

To parent an object using the Outliner

1 From the main menu, select In the main menu bar:.
The Outliner window is displayed. A list of the scene’s components is
listed in the Outliner.

2 In the Outliner, click on the word Cap to select it.

3 Parent the cap to the body by middle-mouse dragging Cap onto
shakerBody1 in the Outliner.


By parenting the objects, you can move, rotate, or scale the cap and the
body as a single entity by selecting only the body.
Notice that the salt shaker displays horizontal curves that wrap around
the body. The curves are the original circles you used to loft the surface.
Because these curves are part of the surface’s construction history, you
can alter their shape if you decide you want to alter the shape of the body
and the body will update based on the construction history.
If you prefer not to see the curves in the scene view, select the curves and
select Hide Selection. The curves won’t appear when you render an image
of the scene. Maya displays only surfaces, not curves, in rendered images.

Beyond the lesson
In this lesson you were introduced to the basic techniques related to lofting
curves to create NURBS surfaces:

■ You made a salt shaker with two surfaces: a body made from lofted curves
and a cap made from an altered sphere. An advantage of creating a separate
surface for the cap and base is that you can easily give each a different
color or texture, for example, one chrome and the other marble. Another
advantage of creating a separate cap is that you can animate the object
separately. For example, you could choose to animate the cap unscrewing
from the shakerBody.

■ You used a Loft operation rather than a Revolve operation to create the
body. The vertical corrugations on the surface would be impossible to
create by revolving a curve.

■ You can alter the position of the profile curves and the shape of the shaker
will update because of the construction history. If you’re certain you won’t
change the body’s shape by editing the shape of the lofted curves, you can
delete the body’s construction history to quicken Maya’s processing of
your interaction with the surface. (For a surface as simple as the salt shaker,
deleting the history won’t boost processing much.)

■ There are many other useful tools for creating and editing surfaces. For a
glimpse of the possibilities, take a look at the Surfaces menu and the Edit
NURBS menu.

presented in this lesson, please refer to the Maya Help.


Subdivision Surfaces
5
Introduction
Subdivision surfaces are a hybrid surface type that possess characteristics of both
NURBS and polygonal surfaces as well as other features not offered by the other
surface types. Like NURBS, subdivision surfaces are capable of producing smooth
organic forms and can be shaped using relatively few control vertices. Like
polygonal surfaces, subdivision surfaces let you extrude specific areas and create
additional detail in your surfaces. You do this by working at different levels of
detail on the subdivision surface and switching between the levels when
necessary. With a subdivision surface you can build a smooth organic object
from a single primitive and not be concerned about attaching or stitching the
various surfaces together as you would for a NURBS surface.


1 Review the Polygon Modeling lesson in this guide. Knowledge of polygonal
modeling tools is essential to becoming proficient in subdivision surface
modeling.

2 If you have not already done so, copy the GettingStarted folder from its
installation location to your projects directory. Then, set the
GettingStarted directory as your Maya project. For more information, see
Copying and setting the Maya project on page 25.

3 Create a new scene.

4 Select the Surfaces menu set.

181


6 In the Preferences window, select Subdivs from the Categories list to
display the subdivision surface preferences.

7 In the Subdivision Surfaces Component Display settings, set the
Component display to Numbers, then click Save.
Setting the subdivision components to display as numbers allows you to
see the subdivision surface level directly on the surface.



Lesson 1: Modeling a subdivision surface

Introduction
In this lesson you learn some of the basic tools for working with subdivision
surfaces as you model a human character's hand.


■ Convert a polygon surface to a subdivision surface.

■ Work with subdivision surfaces in Polygon Proxy Mode.

■ Split subdivision faces to create areas for more detail in a model.

■ Extrude the split faces to create fingers on the hand.

■ Work with subdivision surfaces in Standard Mode.

■ Change the Display Level when working in Standard Mode.

182 | Chapter 5 Subdivision Surfaces

■ Add more detail to subdivision surface models using Refine Selected
Components.

■ Create a crease along a vertex edge.

Creating a subdivision surface
You begin the lesson by creating a polygonal cube. You’ll convert this cube
to a subdivision surface that will be the foundation of the hand. The reason
for starting with a polygonal surface and converting it to a subdivision surface
is that you can thereafter edit the object’s shape with more versatility: you
can edit with subdivision surface tools and polygonal tools.

To create a polygon cube

➤ Select Create > Polygon Primitives > Cube > . In the options window,
select Edit > Reset Settings. Then enter the following values and click the
Create button.
■ Width: 8

■ Height: 2.5

■ Depth: 8

The resulting polygonal cube is roughly proportional to the palm of a
hand.

To convert a polygonal cube to a subdivision surface

1 To convert the polygonal cube to a subdivision surface, select Modify >
Convert > NURBS to Subdiv, Polygons to Subdiv.

Creating a subdivision surface | 183

2 Press 3 on your keyboard (to select Display > Subdiv Surfaces > Fine).

3 Press 5 (to select Shading > Smooth Shade All).

With the smoothness set to Fine, you can see that the conversion to a
subdivision surface creates a rounded, smooth shape. By pressing 3, the
subdivision surface is displayed more precisely in the scene view. This
gives a closer approximation of what the surface will look like when you
create a rendered image of the scene.
As an alternative, you could have chosen a Rough smoothness (press 1)
so that Maya processes your editing changes in the scene view more
quickly. Regardless of the smoothness in the scene view, surfaces always
are displayed precisely in rendered images of the scene.

To display a subdivision surface in polygon proxy mode

➤ Select Subdiv Surfaces > Polygon Proxy Mode.


The wireframe cube looks the same as the original polygonal cube. The
new cube is called a polyToSubd1 for the subdivision surface as a result of
the conversion. Rename it LeftHand. You can use polygonal modeling
tools to edit the shape of the polygonal proxy, which indirectly alters
the shape of the subdivision surface. Unlike working with an actual
polygonal object, your modifications result in perfectly smooth surface
changes rather than faceted changes.

Splitting a surface in polygon proxy mode
Next, you use polygonal modeling techniques to split a face into multiple
faces to be extruded as fingers.

To split the polygon face into multiple faces


2 With LeftHand still selected, select Edit Mesh > Split Polygon Tool >
. In the tool settings window click the Reset Tool button.
You’ll use this tool to split the front face of the proxy into several faces
to be extruded into fingers.

3 In the front view, click the point on the top edge as shown in the
following figure, then click the corresponding point directly below it on
the bottom edge. If the line between the points isn’t perfectly straight,
use the middle mouse to drag the second point to the correct position.
Press Enter (Windows and Linux) or Return (Mac OS X).

Splitting a surface in polygon proxy mode | 185

This splits the face into two faces. You’ll extrude the left face into a finger
later.

4 Repeat the preceding two steps as necessary to split the face as follows:

Notice how splitting the face into multiple faces alters the shape of the
subdivision surface. The front part of the subdivision surface now
resembles the proxy shape more. If you were to split the front face several
more times, especially near the outer edges, the subdivision surface would
sharpen and resemble the proxy shape even more. More faces means finer
control, often at the expense of making the surface harder to work with.
With the added faces, the subdivision surface looks a bit like the palm of
a hand. You’ll build upon this shape to create a left hand with palm facing
downward and fingers extruded outward. You’ll extrude the wide faces
into fingers, and you’ll leave the narrow faces as webbing between the
fingers.


Extruding polygon faces
Next, you’ll extrude faces to create fingers for the hand.

To extrude the polygon faces to create fingers

1 In a perspective view, right-click LeftHand and select Face from the
marking menu.
This lets you select faces.

2 Select the right-most face by dragging a selection box around the tiny
box at its center. (The subsequent illustration shows which face to select.)

3 Select Edit Mesh > Extrude.

4 Drag the blue arrow manipulator outward a little to create the first
segment of the smallest finger.
The blue arrow turns yellow when selected.

5 Repeat the prior two steps to create the middle segment of the smallest
finger.

6 Repeat the prior two steps once again to create the top segment and
complete the finger.
By creating three segments for a finger, you mimic a real finger’s natural
structure. The borders between the segments have vertices (not displayed
currently) that let you reshape those regions, for instance, to create
knuckles.

Extruding polygon faces | 187

7 Similarly, extrude the ring, middle, and index fingers from the appropriate
wide faces. Don’t extrude the three small faces that lie between the wide
spaces. Leave them in position to allow for webbing between the fingers.

NOTE Do not be concerned if the hand you create does not match the
lesson’s illustrations. Your goal in this lesson is to learn the workflow of
subdivision surfaces, not to perfect your modeling technique.

Next, you extrude a thumb using similar techniques as you used for the fingers.
The following steps are abbreviated. See the preceding pages for details on the
described tools, if necessary.

To split and extrude a face for the thumb

1 Select LeftHand.
Make sure it is highlighted in green in the scene view. If it is not green,
select LeftHand in the Outliner.

2 Use Edit Mesh > Split Polygon Tool to split the side face in the thumb
region into three faces.
While splitting, make sure the middle face is larger than the outer faces
as shown below.


3 Extrude the middle face and drag it directly outward.

4 Click the surrounding blue circle and use the rotate manipulator to aim
it in a direction appropriate for a thumb.

5 Extrude three times more to create each segment of the thumb. Use the
extrusion manipulator to rotate, move, and scale each extrusion to create
the desired shape of a thumb. Use the following figure as a guideline.
Again, it’s unnecessary to match the illustration or create a realistic thumb
for this lesson.
The extrusion manipulator is easy to figure out by clicking and dragging
its various elements. If necessary, you can also use the conventional Move,
Scale, and Rotate Tools to reshape the faces that control the thumb’s
shape.

6 fIn the scene view, right-click LeftHand and select Vertex from the
marking menu. The purple vertices at the corners of the faces control the
adjacent region of the hand.

Extruding polygon faces | 189

7 Make coarse adjustments to various parts of the hand by repositioning
the vertices with the Move, Scale, and Rotate Tools.
The Move Tool works on individual vertices or groups of vertices. Rotate
and Scale works on two or more vertices. Undo any changes you don’t
like using Ctrl-Z (Windows and Linux) or Control-z (Mac OS X).

Try to create the approximate thickness, length, and curvature of a cartoon
character’s hand and fingers. There’s no need for perfection. You’ll refine
the fingers later.

Deleting polygon faces
In the next steps, you delete a face in order to create a hole in the wrist where
you might choose to attach an arm. Though you won’t create and attach an
arm in this lesson, it’s useful to learn the technique for future use.

To create a hole at the wrist by deleting a face

1 In the scene view, right-click LeftHand and select Face from the marking
menu.

2 Select the face at the wrist and press Delete to create a hole where you
could attach an arm.


3 Scale the four vertices that surround the hole and scale them inward to
narrow the wrist region of the hand.

Subdivision surface levels
Next, you refine the shape of the fingers by working in Standard Mode. In
Standard Mode, you can make edits to mesh vertices, edges, or faces at different
levels of refinement, that are not possible in Polygon Proxy mode. The different
levels of refinement are referred to as subdivision surface levels.

To refine the fingers using subdivision surface levels

1 Select LeftHand.

2 Select the Surfaces menu set.

3 Select Subdiv Surfaces > Standard Mode. This switches to a mode that
lets you modify the surface at various levels of detail to suit your needs.

4 In the scene view, right-click LeftHand and select Vertex from the marking
menu.

Subdivision surface levels | 191

This displays 0s on the surface in the same positions as the vertices in
Polygon Proxy mode. In fact, the 0s are vertices.
The number 0 refers to the level of detail you are capable of editing. The
0 level is identical to the coarse control possible in Polygon Proxy mode
by manipulating the vertices. You can move, rotate, and scale the 0s to
alter the shape of the surface just as you did for vertices in Polygon Proxy
mode.

5 Right-click the surface and select Display Level > 1.

Though the 1s are displayed in the same regions as the 0s were previously,
there are many more 1s displayed. The 1s are also vertices, and their
increased presence means you can refine the shape with more subtlety.

6 Refine the shape of the fingers, thumb, and hand as desired by selecting
various level 1 vertices and moving, scaling, and rotating them with the
transformation tools. (Scaling and rotating has effect only if you select
two or more vertices.)
It’s essential to tumble the camera from various perspectives to make sure
you’ve selected only the desired vertices.

To return to level 0 to alter the shape with fewer vertices, right-click the
surface and select Display Level > 0. Each level has advantages. Level 1
allows finer control because there are more vertices. Level 0 allows control
of broader regions, and it’s often easier to select the desired vertices since


there are fewer of them. It’s common to switch back and forth between
levels repeatedly in a work session.
The hand has level 2 vertices at various locations, for instance, at the
webbing between the fingers. You can also work at that level of detail if
desired (select Display Level > 2).

Refining surface components
By default, a subdivision surface displays up to three levels of detail (0, 1, and
possibly 2). The 0 level is the least refined. You can increase the level of detail
for a selected region to at most 13 levels. Though increasing the number of
levels allows more precision, it also slows Maya processing. You’ll accomplish
most of your modeling needs at levels 0, 1, and 2.
If you display level 2 vertices on the hand, you’ll notice that there are no level
2 vertices near the fingertips. To create the indentation of a finger nail, you
need more vertices than levels 0 and 1 provide. In the next steps, you’ll add
level 2 vertices at a fingertip so you can create a fingernail.

To create more precision in the fingernail region

1 Switch to level 1.

2 Right-click the surface and select Edge from the marking menu.

3 Shift-click to select the edges that surround the region where you’ll shape
a nail.

4 To increase the amount of detail at the selected edges, select Subdiv
Surfaces > Refine Selected Components. Additional surface curves appear
in the fingernail area, indicating you can edit with more precision.

Refining surface components | 193

5 In the scene view, right-click LeftHand and select Vertex from the marking
menu. This displays additional level 2 vertices in the fingertip region.

6 Select Modify > Transformation Tools > Move Tool, Rotate Tool, Scale
Tool, Show Manipulator Tool > . In the Tool Settings window, turn
on Normal, then close the window. You can thereafter use the Move Tool
manipulator to move vertices in a direction normal (perpendicular) to
the surface.

7 Select the vertices in the nail region.

NOTE Be careful to select only those vertices in the nail region. You may
need to tumble the camera to ensure that all extra vertices are de-selected.

8 Drag the Move Tool’s N manipulator down slightly to form the depression
of a fingernail bed.


Creating a crease in a subdivision surface
One of the unique features of subdivision surfaces is that it’s easy to create a
crease or ridge on a smooth surface. You’ll do this in the next steps.

To crease the edge of the fingernail

1 Switch to Edge selection mode and shift-click the edges around the nail
to select them. (It might be easier to see the desired edges by first selecting
Shading > Wireframe.)

2 After you select the edges, select Subdiv Surfaces > Full Crease Edge/Vertex.
Once you crease an edge, it displays with a dashed line as a visual
reminder that the edge has been creased. If you change your mind, you
can remove the crease using Subdiv Surfaces > Uncrease Edge/Vertex.

3 To create a ridge at the edge of the nail, switch to Vertex selection mode
and select the level 2 vertices on the skin at the perimeter of the previously
selected edges. Move them up so that the skin’s juncture with the nail
forms a slight ridge.

Creating a crease in a subdivision surface | 195

4 Now experiment on your own by moving individual vertices to shape
the nail and surrounding region as desired. A few suggestions follow:

■ In Smooth Shade display mode (Shading > Smooth Shade All), certain
vertices might be below the shaded surface and therefore impossible to
select and move. To display and select such vertices, switch to wireframe
shading (Shading > Wireframe). After selecting the vertices, return to
Smooth Shade display mode so you will be able to more easily see the
results of moving them.

■ You might get better results using the Move Tool’s default World setting
rather than the Normal setting made in a prior step. To return to the default
setting, select Modify > Transformation Tools > Move Tool, Rotate Tool,
Scale Tool, Show Manipulator Tool > . In the Tool Settings window,
click Reset Tool, and then close the window.

■ To extend the front of the nail past the skin with a sharp edge, add a second
crease on the edges below the tip of the nail. (With the appropriate edges
selected, select Subdiv Surfaces > Full Crease Edge/Vertex.)
You might also want to add an additional level of vertices at the edges.
(With the appropriate vertices selected, select Subdiv Surfaces > Refine
Selected Components.)
After you crease the edges and add the extra vertices, you can make the
nail’s edge overhang the skin below it by dragging the vertices at the nail
tip out and away from the finger. Then tuck the row of vertices below the
overhanging vertices in the opposite direction.
An example of a completed nail follows:

1 If you want more practice, repeat the procedure for the rest of the nails.

2 When finished, select Modify > Transformation Tools > Move Tool, Rotate
Tool, Scale Tool, Show Manipulator Tool > . In the Tool Settings


window, click Reset Tool, and then close the window. This returns the
Move Tool to its default settings. This will avoid confusion in future
lessons.

Beyond the lesson
In this lesson, you were introduced to some basic techniques related to
subdivision surface modeling:

■ Modeling with subdivision surfaces is an easy way to create intricate,
smooth objects such as human hands and faces. The ability to create
extrusions, subtle surface alterations, and sharp edges means there are
innumerable types of objects you can model.

■ Many of the techniques used in modeling polygonal surfaces are applicable
to subdivision surfaces.

There are many other features related to subdivision surfaces not covered in
this lesson. These include the ability to:

■ Convert a NURBS surface to subdivision surface.

■ Convert a subdivision surface to a polygonal or NURBS surface.

■ Create subdivision surface primitive shapes from the Create > Subdiv
Primitives menu: Sphere, Cube, Cylinder, Cone, Plane, and Torus. With
these shapes, you can quickly start your subdivision surface model without
converting from polygons or NURBS surfaces.

■ Attach two subdivision surfaces to form a single surface, for instance, to
merge a hand and an arm.

■ Create a mirrored copy of a subdivision surface.

■ You can sculpt subdivision surfaces using the Sculpt Geometry Tool.


Animation
6
Introduction
Maya lets you apply action to the objects in your 3D scene. In Maya, when an
object or attribute changes in relation to time, it is referred to as being animated.
Maya provides a large selection of tools to help you animate the objects in your
scene. You may decide to use a combination of several techniques to achieve
your desired results.
In this chapter, you learn some common techniques and features that highlight
Maya’s computer animation technology:

■ Lesson 1 Keyframes and the Graph Editor: Introduction on page 200

■ Lesson 2 Set Driven Key: Introduction on page 215

■ Lesson 3 Path animation: Introduction on page 220

■ Lesson 4 Nonlinear animation with Trax: Introduction on page 239

■ Lesson 5 Inverse kinematics: Introduction on page 276


1 Select Window > Settings/Preferences > Preferences. Click the Settings
category and set the Time option to Film (24 fps) so your animation plays
at the rate of 24 frames per second. Click the Save button.

199


3 Select the Animation menu set. Unless otherwise noted, the directions
in this chapter for making menu selections assume you’ve already selected
the Animation menu set.

Lesson 1: Keyframes and the Graph Editor

Introduction
When you set a keyframe (or key), you assign a value to an object’s attribute
(for example, translate, rotate, scale, color, and so on) at a specific time.
Most animation systems use the frame as the basic unit of measurement because
each frame is played back in rapid succession to provide the illusion of motion.
The frame rate (frames per second) that is used to play back an animation is
based on the medium that the animation will be played back (for example,
film, TV, or a video game.)
When you set several keys at different times with different values, Maya
generates the attribute values between those times as the scene plays back
each frame. The result is the movement or change over time of those objects
and attributes.
In this lesson, you will use simple keyframing techniques to make a ball fly
over a fence and bounce off the ground.


■ Set keyframes for animatable objects and their attributes.

200 | Chapter 6 Animation

■ Use the Time and Range slider and Playback Controls to control the
playback.

■ Use keyboard shortcuts to set keyframes.

■ Use the Graph Editor to view animation curves.

■ Modify the animation of objects using the Graph Editor.

■ Set preferences to increase the playback quality.

Setting the playback range
In this lesson, you work with a scene we’ve created for your use. In the
following steps, you open the scene and set how long the animation will play.

To open the scene


2 Open the scene file named Keyframing.mb.
This file can be found in the GettingStarted directory that you set as
your Maya project: GettingStarted/Anim.
The scene contains a ball object that is currently positioned on the X-axis
near the edge of a ground plane.
To animate the ball, you key its position at different times of the playback
range.
The playback range is defined by the Time and Range slider. The Time
and Range slider controls allow you to playback or scroll through your
animation or move to a specific point in time of your animation so you
can set keyframes.

To set the playback range for the scene

1 Look over the playback controls, as shown in the figure below:

Setting the playback range | 201

The Time Slider displays the playback range and keys you’ve set for a
selected object. Keys are displayed as red lines. The box at the right of
the Time Slider lets you set the current frame (time) of the animation.
The Playback Controls control animation playback. You may recognize
the conventional buttons for play and rewind (return to the start time).
The stop button appears only when the animation is playing. To find
out which operation a button represents, hold the mouse pointer over
it.
The Animation Preferences button displays a window for setting
animation preference settings such as the playback speed.
The Range Slider controls the range of frames that play when you click
the play button.
The above items will have more relevance as you work through this lesson.
After you complete this lesson, experiment with these items to learn more
what they do.
The playback range is currently set at a range of 1 to 24. At a default
playback rate of 24 frames per second, the scene can play for one second.
Because you’ll animate the ball for a few more seconds than this, you
need to lengthen the playback range.

2 In the Playback End Time box (see above), enter 72.
A frame rate of 24 frames per second (fps) is the frame rate used for motion
picture film. For video, the frame rate can be 30 fps (NTSC) or 25 fps
(PAL) depending on the format being used.
With a playback range of 1 to 72, you’ll be able to create three seconds
of animation. (72 frames divided by 24 frames per second = 3 seconds.)
This is enough time for the short animation you’ll create in this lesson.

Setting keyframes
In the following steps, you use keyframes to set the starting and ending
positions of the ball’s movement.

To set beginning and ending keyframes

1 Click the rewind button to go to the start of the playback range. This
changes the current frame to 1.

2 Select the ball, then select Animate > Set Key. (Keyboard shortcut: s).


This sets a key at frame 1 for all transform attributes of the ball. Transform
attributes are the X, Y, Z move attributes. Although you animate only
the translate X and Y attributes of the ball in this lesson, keying all
transform attributes saves you time having to choose specific attributes
to be keyed.
In the Time Slider, notice the red marker at frame 1, known as a tick.
This tick appeared when you set the key for frame 1. With the ball
selected, ticks in the Time Slider indicate where you’ve set keys.

3 Go to frame 72. A convenient way to do this is to click the desired position
in the Time Slider.

4 With the Move Tool, drag the ball’s X-axis handle to position the ball at
the right edge of the ground as shown in the image below.

5 Set a key at frame 72. (Press s.)

6 Go to the start time and play the animation.
From the two keys you’ve set, Maya creates motion between the positions.
By default, the animation plays in a loop from frame 1 to 72. The ball
travels through the fence at this stage.

7 Press the Stop button on the playback control to stop the animation after
you view a few repetitions.
You can drag the mouse back and forth (scrub) in the Time Slider to see
the animation play back and forth at the speed you drag the mouse.
If you were to display the scene with Panels > Layouts > Four Panes, only
the active panel would show the ball moving.

To make the ball fly over the fence rather than pass through it, you need to
position the ball above the fence and set a key there.

To set intermediate keyframes

1 Go to frame 33 or so—at the moment where the ball sits in the middle
of the fence.

Setting keyframes | 203

2 With the Move tool, drag the Y-axis handle of the ball until it sits slightly
above the fence.

TIP Throughout this lesson, tumble the perspective view or examine a front
view to make sure the positioning is correct.

3 Set a key. (Press s.)

4 Play the animation.
The ball now flies off the ground, over the fence, and back to the ground
in a smooth arc between the keyed start, middle, and end positions.

5 Press the stop button to end the playback.
In subsequent steps, play the animation after each key you set. It’s
generally useful to check your work in progress after each key, especially
when you are learning.

In the next steps, you’ll set keys to bounce the ball in the middle of the right
half of the ground.

To set keyframes to make the ball bounce

1 Go to frame 50. At this moment, the ball sits in a position above the
middle section of the right half of the ground.

2 Move the ball so it sits on the ground.

3 Set a key.

4 Go to frame 60.


5 Move the ball up again, but not as high as its peak height above the fence.

6 Set a key. When you play the animation, the ball travels over the fence
and bounces on the other side.
If you have a fast computer, you might notice that the animation plays
too fast. By default, Maya plays the animation as fast as it can be
processed. Because this scene is simple, the animation might play faster
than the default film rate (24 frames per second).
Do not be concerned that the animation plays with a halting or jerky
motion. When you render all the frames of your animation for final
production, the animation will be smooth. If you want to preview the
animation at the smooth production speed (or nearly so), use Window
> Playblast.

Using the Graph Editor
For a more convincing animation, you need to bounce the ball more sharply
off the ground and speed up the ball’s horizontal movement. You’ll use the
Graph Editor to make both modifications.
The Graph Editor is an editor that graphically represents the various animated
attributes in your scene. The animated attributes are represented by curves
called animation curves. You edit animation curves in the Graph Editor.

To edit animation curves using the Graph Editor

1 With the ball selected, select Window > Animation Editors > Graph Editor.

Using the Graph Editor | 205

The Graph Editor displays several animation curves, one for each keyed
attribute of the ball. The animatable attributes for the ball are listed in
the left column. Specifically, it displays the attributes of the selected
transform node of the ball.
Each curve graphs how an attribute changes value during the animation.
The column of numbers at the left represents attribute values that can
be animated, while the row of numbers at the bottom represents time
(frame) values. At each point on the curve, you can see the value of an
attribute at a particular time. The small black squares on the curves
represent points where you’ve set keys.

2 Shift-Select only the Translate X and Translate Y attributes in the left
column of the Graph Editor.
Now only the animation curves for Translate X and Translate Y appear
in the Graph Editor.
This simplifies the display. With too many curves present, it’s hard to
see specific curves. When you use the Graph Editor, you usually focus on
one or a few curves.

3 To center the display of the animation curves, select View > Frame
Selection (in the Graph Editor window). If you want to see more detail
in the graph, use your mouse to dolly and track the graph view.


The green curve represents Translate Y, while the red represents Translate
X. The color of each curve matches its attribute name. This color scheme
is consistent throughout Maya for X, Y, and Z (red, green, blue).
If you’ve never used a graph editor before, the relationship between a
curve’s shape and the animation it represents might be hard to
understand. With experience, you’ll quickly recognize how curve shape
affects animation.
In the above graph, the straight curve of Translate X indicates that the
ball moves horizontally across the ground at a constant rate over time.
The wavy curve of Translate Y indicates that the ball increases its height
steadily until frame 33, dips more quickly until frame 50, then rises and
dips again until frame 72.
When the ball first bounces off the ground at frame 50, it seems to float
and slip rather than rebound. The shape of the Translate Y curve illustrates
why. Near frame 60, the curve is soft and rounded. The Translate Y values
gradually decrease to the low point then gradually increase. The transition
from decreasing to increasing values is smooth.
The Graph Editor’s usefulness lies in the fact that you can edit the shape
of the animation curves to edit the animation of any keyed attribute. To
create a sharp bounce, you can edit the curve so that the transition from
decreasing to increasing values is abrupt at frame 50. Specifically, you’ll
create a corner at that key point rather than a rounded curve.

4 Select the point on the Translate Y (green) curve at frame 50. This causes
a pair of tangent handles to appear at the point. Each end point of the
newly displayed straight line is a tangent handle. The handles let you
control the curvature near the key point.
Animation curves have a few control structures for curve editing. You
can do any of these operations:
■ Use the Move tool and middle mouse button to move a key point.
You can alternatively use your keyboard to enter precise values for a
selected key’s frame and value in the boxes above the graph area.

■ Use the Move tool and middle mouse button to drag the tangent
handles and change the adjacent curvature.
(You can shift-drag with the Move tool to constrain a move operation
to a single direction.)

■ Use the Scale tool and middle mouse button to scale selected key
points closer together or further apart.

Using the Graph Editor | 207

■ Use the Graph Editor’s Tangents menu items to change the adjacent
curvature. This is the operation you’ll use in the next step.

5 In the Graph Editor, select Tangents > Linear.
This changes the curvature around the key point from rounded to
cornered. Specifically, the setting you select specifies how the key point
tangent handles lie at this key point. This affects the type of interpolation
between key points.

6 Play the animation and you’ll see the ball bounce more sharply.
To sharpen the bounce more, you need to edit the positioning of the
tangent handles to steepen the curvature approaching the key point.

7 Select one of the tangent handles.

8 Use the Move Tool and the middle mouse button to drag it upwards a
little so you can see the how the curvature at the key point changes.
By default, when a pair of tangent handles share a key point, they work
as a unit. Move one and you move the other in an opposing direction.
This is often desirable in an animation curve, because it ensures the
curvature at that point stays symmetrical. Symmetrical curvature often
helps prevent unusual animation shifts.
In this case, however, you want to steepen the curvature’s approach
toward the curve point in the same direction on both sides. You therefore
need to break the symmetrical interdependency between the two tangents.

9 Undo your previous move of the tangent handle.

10 Select the key point at frame 50 (not a tangent handle).

11 In the Graph Editor, select Keys > Break Tangents.
This lets you move each tangent handle independently.


12 Select the right tangent handle and use the Move Tool to move it up a
little. Do the same for the left tangent handle. Be careful not to select the
key point.

This sharpens the bounce to simulate the effect of gravity and elasticity.

Changing the timing of an attribute
The ball seems to move too slowly in its journey. In the following steps, you’ll
use the Graph Editor to hasten its movement. Specifically, you’ll cause the
ball’s animation to finish its journey in two seconds (48 frames) rather than
three (72 frames).

To speed up the animation of the ball’s movement

1 Drag a selection box around all key points of both curves.

2 Select the Scale tool.

3 Click and hold the middle mouse button anywhere in the graph at frame
1 (slightly to the right of 0).
Notice the question mark icon. The location of this icon indicates the
point from which scaling occurs. (Because you need to scale the animation
inward toward frame 1, you need to start your drag operation at frame
1.)

4 Without releasing the mouse button, drag to the left until the right-most
key points on both curves are positioned roughly at frame 48. (When
selected, the right-most key points are yellow.)

Changing the timing of an attribute | 209

This scales the curves symmetrically towards frame 1. The animation of
the ball now plays from frame 1 to 48 rather than 1 to 72. The ball
traverses the scene in less time, which, of course, means it moves faster.
If you had started your drag operation from the middle of the frame
range, the scale operation would have pulled the curves toward the middle
of the frame range. You can snap the keypoints to whole values to keep
the keyframes on a consistent timing.

5 Widen the Graph Editor window as necessary to see the graph clearly.
Also, dolly the view or select View > Frame Selection (in the Graph Editor
window).

Fine tuning an animation
Now you can improvise adjustments to the animation on your own. For
example, you might choose to speed the ball’s horizontal movement up to
the first bounce but not thereafter. You might also decide to raise the peak
height of the ball’s motion so that it doesn’t seem to hover over the fence
unrealistically.
Whatever you choose to do, you’ll likely need to edit both the Translate X
and Translate Y curves, not just one of them. Play the animation after each
adjustment.
The following two figures show examples of curves after modification. The
two graphs are identical, except the curve points are selected in the second
figure. The second graph shows the position of the tangent handles.


If you want your curves to match the shape of the curves in the above figure,
here’s what you would need to do:

To adjust the animation curves to match the above images

1 On the Translate X curve, delete the three key points between the two
key points at the end. To delete keys, select the key points and press
Delete. (The preceding figures show the curve after the points were
deleted.) To delete the points, drag a selection box around them and press
Delete.
With fewer key points on the curve, it’s easier to maintain the curve’s
smoothness for larger distances as you edit its shape. Small kinks in an
animation curve can ruin an otherwise perfect animation, so it’s useful
to remove key points that you aren’t using.

2 On the Translate X curve, select the left-most key point and move its
right tangent handle down slightly. (Remember to use the middle mouse
button when moving a handle or point.) Select the right-most key point
and move its left tangent handle up slightly.
Notice that the slope of the Translate X curve increases slightly in the
early part of the animation, then tapers off toward the end. This causes
the ball to accelerate slightly at the beginning of the animation, then
decelerate after its first bounce.

3 On the Translate Y curve, remove the key point at frame 22. (The
preceding figures show the curve after the point was removed.) This point
wasn’t essential to the curve shape.

Fine tuning an animation | 211

4 On the Translate Y curve, select the left-most key point and move its
right tangent handle up slightly.

5 At the key point where the bounce occurs on the Translate Y curve, move
the left tangent handle up a bit. This raises the high part of the curve left
of that key point, which makes the ball rise higher over the fence.

6 If you want to change the shape of Translate Y curve but lack adequate
control with the existing key points, you can add a key point at the
position of your choice. (No key points were added in the prior figures.)
To add a key, click the Add Keys Tool icon, select the curve, and
middle-click the desired position on or off the curve.

Deleting extra keyframes and static channels
As you set keys, you often create many unintended keys. For example, when
you used the Set Key operation on the ball, Maya created keys on all transform
node attributes of the ball, for instance Rotate Z, not just the intended Translate
X and Translate Y attributes. The curves representing such attributes have
unchanging values. The attributes are known as static channels.
You can identify static channels by examining animation curves in the Graph
Editor. If a curve is horizontally flat its whole length, the value of the attribute
it represents isn’t changing. The attribute is a static channel. Static channels
slow Maya processing, so it’s beneficial to remove them in complex scenes.

To delete static channels

➤ From the main menu, select Edit > Delete by Type > Channels, Static
Channels, Non-particle Expressions.

This deletes all unnecessary keys for all objects in the scene. Alternatively,
you can remove the static channels for a selected object with Edit > Delete by
Type > Channels, Static Channels, Non-particle Expressions.
In addition to static channels, you’ll often create excess keys—keys that aren’t
being used to control the shape of a curve. Whenever you see three key points
that lie in a straight line, the one in the middle is unnecessary. For example,
in this lesson’s original Translate X curve, there were four redundant keys:


When you remove redundant key points, the shape of the curve doesn’t change
and you speed up Maya processing.

Using Playblast to playback an animation
When you play a scene, you see a rough approximation of the animation. The
playback speed and quality is imprecise as compared to rendering each frame
and playing the frames in sequence with a playback utility specifically designed
for this purpose. The reason for this is that Maya processes the animation of
each frame before display, while a playback utility simply plays previously
processed and rendered images.
The more detail that Maya needs to process, the slower the playback. For
example, playback will likely be slow for any scene that has several complex
objects displayed with Smooth Shade All and Hardware Texturing.

To preview the animation with more accurate timing

1 Select Window > Playblast.
For the next several seconds, Maya processes the entire animation frame
by frame. When the process is complete, a playback window appears.

2 Click the play button in this window to watch the animation.

3 Close the Playblast window when you’re done.

Beyond the lesson

■ Set keys for attributes, then use the Graph Editor to refine the animation
and remove unnecessary keys. This is a typical workflow when keyframing.

Using Playblast to playback an animation | 213

You can animate most any attribute in Maya, not just the Translate, Rotate,
and Scale attributes of a surface. For example, you can animate the intensity
of a light, the transparency of a surface, the rotation of a camera view, or
the position of CVs.

■ Work with the Graph Editor to adjust the animation attributes animation
curves directly.
The Graph Editor is the best tool for editing keyed animation by reshaping
animation curves. You can use it to change key positions, add or remove
keys, and alter the fluidity and symmetry of animation.
Each key point on an animation curve has a Tangent setting that specifies
the curvature leading into that point. The default Tangent setting (Spline)
creates rounded curvature—useful for animating attributes that change
smoothly over time. The Linear setting creates angular curvature, useful
for a bounce effect or any other abrupt change in attribute value. Other
Tangent settings are available for different animation effects. For example,
a Stepped setting lets you make an instantaneous leap in value, useful
when you want to flash a light off and on.

■ Use the Time and Range slider to play back your animation.
Although the Graph Editor is a popular animation tool, you can also cut,
copy, paste, and delete keys directly in the Time Slider to edit animation.
Select a key position in the Time Slider, then right-click to select the desired
operation from a pop-up menu.

You may find the following techniques useful when keyframing your
animations:

■ There are alternative object display modes that quicken the display of
animation in the scene view. When you select Shading > Bounding Box
(from the panel menu in the scene view), Maya displays simple box-shaped
geometry in place of the actual objects in your scene. The simpler shapes
enable Maya to respond to any camera and object movement faster. The
drawback is that you cannot edit the shape of the objects in this display
mode.

■ It is generally a recommended practice to animate a parent (group) node
rather than objects themselves. By animating a parent node, you can avoid
problems that occur when the animation of one object in a hierarchy
conflicts with the animation in another part of the hierarchy.


Lesson 2: Set Driven Key

Introduction
With keyframe animation, you key an attribute value to a time in the Time
Slider. You repeat this process with different values at different times to animate
the object.
When you must animate multiple objects or attributes that interrelate, setting
keyframes can quickly become a complex task. Set Driven Key is a technique
for driving one object’s or attribute’s animation from another attribute.
With driven keys, you relate an attribute value to the value of another attribute.
You repeat this with different values to create a dependent link between a pair
of attributes. A change in the driver attribute alters the value of the driven
attribute. In this way the animation of the driven attribute doesn’t need to
be manually set; it occurs automatically once the relationship between
attributes has been established. This makes setting up some types of animations
much more efficient. For example, you can use driven keys to make a door
open when a character walks in front of it.
In this lesson, you will learn how to use Set Driven Key in order to animate a
door rising upwards when a ball approaches it.


■ Link the object attribute behavior between two objects which will link the
movement of one keyframed object to another with no keyframes assigned.

■ Use the Graph Editor to adjust the animation for the driven object.

Lesson setup
In the following steps, you set a playback range that’s long enough to see the
animation clearly. You also create the ball and the door, and position them
in the scene view in preparation for the animation.

Lesson 2: Set Driven Key | 215



3 Go to the start frame.

4 Create a polygonal cube and name it Door.

5 Scale and position it roughly as shown in the previous figure. Have the
bottom edge of the door lie roughly along the X-axis.

Shade All).

7 Create a small polygonal sphere and name it Ball. Scale and position it
roughly as shown in the prior figure in the introduction. Have it sit
roughly at 0, 1, 10 (X, Y, Z).
Use the default color for the door and the ball.

Using Set Driven Key to link attributes
The following steps link the door’s movement to the ball’s movement using
Set Driven Key.

To link the door’s movement to the ball’s movement

1 Select the door and choose Animate > Set Driven Key > Set.
The Set Driven Key window appears with the door in the Driven list.


2 Click translateY in the Driven list.
This is the attribute to be driven by the ball’s movement.

3 Select the ball in the scene view.

4 In the Set Driven Key window, click the Load Driver button.
The ball appears in the Driver list.

5 In the Set Driven Key window, click translateZ in the Driver list.
This is the attribute that will drive the door’s movement.
You can set a driven key only after you select an attribute in the Driver
list and in the Driven list.

6 In the Set Driven Key window, click Key.
This sets a driven key relationship that links the current Translate Z value
of the ball to the current Translate Y value of the door. Whenever the
ball’s Translate Z is at this position, the door’s Translate Y will be at its
current position.

Using Set Driven Key to link attributes | 217

The Time Slider is not involved in a driven key relationship and displays
no red markers for keys.

7 Move the ball to the door’s position and then move the door above the
ball.

This sets another driven key that links the current Translate Z value of
the ball to the Translate Y value of the door.

9 Move the ball to the right of the door and then lower the door to its
previous position as shown in the following figure.

This sets another driven key that links the attributes.
You’ve set three driven keys that link the attribute values at different
positions. Maya interpolates the linked values to generate the values
between the keys.
If you drag the ball toward the door from either side, the door rises
smoothly.
Playing back the animation from the Time Slider doesn’t move the ball
or the door. Driven keys link one attribute to another. They don’t link
attributes to times in the Time Slider. However, if you were to animate
the movement of the ball, the door would move based on the driven key
relationship that has been set.


Viewing the results in the Graph Editor
In the next steps you’ll examine the animation curve resulting from the driven
keys you’ve set. If you are unfamiliar with animation curves and the Graph
Editor, see Lesson 1: Keyframes and the Graph Editor on page 200.

To view the set driven key results in the Graph Editor

1 Select the door. To display the animation curve for a driven key in the
Graph Editor, you must select the object containing the driven attribute,
not the object containing the driving attribute.

2 Select Window > Animation Editors > Graph Editor.

3 From the Graph Editor, select View > Frame All. The Graph Editor shows
the driven keys that link the door’s TranslateY value to the ball’s Translate
Z value. An example follows:

The column of numbers on the left lists the driven attribute values. The
row at the bottom lists driver attribute values. The animation curve shows
the relationship between the values—the door’s Translate Y value rises
as the ball’s Translate Z value approaches 0.
You can use the Graph Editor to edit the shape of the curve to make the
door rise faster, slower, and higher as the ball approaches it.

Beyond the lesson
In this lesson you learned how to:

■ Set driven keys to link one attribute’s values to another.
A driven attribute is not directly affected when you play the animation.
It is linked to a driving attribute’s value, not animation time. However,
you can use regular animation keys, expressions, motion paths, or other

Viewing the results in the Graph Editor | 219

techniques to animate the driving attributes. This indirectly animates the
driven attribute.

You may find the following notes helpful when using Set Driven Key:

■ You can set driven keys to control a driven attribute with multiple driving
attributes. For instance, you can have a muscle bulge when an elbow rotates,
and have the bulge increase when the wrist rotates.

Lesson 3: Path animation

Introduction

Path animation allows you to animate an object along a path specified by a
curve. In this way, the curve controls the motion of the object. With keyframe
animation, Maya calculates the motion of the object for the animation based
on the positions that were set at the keyframes. With path animation the
motion for the object is defined by its location along the path curve.
Path animation is useful for animating objects such as trains, boats, airplanes,
and moving cameras whose motion follows a set path. To animate an object
to do this type of motion smoothly with keyframe animation would require
you to laboriously create and edit many keys for the motion. By having the
object move along a curve, you can easily adjust the object’s path by editing
the curve.


In this lesson, you make an aircraft follow a motion path so it appears to fly
and bank while it changes trajectory. We provide a scene for your use in the
lesson.

■ Set an object to animate along a motion path using a NURBS curve as the
path.

■ Modify the timing and rotation of an object along a motion path.

■ Blend between keyframe and motion path animation.

In this lesson, you work with a scene we created for your use.


2 Open the scene file named PathAnim.mb.
your Maya project: GettingStarted/Anim/PathAnim.mb.

The scene contains two objects named Aircraft and PathCurve. When
the aircraft travels on the path curve it will return to where it began.

3 In the Time Slider, ensure that the Playback End Time is set to 240.

The path animation occurs between frames 60 and 240 (180 frames in total).
Between frames 1 and 60, you keyframe the aircraft’s motion so it rises from
the ground plane. You then blend between the two animation types.


Animating an object along a motion path
To animate the aircraft along the path curve, first select the aircraft and the
path curve and then set appropriate options for the motion path animation.
In the options window, you need to set the required time range for the path
animation. You also need to ensure that the aircraft is oriented facing towards
the direction of travel. The Follow, Front, and Up axis option settings
determine the aircraft’s orientation along the path.

To attach the aircraft to the motion path

1 Set the Time Slider to frame 1.

2 Select the aircraft and then shift-select the path curve.

3 In the main menu, select Animate > Motion Paths > Attach to Motion
Path > .
The Attach to Motion Path Options window appears.

4 In the options window, ensure the options are set as follows, then click
Attach:
■ Time Range: Start/End

■ Start Time: 60

■ End Time: 240

■ Follow: On

■ Front Axis: X

■ Up Axis: Y

■ World Up Type: Scene Up

■ Leave all other settings off


The aircraft is repositioned to the start of the curve, and oriented towards
the direction of travel.

The Start and End Times set the time duration the aircraft travels along
the path curve (240 - 60 = 180 frames). The start and end times are
displayed at the ends of the curve.

5 Click play on the Timeslider playback controls to play back the animation.
The aircraft travels along the path. Observe that it begins its motion at
frame 60.

Animating an object along a motion path | 223

Changing the timing of an object along a motion path
When you first assign an object to a motion path, by default, the object travels
along the path at a constant speed. In this lesson, you want the aircraft to
initially travel along the path slowly, accelerate, and then finally move more
slowly when it nears the end of the motion path.
You can change the rate of travel for the aircraft by keyframing attributes that
affect where the aircraft is positioned on the curve at a given time.

To view the attributes for the motion path


2 Select the aircraft.

3 Open the Channel Box by clicking the Show/Hide Channel Box icon on
the Status Line.

4 In the Channel Box, click on the word motionPath1 that appears in the
Aircraft’s Inputs list.
The attributes for motionPath1 appear at the bottom of the Inputs list.
(Scroll the Channel Box window if the MotionPath1 attributes are not
fully visible).

The UValue attribute controls where the aircraft gets positioned along the
curve. The UValue refers to the curves parameterization. Parameterization is a
method used by Maya to divide a curve into increments of known amounts
so that a location along the curve can be determined.


By default, the parameterization of a path curve is set between zero and one.
At frame 60, the aircraft is at the beginning of the curve where the
parameterization value is zero. When the aircraft is at the end of the curve
(frame 240) the parameterization value for the curve is one. When the aircraft
is halfway through the path animation (frame 150), it is located along the
curve at a UValue of 0.5.
By setting the frame number and UValue and then setting a key, you change
the timing for the aircraft’s motion along the path.

To change the timing for the aircraft along the path

1 Ensure the aircraft is selected so its attributes display in the Channel Box.

2 In the Time Slider, drag the current time indicator to frame 120 using
the middle mouse button.
Middle-dragging the current time indicator, instead of using the left
mouse button, changes the current time without repositioning the aircraft
along the path.

3 In the Channel Box, set the UValue for MotionPath1 to 0.1.
The aircraft is repositioned along the curve near the first bend. When
you set the UValue to 0.1, the aircraft is positioned at a point that is a
distance of 10 percent from the beginning of the curve (that is, the aircraft
has completed 10 percent of the distance along the path).

4 In the Channel Box, select the UValue channel by clicking on its name
so it becomes highlighted.

Changing the timing of an object along a motion path | 225

5 Right-click on the selected name.
A drop-down list appears.

6 From the drop-down list, choose Key Selected.
A position marker appears on the path curve indicating that a key frame
has been set. The position marker is useful for determining where the
aircraft is at a given time. Position markers do not appear when you
render the animation. Using Key Selected ensures that a keyframe is set
only for the item selected and nothing else.

7 In the Time Slider, middle-drag the current time indicator to frame 180.

8 In the Channel Box, set the UValue for MotionPath1 to 0.9.
The aircraft is repositioned along the curve near the last bend. When you
set the UValue to 0.9, the aircraft is positioned at a point that is a distance
of 90 percent from the beginning of the curve. (that is, the aircraft has
completed 90 percent of the distance along the path)

9 In the Channel Box, select the UValue channel by clicking on its name
so it becomes highlighted.

10 Right-click on the selected name and choose Key Selected.
A position marker appears on the path curve.


11 Click play on the Time Slider’s playback control to play back the
animation.
The motion of the aircraft is not smooth as it travels along the path. It
initially moves forwards and backwards a bit at the beginning and end
of the path. This indicates that some adjustment of the animation is
required. You adjust the animation using the Graph Editor.

To view the Graph Editor

1 From the main menu, select Window > Animation Editors > Graph Editor.
The Graph Editor appears.

2 In the Graph Editor, select View > Frame All.
The Graph Editor updates to display the animation curve for the motion
path animation.

The shape of the animation curve provides some clues as to why the motion
of the aircraft is not smooth. Between frames 60 and 84 the curve rises and
then drops slightly. Because the animation curve represents translation along
the curve, a drop in the curve indicates that the object travels backwards. A
similar occurrence happens at the end of the curve as well. To correct this,
you need to modify the tangents for the keys in the Graph Editor.

To edit the tangents for the keys in the Graph Editor

1 In the Graph Editor, press the shift key, then double click on the
animation curve to select the four keys (frames 60, 120, 180 & 240)

2 In the Graph Editor menu, select Tangents > Linear.


The animation curve updates so that the keys connect via straight lines.
This eliminates the dips in the curve that caused the aircraft to travel
backwards.

Next, you modify the tangents for keys 120 and 180 so the aircraft accelerates
and decelerates near those points on the path curve.

1 In the Graph Editor, shift-select only the two keys for frames 120 and
180.

2 In the Graph Editor menu, select Keys > Break Tangents.
Breaking the tangent for the keys allows you to modify the shape of the
curve as it enters or leaves a key.

3 Select only the key for frame 120.
A pair of tangent handles appear on either side of the key. The handles
let you edit the curvature of the animation curve near the key point.

4 Select the tangent handle to the right of the key.
The handle highlights in a yellow color.

5 From the Toolbox, select the move tool.

6 Using the middle mouse button, drag the handle so the curve has a gentle
curvature as it leaves the key as shown below.
Modifying the tangent in this manner changes how the motion transitions
as the curve changes direction as it passes through the key. The aircraft
will accelerate smoothly instead of immediately travelling at a different
rate of speed.


7 Select the key for frame 180.

8 Select the handle to the left of the key.
The handle highlights in blue.

9 Using the middle mouse button, drag the handle so the curve has a gentle
curvature as it enters the key as shown below.
Modifying this tangent for this key will cause the aircraft to decelerate
smoothly near the end of its travel.

The modified animation curve appears as shown below.

10 Close the Graph Editor.

animation.


The backwards and forwards motion that previously occurred is corrected.
The aircraft travels slowly towards the first bend in the path curve, then
accelerates and travels at a constant speed around the curve until it nears
the end of the path where it decelerates and then slowly moves towards
the end of the curve.

Rotating an object along a motion path
As the aircraft travels along the motion path, its orientation remains the same
throughout the animation. A real aircraft rolls to one side (banks) as it flies
in an arc. To make the aircraft roll to one side as it travels along the path you
set keyframes for the Twist attributes in the Channel Box.

To animate the roll of the aircraft along the path

1 Ensure the aircraft is selected.

The aircraft is repositioned along the curve near the first bend.

3 In the Inputs section of the Channel Box, click on motionPath1 to view
its attributes.

4 Ensure the Front Twist value for motionPath1 is set to 0.

5 In the Channel Box, select the FrontTwist channel by clicking on its
name.

6 Right-click on the selected name.


8 To set the remaining keyframes for the rotation of the aircraft, use the
table below as a guide, keeping in mind that you set the keyframes in the
following order:
■ Set the frame in the Timeslider


■ Set the values for Front Twist in the Channel Box.

■ Select the Front Twist channel by clicking its name. Right-click on
the selected name and choose Key Selected.
Frame Select Set channel attrib- Choose
ute

130 Aircraft Front Twist: -15 key selected





180 Aircraft Front Twist: 0 key selected

9 Click play on the Time Slider playback controls to play back the
animation.
The aircraft rolls to one side (banks) as it travels along the motion path.

Blending keyframe and motion path animation
Blending between motion path and keyframe animation types is possible in
Maya. Blending between the two animation types allows you to take advantage
of the characteristics each animation type can provide without having to
expend a lot of effort in determining where the change between the two types
must occur.

Blending keyframe and motion path animation | 231

In the steps that follow, you keyframe the aircraft to rise vertically from the
floor surface and then travel along the motion path by blending between the
two animation types. To accomplish this, you do the following:

■ Move the motion path up above the ground plane.

■ Keyframe the aircraft so it rises vertically above the ground plane.

■ Blend between the keyframe and motion path animations.

To move the motion path

1 In the scene view, select only the path curve.

2 In the Channel Box, set Translate Y to 5 for PathCurve.
The path curve is repositioned above the ground plane in the scene view.
The aircraft moves with the path curve because it is attached to the motion
path.

To keyframe the motion for the aircraft

1 Select only the aircraft.

2 Set the Timeslider to frame 1.

3 In the Channel Box, set the following for the aircraft:
■ Translate Y: 0

The aircraft is repositioned so it rests on the ground plane.

4 Select the Translate X, Y, and Z channels as well as the Rotate X, Y, and
Z channels by click-dragging on their names so they become highlighted.


5 Right-click on any of the highlighted names, and choose Key Selected
from the drop down list that appears.
Keys are set for the selected channels. Keyframing these channels
establishes a blending connection that will be discussed in subsequent
steps.

6 In the Channel Box, set the following:
■ Rotate Y: - 90

The aircraft is rotated 90 degrees from its motion path position.

7 Select the Rotate Y channel by clicking on its name so it becomes
highlighted.

8 Right-click on the name, and choose Key Selected from the drop down
list that appears.
A keyframe is set for the aircraft.

Additional channels have appeared in the Channel Box. When a keyframe is
set for an object that already has motion path animation, the software
automatically creates a connection to blend between the two animation types.
These new channels are used to control the blend between the keyframe and
motion path animation types. They control the blend for the Translation and
Rotation attributes.


1 To set the remaining keyframes for the keyframe motion of the aircraft,
use the table below as a guide, keeping in mind that you set the keyframes
in the following order:
■ Set the frame in the Time Slider.

■ Set the Translate and Rotate values in the Channel Box.

■ Select only the channels for those values. Right-click on the selected
name and choose Key Selected.
Frame Select Set channel attrib- Choose
ute

20 Aircraft Translate Y: 1 key selected


30 Aircraft Rotate Z: 170 key selected


40 Aircraft Rotate Z: 170 key selected

The aircraft rises above the ground plane and then stops at frame 40.


The animation stops because the motion path animation was shut off when
the blend attribute was automatically created when you set the first keyframe.
The blend attribute values are set to zero by default. When the blend values
are set to zero, the keyframe animation has full influence on the object, and
the path animation is shut off. When the blend values are set to one, the
motion path has full influence on the object and the keyframing is shut off.
When the blend values are between zero and one, the aircraft’s motion is
blended between the keyframe and motion path animation.
In the next steps, you keyframe the blending attributes so the blending begins
at frame 30 and ends at frame 70. This blends the two animation types together
over a period of 40 frames.

To blend between the two animation types


2 In the Channel Box, ensure the blend values are set as follows:
■ BlendAddDoubleLinear: 0

■ BlendMotionPath: 0

3 Select the BlendAddDoubleLinear1 and BlendMotionPath1 channels by
click-dragging on their names so they become highlighted.

4 Right-click on one of the names, and choose Key Selected from the drop
down list that appears.


A key is set for the blend starting point for the aircraft. At frame 30 the
two animation types will begin to blend together.


■ BlendAddDoubleLinear1: 1

■ BlendMotionPath1: 1

7 Right-click on one of the names, and choose Key Selected from the drop
down list that appears.

A key is set for the blend ending point for the aircraft. At frame 70 the
motion path animation will have full influence.

The two animation types are combined but the motion does not appear
correct. The aircraft rotation flips upward momentarily when it begins
to travel along the motion path.

The interpolation type for the rotations during the blending is not set
correctly.

Setting the pairBlend Rot Interpolation setting to Quaternions changes how
the rotations are interpolated during the blend. In this example, Quaternions
provides a better interpolation type when blending between the keyframe and
motion path animation. For more information see quaternion rotation in the
Maya Help.


To edit the rotation interpolation type for blending

1 In the Channel Box, click on the pairBlend1 channel.

2 Scroll the Channel Box so you can view the Attributes for pairBlend1.

3 Set the Rot Interpolation setting to Quaternions by clicking on the Euler
angles name with the left mouse button.

4 Click on the pairBlend2 channel.

5 Click on the Euler angles name in the Rot Interpolation attribute and
choose Quaternions.

The animation plays back smoothly. Observe how the blending also takes
into account the rotation of the aircraft so it meets up with the motion
path smoothly.

Using Playblast to playback an animation
Playblast allows you to preview an animation by calculating the separate
frames and playing them back in a multimedia player window based on the
Playblast options. Playblast provides a more accurately timed playback than
using the Timeslider.

To playback the animation using Playblast

1 Select the path curve, and then select Display > Hide > Hide Selection to
hide the curve while you Playblast.

2 Select Window > Playblast.
Playblast calculates the frames for the animation and then plays them
back in the player window.

Using Playblast to playback an animation | 237

You have completed this lesson.

Beyond the lesson

■ Create a motion path animation using a NURBS curve as the motion path.
When you draw your own curves remember that a curve has a defined
start and an end point based on how you create it. If your object is initially
positioned at the wrong end of the curve, you can reverse the direction of
the curve by setting the Menu Set to Modeling and then selecting Edit
Curves > Reverse Curve Direction.
If your objects are not oriented correctly on the path initially, you can
change the options in the Attach to Motion Path Options window. See
Animate > Motion Paths > Attach to Motion Path in the Maya Help.

■ Adjust the timing and rotation of an object when it travels along the
motion path.
In this lesson you were shown how to keyframe the roll (bank) of the
aircraft. The Attach to Motion Path Options window provides an option
called Bank. The Bank option rotates an object as it travels around curved
portions of a motion path. It is useful for simple motion path animation.

■ Blend between keyframe and motion path animation types on the same
object.
For more information on how this works, see pairBlend in the Maya Help.


Lesson 4: Nonlinear animation with Trax

Introduction

Nonlinear animation allows you to create and edit an animation sequence by
arranging smaller animation sequences (known as clips) on a timeline. A clip
is a time-independent sequence of animation that you create from an existing
animation (keyframe animation, expressions, constraints, and motion capture
data - except motion path animation).

Nonlinear animation tools in Maya® TraxTM give you the ability to experiment
with your animation sequences and character animations without having to
redo all of your work when you want to modify or construct a different
animation.
Nonlinear animation is a non-destructive process. You can modify a particular
clip’s attributes without affecting the source animation: the source material
remains untouched. This makes nonlinear animation useful when you want
to experiment, iterate, or change a particular animation sequence.
The primary tool for working with nonlinear animation is the Trax Editor.
You can also store your clips for future use by creating a library of clips.

■ Key animation sequences for use as nonlinear clips in Trax.

Lesson 4: Nonlinear animation with Trax | 239

■ Create clips from your animation sequences for use in the Trax Editor.

■ Use the Trax editor to position, modify, and arrange clips in order to create
and modify animation sequences in the scene.

■ Scale clips to modify the timing of an animation sequence.

■ Trim clips to remove unwanted motion.

■ Cycle clips to create motion that repeats.

■ Use the Graph Editor to modify the animation of a clip.

■ Use the Trax Editor to work with motion capture data.

■ Reuse clips using the Outliner and the Visor.

Open the first scene for the lesson
This lesson is presented in two parts. You work with two separate scene files
we’ve created for your use. In the first part of this lesson, you learn some of
the fundamental techniques for working with clips in the Trax Editor by
animating an aircraft taking off and landing.


2 Open the scene file named Trax_Lesson1.mb.
your Maya project: GettingStarted/Anim/Trax_Lesson1.mb.
The scene contains a model of an aircraft. For the first part of this lesson,
you create and work with animation clips to control the motion of the
aircraft.

3 In the Time Slider, set the Playback range as follows:
■ Playback Start Time: 1


■ Playback End Time: 240

To work more efficiently with the scene and the Trax Editor, you need to set
a panel layout.

To set a panel layout for use with the Trax Editor

➤ From the perspective view’s menu, select Panels > Saved Layouts >
Persp/Trax/Outliner.

The panel layout updates to display the Perspective view, Outliner, and
Trax Editor simultaneously. This allows you to easily work with these
windows without having to open and close them repeatedly.

Next, set the Outliner so it displays clips. The Outliner allows you to manage
the various clips that get created with Trax.

To set the Outliner to display clips

1 In the Outliner menu, make sure that Display > DAG Objects Only is
unchecked.

2 In the Outliner menu, select Show > Objects > Clips.
The Outliner displays an empty list until you create your first clip.

Open the first scene for the lesson | 241

Creating clips with Trax
A clip is a time-independent sequence of animation data for one or more
animated attributes that you create from existing animation (keyframe
animation, expressions, constraints, motion capture data, and so on). A clip
is time independent, allowing you to position, scale, and cycle a clip
independently of other animatable attributes or other clips. This means you
can arrange the clips into a particular sequence, and then play it back to see
the results. You can adjust the timing, length, and rearrange or edit the same
clips in a different order to modify the motion sequence.
Most commonly-used clips are reusable sequences of animation that are easy
to sequence or blend with other clips. For example, suppose you create three
clips: a karate punch, tumble, and kick. You can run the clips in any order,
and you can repeat clips or blend the motion between them. You can scale
or cycle clips to alter the time frame over which the animation occurs. You
can either return the clip to its original state or reload a duplicate of the original
source clip and begin again. In this way, the Trax Editor allows you to
experiment with animation sequences on a character.
In the steps that follow, you key some animation for the aircraft and then
create clips from the keyed animation for use in the Trax Editor.

To create keyframe animation for the aircraft

1 From the perspective view’s panel menu, select Panels > Orthographic >
front.
The panel updates to display the aircraft’s side from the front view.

2 In the front view, click on the aircraft to select it.

■ Translate X: -25

The aircraft is repositioned at -25 along the X axis. The aircraft disappears
from the front view because it has been repositioned outside of the
viewing area.

4 Dolly and track the front view until the aircraft appears on the lower left
hand side of the front view as shown below.


5 Press s to set a keyframe.
In the Channel Box, the channels display in a different color. The color
change indicates that the channels now have animation applied to them.

NOTE If you normally use the Auto Keyframe function, you must shut it off
for this lesson. For more information see Auto Key in the Maya Help.

6 In the Time Slider, set the current time indicator to frame 240.

■ Translate X: 25

The aircraft is repositioned at 25 along the X axis (the right hand side of
the current front view).

8 In the Channel Box, select the Translate X channel by clicking on the
name.
The Translate X name becomes highlighted.

9 Right-click on the selected name and choose Key Selected from the
drop-down list that appears.
Key Selected sets a keyframe for only the selected attribute.

Confirm that the animation sequence works as expected in the steps that
follow.

To playback the animation using the playback controls

animation.

Creating clips with Trax | 243

The aircraft travels from left to right in the front view.

2 Click stop on the Time Slider’s playback control.

Now that you have keyframed an animation sequence and confirmed that it
works, you can create an animation clip.

To create an animation clip of the keyframe animation

1 In the Trax Editor menu, with the aircraft still selected, select Create >
Animation Clip > .

2 In the Create Clip Options window, select Edit > Reset Settings, and then
click on the Create Clip button.
The Outliner updates and lists two items: clip1 and clip1Source. If the
clips do not display refer to To set the Outliner to display clips on page
241

When you created the clip, two clips were generated: a regular clip and a
source clip. The source clip contains the animation curves for the character
(based on the keyed attributes that the clip was created from). The source
clip is stored with the file and can only be accessed from the Visor or
Outliner. Maya saves the source clip outside of the Trax Editor to protect
the original animation curves from being accidentally modified and
ensures you have an unmodified clip to revert back to.
A regular clip (referred to simply as a clip) contains the same information
as the source clip, and is placed in a track in the Trax timeline. It is this
regular clip that you work with and modify in Trax.


A clip does not yet appear in the track area of Trax Editor because the
character set associated with the clip (the aircraft) has not been loaded
to display.

3 In the Trax menu, with the aircraft selected, click the Load Selected
Characters icon.

The clip appears as a blue rectangular box in a track in the Trax Editor. A
track is an area in the Trax Editor to place and work with one or more
non-overlapping clips in relation to the animation timeline. Tracks allow
you to work with your clips in a nonlinear manner by allowing you to
reposition and scale clips in time or juxtapose them with other clips. You
can work with multiple tracks in the Trax Editor.

4 In the Trax menu, select View > Frame All.
The Trax Editor updates to show the beginning and end point for all of
the items displayed in the Trax Editor. (In this case the new clip.) The
clip represents the Translate X animation for the aircraft going from -25
to 25, for a time range of 1 to 240 frames.

Anatomy of a clip
Every clip contains interaction controls that relate to information about the
clip:

■ Frame In and Frame Out indicates the current start and end frame numbers
for the clip in relation to its position on the timeline.


■ Source In and Source Out indicates the range of frames from the original
source clip.

■ Duration indicates the length (duration) of the original source clip in frames.

■ Clip Name...the name of the clip. A default clip name is assigned to the
clip, unless you specify it from the Create Clip Options window when you
first create the clip.

■ Scale indicates the scale percentage for the clip. The scale percentage is the
multiplier on the length of the original clip. For example, if you scale a
clip fifty percent longer than its original length, the scale value would read
150%.

Each area on the clip has a hot spot which you can either double-click on for
numeric values, and in some cases, click-drag to modify the related attribute.
For example, you can double-click on the hot spot for the clip name to edit
the name. For more information about clips and tracks, see Track view area
in the Maya Help.

To edit the name of the clip in the Trax Editor

1 In the Trax Editor, double-click on the clip1 name on the clip.
The clip highlights in yellow to indicate it is selected and the clip1 name
becomes highlighted.

2 Type Travel_Forward and then press Enter.
The clip is renamed to Travel_Forward. The clip and the source clip’s
name are updated in the Outliner to reflect the change.

If you play this clip in Trax, the animation is played back from the clip data,
not the keyframe data that you set previously in the scene. When you created
the clip, the source of the animation for the aircraft was changed to come
from the clip instead of the keyframes.
When you create a clip, Maya creates a character set to contain the clip. A
character set is the parent of the hierarchy of clips and tracks for a particular
animated object. A clip’s animation resides under the character set node and
additional clips are placed under that node unless you specify otherwise.


For more information see Nonlinear animation components in Trax in the
Maya Help.
Now that you have created your first animation clip and renamed it using the
Trax Editor, you need to create a few more clips by setting additional keys and
creating clips of the sequences. You need to create separate clips of the aircraft
taking off and landing.

To create an animation clip of the aircraft taking off

1 In the scene view, select the aircraft.

■ Translate Y: 0

3 In the Channel Box, select the Translate Y name so it becomes
highlighted.

4 Right-click on the name and choose Key Selected to set a keyframe for
this position.
Key Selected sets a keyframe for only the selected attribute.

5 In the Time Slider, drag the current time indicator to frame 60.

■ Translate Y: 7.0

highlighted.

this position.

9 In the Trax Editor menu, with the aircraft selected, select Create >
Animation Clip (or click the Create Clip icon on the Toolbar).


The Trax Editor updates to create an additional track and places the new
clip on the new track. The Outliner updates to list the new clip and source
clip.

10 In the Trax Editor, double-click on the new clip and rename it to
Aircraft_Rise.

animation.

The aircraft rises as it travels forward.


To create an animation clip of the aircraft landing

1 In the Timeslider, set the current time indicator to frame 180.

2 In the Channel Box, with the aircraft still selected, set Translate Y to 7.

highlighted.

this position.


6 In the Channel Box, set the Translate Y to 0.


highlighted.

this position.

animation.

The aircraft travels forward and then lands as it nears the end of its travel.


11 In the Trax Editor menu, with the aircraft selected, select Create >
Animation Clip.
The Trax Editor and Outliner update to show the new clip.

12 In the Trax Editor, double-click on the new clip and rename it to
Aircraft_Lower.

Changing the position of clips with Trax
It’s easy to alter the start time of clips to synchronize the action between clips.
For example, the aircraft rises as it travels forward because the Travel_Forward
and Aircraft_Rise clips overlap in time. If you position the clips on their
respective tracks so that one clip’s action occurs in the Trax timeline before
or after the other, the motion occurs separately.
In this section, you learn how to reposition the clips so that the aircraft takes
off before it travels forward in X, and then have the aircraft land at the end
of the sequence.

Changing the position of clips with Trax | 249

To change the position of a clip in a track

1 In the Trax Editor, move the mouse cursor over top of the Travel_Forward
clip.
When the mouse cursor is over top of a clip in the Trax Editor, the cursor
icon changes to a pointer indicating that you can drag the clip to either
side or up and down between tracks.

2 Click-drag the Travel_Forward clip horizontally to the right in its track
until the Frame In reads 60 as shown below.

animation.

The aircraft takes off vertically, then travels to the right, and lands while
it is still travelling to the right. Because the two clips (Travel_Forward
and Aircraft_Rise) are positioned one after the other, the actions occur
in a series versus simultaneously.


5 Click-drag the Aircraft_Lower clip horizontally to the right until the
beginning of the clip matches the end of the Travel_Forward clip on the
track above it. (Frame In = 299)
If the view of the clips appears limited, select View > Frame All in the
Trax Editor to resize the view to encompass the clips.


You also need to modify the Playback End Time because the animation timeline
is longer as a result of repositioning the clips.

1 In the Time Slider, edit the Playback range as follows:

animation.

The aircraft takes off vertically, then travels to the right, and then lands
vertically once the Travel_Forward clip’s motion is complete. Because the
three clips are positioned end to end in relation to the timeline, the
animation occurs as a series of separate events.


Editing the animation of clips
You can modify the animation of a clip using the Graph Editor in the same
way that you would modify any other type of animation. Because you are
working with the clip, and not the original animation, you won’t change the
original source clip animation.
In this section, you use the Graph Editor to modify the animation for each
clip so the aircraft’s motion accelerates and decelerates at the beginning and
end of each clip.

To use the Graph Editor to modify a clip in Trax

1 Click on the Aircraft_Rise clip to select it.

Editing the animation of clips | 251

The selected clip highlights in yellow.

2 From the Trax menu, select View > Graph Anim Curves.
The Graph Editor appears.

3 In the Graph Editor, shift-select the two keys on the animation curve as
shown below.

4 In the Graph Editor, select Tangents > Flat.

The shape of the animation curve updates to a gentle S-shape. Setting
the tangents for the animation curve in this manner modifies the clip’s
animation to cause the aircraft to accelerate when it first rises, and
decelerate when it nears the end of its vertical travel.

5 Repeat steps 1 through 4 to set the animation curve tangents in a similar
manner for the two remaining clips: Travel_Forward and Aircraft_Lower.
The shape of the animation curve for Aircraft_Lower will be reversed from
the other clip curves because the motion is occurring in the opposite
direction.

6 Close the Graph Editor window.

7 Set the Time Slider’s current time indicator to frame 1.

animation.
The motion accelerates and decelerates at the beginning and end of each
clip. As a result, the motion appears more natural. It’s important to note
that the modified tangents for each clip are independent from the other
animation clips and do not affect any other motion.



Reusing clips within Trax
You can save and reuse clips for future use. You can key specific types of
motion or attribute effects, save them as clips, and reuse the clips for other
characters.
When you reuse a clip created for one character and apply it to another, the
clip attributes must be mapped to correspond between the two characters. For
more information, see Mapping animation between characters in the Maya
Help.
In this lesson, you work with clips created for this aircraft animation. The
clips contain animation to make the aircraft shift to the left and right and
bank left and right.

To load a clip from disk

1 From the Trax menu, select File > Import Animation Clip.
The File Browser appears. When importing a clip, the File Browser defaults
to the clip directory of your current project.

2 Find the clip file named Bank_Left.ma in the GettingStarted/Anim/clips
directory.

3 Select the file named Bank_Left.ma and click the Import button.
The clip is imported and appears in the Outliner named as
Bank_LeftSource to indicate it is a source clip.

4 Repeat steps 1 and 2 to import the clips Bank_Right, Shift_Left and
Shift_Right.
When you have finished, four new clips appear in the Outliner as source
clips. In the steps that follow, you place and position the clips on tracks
in the Trax Editor.

NOTE When you import clips they also appear in, and can be accessed from,
the Visor (Window > General Editors > Visor). The Visor is a graphical interface
that allows you to import items that reside on disk or in your current file (
such as files, textures, clips, or poses). Clips that are assigned to a character
in Trax will appear listed under the Character Clips tab in the Visor. Clips that
have not yet been placed on a track will appear listed in the Visor under the
Unused Clips tab.

Reusing clips within Trax | 253

To place clips into a track from the Outliner

1 In the Outliner, using the middle mouse button drag the clip named
Bank_LeftSource into the same track as the Rise and Lower clips. Ensure
you drag into an open area on the track that the clip will fit into.

2 Position the Bank_Left clip on the track so its Frame In number matches
the Frame Out number on the Aircraft_Rise clip, as shown below.

3 Using the middle mouse button drag the clip named Bank_RightSource
from the Outliner into the same track as the Rise and Lower clips. Ensure
you drag into an open area on the track that the clip will fit into.

4 Position the Bank_Right clip on the track so its Frame In number matches
the Frame Out number on the Bank_Left clip, as shown below.

You can also drag clips from the Outliner or Visor into the Trax Editor and
create a new track for them to be placed in.

1 Drag the clip named Shift_Left1Source from the Outliner using the middle
mouse button, but this time, drag to the narrow blue area above the tracks
before releasing your middle mouse button.


A new track appears in the Trax Editor and the clip is placed on the new
track.
The narrow blue box is the summary track for the character set (in this
case the Aircraft) The summary track represents all of the clips under a
character, subcharacter, or group. When you import a clip onto the
summary area by dragging it from the Outliner or Visor, the Trax Editor
creates a new track for the clip.

2 Click-drag the Shift_Left clip so it lies directly below the Bank_Left clip
on the track above it.

Because the Shift_Left clip is positioned directly below the Bank_Left clip,
the actions will occur simultaneously when the animation is played back.

3 Using the middle mouse button drag the clip named Shift_Right1Source
from the Outliner into the same track as the Shift_Left clip . Ensure you
drag into an open area on the track.

4 Position the Shift_Right clip on the track so its Frame In number matches
the Frame Out number on the Shift_Left clip, as shown below.

5 In the front view menu, select Panels > Perspective > persp.
The view updates to display the aircraft from a perspective view.

Reusing clips within Trax | 255

6 Dolly and track the view so you can fully see the area the aircraft will
travel within.

animation.

After the aircraft rises, it travels forwards as before but now it shifts
sideways to the left while one wing tips downwards, and then shifts
sideways to the right, while the opposite wing tips downwards.


Soloing and muting tracks
Soloing a track allows you to see a track play back in isolation from other
tracks. When a track is soloed, the other tracks are disabled and do not play
back. Soloing is useful when you want to review the effect a specific track will
have on a character.

To solo a track

1 In the Trax control area, click the Solo button for the track that contains
the Aircraft_Rise and Bank_Left clips.
The other tracks dim to indicate that they will be disabled when the
animation is played back.

animation.


The aircraft rises, tilts left and right, and then lowers, without moving
forward. Because the other tracks have been shut off temporarily, the
aircraft’s motion is controlled by only one track.


4 Click the Solo button again to enable all the tracks.
The dimmed tracks become active again.

Muting a track disables only the selected track so it does not play back. Muting
is useful when you want to review the animation on one or more tracks
together without specific tracks being activated. You can mute one or more
tracks.

To mute a track

1 In the Trax control area, click the Mute button for the track that contains
the Shift_Left and Shift_Right clips.
The muted track dims to indicate it is disabled.

animation.
The aircraft rises and tilts left and right as it travels forward, and then
lowers. Because the Shift_Left and Shift_Right track is temporarily muted,
only the two remaining tracks affect the animation playback.


4 Unmute the track by clicking its mute button before proceeding to the
next section.

Scaling clips within Trax
You can scale single or multiple clips within the Trax Editor. Scaling a clip
either compresses or expands the animation of a clip so it occurs over a shorter
or longer period of time. The resulting animation occurs faster or slower as a
result.

Scaling clips within Trax | 257

In the next steps, you select the four clips you imported to Trax, and scale
them together so they occur over the same time frame as the Travel_Forward
clip.

To scale multiple clips in the Trax Editor

1 In the Trax Editor, shift-click on the clips: Bank_Left, Bank_Right,
Shift_Left1, and Shift_Right1.
The clip manipulator appears. The clip manipulator appears as a white box
that encompasses the four clips with handles (triangles) on either end
and a circle handle in the center. The clip manipulator allows you to
move or scale multiple clips.

2 Using the clip manipulator, click-drag the right-hand scale handle to the
right until the Frame Out numbers on the Bank_Right and Shift_Right
clips match the Travel_Forward clip (Frame 299).

animation.

When the aircraft travels, the sideways and banking motions occur over
the entire length of the Travel_Forward clip.

4 Click the stop button on the playback controls to stop the playback.

This completes the first half of the Trax lesson. In the second half of this lesson
you work with motion capture data in Trax.


Open the second scene for the lesson
In this second half of this lesson, you work with a second scene file that
contains motion capture data applied to a skeleton.
Motion capture data is produced by capturing the movement of a real human
or animal and digitizing it so it can be applied to a 3D animation character.
Motion capture data contains keyframe animation. Motion capture data is
useful because it can capture the subtle nuances of motion and gesture that
make a character’s actions appear life-like. Motion capture data can
substantially reduce the work related to posing and keyframing your characters.

➤ Open the scene file named Trax_Lesson2.ma.
your Maya project: GettingStarted/Anim/clips.

The skeleton appears in the Maya scene in the standard da Vinci pose.
In this pose, the character stands straight with its arms extended out to
either side. This pose is useful when you need to skin a character, retarget
animation from one skeleton to another, or set a rest pose for the skeleton.
In this half of the lesson you learn how to use the Trax Editor to work
with motion capture data by extending and redirecting the motion for
a character.

NOTE If you are beginning the lesson from this point, you must first set your
panel layouts and display settings for the Trax Editor and Outliner. Refer to
To set a panel layout for use with the Trax Editor on page 241 and To set the
Outliner to display clips on page 241.

Open the second scene for the lesson | 259

If your skeleton doesn’t appear as shown, you will need to increase the
size of the skeleton’s joints.

To resize the joints on the skeleton

1 From the main menu, select Display > Animation > Joint Size.
The Joint Display Scale window appears.

2 Set the Joint Display Scale to 10.

3 Close the Joint Display Scale window.

To preview the motion capture animation

animation.
The skeleton is repositioned and then walks from left to right, stops, and
then sits.

2 Press stop on the Time Slider’s playback control.

Creating clips from motion capture data
When creating a clip from motion capture, it is a good practice to begin by
creating a source clip from the entire motion sequence that excludes the Da
Vinci pose. You can create the clip and save it to the Visor or Outliner directly
without loading it onto a track. You can later revert back to the source clip
and load it into a track if necessary.

To create a source clip of the motion capture data

1 In the Time Slider, set the Playback Start Time to 1.

2 Press the Go to Start of playback range button to return to frame 1 in the
Time Slider.

The skeleton is repositioned at frame 1 where the walking motion begins.


3 In the persp view, select the skeleton by click-dragging a bounding box
around the skeleton.
The skeleton is highlighted. When the skeleton is selected, many red
ticks appear in the Time Slider. The red ticks represent keyframes from
the motion capture data.

4 In the Trax Editor menu, select Create > Animation Clip > .
The Create Clip Options window appears.

5 In the Create Clip Options window, click Edit > Reset Settings to set the
tool to its default settings, and then set the following:
■ Type WalkSit in the Name field.

■ Keys - Leave Keys in Timeline: On

■ Put Clip in Visor Only: On

■ Click Create Clip.

The source clip appears in the Outliner named as WalkSitSource. (If you
use the Visor, the clip appears under the Character Clips tab.)

Extending the length of motion capture data
You often need more animation of a motion sequence than is provided in the
motion capture data. For example, you may need to have a walk cycle that is
substantially longer than what was provided in the original file. You can use
the Trax Editor to edit the motion capture data and create clips that can be

Extending the length of motion capture data | 261

cycled to make longer animation sequences. When you cycle a clip, the clip is
extended in length with duplicate animation from the original clip over a
defined interval of time.
If you want to cycle a clip, you must first determine areas within the animation
sequence where the clip repeats seamlessly. For example, if you want to create
a walk cycle from the motion capture data, you need to determine the time
(frame) where the right foot is planted on the ground, and then move forward
in the Time Slider, frame by frame, until you find the next frame where the
right foot is planted on the ground in exactly the same (or very similar)
manner, and then create a clip. The resulting clip will contain two steps of
the walking motion. The clip can then be cycled to produce a motion that
repeats. How seamlessly it cycles depends on the original motion capture data.
In the steps that follow you create a walk cycle from the motion capture data
by:

■ Creating a clip from the walking portion of the motion capture sequence
that can be repeated.

■ Cycle the clip to create a longer walk sequence.

To create a clip that can be cycled

The skeleton updates in the scene to a walking pose where the right foot
is planted on the ground.

2 Drag the current time indicator forward in the Time Slider until you reach
frame 45.
At frame 45, the skeleton is posed in a similar manner as it appeared at
frame 6. If you use this range of frames (6 to 45), you can create a clip
that can be cycled.

3 In the persp view ensure the skeleton is selected.

4 In the Trax Editor menu, select Create > Animation Clip > .
The Create Clip Options window appears.

5 In the Create Clip Options window, click Edit > Reset Settings to set the
tool to its default settings, and then set the following:
■ Type WalkCycle in the Name field.

■ Put Clip in Trax Editor and Visor: On


■ Time Range: Start/End

■ Start Time: 6

■ End Time: 45

■ Click Create Clip

Two clips appear in the Outliner named WalkCycle and WalkCycleSource.

6 In the Trax Editor, with the skeleton selected, click the Load Selected
Characters icon.

The clip named WalkCycle appears in a new track. Loading the Character
displays any tracks associated with the character; in this case the
WalkCycle clip.


8 Click play on the Time Slider playback controls to play back the clip.
The skeleton takes two steps and stops.


9 Press stop on the playback controls to stop the playback and reset the
current time indicator to frame 1.

10 In the Trax Editor, drag the clip to the left in its track until the Frame In
number reads 1.

This sets the clip to begin at frame 1 in the Time Slider.

In the steps that follow, you cycle the clip to extend the animation so the
skeleton repeats the two step motion and travels farther in the scene.

To cycle the motion for the walk clip

1 In the Trax Editor, shift-drag the lower right corner of the Walk clip to
the right until a C2.0 number appears in the new region of the clip.
When you shift-drag over the Frame Out area, the mouse cursor changes
to a circular pointing arrow to indicate you are cycling the clip.

2 Double-click on the cycled clip in the C2 region.
The region is highlighted to indicate you can edit the values in the region.
The number will likely not be exactly 2.0. This means that the cycle will
not repeat exactly twice.

3 Type 2.0 to modify the clip so it cycles exactly twice.


4 With the clip selected in the Trax Editor, open the Attribute Editor. Open
the Channel Offsets menu and ensure that the WalkCycle clip’s root.scale
and root.translate offset attributes are set to Relative and root.rotate offset
attributes are set to Absolute.

Setting the offset attributes for the clip to Relative ensures that each cycle
begins at the position where the last sequence left off. This ensures that
the skeleton doesn’t jump back to its start point after each cycle.

The skeleton takes six steps and then stops.

When the clip is cycled twice, the two-step walking motion occurs three
times in total.



Redirecting the motion within a clip
Motion capture data can be used in a variety of ways. You can redirect the
motion of a character using the same motion capture data. The Redirect tool
allows you to alter the original animation for a character by modifying its
path or orientation at any time during its animation. The Redirect tool does
this by offsetting the translation and rotation attributes for the selected
character.
For example, you can change the start or end point of a character’s animation
by redirecting the character’s starting position or by redirecting its motion
during the animation. You can redirect a character in an existing animation
sequence in the scene or a character associated with a clip within the Trax
Editor.
In the steps that follow, you redirect the skeleton to turn to the right while
walking. The workflow for the redirection is as follows:

■ Scrub forward in the animation to determine a location in the clip where
you want the character to turn. A realistic choice is where the ball of the
skeleton’s right foot is planted on the ground plane because this accurately
simulates how a real person might turn.

■ Select the entire skeleton. In this example, selecting the entire skeleton
selects it at the root joint (the top node of the skeleton’s hierarchy)
Selecting at the root joint ensures that the entire skeleton gets redirected
when the redirection control is applied.

■ Create and position a rotation redirection control using the Redirect tool.

■ Keyframe an initial starting rotation for the redirection control.

■ Rotate the redirection control so the skeleton faces the new direction of
travel.

■ Keyframe the second rotation for the redirection control.

To create a redirection control for the skeleton

This frame is where the ball of the skeleton’s right foot is planted on the
ground plane. Use this frame as the location where the skeleton will turn
to the right.

2 Select the skeleton in the scene view by click-dragging a bounding box
around it.


3 In the main menu, select Character > Redirect > .

4 In the Character Redirection Options Window set the Redirection Type
to Rotation only and then click the Redirect button.

A Rotation redirection control appears between the hips of the skeleton,
where the root joint for the skeleton’s hierarchy is.

You want the skeleton to pivot (rotate) while standing on the ball of its right
foot. To do this, you need to move the redirection control to the ball of the
right foot of the skeleton.

To move the redirection control to the ball of the foot

1 From the Toolbox, select the Move tool.
The Move tool manipulator appears on the redirect manipulator.

2 Press the v key and click-drag the redirection control until it is located
on the ball of the right foot as shown below.
Pressing the v key while using the Move Tool momentarily enables the
Snap to Points tool.

Redirecting the motion within a clip | 267

The redirection control is now positioned to redirect the skeleton’s walking
motion. To complete the redirection process, you need to set keyframes while
setting the redirection control so the redirection of the skeleton can occur.

To keyframe the redirection control

1 With the redirection control selected, press s to set a keyframe.
A red tick appears in the Time Slider at frame 36 indicating the keyframe.
Setting a keyframe establishes the starting rotation for the redirection
rotation of the skeleton.

The skeleton updates to a position where its left foot is planted on the
ground plane. This is the location where you want the skeleton to be
rotated to its new direction of travel.

3 In the Channel Box, with the redirection control still selected, set the
Rotate Y attribute to -45.

4 Rotate the redirection control approximately -45 degrees about the Y axis
until the skeleton is facing in the direction shown below. (You can use
the Channel Box values as a guide.)


5 With the redirection control still selected, press s to set a keyframe.
Setting a second keyframe establishes when the redirection rotation for
the skeleton ends.

6 Set the current time indicator to frame 1.

7 Click anywhere in the perspective view to deselect any items in the scene.

The skeleton takes two steps and then turns to its right after it reaches
the redirection control, and continues walking in the new direction of
travel and stops when it completes its walk cycle.



NOTE When redirecting motion within Trax, you may want to consider
creating a clip that contains the redirection animation to make it possible to
reposition the redirect animation as a clip.

Now that you’ve redirected the character to a different direction of travel
during the walk cycle, you can reuse some of the motion from the original
source clip you created earlier in the lesson and saved to the Outliner/Visor.
You insert the source clip from the clip Library in Trax. The clip Library keeps
track of the source clips and poses for the current character set. When the
source clip is inserted from the Library, a copy of the source clip is created in
a new track.
Once you import the source clip and make a copy of it, you trim the duplicate
clip to make the character stop walking and then sit in a different location
than the original motion capture.

To insert the source clip

1 In the Trax Editor, select Library > Insert Clip. Choose WalkSitSource
from the drop-down list.
A duplicate copy of the WalkSitSource clip is created, and inserted onto
a new track.

2 In the Trax Editor, select View > Frame All.
The track view area updates to display all clips in their entirety.

3 In the Trax control area, click the Mute button for the track that contains
the WalkCycle clip.

The muted track dims to indicate it is inactive. When the walk cycle track
is muted, the character updates to appear in the Da Vinci pose at the
origin based on the original source clip.

4 Drag the current time indicator to frame 98.
The skeleton updates in the view and the redirection that was applied
also occurs. Remember that the redirection occurs for the character, and
not the clip.

5 Click on the WalkSit clip in the track to select it.


6 In the Trax tool bar, click the Trim Clip Before Current Time icon to trim
the section of the clip that occurs before frame 98.

The WalkSit clip is trimmed and the portion of the clip before frame 98
is discarded.

7 Click the Mute button again for the track containing the WalkCycle clip
to reactivate the track.
The dimmed track becomes active again. The skeleton however has
updated to an incorrect pose near its previous position. This occurs
because the two active clips overlap, and the character is receiving
conflicting positional information as a result. (That is, double translation
and rotation information.)

8 Drag the WalkSit clip to the right in its track until its Frame In number
matches the Frame Out for the WalkCycle clip.
The pose for the skeleton is updated to the correct position.

9 Reset the current time indicator to frame 1.

animation.
The skeleton takes two steps and then turns to its right after it reaches
the redirection control, and continues walking in the new direction of
travel, stops, and then sits.



A small jump cut occurs during the transition between the two clips. The jump
cut occurs because the poses for the skeleton do not match from the end of
the first clip and the beginning of the second. In your own work, try to
anticipate how motion will blend between clips when working in Trax. You
can correct the jump cut in this particular example by extending the WalkCycle
clip.

To extend the WalkCycle clip to correct the jump cut

1 In the Trax Editor, double-click on the WalkCycle clip in the C2 region.
The number becomes highlighted indicating you can edit the number.

2 Type 2.2 to edit the clip so it cycles 2.2 times.
The new Frame Out number for the WalkCycle clip becomes 126. It now
overlaps in time with the WalkSit clip.

3 Drag the WalkSit clip to the right until its Frame In number becomes
126.


animation.
The jump cut is less noticeable than before.

5 Press stop on the Time Slider’s playback control.
You have completed this lesson. Before leaving this lesson, reset the joint
size back to its default setting.

To reset the joint size

1 From the main menu, select Display > Animation.
The Joint Display Scale window appears.

2 Set the Joint Display Scale to 1.

3 Close the Joint Display Scale window.

Beyond the lesson
In this lesson, you learned some fundamental techniques for using the
nonlinear animation tools in Trax. You learned how to:

■ Key animation sequences for use as nonlinear clips in Trax.
Clips can contain minimal or many animated attributes. You can create
clips from existing animation or key animation specifically for use in clips.
You should consider what attributes you need represented in a clip when
you key the animation before you decide to use nonlinear animation in
your work. In this way, a clip can be used to control a specific attribute.

■ Create clips from your animation sequences for use in the Trax Editor.


When you create a clip, a character set is created if one does not already
exist. You can load and work with multiple character sets in the Trax Editor.
To select different character sets when working in Trax you can use the
Select Current Character drop-down menu. Clips can also be arranged,
scaled, and moved as groups. For more information see Move clips and
Track view area in the Maya Help.

■ Use the Trax editor to position, re-arrange, cycle, and scale clips in order
to create and modify animation sequences in the scene.
If a character animates or scales in a manner you had not expected when
working in Trax, you may want to check to see if the clips overlap or are
arranged in a manner that doesn’t provide the expected results. In addition,
a clip containing motion that is intended to be appended to another clip’s
motion must have its Offset attribute set to Relative, and Absolute Rotations
set to On (in most instances). There are many other tasks you can perform
with clips in the Trax Editor that are beyond the scope of this lesson. For
more information see Nonlinear animation components in Trax in the
Maya Help.

■ Use the Trax Editor to work with motion capture data.
The Trax Editor is useful when working with motion capture data. Since
motion capture data usually contains a lot of keyframe information, the
Trax Editor can be useful for creating, modify, and extending the motion
data provided. Cycling and redirecting motion are two methods that can
be used to get more from your motion capture data. For more information
see the section on Motion Capture Animation in the Maya Help.

■ Redirect the motion for a character using the Redirect tool.
You can use redirection controls to redirect any type of motion in Maya
(Keyframe, motion capture, expressions, dynamics, and so on). For more
information and additional examples on redirection see Redirect the motion
of an animated character in the Maya Help.

■ Trim clips in the Trax Editor.
You can trim a clip either before or after the current time indicator
discarding the remainder of the clip in the process. You can also split a
clip into two parts. The original source clip is not affected. For more
information see Split clips in the Maya Help.

Blending clips
You can blend the animation between clips. Blends allow you to create smooth
transitions and mixes between different motions. A blend can be applied
between any two clips that overlap entirely, partially, or not at all. The best
results are obtained when blending between similar motions. In some


situations, a blend can be used to correct jump cuts. For more information
see Create and edit blends in the Maya Help.

Key into clip
You can set keyframes to alter the animation within a clip. This process is
called Keying into a clip. When you key into a clip, keyframes are placed at
the current time on all the animation curves in the selected clip. For more
information see Key into a clip in the Maya Help.

Time Warps
Time Warps let you change the timing of a clip without modifying the clip's
animation curves. You modify the Time Warp by editing the animation curve
that controls the warp. Time Warps can also be used to reverse the animation
in a clip. For more information see Create and edit time warps in the Maya
Help.

Visor and Outliner
Both the Visor and Outliner can be used to access clips. The Visor provides a
graphical interface to access other resources (such as clips, poses, shaders,
textures, and brushes) in your scene. The Outliner displays clips in a textual
manner, and is a bit more compact.

Audio clips
You can display and play multiple audio files in Trax allowing you to
synchronize your motion clips to specific audio events (sound effects, musical
notes, drum beats) in the audio file. Once you import an audio file into Trax,
you can then move and rename the audio clip. For more information see
Work with audio in the Maya Help.


Lesson 5: Inverse kinematics

Introduction

Inverse Kinematics (IK) allows you to efficiently pose your models and
characters for animation. You pose the skeleton by positioning IK handles,
usually located at the end of an IK joint chain (for example at the hand). The
rotations for the other joints are calculated automatically by an IK solver. An
IK solver calculates the rotations of each joint back up the hierarchy of the
joint chain based on the position of the IK handle. See Creating a skeleton
hierarchy on page 281 for more information on skeletons and joints.
By contrast, Forward Kinematics (FK) requires you to rotate each joint in turn
until you have the desired pose for a keyframe. This can be a tedious process
when posing a complex skeleton. When using Inverse Kinematics, it’s faster
to pose a character because the joint rotations further up the hierarchy are
calculated automatically based on the placement of the IK Handle. Using both
FK and IK techniques on the same skeleton is called FK/IK blending.
IK is obviously useful for posing animated characters that have a skeleton and
has other applications, such as posing skeletons within mechanical-like models.
The goal of this lesson is to animate a mechanical arm so that it extends into
a position over a cargo box, picks up and moves the cargo box to another
location, and then sets it down.
As you work through the lesson, you’ll learn about many of the basic features
related to skeleton hierarchies, IK, and parent constraints. Some initial setup


of the model and IK is required so that it can be posed and keyframed to
provide a convincing animation.

■ Create and use hierarchies to define logical relationships between
animatable objects.

■ Combine the components of a 3D mechanical arm model into a
hierarchical grouping.

■ Construct a skeleton for use with IK.

■ Combine the skeleton with the mechanical arm model by parenting the
components into a hierarchy.

■ Create an IK system to allow the skeleton hierarchy to be posed.

■ Create a control object to manipulate the IK system.

■ Use constraints to control the position and orientation of components
within the IK system.

■ Limit the range of movement on the IK system.

■ Pose and set keyframes for the IK system.

■ Animate an object by constraining its motion to two or more objects.

In this lesson, you work with a scene we created for your use. In the first steps
of this lesson, you open the scene and view the various elements that have
been created for your use.


2 Open the scene file named IK_MechArm.mb.
your Maya project: GettingStarted/Anim.
The scene contains a model of a mechanical arm and a cargo box to be
moved by the arm. The components of the mechanical arm include:
■ A cargo magnet cup on the end

■ Three arm segments


■ A base for the arm to swivel about

■ A four-legged base for the assembly

To work with this model using IK you must create a hierarchy for it.

Understanding hierarchies
Inverse Kinematics relies on hierarchical relationships between the components
of a model and the IK system to pose and animate the components. Before
using Inverse Kinematics it is important to understand hierarchies in Maya.
A hierarchy is composed of a series of nodes that are combined for some
purposeful relationship. Individual nodes may represent the surfaces of a
model, a network of textures that describe a shading material, or series of
joints in a skeleton. Hierarchies are structured in a top-down manner, with
one node at the top (the parent node or root node) and other nodes (child nodes
or leaf nodes) attached and interconnected beneath the top node.

Selecting the parent node at the top of the hierarchy also selects the items
contained in the hierarchy below. Selecting a child node lower in the hierarchy
selects any child nodes that are lower in the hierarchy.
Hierarchies allow you to create complex structures with relationships between
components. For example, when you animate a hierarchical model, you simply


need to select and move the parent node of the hierarchy and the rest of the
model (child nodes) also moves.
Regardless of whether you decide to animate the mechanical arm using FK or
IK, or a combination of both methods on the same model, the best approach
involves making the mechanical arm model into a hierarchical structure.
Creating a hierarchy for the mechanical arm ensures that:

■ Components of the hierarchy can be rotated as if they were one unit. A
common pivot point is created at the parent node level. This allows the
separate components to rotate as one unit based on their membership in
the hierarchy. For example, if the mechanical arm’s base (parent node) is
rotated, anything lower down the hierarchy, for example, the mechanical
arm which is constructed of child nodes, will also rotate because of its
membership and position in the hierarchy.

■ When a particular segment of the model is posed and keyframed, the
components that are lower in the hierarchy are also posed and keyframed.

Viewing hierarchies using the Hypergraph
In the following steps, you use the Hypergraph to view the hierarchy for the
mechanical arm. The Hypergraph is a scene management editor that presents
a graphical view of the scene hierarchy. It allows you to more easily create,
understand, and manage the hierarchy of objects and nodes in your scene.

To view hierarchies using the Hypergraph

1 From the perspective view’s panel menu, select Panels > Layouts > Two
Panes Stacked.
The workspace displays two panels stacked on top of each other with an
identical perspective view of the scene.

2 In the lower panel, select Panels > Hypergraph Panel > Hypergraph
Hierarchy.
The lower panel displays the Hypergraph.

Viewing hierarchies using the Hypergraph | 279

3 In the Hypergraph menu, select Graph > Scene Hierarchy.
If the menu item appears dimmed, it indicates that the Hypergraph is
already displaying the scene hierarchy
The Hypergraph displays with a black background by default. In order
to see the relationships between the items, the background has been
modified for the images in this lesson.

4 In the Hypergraph menu, select View > Frame All to see all the
components of your scene.

The boxes represent the nodes for the various items in the scene. Some items
in the scene have already been parented into a hierarchy. This is indicated by
the lines connecting some of the nodes. Selecting the nodes in the Hypergraph
also selects the item in the scene view.

To select an item using the Hypergraph

➤ In the Hypergraph, click each of the separate items in the hierarchy at
the parent level to select them. At the same time, observe which objects
become highlighted on the model in the perspective view.


Hierarchies combine the various objects into discrete components for the
mechanical arm, such as the base, lower arm, middle arm, and upper arm. If
you select and rotate any of the parent nodes in the hierarchies, none of the
other arm components follow because they are not combined into one unified
hierarchy.

Creating a skeleton hierarchy

To link the various components of the mechanical arm into a hierarchy that
can be posed, you need to create a skeleton. A skeleton is a hierarchy of joints
that are connected together with bones.
In the scene, a joint represents a special type of node that gets created in a
skeleton hierarchy. A joint acts as the parent node for any other joints that
occur in the hierarchy below it. Each joint has a rotational pivot point
associated with it. A bone is the visual representation used in the scene view
to connect the joints and help visualize the joint chain.
A skeleton is similar to a skeleton in the real world in that it acts as the
underlying structure for the surfaces to be attached. While you can view the
skeleton with its bones and joints in the scene view, it does not appear in your
rendered images. Its purpose is to assist you in setting up and posing your
models and characters and to visualize the motion you want to achieve.

Creating a skeleton hierarchy | 281

Skeletons are integral to the animation of any character or hierarchical model.
Examples of characters that use skeletons are two and four legged animals.
Skeletons are also useful for animating other organic components such as the
tail of an animal, a tentacle of an octopus, or a snake.
In the following steps, you create a simple skeleton consisting of four joints
that you combine with the mechanical arm model into a skeleton hierarchy,
allowing you to pose and animate the model.

To create a skeleton for the mechanical arm

1 In the perspective view menu, select Panels > Orthographic > side.
The view updates to display the side view.
You need to view the components of the mechanical arm fully in the
side view so you can draw the joints for the skeleton.

2 Resize the side view to a larger size by dragging the border between the
side and Hypergraph panel views downwards.

3 In the side view menu, select Shading > Wireframe (Hotkey 4).


4 From the main menu, select Skeleton > Joint Tool > .
The Tool Settings window for the Joint Tool appears. The Joint Tool is
used to create the joints and bones for a skeleton.

5 In the Joint Tool settings window, do the following:
■ Click Reset Tool to set the tool to its default settings.

■ Hide the Tool Settings window by clicking the right-pointing arrow
that is located in the upper left corner of the Tool Settings window.

6 In the side view, starting from the base of the mechanical arm, do the
following:
■ Click in the center of each pivot pin on the mechanical arm to place
four joints as shown in the image below.

Try to click as close to the center of each pivot pin as you can, as the
rotation of the joints on the model will be based on the location of the
joints on the skeleton. As you place the joints, a bone appears, connecting
each joint. (Because the model lies along the YZ plane, the joints are
created close to the center of each corresponding joint on the mechanical
arm model.)
■ After you place the fourth joint, press Enter to indicate that the last
joint has been placed.


7 In the Hypergraph, dolly the view to see the skeleton node hierarchy you
just created. (It appears at the right side of the view.)

8 In the Hypergraph, select the joint1 node.
The entire skeleton becomes selected. Any rotations on this node also
affect anything lower down the hierarchy.

9 Select joint2 (You can also press the down arrow on your keyboard to
select further down the hierarchy).

The skeleton is selected from joint2 downwards in the hierarchy. Any
rotations that you make on this node affect only joint2 and nodes below
joint2.


Once a skeletal hierarchy is created, the various surface components can be
added to the hierarchy.

Parenting a model into a skeleton hierarchy
Parenting is the term used when placing a node beneath another in a hierarchy
so it becomes the child of the node above it (its parent) in the hierarchy.
In the following steps, you add the surfaces of the mechanical arm model into
the skeleton hierarchy. This process links the models’ surfaces to the skeleton
hierarchy making it possible to pose and animate the model like a real
mechanical arm. Using the Hypergraph to select the nodes allows you to better
visualize the process and the hierarchical relationships that result.

NOTE The following parenting procedure works well for the mechanical arm (no
organic bending or deformation occurs) and provides one technique for adding
modeled objects to a skeletal hierarchy.
A more common technique for combining a character model into a skeleton
hierarchy is referred to as skinning or binding. The Bind Skin tool combines the
surface components and joints together into a hierarchy and also takes into account
any deformations that may occur when a character bends or flexes (such as at the
knees, waist, neck, or elbows). Maya provides a few methods for skinning. For
more information see Skeletons and skinning in the Maya Help. For a tutorial on
skinning see the Smooth Skinning lesson in the Character Setup chapter in this
guide.

To parent the mechanical arm into the skeleton

1 In the Hypergraph menu, select View > Frame All.
The Hypergraph displays all the nodes for the scene.

2 In the Hypergraph, select the node named ArmEnd and then shift-select
the node named joint4.
The order of selection is important. You want to select the child node
first, and then shift-select the item that will become the parent node
second.

3 In the main menu, select Edit > Parent (Hotkey p).
In the Hypergraph, joint4 is now the parent node for the Arm_end node
in the skeleton hierarchy.

Parenting a model into a skeleton hierarchy | 285

4 Repeat the parenting process for the following items:
■ pin3 is parented under joint3



Your new hierarchy should appear as shown in the diagram below.

In the next steps, SwivelBase becomes the parent node for the new
hierarchy so that the entire arm assembly swivels about the center of the
base component.

5 In the Hypergraph, select the node named joint1 and then shift-select
the node named SwivelBase.

Change the panel display to a layout that allows you to view the hierarchy
in the Hypergraph.

7 In the side view menu, select Panels > Layouts > Two panes side by side.
The panels display in a side by side configuration.

8 Dolly the Hypergraph view as required to view the new hierarchy.


9 In the Hypergraph, select the node named Swivel_base.
In the side view, observe that both the mechanical arm model and the
skeleton are selected. Swivel_base is the parent or root node for the
hierarchy. If you rotate SwivelBase, everything else below that node (the
entire arm with skeleton) rotates.

10 Select the node named joint3.
Observe that the last two components of the mechanical arm are selected.
If you rotate joint3, only the components below that node in the
hierarchy will be affected.

11 Select the node named pin2.
Observe that only one isolated segment of the model is selected. No other
components or joints are selected when pin2 node is selected. If you
rotate the model at pin2, only the component at pin2 will rotate in
isolation from the rest of the hierarchy because it is located lower in the
hierarchy.

It is now possible to select and rotate the skeleton joints to pose the mechanical
arm as a unit, and then set keyframes to animate it. Posing a character using
joint rotations is referred to as Forward Kinematics (FK). FK allows for precise
control when setting up a pose, but it can be a time consuming process to
select and rotate each joint into the desired position.
When an animation is more focused on the goal of placing the end joint in
a hierarchy in a particular position, (for example, a hand or a foot), it is more

Parenting a model into a skeleton hierarchy | 287

efficient to use Inverse Kinematics to pose the skeleton. For more information
on forward and inverse kinematics, see Posing skeletons in the Maya Help.

NOTE It’s not a simple matter to state that one technique or another is the only
approach to achieving a desired result when animating in Maya. You must decide
whether a particular technique works for a particular scenario based on the options
it provides. A combination of animation techniques can be creatively used in a
variety of ways.

Applying IK to a skeleton hierarchy
IK allows you to control the joint rotations in a skeleton using an IK handle.
You pose the skeleton by positioning the IK handle (usually located at the
end extremity of the skeleton) and having the rotations for the other joints
calculated automatically by the IK solver. In the steps that follow, you apply
IK to the skeletal hierarchy.

To create an IK handle for the mechanical arm

1 From the main menu, select Skeleton > IK Handle Tool > .
The IK Handle Tool Settings window for the Joint Tool appears. When
the mouse pointer is in the orthographic view its appearance changes to
the tool's cross hair cursor.

2 In the IK Handle Tool Settings window, do the following:
■ Click Reset Tool to set the tool to its default settings.

■ Set the IK Handle Settings: Current Solver - ikSCsolver.


■ Hide the Tool Settings window by clicking the right-pointing arrow
that is located in the upper left corner of the Tool Settings window.

The ikSCsolver setting selects the IK Single Chain Solver. This solver
ensures that the joints in the skeleton will lie along a single plane. This
solver is well suited for the mechanical arm, because the arm doesn’t
need to twist, unlike a real arm.

3 Working in the side view, starting from the base of the mechanical arm,
do the following:
■ Click on the skeleton joint at the base of the mechanical arm.

■ Click on the skeleton joint at the tip of the mechanical arm. (The IK
Tool is designed to attach to the joints closest to your selection point.)

In the side view, the IK handle is drawn as a line from the start and end
joints of the IK chain.

In the Hypergraph, two new nodes appear in the hierarchy that represent
the IK chain: an IK Handle node and an end effector node.

Applying IK to a skeleton hierarchy | 289

5 In the Hypergraph, select the node named ikHandle1.
The IK Handle (in combination with the end effector) is used by the IK
solver to calculate the rotation of the joints in the IK chain. By default,
the IK Handle is located at the last joint of the IK chain in the scene view.

6 Select the Move Tool from the Toolbox, and drag the Move Tool’s Z axis
manipulator (blue arrow) to reposition the mechanical arm.
When you drag the manipulator, the skeleton and mechanical arm model
are repositioned.

7 Reset the mechanical arm to its previous position by selecting Edit >
Undo, Redo, Repeat until the mechanical arm is positioned into its
previous orientation.

NOTE When using the Undo feature, do not undo so many times you
inadvertently undo the IK handle you’ve just created.

The next steps describe how to manipulate the IK Handle using a control
object.

Creating a control object for an IK system
Using the IK Handle to pose an IK chain is generally not a good practice. The
IK Handle can be challenging to select in the scene view, especially when it’s
grouped into a hierarchy that includes a skeleton and other surface
components. A better practice is to create a control object.


You create a control object to select and manipulate an IK system instead of
directly using the IK Handle. You can create a control object with a curve or
a locator, which are often used because they don’t appear in the rendered
image.
The control object controls the movement of the IK Handle using a constraint.
You can constrain the position, orientation, or scale of an object to other
objects using constraints.
To create a control object:

■ Create and position the control object in the scene view.

■ Name the node for the control object in the Hypergraph.

■ Freeze transformations for the control object.

■ Label the control object in the scene view.

■ Constrain the IK Handle to the control object.

To create a control object using a locator

1 From the main menu, select Create > Locator.
A three-dimensional cross is created at the origin in the scene view.


3 In the side view, reposition the locator slightly above and in front of the
end of the mechanical arm as shown in the image below.

To easily identify the locator as a control object in the Hypergraph, rename
the locator.

Creating a control object for an IK system | 291

To rename the control object using the Hypergraph

1 In the Hypergraph, right-click the node named locator1. Choose Rename
from the pop-up menu that appears.
The locator1 name is highlighted on the node.

2 Type the name ArmControl and press Enter to save the name for the
locator.

Before you constrain the IK handle to the control object, you need to freeze
the transformations for the control object. Freeze Transformations zeros the
transformations for an object without changing the position of the object.
This is another good practice; If it becomes necessary to reset the arm to its
default position, you can set the transformation on the control object to zero,
and the arm will return to this default pose.

To freeze the transformations for the control object

1 In the Hypergraph, select the node named ArmControl.
The control object is selected in the scene view.

2 In the main menu, select Modify > Reset Transformations, Freeze
Transformations > .

3 In the Freeze Transformation Options window do the following:
■ Select Edit > Reset Settings to set the tool to its default settings.

■ Click the Freeze Transform button.

The transformations for ArmControl are set to zero. From this point
onwards, you can reset its position to this location by zeroing its
translations in the Channel Box.


To easily identify the locator as the control object in the scene view, label the
control object using an annotation. An annotation is a text label that can be
set to point at the labeled item. Annotations are useful because they always
face the viewer, regardless of the orientation of the model in the scene view.

To label the control object in the scene view

1 In the Hypergraph, select the ArmControl node.

2 In the main menu, select Create > Annotation.
A input window appears.

3 Type ArmControl and click OK.
In the scene view, the word ArmControl appears near the locator/control
object. In the Hypergraph, two new nodes appear in a hierarchy beneath
ArmControl.

4 With the annotation still selected, select the Move Tool.

5 In the side view, drag only the annotation so it appears slightly offset
from the locator object as shown below.
The annotation displays in any scene view so you can easily identify the
control object for selection.

Creating a control object for an IK system | 293

To simplify the display of the Arm Control node

➤ In the Hypergraph, right-click the ArmControl node. Choose Collapse
from the pop-up menu. (You can also double-click a node to collapse or
expand the hierarchy below it.)
The ArmControl node appears as a single node instead of the previous
three node hierarchy. The small arrowhead on the lower left-hand corner
of the node indicates that the node is collapsed.

The control object must be linked to the IK Handle to control the IK Handle.

Constraining an IK system
You can constrain the IK Handle to the control object (ArmControl) using a
point constraint. A point constraint allows the transformation attributes of one
object to be controlled by the transformations of another object. For example,
you select and position ArmControl without having to touch the IK Handle.
You also set the constraint so ArmControl maintains the current distance
(offset) from the IK Handle. The offset ensures that the constrained IK handle
doesn’t move to the same position as the control object.

To constrain the IK Handle to the control object

1 In the Hypergraph, select the ArmControl node and then shift select the
ikHandle1 node.
The order of selection when applying a constraint is important: you must
select the constraining object first, and the item to be constrained second.

2 In the main menu, select Constrain > Point > .
The Point Constraint Options window appears.

3 In the Point Constraint Options window, do the following:

■ Turn on the Maintain Offset setting.

■ Click the Add button.


The IK handle is constrained to the control object. In the Hypergraph, a
constraint node is created beneath the ikHandle1 node.

4 In the Hypergraph, select only the ArmControl node.

5 In the Toolbox, select the Move Tool.

6 In the side view, drag the manipulator to reposition the control object.
(Experiment with a few different positions in the side view only.)
When you drag the manipulator, the control object moves, which in turn
moves the IKHandle. Because the IK handle controls the skeleton and
the mechanical arm model, they also move. The offset between the control
object and the IK Handle is maintained.

The Cargo Magnet does not continuously point downwards when rotated. Its
orientation is based on the rotation it had in its original position.
The mechanical arm will be easier to pose if you set Cargo Magnet to be
oriented downwards towards the floor of the scene regardless of the orientation
of the other components of the arm.

Constraining an IK system | 295

You make CargoMagnet point downwards using an orient constraint. An orient
constraint constrains the orientation (rotation) of the X, Y, and Z axes of one
object to match those of the constraining (target) object.
In the next steps, you reset the position of the mechanical arm to its default
position, and then apply an orient constraint to the last joint in the IK system
so that its orientation matches the control object. The effect is that
CargoMagnet points downwards regardless of any other movement in the
scene.

To set the IK system to its default position


2 Open the Channel Box by clicking the Show/Hide Channel Box icon.

3 In the Channel Box, set the X, Y, and Z transformations for ArmControl
to 0.
Zeroing the transformations on ArmControl resets the mechanical arm
to its home position because of the freeze transformations step you
performed in the previous section.

4 Close the Channel Box by clicking the Show/Hide Channel Box icon.

To apply an orient constraint for the IK system

The Hypergraph displays all the nodes in the scene.


2 In the Hypergraph, select ArmControl and then shift-select the node
named joint4. (You may need to dolly and track the Hypergraph view to
view these nodes.)

3 In the Main Menu bar, select Constrain > Orient > .

4 In the Orient Constraint Options window, do the following:
■ Select Edit > Reset Settings to set the tool to the default settings.


Joint4 is constrained to have the same orientation as the control object.
In the Hypergraph, the constraint node is created below the joint4 node
in the hierarchy.

5 With only the ArmControl node selected, use the Move Tool to reposition
ArmControl in the side view.

CargoMagnet maintains an orientation facing the floor of the scene
regardless of how the mechanical arm is positioned in the side view.

In the next section, you learn how to limit the range of movement for the IK
system.

Constraining an IK system | 297

Limiting the range of motion of an IK system
It’s possible to move ArmControl so that the mechanical arm fully extends
to a straight position or orients itself to other positions that you don’t
necessarily want.
You can limit the range of motion of the arm to ensure that the IK system
poses in a predictable manner. In the following section, you limit the motion
for the IK system as follows:

■ Lock the translation of the control object (ArmControl) so that it can only
move in Y and Z. By locking the X channel so it cannot be selected or
modified, the arm will not be able to move from side to side.

■ Lock the rotations on the swiveling base for the arm so it only rotates
about its Y axis, and not about its X or Z axes.

■ Limit the translations for the Arm Control so the mechanical arm cannot
fully extend to a straightened position.

To lock the Translate X channel for ArmControl


2 Open the Channel Box to view the transform channels for ArmControl.

3 Set all Translate or Rotate channels to 0, if they are not already.

4 In the Channel Box, select the Translate X channel by clicking on its
name.

5 Right click on the word Translate X.
A drop-down menu appears.

6 From the drop-down menu, choose Lock Selected.


The numerical field for Translate X is dimmed indicating that the channel
is locked. If you try to move ArmControl in X, it will not be possible
unless you unlock the Translate X channel.

To lock the Rotate X and Z channels for SwivelBase

1 In the Hypergraph, select only the SwivelBase node.

2 Open the Channel Box to view the rotation channels for SwivelBase.

3 Set all Translate or Rotate channels to 0, if they are not already.

4 In the Channel Box, select the Rotate X and Rotate Z channels by
control-clicking on their names.

5 Right click on either of the selected names.
A drop-down menu appears.

6 From the drop-down menu, select Lock Selected.

To confirm that the Rotate X & Z channels are locked

1 In the Hypergraph, ensure only the SwivelBase node is selected.

2 In the view, select Panels > Orthographic > top.

3 In the view, select Shading > Smooth Shade All.

4 Dolly the top view so you can fully view the mechanical arm as shown
below.

5 Using the Channel Box, rotate SwivelBase by typing 45 in the Rotate Y
channel and pressing Enter.

Limiting the range of motion of an IK system | 299

SwivelBase rotates in the view but the mechanical arm does not rotate.
You first might think something is wrong because SwivelBase and all of
the arm’s skeletons and surfaces are parented into the same hierarchy.

NOTE You may sometimes discover that something doesn’t work in the
manner you originally anticipated when setting up an IK system. When this
occurs, it’s useful to stop and diagnose why something is working the way
it is (or not working the way it should). In that way you can retrace your
actions to determine where the problem resides.

ArmControl and IK Handle are not parented into the SwivelBase hierarchy.
Because ArmControl and IK Handle control the movements of the mechanical
arm, they must be parented into the SwivelBase hierarchy in order for the arm
to rotate when SwivelBase is rotated.

To parent the IK Handle into the skeleton hierarchy

1 In the Hypergraph, select the SwivelBase node.

2 In the Channel Box, reset the Rotate Y channel for SwivelBase to 0.
Setting any previous transformations to zero is necessary before parenting
the IK Handle beneath SwivelBase in the hierarchy.

3 Unselect the SwivelBase node before performing the following steps.

The Hypergraph displays all the nodes for the scene.

5 In the Hypergraph, shift-select the nodes named ikHandle1, ArmControl,
and SwivelBase.


The order of selection is important. You want to shift-select the items
that will be the child nodes first, and then shift-select the item that will
be the parent node last.

In the Hypergraph, IKHandle and ArmControl are now child nodes for
the SwivelBase node in the skeleton hierarchy.

7 In the Hypergraph, select only SwivelBase.

8 Using the Channel Box, set Rotate Y for SwivelBase to 45.

When SwivelBase is rotated, the mechanical arm rotates because of its
relationship within the hierarchy.

9 Reset the Rotate Y value for SwivelBase back to 0.

Finally, you want to limit how far Arm Control can translate away from the
base of the model so the arm does not extend to a fully straightened position.
To determine the settings for the translation limits you need to examine the
position of the mechanical arm in various positions while simultaneously
viewing the translation values in the Channel Box.


To determine translation limits for the Arm Control

1 In the Hypergraph, select ArmControl.

2 Ensure the Channel Box is open so you can view the translate channels
for ArmControl.

3 In the view, select Panels > Orthographic > side.

4 Dolly the side view so you can fully view the mechanical arm.

5 Select the Move Tool.

6 In the side view, press the middle mouse button and drag the mouse
diagonally until the mechanical arm is fully extended as shown below.

7 In the Channel Box, observe the number that displays in the Translate
Y and Z channels.
When the arm is diagonally articulated above the cargo box, it is almost
fully extended when the translation values are roughly as follows:
■ Translate Y: 7.5

■ Translate Z: 1

8 In the side view, press the middle mouse button and drag the mouse in
a diagonally until the mechanical arm is almost fully compressed as
shown below.


9 In the Channel Box, observe the numbers that display in the Translate
Y and Z channels.
When the arm is articulated to a compressed pose, the translation values
are roughly as follows:
■ Translate Y: -13

■ Translate Z: -13

These minimum and maximum values will be used in the steps that
follow as the minimum and maximum translation limits for the
ArmControl.

To set translation limits for the Arm Control


2 Open the Attribute Editor (Window > Attribute Editor or click on the
Show/Hide Attribute Editor icon on the Status Line).

The Attribute Editor displays the nodes associated with Arm Control.

3 In the Attribute Editor, click the ArmControl tab.
If the ArmControl tab is not visible, use the left and right scrolls arrows
to scroll the view sideways to view it.

4 In the Attribute Editor, expand the Limit Information attributes, and
then the Translate attributes.


5 In the Translate attributes, click the Trans Limit Y and Z check boxes to
undim the numerical boxes and then set the following values:
■ Trans Limit Y (Min): -13

■ Trans Limit Y (Max): 7.5

■ Trans Limit Z (Min): -13

■ Trans Limit Z (Max): 1

6 Hide the Attribute Editor.

7 Select ArmControl.

8 In the side view, move ArmControl to test the range of movement for
the IK system.
The mechanical arm moves with a limited range of motion.

Simplifying the display of a hierarchy
The number of nodes in the IK system’s hierarchy at this point may appear a
bit overwhelming, but it allows the posing of the mechanical arm to be efficient
and effective. You can simplify the display of the nodes by collapsing portions
of the hierarchy.

To collapse the display of the hierarchy

1 In the Hypergraph, right-click on joint1, and choose Collapse from the
pop-up menu.


The child nodes below joint1 disappear, simplifying the display of the
hierarchy. The small arrowhead on the corner of the joint1 node indicates
that a hierarchy exists below joint1. If you later need to view or select
these nodes you can expand them again.

2 Collapse the ArmControl and IKHandle nodes.
The display of the hierarchy is simplified as shown below.

The IK system is now rigged and ready for animation.

Applying parent constraints on an IK system
To animate the cargo box so that it is picked up by the mechanical arm you
need a method of constraining the cargo box to the mechanical arm so that
it moves with the arm at specific times in the animation. This is accomplished
using a parent constraint.
When a parent constraint is applied to an object, the constrained object
behaves as if it were a child node of the constraining object.
An object can have multiple constraints applied to it. The influence each
constraint has on the object can be changed by modifying the weight attribute
for the parent constraint. The weight attribute is an animatable parameter
and can be set to be on or off at specific frames.
In this lesson, the cargo box is constrained to both the ArmControl and the
Platform on the floor. By animating the weight attributes for these two parent
constraints, the cargo box will move from one location to another depending
on which constraint is influencing it at specific times in the animation.
To set up the parent constraints you need to position the constrained object
at the locations where the influence will begin or end, and then set the parent
constraints.

To set parent constraints for the cargo box

1 In the side view menu, select Shading > Smooth Shade All.

2 In the side view menu, select Panels > Perspective > persp.

3 In the Hypergraph, select ArmControl.

Applying parent constraints on an IK system | 305

4 In the Channel Box, set the Translate Y and Z values as follows:
■ Translate Y: -9

■ Translate Z: 0

The arm is repositioned so that the cargo magnet is directly above the cargo
box as shown below. Track, tumble, or dolly the view if required so you can
see the mechanical arm unobstructed.

1 In the Hypergraph, with ArmControl still selected, shift-select the
CargoBox node.
The order of selection is important when you apply constraints. You must
select the constraining object first, and the item to be constrained second.

2 In the main menu, select Constrain > Parent > .

3 In the Parent Constraint Options window, do the following:


CargoBox is constrained to ControlArm. A new constraint node has been
created below the CargoBox node in the Hypergraph. If you reposition
the mechanical arm, CargoBox moves with it because of the constraint
that is now applied.

4 In the Hypergraph, select only SwivelBase.


5 In the Channel Box, set the Rotate Y value for SwivelBase as follows:
■ Rotate Y: -100

The mechanical arm and the cargo box are positioned as shown below.

6 In the Hypergraph, select Platform and then shift-select the CargoBox
node.

7 In the main menu, select Constrain > Parent.
CargoBox is constrained to Platform. This is the second constraint for
the CargoBox.

8 In the Hypergraph, select only CargoBox.

9 In the Channel Box, view the parent constraints for CargoBox.

CargoBox has two parent constraints applied to it: Arm Control and
Platform. In the Channel Box, the numerical settings beside ArmControl
W0 and Platform W1 represent the influence weight each parent
constraint has on CargoBox. At this point, each influence weight is set

Applying parent constraints on an IK system | 307

to a value of 1. If you move the mechanical arm, the cargo box will move
somewhere between its first and second position. This occurs because
each constraint has equal influence on the cargo box at this point.

Before you can animate the objects in the scene, you also need to reset the
default weight values for each constraint, so that one parent constraint has
full influence on CargoBox when the other does not.

To set the weighting for the parent constraints


■ Platform W1: 0

3 Select only SwivelBase.

4 In the Channel Box, set the Rotate Y value to 0.
The mechanical arm and cargo box are rotated back.


6 In the main menu, select Constrain > Set Rest Position.
Setting a rest position for CargoBox sets a position for the cargo box when
no constraints are acting upon it. If the rest position is not set, CargoBox
will be repositioned to the second constraint position.

■ ArmControl W0: 0

At this point, both parent constraints are set to have no influence on the
cargo box because their weight attributes are set to zero. When you
animate the components in the scene, the weight attributes for the parent
constraints will be set and keyframed depending on which constraining
object (Arm or Platform) is required to have full influence.

In the next steps, you plan the action for animation of the IK system.

Planning an animation for an IK system
Now that the mechanical arm and cargo box are fully set up for animation
it’s a simple matter to pose the arm and set keyframes. Prior to setting any
keyframes you should take a few moments to plan the action for the scene.


Planning the action usually involves sketching a simple storyboard, and writing
out a brief timeline for the action for each component. In this lesson we’ve
provided a simple version for you. The basic premise for the action is as follows:

■ The cargo box is positioned directly in front of the mechanical arm.

■ The mechanical arm extends, and positions the cargo magnet to be directly
touching the top of the cargo box.

■ The mechanical arm extends upwards, lifting the cargo box, and rotates
to the side.

Planning an animation for an IK system | 309

■ The mechanical arm lowers the box, placing it in a new position.

■ The mechanical arm extends upwards, leaves the cargo box in the new
location, and rotates back to its original position.

The table below breaks down the action indicating what action occurs for
each object at the specified keyframes.

Frame Mechanical Arm Cargo Box

1 Collapsed position Initial position

30 Vertically extended position Initial position

60 Vertically lowered so that Initial position
cargo magnet is positioned
on top of cargo box

80 Vertically lifted to extended Cargo box lifted with
position with cargo box mechanical arm

100 SwivelBase rotated along Cargo box repositioned
with arm to side along with mechanical arm

120 Vertically lowered along Cargo box is lowered along
with cargo box to second with mechanical arm to
position above surface second position

140 Vertically lifted to extended Second position
position

160 SwivelBase rotated with Second position
arm to original position

180 Collapsed position Second position


To pose the mechanical arm you select either the ArmControl or SwivelBase
nodes and set a keyframe depending on which component you want to pose:

■ ArmControl controls the movement of the mechanical arm.

■ SwivelBase controls the rotation of the arm.

■ CargoBox’s position is based on the parent constraint weights.

Animating an IK system
The animation sequence occurs over a 180 frame period. Before you begin to
set keyframes you set the playback range in the Animation Timeline/Slider.

To set the playback range in the Time Slider

➤ In the Animation Time and Range Slider, set the following start and end
times for the animation:
■ Playback Start Time: 1


To simplify the keyframe workflow, you first set keyframes for the mechanical
arm, and then set keyframes for the weight attributes of each parent constraint
for the cargo box.

To set keyframes for the mechanical arm

1 In the Timeline, set the Time Slider to frame 1.

2 Select only ArmControl.

3 In the Channel Box, set the following values:
■ Translate Y: 0

■ Translate Z: -13

4 From the main menu, select Animate > Set Key.

Animating an IK system | 311

To set the remaining keyframes for the arm and the swivel base, use the table
below as a guide, and set the attributes in the following order:

■ Set the frame using the Time Slider.

■ Set the attributes for the object in the Channel Box.

■ Set the keyframe (Animate > Set Key).

NOTE Don’t be concerned if the list of keyframes indicates to set a key twice
for the same position over two frames. This is necessary to animate the parent
constraint weights over a period of one frame.

Frame Select Set attribute Select

1 ArmControl TransY: 0 Set Key
TransZ: -13

TransZ: -13

59 ArmControl TransY: -9 Set Key
TransZ: 0

TransZ: 0

TransZ: -13

80 SwivelBase RotateY: 0 Set Key

100 SwivelBase RotateY: -100 Set Key

TransZ: -13

TransZ: 0

TransZ: 0

TransZ: -13

140 SwivelBase RotateY: -100 Set Key

160 SwivelBase RotateY: 0 Set Key



TransZ: -13

TransZ: -13

Once the keyframes for the mechanical arm are set you can use the playback
controls to playback the motion for the mechanical arm.


1 Click play on the TimeSlider playback controls to play the animation.
The mechanical arm animates over 180 frames. The cargo box does not
move because the weight attributes for the parent constraints are set to
zero and have not yet been set for the animation.

2 Click stop on the TimeSlider playback controls to stop the playback.

In the next steps, you set keyframes for the parent constraint weight attributes
so the cargo box is lifted, moved, and placed in the second location. You set
keys for the weight attributes on the parent constraint node.

To set keyframes for the parent constraint weights

1 In the Timeline, set the Time Slider to frame 1.

2 In the Hypergraph, select the node for the parent constraint directly
below CargoBox.

3 In the Channel Box, set the following values (if they are not set already):
■ ArmControl W0: 0

■ Platform W1: 0

4 In the Channel Box, select the ArmControl and Platform channels by
shift-clicking on the names.

Animating an IK system | 313

5 Right-click on either one of the selected names.

Key Selected sets a keyframe for the selected attributes only.

To set the remaining keyframes for the parent constraint weights, use the table
below as a guide, keeping in mind that you set the attributes in the following
order:

■ Set the frame using the TimeSlider.

■ Set the parent constraint attributes in the Channel Box.

■ Right-click on the selected names and select Key Selected.

1 CargoBox parent- ArmControl W0: 0 key selected
Constraint Platform W1: 0






1 Click play on the TimeSlider playback controls to play back the animation.
The mechanical arm moves through the motion of the animation and
picks up and moves the cargo box to the new location.


2 Click stop on the TimeSlider playback controls to stop the playback.
You have completed this lesson.

Beyond the lesson
In this lesson, you completed the animation of a mechanical arm model that
picked up and moved a cargo box. You learned how to:

■ Construct a model hierarchy to provide relationships between the
components for posing and keyframing.

■ Construct a single chain skeleton to pose the arm model using Inverse
Kinematics.
It is common to create characters with multiple joint chains. For example,
two and four-legged characters would use multiple joint chain skeletons
to assist with posing their hierarchical structure. See Skeleton hierarchy in
the Maya Help. For a tutorial on creating a multiple chain skeleton see
Lesson 1: Skeletons and Kinematics (Introduction on page 318).

■ Parent the components of the mechanical arm model into the skeleton
hierarchy.
Parenting is one method for combining a model into a skeleton hierarchy.
When using characters that have bending or deforming features a more
common technique is to use Skin > Bind Skin. For more information see
Skeletons and skinning in the Maya Help. For a tutorial on smooth skinning
see Lesson 2: Smooth Skinning (Introduction on page 318).
An easy method to parent one node to another using the Hypergraph is
to drag one node over top of the other using your middle mouse button.

■ Create an IK system with a control object for manipulation.
It is very common to create characters with multiple joint chains and
multiple IK handles to control them. Control objects simplify the selection
and posing of the character.

■ Use three types of constraints (Point, Orient, Parent) to control components
of the IK system and other components in the scene.
Constraints are useful for animating the attributes of one object based on
the attributes of another. Other types of constraints not covered in this
lesson include aim and scale constraints. See Aim constraints and Scale
constraints in the Maya Help.
Using the parent constraint, the platform could also be animated to move
the cargo box as if it were on an elevator, or a conveyor belt.


■ Apply limits to the movement of the IK system.
In this lesson, you constrained the translation of the control object in
order to constrain the movement of the IK. It is not recommended that
you set limits on the rotation of an IK system as it limits how the solver
calculates the position of the joints. See Setting up joints for posing and
animation in the Maya Help.
Although not covered in this lesson, it is possible to simplify the display
of attributes in the Channel Box so that only the animatable attributes
associated with a character are displayed.

■ Pose and set keyframes for an IK system.


Character Setup
7
Introduction
A typical 3D character can be made up of many surfaces and components. To
ensure that the character animates in the way that you want, it is important to
carefully plan the process of character setup.
Character setup or rigging is the general term used for the preparation of 3D
models with their accompanying joints and skeletons for animation.
Depending on the model to be animated, character setup can involve the
following techniques:

■ Creating a skeleton with joints that acts as a framework for the 3D character
model. You set limits on the joints so they rotate in a convincing manner.
When you animate the character, you will be posing the character via its
joints using either forward or inverse kinematic techniques (FK or IK).

■ Binding the 3D surfaces to the skeleton so that they move together. The
process of binding may also include defining how the character’s joints bend
or how the skin surfaces bulge to simulate muscles.

■ Defining and setting constraints for particular animated attributes in order
to restrict the range of motion or to control an attribute based on the
movement of another.

■ Grouping surface components such as CVs into sets called clusters so that
parts of the character can be animated at a more detailed level.

This chapter introduces you to the most common character setup features:

■ Lesson 1 Skeletons and kinematics: Introduction on page 318

317

■ Lesson 2 Smooth skinning: Introduction on page 333

■ Lesson 3 Cluster and blend shape deformers: Introduction on page 344

1 To ensure the lessons work as described, select the Animation menu set.
Unless otherwise noted, the procedures in this chapter assume the
Animation menu set is selected.



Lesson 1: Skeletons and kinematics

Introduction
After you model the surfaces that make up a human, animal, or other character,
you create a skeleton and bind it to the character’s surface (called skin).
A skeleton provides a structure for animating the character. When you create
a skeleton in Maya, you create a series of bones with joints in the skeletal
locations where you want the character to bend or twist. (You can animate a
skeleton without having a skinned character.)
In this lesson, you learn the techniques for creating a simple skeleton for a
human character. You will learn how to:

■ Create joints for a character.

■ Name joints in the Hypergraph.

■ Use symmetry when creating a character.

■ Parent joints into an existing skeleton.

■ Use Inverse Kinematics (IK) techniques to pose a skeleton.

318 | Chapter 7 Character Setup

Learning how to bind a character to a skeleton is described in the next lesson.


In this lesson, you’ll work with a scene that we created for your use. The scene
contains a human character. In the remainder of the lesson, you’ll create and
animate a skeleton for the character.

To open the scene


2 Open the scene file named Skeleton.mb.
your Maya project: GettingStarted/CharSetup.
The character displayed in the scene, Jackie, is a template, so you cannot
unintentionally select it during the lesson. Jackie was modeled in the Da
Vinci pose, the position that’s easiest for creating a skeleton.

Creating joints
A skeleton is made of bones and joints. When you create a skeleton in Maya,
you create a series of joints in the skeletal locations where you want the
character to bend or twist.
A common technique for creating a skeleton is to create several independent
joint chains—one for each arm, one for each leg, one for the spine/head—then
group the chains together to create a single skeletal hierarchy. In the steps
that follow, you create the joints for the legs.


To create joints for the legs

1 Select Window > Settings/Preferences > Preferences. In the Preferences
window, click the Kinematics Category. Enter 0.4 for the Joint Size, then
click Save.
This displays the joints smaller when you create them in the next steps.
At the default size, 1.0, the size of the joints makes them hard to position
accurately for this character.

NOTE The default joint size of 1.0 has been used to create the joints pictured
in the following illustrations. The joints you create may appear smaller than
those pictured in this lesson.

2 Select Skeleton > Joint Tool. This is the tool for creating the joint chains
that make up a skeleton.

3 In a side view, click at the hip, knee, ankle, ball of foot, and toe to create
joints at these positions. Make sure the knee joint is in a position that
creates a slight forward bend. The forward bend ensures that you will be
able to animate the leg easily in a direction natural for a leg.


4 Press Enter (Windows and Linux) or Return (Mac OS X) after creating the
toe joint. This completes the joint chain.

5 Select Window > Hypergraph: Hierarchy.
The Hypergraph is a convenient place to select, rename, and parent
objects. It is similar to the Outliner, but it has features tailored for
character setup. For example, it depicts all parent-child relationships in
an easy-to-read indented format.
The Hypergraph shows the default names given to the joints just created:
joint1, joint2, and so on. The joints have a hierarchical relationship.
Joint1 is the parent of joint2, which is the parent of joint3, and so on.
Joint1 is the root of the hierarchy. If you reposition joint1, you reposition
the whole joint chain.
In the scene view, joints are represented by spherical icons. Bones separate
the joints, and are represented by elongated pyramid icons. The narrow
part of a bone points in the downward direction of the hierarchy.
The reason you create the hip joint first and the toe joint last is to have
the hip at the top of the hierarchy and the toe at the bottom. You’ll
usually want the toe (and other joints) to move whenever you move the
hip, but not necessarily vice versa. In general, joint chains emanate from
the interior of the character outward.

6 Rename the joints as left_hip, left_knee, left_ankle, left_ball, and left_toe.
To rename a joint, right-click the joint name in the Hypergraph and select
Rename from the drop down menu. Type the new name and press Enter.

7 In the front view, click the left_hip joint to select it. Move it along the
X-axis to the center of the top of the left leg. (In this lesson, left and right
refer to directions from Jackie’s point of view, not from your view of the
scene.)
As mentioned before, when you move a joint, all joints lower in the
hierarchy move with it. If you press Insert (Windows and Linux) or Home
(Mac OS X) while a joint is selected, you can move the joint without

Creating joints | 321

moving joints below it in the hierarchy. (To exit this mode, press Insert
or Home again.)

NOTE You may need to rotate left_hip so that the skeleton fits inside the leg.
It’s unnecessary to fit the skeleton perfectly inside the character, as it won’t
be displayed when you render an image from the scene.

8 To create the joints for the other leg, you can save time and ensure
symmetry by duplicating the existing leg joint chain with mirroring.
With left_hip selected, select Skeleton > Mirror Joint > . In the options
window, turn on YZ for Mirror Across.

Jackie’s legs straddle the YZ plane, so mirroring the joint chain across the
YZ plane positions the duplicate joint chain in the desired location. This
operation illustrates that Jackie’s original position affects the ease with
which you can create the skeleton. Had Jackie been positioned away from
the origin, you would not have been able to use Mirror Joint conveniently
to duplicate the leg’s joint chain.

9 Enter left in the Search For field and enter right in the Replace With field.
The Replacement names for duplicated joints feature automatically
replaces the names of all duplicate joints with the specified joint prefix.

10 Click the Mirror button.
The right leg bones and joints appear in a mirrored position.

In the next steps, you create a joint chain for the spinal column. You also
extend a joint from the upper neck region of the joint chain so that you can
animate the jaw.


To create joints for the spine and jaw

1 In the side view, use the Joint Tool to create a series of joints at the
locations shown here. Start at the base of the spine near the existing hip
joints (left_hip and right_hip) and end at the top of the head. Make sure
you create the first joint a little bit away from the existing hip joint
displayed in the front view. Otherwise the first joint will be connected
to the hip joint. Remember to press Enter (Windows and Linux) or Return
(Mac OS X) when you are done creating the joint chain.

With the exception of the joints at each end of the joint chain, the joints
are located where the character is likely to bend or twist at the spine and
neck.
The S-shaped curvature of the joint chain resembles Jackie’s spinal
curvature. This makes it easier to animate the character’s torso and neck
naturally.

Creating joints | 323

2 Starting at the base of the spine, name the joints back_root, pelvis,
lower_back, mid_back, upper_back, lower_neck, upper_neck, and crown.

3 To set up the skeleton for jaw movement, extend a joint from the
upper_neck joint. With the Joint Tool selected, click the upper_neck joint
in the Hypergraph to select it, then click to create a new joint near the
lips, and press Enter or Return. Name the new joint as jaw.

Creating joints for the arms is similar to creating joints for the legs.

To create joints for the arms

1 In the front view, create a series of joints at the locations shown in the
figure. Start at the pectoral region (near the upper_back joint) and end
at the wrist.

2 Name the joints left_arm_root, left_shoulder, left_elbow, and left_wrist.

3 In the top view, select the left_elbow joint, select the Move tool, press
Insert (Windows and Linux) or Home (Mac OS X), then move the joint
to the back of the arm. Press Insert or Home again.


Moving the joint to the back of the arm creates a bend at the elbow. This
will make it easier to animate the character’s arm in the direction an arm
naturally bends.

4 In the perspective view, select left_arm_root. Select Skeleton > Mirror
Joint. This creates a copy of the left arm’s joint chain for the right arm
and renames them in the process.
The right arm bones and joints appear in a mirrored position.

Adding joints to a skeleton
When you bind a character to a skeleton (described in the next lesson), the
skeleton provides a structure for the character’s skin and prevents the skin
from collapsing as you pose the skeleton.
It’s useful to add extra joints in areas of the character where you want the
surface to keep its volume upon deformation. In the next steps, you’ll add
ribs to Jackie’s skeleton. Although you will not bind the character in this
lesson, the technique of adding ribs is important to learn so that when you
do bind a character, the skin in the torso area will not collapse as you pose

Adding joints to a skeleton | 325

shoulder and spinal rotations. The rib joints are for structure only, not for
posing the skeleton.

To add ribs to the skeleton

1 In the Hypergraph, click the mid_back joint to highlight the joint in the
front view. Remember the location of the joint in the front view so you
can select it later.

2 Select Skeleton > Joint Tool.

3 In the front view, click on the mid_back joint to select it again.

4 Click to the side of the joint to add a rib bone, then press Enter (Windows
and Linux) or Return (Mac OS X).

5 With the same technique as in the prior steps, create two more ribs for
the left side. The ribs extend from the mid_back, lower_back, and pelvis
joints.

6 For easy identification in the Hypergraph, you can optionally name the
ribs as desired. For instance, name them left_top_rib, left_mid_rib,
left_bottom_rib, and so on.

7 Mirror the left rib joints to create ribs for the right side of the skeleton.


Creating a skeleton hierarchy
So far you have created five separate joint chains: one for the spine, and one
for each arm and each leg. You need to create a single hierarchy from the five
joint chains so you can move all of them as a single unit. To create the single
hierarchy, you parent the arms and legs to the nearest joint in the spine.

To parent the arm and leg joint chains to the spine

1 In the Hypergraph, use the middle mouse button to drag left_arm_root
to upper_back.
When you parent one joint to another, Maya creates a bone that connects
the parent to the child. In this case, the bone connects upper_back to
left_arm_root.

2 Use the middle mouse button to drag right_arm_root to upper_back.

3 Use the middle mouse button to drag left_hip to back_root.

4 Use the middle mouse button to drag right_hip to back_root.
Now if you need to move the entire skeleton, you can move
back_root—the root of the hierarchy. The completed skeleton is shown
in the following figure (with Jackie hidden):

Forward and inverse kinematics
There are two techniques for posing a skeleton: forward kinematics and inverse
kinematics.


Forward kinematics (FK)
To pose a character with forward kinematics, you rotate each joint individually
until you get the desired positioning. For example, to move a hand to some
location, you must rotate several arm joints to reach the location.
When you animate a skeleton posed with forward kinematics, Maya
interpolates the joint rotations starting with the root joint, then the root’s
child joints, and so on down through the skeleton’s action hierarchy. Maya
proceeds forward through the action hierarchy, starting at the root joint.
Forward kinematics is intuitive for creating simple arc motions, but it’s tedious
if you are animating a complex skeleton. It’s also not intuitive for specifying
goal-directed motion. For example, to move a hand to some location, it’s not
obvious how to rotate the joints in an arm.

Inverse kinematics (IK)
With IK, you create an extra control structure, an IK handle, for certain joint
chains such as arms and legs. An IK handle lets you pose and animate an entire
joint chain by moving a single manipulator.
As you pose the IK handle, it automatically rotates all the joints in the joint
chain. For example, if you move a hand to a doorknob, the other joints in the
arm rotate to accommodate the hand’s new positioning.
IK is more intuitive than forward kinematics for goal-directed motion because
you can focus on the goal rather than on how you need to rotate each joint
to achieve that goal.

Posing and animating using inverse kinematics
Next, you create IK handles that you’ll later use to pose the arms and legs.
The next steps describe some initial setup you should perform before creating
the IK handles.

To set up the character prior to creating IK handles

1 Select the root of the hierarchy, back_root, and then select Skeleton > Set
Preferred Angle.
This sets the current joint angles throughout the skeleton as the preferred
angles. This is a useful step after you complete a skeleton. Maya thereafter
uses the current bend in the knees and elbows as the preferred initial
rotation direction of these joints during inverse kinematics (IK) posing.


This makes it easier to pose the character with motion that is natural for
a human character.

2 Select Jackie in the Outliner and, from the main menu, select Display >
Hide > Hide Selection. (You must select Jackie from the Outliner because
Jackie is a template object.) By hiding Jackie, you’ll lessen scene clutter
as you pose the skeleton in the following steps.

To create, pose, and animate IK handles for the legs

1 Select Skeleton > IK Handle Tool > .

2 In the Tool Settings window, make sure Current Solver is set to ikRPsolver.
This type of IK solver has characteristics that work well for this
application.

3 In the perspective view, click left_hip and left_ankle.
This creates an IK handle that lets you control all joints from left_hip
through left_ankle. The handle’s main manipulator is at the left_ankle.
The IK handle is the selected object after you create it. If you
unintentionally cancel the selection of the handle, you can select it again
by clicking the left_ankle—the last joint you clicked after using the IK
Handle Tool. Whenever you select a handle, make sure you do not select
joints or other objects along with the handle. You can check the Outliner
to confirm your selection.

4 Go to the start of the playback range.

5 With the IK handle selected, select Animate > Set Key to key the leg’s
current position at the first frame.

6 Go to frame 12.

7 In the side view, use the Move tool to drag the IK handle up and to the
left, as if Jackie were stepping up a staircase. The foot and knee move
while the hip stays in place.

Posing and animating using inverse kinematics | 329

8 Set another key for the IK handle.

9 Go to frame 24. Move the IK handle back to its prior position. Set another
key.

10 Play the animation to see the leg step up and down during the first 24
frames.
This completes a simple animation of the leg using an IK handle to control
its position.

To practice additional IK techniques

1 Go the start of the animation.

2 In a perspective view, practice posing the leg in various directions by
moving the IK handle.
No matter how far you drag the handle manipulator, the joints of the
leg will not stretch beyond the straight leg position. This is desirable; you
do not want the size of a skeleton to change as you pose it. However, if
you drag a leg joint, the bone hierarchically above that joint will lengthen.
This is why it’s important to check that you haven’t selected a joint with
the IK handle before you move the handle.
As you drag the handle to some positions, you might notice the leg joints
flip abruptly (see the next figure for an example position). It’s therefore
hard to control the leg positioning in this region.


The default IK handle (IK Rotate Plane handle) has manipulators you can
use to avoid joint flipping. With the handle selected, select Modify >
Transformation Tools > Move Tool, Rotate Tool, Scale Tool, Show
Manipulator Tool. Move the Pole Vector XYZ manipulator to a slightly
different position (see the following figure).
If this doesn’t solve the problem, rotate the Twist manipulator to rotate
the leg. You can key the Pole Vector XYZ and Twist attributes to fixed
values to avoid the flipping as the character moves.
A more precise way to avoid joint flipping, which requires some initial
setup, is to use a Pole Vector Constraint. For more information see the
Maya Help.

3 Repeat the preceding steps for the right leg. (Create an IK handle for the
right_hip to right_ankle, then practice posing and animating the handle.)

NOTE If you want to move the entire skeleton, group the back_root and all
IK handles under a single node, select the group node, and then use the
Move tool. With this grouping, the motion of the entire skeleton won’t conflict
with the keys you set for the handles.

To create, pose, and animate IK handles for the arms

1 Select Skeleton > IK Handle Tool.

2 Click left_shoulder, and then click left_wrist. This creates an IK handle
for the left arm.

Posing and animating using inverse kinematics | 331

3 Select Skeleton > IK Handle Tool.

4 Click right_shoulder, then click right_wrist. This creates an IK handle for
the right arm.

5 Practice posing and animating the handles.

Posing and animating using forward kinematics
As the last part of the lesson, you can optionally practice posing and animating
the character by rotating joints that are not controlled by IK handles—the
ball joints of the feet, and joints from the back_root through the upper_neck.
Rotating such joints is forward kinematics.
With the exception of the back_root, you’ll invariably rotate rather than move
the joints that aren’t part of an IK handle. If you move the joints, the bones
lengthen. This deforms bound skin undesirably unless you are creating
cartoon-like distortions.
Because you’ve already set keys for IK handles, some joint rotations on non-IK
handle joints will be restrained by the IK handle positioning. If this interferes
with the intended poses, you can remove all prior animation from an IK handle
by selecting Edit > Keys > Delete Keys. You can also use Delete Keys to remove
all animation from keys you’ve set with forward kinematics.

Beyond the lesson

■ Create a skeleton with bones and joints.

■ Pose the skeleton using Inverse Kinematics.

Additional things to consider when working with skeletons:

■ The appropriate number of joints in a skeleton depends on the anatomical
parts of the character you want to manipulate. More joints means finer
control at the expense of greater complexity.

■ As you created the skeleton in this lesson, you ended the arm’s joint chain
at the wrist. This prevents you from animating hand motion. If you need
to animate hand motion or even finger motion, you would need to make
additional joints and IK handles. The same applies to foot and toe motion.


■ When you create a skeleton, you can animate a character bound to it to
produce natural skin deformations. Although you animated an unskinned
skeleton in this lesson, it’s more common to animate a skinned skeleton.
Binding a character is the topic of the next lesson.

■ It’s typically best to animate the entire skeleton from pose to pose at desired
frames. It’s hard to get desired results by animating one limb for a frame
range, another limb for a frame range, and so on.

There are many other ways to work with skeletons not described in this lesson:

■ You can blend or switch between IK and forward kinematics on joints
controlled by an IK handle.

■ There are other types of IK handles that provide different controls for
manipulating parts of a skeleton. Especially noteworthy is the IK spline
handle, which makes it easy to animate the twisting, wavy motion in tails,
necks, spines, snakes, and so on.

For more details on these and other features, please refer to the Maya Help.

Lesson 2: Smooth skinning

Introduction
After you create a skeleton, you bind it with the character’s surface so that the
surfaces move with the skeleton during animation. Binding is also called
skinning, and a character’s surface after binding is called a skin.
It is important that the character’s skin deforms naturally as the skeleton
moves. Near joints, the skin bulges or indents when you rotate the joints.
In Maya, the skin deforms because the surface’s vertices (or CVs) move in
response to the rotation of adjacent joints. The vertices are known as skin
points. This is useful for animating elbows, shoulders, necks, and so on.
By default, the influence a joint has on a skin point’s movement depends on
how close it is to that joint. You can edit skin point weighting to change the
default movement.

■ Bind a skeleton using a smooth bind technique.

Lesson 2: Smooth skinning | 333

■ View and modify skin weights using the Skin Weights Tool.

■ Use influence objects to enhance the skin deformation of a character.


In this lesson, you work with a scene we created for your use. The scene
contains a human character and skeleton. Each leg and arm of the skeleton
has an IK handle that lets you pose the limbs conveniently. If you completed
the prior lesson, the character, skeleton, and IK handles will be familiar.


2 Open the scene file named SmoothSkin.mb.
your Maya project: GettingStarted/CharSetup.mb.
The character in the scene, Jackie, is displayed in a transparent fashion
so you can see the skeleton beneath the surface.

Smooth binding a skeleton
You use Jackie as the surface to be bound to the skeleton.

To bind the skeleton using smooth skinning

1 Select Jackie.

2 Shift-select the back_root joint.


The back_root joint is at the base of Jackie’s spine. If you are not sure
which joint it is, select it in the Hypergraph (Window > Hypergraph:
Hierarchy).

3 Select Skin > Bind Skin > Smooth Bind > .
The Smooth Bind Options window appears.

4 In the Smooth Bind Options window, set Max Influences to 3, then click
Bind Skin.
A Max Influences value of 3 specifies that three joints influence each skin
point. By default, the joint closest to the point has the most influence.
The second most influential joint is that joint’s parent or child joint,
whichever is closest to the point. The third most influential joint is the
nearest parent or child of the second joint. The influence drops with the
distance from the joints. The amount of influence each joint has on any
skin point is the skin weight.
The default skin weights create smooth deformations of the skin at elbows,
knees, and elsewhere as the nearby joints rotate.

5 Select and move any or all of the four IK handles to pose the arms and
legs in various positions in order to get used to posing with the IK handles.
To select an IK handle, drag a selection box around a wrist or ankle joint.
To move a handle, use the Move tool to drag the handle in the desired
direction.
Note that you can also select the IK handles in the Hypergraph. The
handles are indented under jackieSkeleton. Each is named for a leg or
arm, for example, ikHandleLeftLeg. For more details on IK handles, see
Lesson 1: Skeletons and kinematics on page 318.

6 If you prefer to turn off the skin’s transparency so you can see the skin
more clearly, turn off Shading > X-Ray. Do not be concerned that the
skeleton pokes through the skin, as the skeleton is not displayed in a
rendered image.
As you pose the arms and legs, examine the skin in the regions where
joints bend. For many poses, the skin looks natural. For others, the skin
folds, compresses, or bulges unnaturally. The pelvis, shoulders, and torso
are common problem areas for various poses. For example, if you move
an arm straight up, the shoulder compresses as in the following figure.

Smooth binding a skeleton | 335

There are two ways to improve the smooth skin deformations:

■ Add an influence object to eliminate collapsing regions or to create muscle
bulge. For example, you can use an influence object to make the shoulder
region look more natural in the prior pose.

■ Edit skin weights—to remove minor lumps or indented regions. For
example, you can fill out an undesirable concave region at the chest that
appears when you move the arm to certain poses.
The following procedures explain the techniques.

Skin weighting and deformations
In the next steps, you’ll learn how joints and skin weights influence
deformations at Jackie’s chest. In a subsequent section, you’ll improve uneven
deformations.

To see how skin weights affect a skin’s deformation

1 Pose the left arm similar to the following figure. The left breast becomes
irregularly shaped.


2 Select Jackie.

3 Select Skin > Edit Smooth Skin > Paint Skin Weights Tool > .

4 In the Influence list of the Tool Settings window, select any joint, for
instance, pelvis. The grayscale color of Jackie’s skin indicates how much
influence that joint has on the skin’s deformation.
White means the skin is maximally influenced by the joint. Black means
the skin is not influenced by the joint. Gray means the influence is partial.
The lighter the gray, the more the influence.
Each point on the surface is influenced by three joints, as specified by
the Max Influence setting in a prior step. However, one or two of the
three joints might have so little influence as to be insignificant.
In general, a white region of skin is influenced nearly entirely by the joint
selected in the Influence section of the Tool Settings window. A gray
region is influenced significantly by one or two additional joints.
The reason the left breast becomes irregularly shaped as you pose the arm
is that some joint is exerting too much or too little influence on the
breast.

5 Select each entry in the Influence list to determine which joints are
influencing the irregular region of the breast. The region will be a shade
of gray (or white) when you select the appropriate joints. The
left_arm_root is the main influence. The upper_back, mid_back, and
left_top_rib also have influence, though not exactly in the same region.

Skin weighting and deformations | 337

Modifying skin weights
You can modify the skin weights for any of the influencing joints to alter the
irregular region. If you don’t get the desired results when you change the skin
weights of one of the influencing joints, you can undo your changes and try
another influencing joint.
In general, it’s best to modify the skin weights of the most influential joint
first, then work with less influential joints if you don’t get the desired results.
Modifying skin weights requires experimentation.
In the next steps, you’ll modify the skin weights for the left_arm_root joint.

To modify skin weights using the Paint Skin Weights Tool

1 Select left_arm_root in the Influence list.

2 In the Paint Weights Menu section of the window, set Value to 0.1 and
turn on Add.

3 Drag the mouse pointer to paint the irregular region of the breast. Each
stroke adds 0.1 (10%) to the skin weight. The weight for a skin point has
a maximum value of 1 (fully white).

TIP Painting skin weights using a tablet with stylus allows you to take
advantage of pressure sensitivity.

Repeat the strokes several times until the irregular region becomes
smoother. The jagged, asymmetrical wireframe at the breast becomes
more symmetrical as the skin becomes smoother. The region whitens,
which indicates increased influence from the left_arm_root joint. Note
that increasing the influence of one joint lessens the influence of the
other influencing joints.

4 To check the shape with full-color shading, click the Select Tool. (You
might also prefer to cancel the selection of Jackie to eliminate the display
of the highlighted wireframe.)


5 To continue modifying the skin weights with the Paint Skin Weights
Tool, select Jackie and once again select Skin > Edit Smooth Skin > Paint
Skin Weights Tool.
There are several additional tool settings you might find useful as you
modify skin weights:
■ The Smooth operation smooths the weights of points by averaging
the stroked points with the weights of the surrounding region. This
is useful if you add to the weight values in some region but the points
become unevenly weighted. Uneven weights are indicated by mottled
gray skin.

■ You can use the Scale operation with a Value less than 1 to scale down
the point weights of a stroked region.

■ As you stroke a region, the red circle icon displays the radius of the
region affected by the stroke. The Radius(U) value changes the radius.

■ You can select any of the Profile icons to specify the region affected
by strokes. The two leftmost icons are the most commonly used shapes.

6 (Optional) If you want more practice, pose the right arm as you posed
the left arm and fix the corresponding irregular region in the right breast.
This time, fix the region by modifying the weights for the upper_back
joint rather than the right_arm_root. As mentioned previously, you can
modify point weights of alternative joints to get a similar effect.

7 After you eliminate the irregular region from the left breast, move the
arm to different positions to see if the breast’s shape stays natural in
various poses. It is common for a surface to look good in one pose but

Modifying skin weights | 339

not in another. Strive to make the surface look good in the poses that
you are likely to use during animation.

Influence objects
You can create an object and use it to influence the shape of smooth skin.
The object, called an influence object, acts like a surgical implant against
which the skin deforms. For example, you can create a sphere and use it to
simulate a muscle or bone that bulges as you pose the character in certain
positions. You can also use an influence object to smooth deformation and
maintain volume in regions that collapse while bending.
In the next steps, you’ll use a sphere as an influence object to simulate an
elbow jutting out as Jackie’s arm bends. To use an influence object, the skeleton
must be in the bind pose—the original pose at which the skin was bound to
Jackie.

To return the skeleton to the bind pose

1 Click the Select Tool and cancel the selection of Jackie.

2 Turn off Modify > Evaluate Nodes > IK Solvers.
After you use an IK handle to pose a character, you must do this step
before you can return the skeleton to the bind pose.

3 Select back_root, the root of the skeleton.

4 Select Skin > Go To Bind Pose.

5 Select the ikHandleLeftArm in the Hypergraph. Use the Move Tool to
move the handle manipulator slightly in any direction. When you release
the mouse, note that the arm does not move and that the IK handle
manipulator snaps back to the desired position at the end of the joint
chain. Repeat this step for any other IK handles you posed previously.


6 Turn on Modify > Evaluate Nodes.
You must do this step to enable the IK solvers so you can manipulate IK
handles in the scene again.

To position a sphere to be used as an influence object

1 Right-click Jackie’s surface (anywhere but on the skeleton) and select
Actions > Template from the marking menu.
By making Jackie a template, you won’t accidentally select Jackie in
subsequent steps.

2 Create a sphere (select Create > Polygon Primitives > Sphere >) and name
it elbow_influence.

3 Scale the sphere to be slightly smaller than any of Jackie’s joints (see
illustration below).

4 Move the sphere so that its surface is positioned where the elbow would
jut out, but still within the skin. You can optionally reshape the sphere’s
curvature to resemble the tip of an elbow jutting out from a bent arm.
For example, you can scale the sphere in one dimension to squash its
shape or you can move individual vertices. A top view of the sphere’s
shape and position follows:

The exact position and scale of the sphere is unimportant. You can make
slight position and scale adjustments later to enhance the deformations
that result from its use.

To make the sphere an influence object

1 In the Hypergraph, select Jackie and Shift-select elbow_influence.

2 Select Skin > Edit Smooth Skin > Add Influence > . In the Add Influence
Options, select Edit > Reset Settings, and then click the Add button.
Maya completes the operation within a few moments. To ensure the
influence object stays in the correct position at the elbow, you will parent
it to the left_shoulder joint.

Influence objects | 341

3 In the Hypergraph, Shift-select elbow_influence, elbow_influenceBase,
and left_shoulder joint, in that order.
The order of selection is important. The parent object should be selected
last.

4 Press p to parent the elbow nodes under the left_shoulder joint.
The elbow_influence nodes appear in the skeleton hierarchy below the
left_shoulder joint.
The elbow_influenceBase is known as a base object. It stores vertex
position information for the influence object. The reason for parenting
the base object to the left_shoulder joint is so that the influence object’s
vertices stay in the correct position at the elbow whenever the elbow
moves to a new position. Other than this step, you do not work with the
base object.

5 Right-click Jackie and select Actions > Untemplate. It is easier to see
subsequent skin deformations when Jackie is displayed with smooth
shading rather than as a template.

6 From the menus at the top of the top view, turn off Show > Joints to
avoid having the joints obstruct your view of the skin.

7 Use each arm’s IK handle (ikHandle1 and ikHandle2) to pose the arms
in the following position.

The left elbow looks more natural than the right elbow. To tune the
elbow’s deformation during bending, change the position, scale, and
rotation of elbow_influence.
Do not be concerned if the influence object pokes through the skin. It
won’t be displayed when you render the animation.


Beyond the lesson

■ Bind a skeleton to a single surface.
You can bind a skeleton to multiple surfaces or even to a selection of
polygonal vertices or NURBS CVs or subdivision surfaces.

■ Use the Paint Skin Weights Tool to prevent a region from collapsing upon
deformation.
To control skin weights with more precision than shown in the lesson,
you can modify skin weights numerically with the Window > General
Editors > Component Editor. If you smooth skin multiple surfaces which
have been seamed together, there are many tool settings for the Paint Skin
Weights Tool that make the task easier.

■ Use an influence object to make an elbow stick out upon bending.
Another common use of an influence object is to simulate a muscle bulging
during joint rotation. The technique requires use of Set Driven Key to link
the bulging influence object’s scale values to the rotation of the appropriate
joint. A brief example of this technique is in the Maya Help for Smooth
Skin.

Skin weights and influence objects cannot overcome all modeling problems.
For instance, if you further separate Jackie’s legs sideways, you will see an
undesirable fold at the hips. This occurs because of the asymmetrical
arrangement of polygonal edges in the hip region of the original model. To
fix the problem, you would need to detach the skin, alter the original model,
then smooth bind the model again.
Maya has an alternative skinning method, rigid skinning, which gives results
similar to smooth skinning but requires use of different enhancement tools:
flexor and lattice deformers. In general, smooth skinning gives more natural
deformations with less effort than rigid skinning. If you skin multiple seamed
surfaces, however, processing is faster with rigid skinning than with smooth
skinning.
Smooth skinning is just one of the techniques for perfecting a character’s
deformations during animation. You can use Maya’s other deformers alone
or in addition to smooth skinning to achieve the results you want.
For more information, please refer to Smooth skinning in the Maya Help.


Lesson 3: Cluster and blend shape deformers

Introduction
Facial animation is an integral component of character animation. The face
of a character can be animated to impart a range of emotions and expressions.
Maya has two deformation tools that ease character setup for facial animation:
cluster deformers and blend shape.
Cluster deformers enable you to control a set of an object's points (CVs,
vertices, or lattice points) with varying amounts of influence to create a target
shape for an animation.
A Blend Shape deformer provides an interface for blending between various
target shapes, to control the range of movement for the cluster on an object
or face.
In this lesson, you will be introduced to cluster deformers in order to shape
a characters mouth into a smile pose. You will learn to use the Blend Shape
feature so you can animate the face from a neutral pose to a smile. In this
lesson, you learn how to:

■ Select CVs in a region and create a cluster deformer.

■ Use the cluster deformer handle to adjust the position of a cluster deformer.

■ Use the Paint Cluster Weights Tool to refine the cluster weight values.

■ Create a Blend Shape deformer to control the blending between target
shapes.

In this lesson, you’ll work with a scene we created for your use.


2 Open the scene file named ClusterBS.mb.
your Maya project: GettingStarted/CharSetup.


3 Select Shading > Smooth Shade All and then Shading > Hardware
Texturing, and Lighting > Use All Lights to view the head fully textured
(Hotkey 7).

Creating a target object for a blend shape
In the next steps, you duplicate the face of the head to create a target object
for the blend shape. Later in the lesson, you apply a cluster to the duplicated
face (target object) so you can create a smile. The facial expression on the
target object is what the original base object will match.

1 Using the Outliner, select only the face. That is, select only the head
surface without the eyes.
In the Outliner, the face is named baseFace and is indented under head.

2 Select Edit > Duplicate Special > . In the options window, select Edit
> Reset Settings, turn on World for the Group Under option, then click
the Duplicate Special button. By grouping the duplicate under the world,
you create an object independent of the original.

3 Move the duplicate face to a position where both faces are visible for
comparison, for instance, to the right side of head.

Creating a target object for a blend shape | 345

4 Rename the duplicate face as smilingFace.
This duplicate face will be modified so it can be used to influence the
original.

Creating a cluster deformer on a target object
In the next steps, you create a cluster deformer on the duplicated face (target
object) to reshape the expression into a smile. The cluster deformer on the
target object will be used to change the unsmiling baseFace (base object) into
a smiling face.
A cluster deformer creates a set whose members consist of selected points (CVs,
vertices, or lattice points). You assign a percentage weight to each point,
indicating how much you want each point to be affected by any translation,
rotation, or scale of the cluster set. When you transform the cluster, the points
are transformed according to the percentages you have specified. A cluster is
useful for stretching, moving, or compressing part or all of a surface.

To create a cluster deformer

1 Position the mouse pointer over the face. Right-click to select Vertex,
then select the smilingFace vertices shown in the following illustration,
which are roughly the vertices at the chin, cheeks, and lips (but not the
nose):


The region of selected vertices does not need to be exact. The objective
is to select all vertices where a smile might deform the face. You might
want to look in a mirror to see which parts of a face move while smiling.
It’s better to select too many vertices than too few. It’s easier to work
with too many vertices than too few.

TIP An easy way to select the vertices is to use the Paint Selection Tool. First,
right-click smilingFace in the scene view and select Vertex from the marking
menu. Next, select the Paint Selection Tool by double-clicking the icon in
the Toolbox to display the Paint Selection Tool settings.

In the settings window, set Radius(U) to 0.2. Drag the mouse over the desired
vertices to select them. Ctrl-drag (Windows and Linux) or Control-drag (Mac
OS X) to cancel the selection of unwanted vertices. Close the Tool Settings
window when you are done.

Make sure you don’t select vertices at the back of the head inadvertently.
Also make sure you don’t inadvertently miss a few vertices in the region
you select.

Creating a cluster deformer on a target object | 347

2 Select Create Deformers > Cluster.
This puts the vertices into a cluster—a set of points you can move as
single entity. The cluster’s handle appears in the view as a C icon.

3 In the Outliner, make sure the cluster2Handle is selected.

4 Use the Move tool to drag the cluster handle up along its Y-axis a small
amount until smilingFace is deformed as follows:

The cluster set on smilingFace should be slightly higher than the cluster
on the original face. This will become the basis for the blend shape
deformer.

Editing cluster weights
In this section you will use the Paint Cluster Weights Tool to further refine
the smilingFace. As you saw in previous steps, the points in a cluster move
when you move the cluster handle. The distance a particular point moves
depends on its weight. Lower weights cause less movement, while higher
weights cause exaggerated movement. In the next steps, you create a smile
by editing the weights.

To edit cluster weights using the Paint Cluster Weights Tool

1 Select smilingFace.


2 Select Edit Deformers > Paint Cluster Weights Tool > . This displays
the smilingFace in grayscale.

The white area shows the points that make up the cluster. The whiteness
also indicates the weights—how much the points move in response to
the movement of the cluster handle. White indicates a cluster weight of
1—the points move the same distance as the handle. By default, each
point has a weight of 1.
Black indicates a cluster weight of 0. The points do not move in response
to cluster handle movement. Note that regions that are not part of the
cluster are also black.
Although there are no gray regions currently, gray means the movement
is partial. The lighter the gray, the more the movement. Gray regions
indicate a cluster weight between 0 and 1.

3 In the Paint Attributes Section of the Tool Settings window, set the
following:
■ Paint Operation: Replace

■ Value: 0.5

4 Click the Flood button.
This gives all the cluster points a weight of 0.5. The white region is now
gray:

Editing cluster weights | 349

The selected vertices move down a bit, as the weight of 0.5 lessens the
effect of the prior movement of the cluster by 50%.

5 To check the shape with full-color shading, click the Select Tool. (You
might also prefer to cancel the selection of smilingFace to eliminate the
display of the highlighted wireframe.)

6 To return to the Paint Cluster Weights Tool, select smilingFace and Edit
Deformers > Paint Cluster Weights Tool > again.

7 In the Tool Settings window, set the following
■ Radius(U): 0.1
A Radius(U) of 0.1 sets the radius of the region affected by the stroke.
The red circle icon on the face displays the radius.

■ Opacity: 0.3
An Opacity of 0.3 scales down the effect of painting weight values so
you can build up values gradually with repeated strokes.

A Replace operation paints the Value specified on the points stroked.

■ Value: 1
A Value of 1 sets the weight value you paint on the points.

8 Paint the region at the corners of the mouth with repeated strokes until
the face looks roughly like the following figure. If your results differ from
the figure significantly, undo the strokes and try again.


While painting weights, it’s useful to intermittently check the shape with
with full-color shading rather than with the grayscale shading. To do
this, click the Select Tool to turn off the Paint Cluster Weights Tool. (You
might also prefer to cancel the selection of smilingFace to eliminate the
display of the highlighted wireframe.)

9 Enter a Value of 0.25 and paint the central region above and below the
lips as follows:

Because the corners of the mouth have a high weight and the central
region around the lips have a low weight, the corners move up more in
response to the prior positioning of the cluster handle. This creates a
smiling mouth. The cheeks and chin have a medium weight, so they also

Editing cluster weights | 351

move up slightly also. (For many people, skin at the chin and neck moves
during smiling.)

10 In the tool settings editor for the Paint Cluster Weights Tool, set the Paint
Operation to Smooth. Paint any region where the surface has become
irregular. Irregular regions are typically indicated by jagged wireframe
curves (isoparms) or where a grayscale color makes an abrupt change to
a lighter or darker color. Smoothing averages the weights of the stroked
points with the weights of the surrounding region. The Value setting has
no effect on smoothing.

11 Replace and smooth weights in other regions of the face until you are
satisfied with the smile. For example, you might want to reduce the weight
values at the side of the nose and immediately below the nose.
Your smilingFace should now have a slight smile as a result of your cluster
weight edits.

12 Hide the Paint Attributes Tool settings window.

Creating a blend shape
In this section, you create a blend shape deformer to control the smile on
baseFace (base object) using the smilingFace (target object). A blend shape
deformer is ideal for facial animation, where you need a number of facial
positions to be readily available for use in an animation sequence. With a
blend shape deformer, you can set up a character’s face to blend between a
smile, frown, smirk, and so on.
In the next steps, you create a blend shape deformer to change the baseFace
into the smile of smilingFace.

To create a blend shape deformer

1 In the Outliner, select smilingFace and shift-select baseFace, specifically
in this order.
The smilingFace (the first selection) is called the target object, while
baseFace (the second selection) is called the base object. The objective of
a blend shape operation is to morph the base shape into the target shape.

2 Select Create Deformers > Blend Shape > .

3 In the Blend Shape node text box, type blendShape, then click Create.


4 Select Window > Animation Editors > Blend Shape. This displays the
Blend Shape editor, which has a slider for changing the base into the
target shape, and buttons for setting keys.

5 Cancel the selection of the faces so you can see the surfaces without the
obscuring highlighted wireframe.

6 Drag the slider from 0 to 1 to morph the baseFace into the target,
smilingFace.

Note that you can click the Key button below the slider to set an
animation key for the shape of the face at the current frame. By setting
a few keys with different slider values at different points in the timeline,
you can animate from the neutral expression to a full or partial smile or
vice versa.
When you key the shape, Maya applies the key to the blendShape node
that was created when you selected Create Deformers > Blend Shape >
. If you need to select the blendShape node, for instance, so you can
see or delete the keys in the Time Slider, click the Select button in the
Blend Shape editor.

Creating a blend shape | 353

Refining deformation effects
The combination of a cluster and blend shape is ideal for facial animation
because it lets you tune various subtle deformations. A few common techniques
follow.

■ In the box below the slider of the Blend Shape editor, you can enter a
numerical value below 0 to invert the deformations, or above 1 to amplify
the deformations. For example, -1 creates a frown, while 1.6 creates a
brimming smile:

■ With or without changing the Blend Shape slider, you can move, rotate,
and scale the cluster handle to modify the blend shape. The following
figure shows some examples. The face you created will be slightly different
because your original smile is different.

■ You can use the Paint Cluster Weights tool again to change cluster weights
when the cluster and blend shape editing deforms certain regions


undesirably or doesn’t give the exact look you desire. You can also use Ctrl
- Z (Windows and Linux) or Control-z (Mac OS X) to undo any undesired
changes.

Adding target objects to an existing blend shape
In the next steps, you duplicate the face again and reshape the duplicate into
a new facial expression. You then add the new face to the blend shape node
to create another slider in the Blend Shape Editor.

To create another facial expression

1 Set the Blend Shape editor slider value to 0 to return baseFace to the
position it had at the beginning of the lesson.

2 Make a duplicate of baseFace, name it raisedBrow, and move it to the left
of baseFace so that all three faces are visible for comparison.

3 Make sure raisedBrow is selected.

4 In the perspective view, select Show > Isolate Select > View Selected. Select
this menu item again in the front view.
This displays only the selected object (raisedBrow) in the views. This is
necessary to avoid selecting unwanted vertices in the next steps. The
view’s label indicates isolate is turned on.

5 In the front view, position the pointer over the face, right-click and select
Vertex. Drag a selection box around the vertices in the region of the
eyebrows and forehead as shown below.

Adding target objects to an existing blend shape | 355

For these vertices, you need to select the vertices by dragging a selection
box rather than by using the Paint Selection Tool. The eyebrows have
vertices that lie behind its outer surface. The Paint Selection Tool selects
only vertices at the outer surface. Dragging a selection box selects all
vertices in the boxed region, including vertices that lie behind the outer
surface.

6 In the side view, hold down the Ctrl (Windows and Linux) or Control
(Mac OS X) key and drag a selection box around the vertices at the side
of the head to turn off their selection (see the following figure).

7 Switch to wireframe display mode and dolly the camera from various
close-up views to make sure you select all the vertices on and under the
eyebrow. If you miss a few vertices, subsequent deformations will not
work correctly. Also, make sure you don’t select vertices at the side or
back of the head.


8 Select Create Deformers > Cluster.

9 In the perspective view, turn off the selection of Show > Isolate Select >
View Selected. Do this again in the front view.
By turning off these menu selections, Maya displays all objects in the
views again.

10 In the perspective view, drag the cluster up along its Y-axis a small amount
until raisedBrow looks like the face on the left:

To add the new target object to the blend shape

1 In the Outliner, select raisedBrow and ctrl-select baseFace (the order of
selection is important). The raisedBrow is the target, while baseFace is
the base object.

2 Select Edit Deformers > Blend Shape > Add > . In the options window,
turn on Specify Node and enter blendShape in the BlendShape Node box.
Click the Apply and Close button.
When you created the blend shape for the smile, Maya created a node
named blendShape that contains the slider attributes that adjust the
blend into the smilingFace target. The Add operation creates a blend
shape for the raisedBrow and adds it to the blendShape node. This adds
a slider to the node’s Blend Shape editor for adjusting the raised brow
deformations.

3 To display the Blend Shape editor, select Window > Animation Editors
> Blend Shape.

Adding target objects to an existing blend shape | 357

4 You can use the sliders alone or in combination to create a smile with
raised eyebrows, a frown with lowered eyebrows, and so on.

5 You can optionally select raisedBrow and edit the cluster weights to tune
the deformation of the eyebrow region as desired. See Editing cluster
weights on page 348 for details. An example weighting follows:


TIP After you create a blend shape, you can optionally hide or delete a target
object (in this lesson, smilingFace and raisedBrow). If you delete a target, you
improve Maya processing time but lose the capability to manipulate the
cluster handle. For versatility, many animators hide the target rather than
delete it. Hiding the target is necessary when you render the scene. It is also
useful when you want to unclutter the scene view.

Beyond the lesson

■ Use two clusters and a blend shape deformer to manipulate facial
expressions.
In professional productions, it’s common to create several more clusters
with a blend shape deformer for finer control of facial expressions. For
example, you can create clusters for a number of mouth positions that you
can use to simulate the phonemes of speech.
When you used certain blend shape slider values, you may have noticed
that the face looked good in all regions except for a few vertices. To fix
such regions, delete the cluster, move the problem vertices of the target
face to a better position, then create a blend shape for the improved target
face.
As much as possible, use a target shape that’s not extremely different from
the base shape. If you need to use an extremely different target shape,
create a blend shape with multiple targets. Each of the multiple targets
must have a shape that is progressively more like the extreme target shape.


Before you create the blend shape, turn on In-Between in the Create Blend
Shape options window, and select the multiple targets in this order: least
extreme shape difference first, most extreme shape difference last.
Although the lesson showed how to blend individual objects, you can also
blend hierarchies of objects. See the Maya Help for more information.

There are some additional notes on clusters which are not explained in this
lesson:

■ You can add or remove vertices from a cluster with Edit Deformers > Paint
Set Membership Tool.

■ You can use the Component Editor to edit weight values more precisely
than by painting.

■ Avoid changing the number of vertices (or CVs) for a surface after you
apply a cluster or other deformer. Unexpected deformations may occur.


Polygon Texturing
8
Introduction

Texture maps let you modify the appearance of your 3D models and scenes in
Maya. Texture maps are images you apply and accurately position onto your
surfaces using a process called texture mapping. When an image is texture mapped
onto a surface, it alters the appearance of the surface in some unique way.
Texture maps let you create many interesting visual effects:

■ You can apply labels and logos to your surfaces.

■ You can apply surface relief details and features to a surface instead of having
to model the details on the surface directly.

■ You can use illustrations as texture maps to create interesting backdrops in
your scenes.

361

Most shading attributes for a surface material can be altered by a texture map.
For example, color, specular, transparency, and reflectivity are examples of
attributes that can be modified by a texture map.
Texture mapping is a key component in the 3D production workflow. Many
production environments employ texture artists whose only role is to create
and apply the texture maps to 3D models.


1 Select File > New Scene to create a new scene.

2 Make sure the Construction History icon (below the menu bar) is on:

(If it is turned off, it has a large X across it.)


4 Select the Polygons menu set. Unless otherwise noted, the directions in
the Polygons menu set.

5 Make sure Display > UI Elements > Help Line is turned on. You will use
the Help Line while modeling.

6 Ensure that the interactive creation option for primitives is turned off by
selecting Create > Polygon Primitives > Interactive Creation. The option
is off when a check mark does not display beside the item’s name in the
menu.


362 | Chapter 8 Polygon Texturing

Lesson 1: UV texture mapping

Introduction

There are several techniques for texture mapping 3D surfaces depending on
the surface type (NURBS, polygons, subdivision surfaces). Some techniques
involve preparing the surfaces for texture mapping. For example, when texture
mapping polygonal and subdivision surface types you need to understand
how textures are applied using UV texture coordinates.
UV texture coordinates, or UVs as they are more commonly called, are
two-dimensional coordinates that reside with the vertex component
information for a 3D surface. UVs control the placement of a texture map on
a 3D model by correlating the pixel position of the 2D texture map to the
vertex positions on the model, so that the texture gets positioned (mapped)
correctly.
For NURBS surfaces which have an inherent rectangular topology, the UV
texture coordinates are implicit. That is, the UVs reside in the same location
as the control vertices, so have a natural correlation to a rectangular shaped
texture map.
For polygonal and subdivision surface type models, which have an arbitrary
surface topology, the UVs can be explicitly created and modified to suit the
requirements of the texture map.
In this lesson you’ll learn the basic principles of UVs by applying (mapping)
an existing image (texture) to a simple polygonal model and creating and

Lesson 1: UV texture mapping | 363

modifying the UV texture coordinates so that the texture map appears correctly
on the surface.

■ Assign a 2D texture map to a polygonal model.

■ Map UV texture coordinates (UVs) to a polygonal surface.

■ Correlate the UVs between the scene view and the UV Texture Editor.

■ Use the UV Texture Editor to visualize how the UV texture coordinates
from a three-dimensional model relate to an assigned two-dimensional
texture map.

■ Determine basic UV layout requirements.

■ Set preferences to let you visualize the texture borders in both the UV
Texture Editor and the scene view to better understand how the texture
map is placed on the polygonal model.

■ Select and reposition UV texture coordinates within the UV Texture Editor
using the transformation tools to make the UVs match a pre-defined texture
map.

■ Sew UV texture coordinates to existing UV shells.

Creating a cracker box model
You begin the lesson by creating a model of a cracker box using a polygonal
cube primitive. The dimensions you’ll use for the cracker box are based on a
texture map you’ll apply to the model in this lesson.

To create a cracker box model using a cube primitive


2 In the Polygon Cube Options window, select Edit > Reset Settings, set
the following options, and then click Create:
■ Width: 8

■ Height: 10

■ Depth: 3

■ Width divisions: 1



■ Depth divisions: 1

■ Axis: Y

■ Create UVs: On

■ Normalize: Off

A cube primitive in the shape of a rectangular box appears in the scene
view.
When the Create UVs option is on it ensures that the primitive object is
created with a set of default UV texture coordinates. All polygon primitives
in Maya provide an option for creating UV texture coordinates at the
time of creation.

3 Using the Channel Box, set the Translate Y attribute to 5 so that the
cracker box is repositioned to rest on the X axis.

4 Rename the pCube1 primitive to: cracker_box.

Applying a texture map to a polygon mesh
In Maya, surfaces appear in a rendered image based on the shading materials
you apply to them. The default shading material that gets assigned to surfaces
provides basic attributes such as color, transparency, and incandescence.
Depending on your final image requirements, you can enhance the visual
impact of an object by adding one or more texture maps to the assigned
shading material. One basic texture map you can apply is a bitmap image also

Applying a texture map to a polygon mesh | 365

referred to as a file texture. In this lesson, you apply a texture map we’ve created
for your use on the cracker box.
For more basic information on shading materials and texture maps see the
Rendering chapter of this guide and the Maya Help.

To assign a shading material to the cracker box

1 In the scene view, select Shading > Smooth Shade All from the panel
menu.
This displays the cracker box with a default gray, smooth shading material,
lit using default lighting. Turning on Smooth Shade All displays the
assigned shading material you apply to the cracker box in the steps
following.

2 In the scene view, right-click on any region of the cracker box and select
Assign New Material > Lambert from the marking menu.
A new Lambert shading material is created and assigned to the cracker
box. The Attribute Editor appears and displays the various attributes for
the new Lambert shading material.


The new Lambert material is identical to the default gray material that
was previously assigned to the cracker box. However, it’s always a good
practice not to modify the default shading material in the scene and
create a new shading material and modify it to suit your requirements.

3 In Attribute Editor, double-click in the lambert2 box and then type:
box_material to rename the shading material.

Renaming the shading material lets you easily identify it later on when
you need to edit it. Naming items uniquely in Maya is a useful habit.

4 In the Attribute Editor, move the Color slider fully to the right so that the
color box appears white.

The shading material assigned to the box model also updates in the scene
view so it appears in a brighter tone.


5 Click the Map button located to the right of the Color slider.
The Create Render Node window appears and lists the various texture
options you can apply (or connect) to the color channel of the box
material.

6 Click PSD File from the list of 2D Textures.

Choosing this option specifies that you want to apply an Adobe®
Photoshop® format file as a texture. A PSD format file lets you keep the
various components of your texture map on multiple layers. This is useful
when you need the ability to edit a component of the texture during
production.
The Attribute Editor updates to display the options for the PSD File
texture.

TIP If the Attribute Editor suddenly appears empty, it indicates that no objects
are selected in the scene. Simply select the box model again in the scene to
display the attributes for the box.

7 Click the Browse button (folder icon) to the right of the Image Name
attribute to specify the image file for the texture map.


A browser window appears with the path set to the default project
directory. By default, Maya looks for source images for texture maps in
a sourceimages folder whenever the project folder is set. Maya can use
file texture images from anywhere on your workstation or local network.
For example, you can have images on a central disk drive that is shared
among users in a production environment.

8 Select the image file named UVLesson.psd.
your Maya project:
GettingStarted/UVMapping/sourceimages
The image contains 2D artwork for the front, back, top, bottom, and sides
of the cracker box that was generated in Adobe® Photoshop®.


A small preview of the image appears in the Texture Sample box in the
Attribute Editor.
When a texture is applied to a shading material its attributes get added
to the existing attributes for shading material. That is, all of the existing
shading attributes remain unchanged except for the attribute that gets
modified by the texture. In this case, the grey color is substituted by the
image of the cracker box artwork.

9 In the scene view, select Shading > Hardware Texturing from the panel
menu to display the texture map on the cracker box model.


The texture map does not appear correctly on the cracker box model.
The texture map was designed so that specific sides of the box receive
specific regions of the image. Instead, the complete image is being placed
on every side of the object.
To correct this problem you must modify the default UV texture
coordinates for the model so they match the layout of the texture image.
To do this, you use the UV Texture Editor.

Viewing UVs in the UV Texture Editor
The UV Texture Editor lets you view and interactively edit the UV texture
coordinates for polygon and subdivision surface types. UVs appear laid flat
within the UV Texture Editor’s 2D view. It also lets you display the 2D image
for the texture map in relation to the UVs. These features are critical for
accurate and efficient placement of texture maps on polygon and subdivision
surface types.
In this lesson, your goal is to ensure that the shape and placement of the UVs
match the image as it appears in the 2D view of the UV Texture Editor. This
will ensure that the map appears correctly on the cracker box model in the
3D scene view.

To open the UV Texture Editor in a two pane layout

➤ In the scene view, right-click any of the Quick Layout buttons on the
Toolbox to display the pop-up menu of Quick Layout shortcuts and select
Persp/UV Texture Editor from the list.

Viewing UVs in the UV Texture Editor | 371

The panel layouts update to display the Perspective view in the left pane
and the UV Texture Editor in the right pane simultaneously. (You can
close the Attribute Editor if it is still displayed.)

This two pane layout is helpful for two reasons:
■ The two view layout shows you how one item selected in the 3D view
relates to the UVs displayed in the 2D view of the UV Texture Editor
and vice versa, without having to open and close the views repeatedly.


■ When you edit UVs for a surface mesh in the UV Texture Editor, you
can immediately see the effect of the texture map on the model in
the 3D scene view.

UVs do not initially appear in the 2D view of the UV Texture Editor until you
select an object or change the selection mode for an object in the scene view.

To view UVs in the UV Texture Editor

1 In the scene view, right-click any region of the cracker box model and
select Object Mode from the marking menu.

2 Select the cracker box model.

3 In the UV Texture Editor, dolly the view outwards so you can see the UVs
for the cracker box as shown below. (To dolly, press the Alt key and drag
the mouse to the left while holding down the right button on your
mouse.)
The UV texture coordinates for the cracker box model appear in the 2D
view of the UV Texture Editor as a flattened, two-dimensional
representation. The UVs appear highlighted with lines connecting the
UVs to indicate the region of the texture the UVs represent.
The image you specified as the texture map for the box also appears in
the 2D view of the UV Texture Editor in the upper right quadrant of the
2D cartesian graph called the UV image range or UV Texture Space. The
coordinates for this quadrant range from 0,0 to 1,1 and represent the
texture space for the surface. How the UVs appear in this quadrant in

Viewing UVs in the UV Texture Editor | 373

relation to the displayed image has a direct bearing on how the texture
gets mapped onto the surface.

TIP If the texture map for the cracker box doesn’t appear in the 2D view,
select Image > Update PSD Networks in the UV Texture Editor to refresh the
2D view of the UV Texture Editor. Update PSD Network is normally used to
refresh a PSD texture in Maya after you have modified the PSD texture in
Adobe® Photoshop®.

In this example, the UVs for the cracker box appear like a box where all
six sides have been cut open and then unfolded flat.
The texture map does not appear correctly on the cracker box for a
number of reasons:
■ The UVs for the cracker box extend well beyond the default 0 to 1
UV range for the texture map in the 2D view of the UV Texture Editor.
As the texture map displays within the 0 to 1 range, the UVs should
also be positioned to fit within the 0 to 1 UV range, in most cases.
Otherwise, the texture map repeats on the surface mesh, as it does in
this case.

■ The position of the UVs do not match the specific regions of the image
we’ve provided for the texture map. The regions of the image show
the front, back, top, bottom, and sides of the box. The UVs should
specifically match these regions to display the texture correctly. UVs
do not automatically align themselves to a texture, you must manually
reposition them.

■ The shape of the UVs don’t match the aspect ratio of the cracker box
model in the scene view: -10 (Height) X 8 (Width) X 3 (Depth). This


is because the default UVs for a Maya cube primitive are created based
on a predetermined default shape and do not get updated if the shape
or scale of the primitive is modified later on.

There are a number of things you can do to correct these issues depending on
the situation. For this lesson, you will correct the UV and texture map
misalignment by doing the following:

■ Map a new set of UVs for the cracker box model that better matches the
individual faces of the cracker box. (While the existing UVs could be
modified, you’ll learn how to create new UVs in this lesson that will better
match the size and scale of the 3D model.

■ Ensure the new UVs fit within the 0 to 1 UV range in the UV Texture
Editor.

■ Reposition the UVs so that they correlate to specific locations on the 2D
image using the UV Texture Editor. This will ensure that the various sides
of the box receive the correct regions of the texture map.

Mapping UV texture coordinates
It is often necessary to create new UVs for a surface mesh in order to texture
map it correctly. These situations include:

■ Texture mapping a surface that doesn’t have existing UVs.
This can occur when you import 3D models from other software
applications that don’t create UVs.

■ When the UVs for a surface are badly jumbled or are missing some UVs.
This can occur when a surface has been edited or modified in some way
and it becomes hard to determine what UVs may be missing as a result.

■ When you need a unique set of UVs for a particular purpose.
For example, if you want to paint a texture map directly onto a 3D surface,
you may want to map UVs that allow you to paint using the 3D paint tools
in Maya. Alternatively, you may want to create a unique set of UVs
specifically for baking textures or light maps.

Maya lets you create UVs for polygonal and subdivision surfaces using a process
called projection mapping, also referred to as mapping UVs. Maya provides several
projection mapping types that map what gets viewed by a particular projection

Mapping UV texture coordinates | 375

to a flat 2D view that can be subsequently correlated to your texture map
using the UV Texture Editor.
In this lesson, you use a feature called Automatic Mapping to create new UVs
for the cracker box model. Automatic mapping lets you specify the number
of planes that will be used for the UV projection.
Automatic Mapping is normally used when mapping UVs that require multiple
projections of organic shaped models as it has the advantage of producing
UVs that are proportional in scale to the world space area of the mesh faces
of the surface.
Automatic mapping is useful when your mapping requirements are for
non-overlapping UVs which fit within the 0 to 1 texture space, but which do
not have to be contiguous; for example, when using the 3D Paint tool, Maya®
Paint EffectsTM, Maya® FurTM or Maya® HairTM.
You use Automatic Mapping in this lesson because it can produce a UV
projection from three planar directions simultaneously which makes it a good
choice for the shape of the cracker box model. That is, you can map UVs for
the front and back, top and bottom and the two sides in one operation. This
projection type is referred to as a triplanar projection.

To map UVs using Automatic Mapping

1 In the perspective view, select the cracker box as an Object.

2 From the Polygons menu set, select Create UVs > Automatic Mapping >
.
The Automatic Mapping Options window appears.

3 In the Automatic Mapping Options window, select Edit > Reset settings,
set the following options, and then click Project:
■ Planes: 3

■ Percentage Space: 2


Setting Planes to 3 creates UVs based on projections from three separate
directions. Setting the Percentage Space option to 2 sets the size of the
space that appears between each of the separate UV projections when
they are laid out in the UV Texture Editor.

When the projection is complete the new projected UVs from the triplanar
projection appear in the UV Texture Editor.

NOTE Whenever a UV projection is performed on a surface, any existing UVs
for the surface get replaced by the UVs from the new projection. To avoid
replacing existing UVs you can explicitly save the UVs in a UV set. For more
information on UV Sets see the Modeling guide in the Maya Help.

4 In the UV Texture Editor, dolly the view so it shows only the 0 to 1 UV
range area that displays the image for the texture map and the new UVs
(as shown below).

5 In the UV Texture Editor, select Image > Dim Image.

Mapping UV texture coordinates | 377

The intensity of the image map is reduced so you can view the UV borders
on the projected UVs more easily. The new UVs appear in the UV Texture
Editor as shown below.

■ The six rectangular UV shapes, referred to as UV shells or simply shells,
now match the aspect ratio for each of the six sides of the cracker box
better than the earlier UVs.

■ The UV shells fit within the 0 to 1 UV texture range. Automatic
mapping fits the UVs to the 0 to 1 range by default.

The texture map still does not appear correctly on the cracker box because
the UV shells need to be repositioned so they align with the corresponding
components of the image map.
While the shape of each UV shell is now recognizable as being associated with
the cracker box, it is not apparent which components in the UV Texture Editor
correspond to a particular face on the cracker box.
In the next section you learn how to select and reposition the UV shells so
they better match the image for the texture map.


Working with UVs in the UV Texture Editor
When texture mapping a polygon or subdivision surface type model it is often
necessary to modify the UV components for a model so they match the texture
map. The UV Texture Editor provides many tools for working with UVs. In
this section you learn how to:

■ Select UVs from either the scene view or the UV Texture Editor and
accurately correlate them. Selecting UV components is critical to modifying
them accurately.

■ Sew UV shells together to reduce the number of UV components you need
to work with.

■ Move and rotate UVs within the UV Texture Editor to make the UV shells
align to the cracker box texture map.

Selecting UV components
You can select UV components from either the scene view or within the UV
Texture Editor. Displaying both the 3D scene view and the 2D view of the UV
Texture Editor lets you easily correlate which UV components are associated
with a particular edge or vertex on the 3D model.
This is very helpful to understand the layout and orientation of your UV
texture coordinates in relation to the image used for a texture map and how
the map appears on the model in the 3D scene view.

To select UVs for a 3D model in the scene view

1 In the UV Texture Editor, select Image > Display Image to turn off the
display of the texture image.
Display Image works by turning the display of the assigned texture on
or off in the 2D view of the UV Texture Editor. Turning the image off
temporarily aids in viewing only the UV components. This will be useful
in the steps that follow.

Working with UVs in the UV Texture Editor | 379

2 In the scene view, right-click on the cracker box model and select UV
from the marking menu that appears.

3 In the scene view, select one UV on any corner of the cracker box.
Selecting a UV is very similar to selecting a vertex on an object. That is,
you select a point that resides in exactly the same position as the vertex.
When you select a UV in the scene view, the corresponding UV is also
selected in the UV Texture Editor.

NOTE If more than one UV gets selected in the UV Texture Editor when you
select a UV in the scene view it indicates that multiple UV components share
the same UV on the 3D model (similar to how polygon faces share common
vertices). This is important to remember when you move one of these UV
components in the UV Texture Editor and other UVs also move.

4 In the scene view, right-click on the cracker box model and select Edge

5 In the perspective view, select the top front edge of the cracker box.


When you select this edge in the scene view, notice that two
corresponding shell edges also get selected in the UV Texture Editor. This
indicates the following:
■ The selected edge is shared by two faces; the front and the top.

■ Selecting the top front edge in the scene view, identifies the
corresponding front and top UV shells for the box. (Indicated by the
selection in the UV Texture Editor.)

This is useful when you need to understand how the various UV shells
relate to each other, especially when you have many UV shells for a model
in the scene; for example, when you sew two UV shell edges together.

In the steps that follow you select edges in the UV Texture Editor so you can
sew them together.

Sewing UVs
Sewing UV shells together merges the UV shells along a shared edge that you
specify. Sewing UVs is useful for the following reasons:

■ You can move and modify the UV shells as larger contiguous texture units.
This makes it more efficient to match the UVs to the texture in many
situations.

■ Texture maps can appear more uniform across texture borders when the
texture is applied to one or more sewn UV shells compared to many
separate UV shells. Sewing shells together reduces the chance that an
unwanted texture mismatch occurs along the texture edge.

To sew shell edges together in the UV Texture Editor

1 In the scene view, ensure that only the top front edge of the cracker box
is still selected.
When the top front edge is selected in the scene view, the top edge of
one of the large UV shells is also selected as well as the left side of the
middle UV shell in the top row of the UV Texture Editor. For the cracker
box texture map, you need to sew these together so they correlate to the
map correctly.


2 In the UV Texture Editor, select Polygons > Move and Sew UV Edges.
The small rectangular UV shell is repositioned to match the top of the
large UV shell and the two shells are combined into one. When you later
select and move this sewn shell, it will move as one piece. When two UV
shells are selected for sewing, the smallest UV shell is moved to the larger.

3 Repeat steps 1 and 2 for the remaining three edges on front face of the
cracker box keeping in mind the following:
■ Select only one edge at a time in the scene view.

■ When you’ve completed the move and sew operation, your UV Texture
Editor should show the front UV shell with the corresponding top,
bottom, and side shells sewn to it. When fully complete, you will
have only two UV shells to match to the texture image for the cracker
box.


4 To display the texture borders for the two shells, select Texture Border
Edges. (You can also launch this window by right-clicking the Toggle
Texture Borders button on the UV Texture Editor’s toolbar.)

In the UV Texture Editor, the texture borders for two UV shells now
appear with a thicker line.

Displaying texture borders on the UV shells is useful for visualizing where the
texture borders exist on the 3D model in the scene view. That is, any portion
of the texture image that appears outside of the texture border will not appear
on the surface. It is particularly useful for troubleshooting texture mismatches
when they occur. Displaying the texture borders can also help to identify


which UV shells are combined and which shells are not when you have many
UV shells displayed in the UV Texture Editor.
If you want to be able to view areas where UV shells overlap in the UV Texture
Editor select Image > Shade UVs. When Shade UVs is turned on any selected
UV shells appear shaded in a semitransparent fashion. Areas where the shading
appears more opaque indicate the regions of shell overlap.
In the steps that follow, you reposition the two UV shells in the UV Texture
Editor so they coincide with the texture image.

Moving UV components
You manually reposition UV components in the UV Texture Editor using the
tools within the Toolbox. To reposition an individual UV component you
must first select it before selecting the Move Tool. To reposition an entire UV
shell you must first select one individual UV from the shell it belongs to and
then convert the selection to a shell before using the Move Tool.

To move UVs in the UV Texture Editor

1 In the UV Texture Editor, select Image > Display Image.
The texture image displays in the 2D view of the UV Texture Editor
dimmed, as before. You need the image displayed so you can accurately
reposition the two UV shells. Dimming the image aids in seeing the
selected UVs.

2 In the UV Texture Editor, right-click and select UV from the marking
menu that appears.

3 In the UV Texture Editor, select one UV on the UV shell you sewed earlier
in the lesson.
The UV coordinate appears highlighted in the 2D view.

4 Convert the selection to a UV shell by pressing the Ctrl key and
right-clicking in the 2D view of the UV Texture Editor. Choose To Shell
The selection changes from a single selected UV to selecting the entire
UV shell.

5 From the UV Texture Editor menu, select Tool > Move UV Shell Tool >
.

6 In the Move UV Shell Tool options window, turn off the Prevent overlap
option which prevents UV shells from being moved so they overlap and
then select Apply and Close.


The Move Tool manipulator icon appears over the selected UV shell.

7 Drag the green (Y axis) and red (X axis) Move Tool manipulator handles
to reposition the UV shell so it matches the displayed texture image.

The position of the texture updates on the cracker box model in the scene
view as you do this.

8 Select one UV on the other remaining UV shell.
The UV coordinate appears highlighted.

9 Convert the UV selection to a shell selection by pressing the Ctrl key and
right-clicking in the UV Texture Editor. Choose To Shell from the marking
menu that appears.
The selection changes from a single selected UV to selecting the entire
UV shell.

10 In the UV Texture Editor’s toolbar, click one of the Rotate UVs buttons
to rotate the UV shell so it appears in the same orientation as the texture
image. (Click the other Rotate UVs button to rotate it in the opposite
direction.)


11 Confirm that the texture appears correctly on the cracker box model in
the scene view by tumbling the scene so you can view the back of the
box.

TIP If the texture appears upside down, you can continue to rotate it another
180 degrees. If the texture appears reversed, that is, the letters are backwards,
you can correct this by selecting Polygons > Flip from the UV Texture Editor
menu and choosing the appropriate option setting.

12 From the UV Texture Editor menu, select Tool > Move UV Shell Tool.
A move manipulator icon appears over the selected UV shell.

13 Drag the green (Y axis) and red (X axis) manipulator handles to reposition
the UV shell so it matches the displayed texture image.
The texture map should now appear correct on all sides of the cracker
box when you’re finished.

TIP You can confirm that the UV shells are positioned accurately by dollying
in closer on the 2D view of the UV Texture Editor. If a minor correction is
required, simply select and move the UVs or move the entire UV shell.


TIP The exact UV boundaries can be viewed more clearly when the
anti-aliasing for the texture image is temporarily turned off. To do this, select
Image > Display Unfiltered to view the texture image without anti-aliasing.
If you need to move a single UV so it precisely matches a particular location
on the texture map you can turn on Pixel Snap (Image > Pixel Snap). When
you select and move the UV using the Move Tool, it will reposition the UV
coordinate based on pixel boundaries.

Beyond the lesson
In this lesson you were introduced to a few of the basic techniques required
to assign and accurately position texture maps on polygonal models using UV
texture coordinates:

■ UV coordinates are essential for applying and accurately positioning texture
maps on polygonal and subdivision surfaces.

■ UVs can be explicitly created for a surface mesh using a variety of UV
mapping techniques. (Planar mapping, spherical mapping, cylindrical
mapping, and Automatic mapping.)

■ UVs are represented as 2D coordinates and are viewed and edited with
respect to the 2D texture map using the UV Texture Editor. The UV Texture
Editor provides many other tools for editing UVs.

■ UVs are usually positioned to fit within the 0 to 1 UV coordinate space
unless the texture map requirements are such that the map needs to repeat
across the surface mesh.

■ It is useful to display both the 3D scene view and the 2D UV Texture Editor
simultaneously when texture mapping so that a correlation between the
3D model and 2D UV coordinates can be made.

■ You can visualize texture borders using Texture Border Edges.

■ You can view the regions where UVs overlap each other in the UV Texture
Editor by selecting the UV shells and selecting Image > Shade UVs.

You can open the PSD file you used in this lesson using Adobe® Photoshop®
to learn how layers were used for the texture map. You can edit one or more
of the layers to experiment with how the texture can be modified. After you
modify and save the file in Photoshop®, remember to select Image > Update


PSD Network in the UV Texture Editor so the texture map gets updated on
the model in the Maya scene.
If you would like to learn how to render an image of the cracker box model
see the Rendering chapter of this guide as well as the Maya Help to learn more
about lighting, shading, and rendering.
This lesson used a simple polygonal model to introduce the fundamental
concepts. When you work with more complex polygonal and subdivision
surface models, you can also:

■ layout overlapping UV shells that occur as a result of UV projection
mapping to ensure they fit within the 0 to 1 texture space using Edit UVs
> Layout.

■ maximize the use of texture space by forcing the UV borders to be mapped
to the full area of the 0 to 1 UV texture range using Edit UVs > Map UV
Border

■ align UVs to one another or snap them to the grid in the 2D view

■ untangle a UV mesh that contains overlapping UVs using Edit UVs > Relax.

■ modify a group of selected UVs using UV Lattice and UV Smudge tools

In general, you should begin texturing a model only after the model is fully
complete. Otherwise, changes to the model may affect the associated UV
texture coordinates which in turn will affect how the texture appears on the
model.
In this lesson you matched the UVs to an existing texture image. Many texture
artists create good UV layouts for their models prior to creating the actual 2D
images for their texture maps. This is done only after the model is fully
complete.
You can export a bitmap image of the 2D view of the UV Texture Editor to
use as a guide for painting a texture in your favorite image creation software.
In the UV Texture Editor, select Polygons > UV Snapshot to export the image.

If you use Adobe® Photoshop® for image creation and editing you can create
a UV snapshot in a .PSD file format that creates the UV image on a separate
layer. To create the .PSD format file while working in the UV Texture Editor,
select Image > Create PSD Network.
If you want to learn more about a particular tool or feature that was used in
this lesson, please refer to the Maya Help.


Lesson 2: UV unfolding

Introduction

While texturing a flat object is fairly straightforward, texturing an object with
curves can pose some unique problems. How do you paint a 2D texture on a
curved surface? How do you deal with a texture warping over bumps and
grooves? If you try to break apart the UV mesh like Lesson 1, you can
potentially end up with hundreds of small pieces.
To deal with these problems, artists typically use a workflow called unfolding
or pelting. Unfolding a UV mesh refers to the process of cutting a seam in the
UV mesh (a mesh made up of UVs similar to how a polygon mesh is made of
vertices) and then unfolding along that seam. The process is similar to cutting
a seam along a shirt and laying it flat on a table. By laying out the UVs this
way, you can easily paint a texture on the 2D surface, which you can then
wrap around the model.

Lesson 2: UV unfolding | 389


■ Divide a mesh into separate parts for texturing.

■ Assign a basic checker pattern to judge the quality of a mapping.

■ Create a planar mapping.

■ Cut UV edges.

■ Unfold a UV mesh using the Unfold option.

■ Fix an unfolded mesh using the Smooth UVs tool.

Lesson Setup

■ Make sure you’ve done the steps in Preparing for the lesson on page 362.

■ Select the Polygons menu set by selecting it from the pull down menu on
the status line.

■ Open the scene file named Soldier.mb.
This file can be found in the GettingStarted directory that you set as your
Maya project.
GettingStarted/UVMapping/Soldier.mb
The scene contains a polygon soldier.

■ In the panel menu, select Panels > Saved Layouts > Persp/UV Texture Editor.
Your view is split between the perspective view and UV Texture Editor.


Dividing the mesh

If you select the polygon soldier and look at the UV Texture Editor, notice
that the UVs for the body, arms, and legs are scattered in a pattern that doesn’t
resemble the actual model. This isn’t very helpful for painting a texture map.

Dividing the mesh | 391

To simplify the job, you need to divide the mesh into multiple pieces that
you can then texture individually. Generally, you want to divide the mesh
into pieces that can be unfolded into approximate square or rectangle shapes.
This requires some pre-planning.
In this lesson you divide the body mesh into a torso, arms, and legs.

To divide the mesh into pieces

1 In the panel menu select Panels > Orthographic > front.
The perspective view changes to an orthographic front view of the soldier.


2 Right-click the mesh and select Face from the marking menu.

3 Drag-select the faces on the right arm up to the shoulder.

4 Select Mesh > Extract.

Dividing the mesh | 393

Now you change the selection mask back to Object, you can select the
hand separately from the rest of the body.

5 Repeat steps 1-3 for the following areas (use the pictures as reference for
the boundaries of each extraction).
Extract Point Example

Left arm

Legs


This leaves you with individual meshes for the arms, legs, and chest. The head,
feet, and hands have already been done for you. This division allows you to
texture each part individually.

Creating a planar mapping
To texture an organic object, you must start by creating a planar mapping as
a base, which you can then unfold.

To create a planar map for the torso

1 Right-click the torso and select Object mode from the marking menu.

2 Select the torso.

3 Select Create UVs > Planar Mapping > .
The Planar Mapping Options window appears.

4 Select Edit > Reset Settings.

5 Set Project From to Z axis.

6 Click Project.

Creating a planar mapping | 395

Maya creates a new UV mapping for the torso. If you look at the UV Texture
Editor, you can see the new UVs look like a flattened version of the front of
the chest. At first glance this may seem perfect, but there’s a major problem
here that you need to change the UV Texture Editor view to shaded mode to
see.

To turn on shaded UV display

1 Select Window > UV Texture Editor.
The UV Texture Editor appears.

2 In the UV Texture Editor, click the Shade UVs icon ( ), or select
Image > Shade UVs.

In shaded UV mode, overlapping faces appear red while non-overlapping faces
appear blue.


Notice that all the faces for the torso are red. This is because the faces of the
front and back of the torso are overlapping. If you tried to apply a texture to
the UV mesh like this, you would get the exact same image on the front and
the back of the torso.
To fix this, we need to unwrap the texture so that front and back no longer
overlap.

Unfolding a UV mesh
Unfolding a UV mesh is the process of cutting a mesh so that you can lay its
entire surface area flat. However, before you do this, you want to make sure
your UVs are spread out evenly along the surface. You can do this by applying
a basic checker pattern to the mesh.

To apply a checker pattern to the torso

1 Right-click the torso and select Assign New Material > Lambert.

2 Open the Attribute Editor.

3 In the lambert tab, set the lambert field to checker_pattern.

4 Click the box next to Color.
The Create Render Node window appears.

5 Select Checker.

6 Press ‘6’ to enter Smooth Shade mode.
The torso is covered in a checker pattern.

Unfolding a UV mesh | 397

7 In the panel menu, select Panels > Perspective > persp.

From the front view, the checker pattern looks roughly even with very little
distortion. This indicates that the spread of UVs is fairly even. An even spread
of UVs is important to avoid texture warping when you apply your texture.
In some cases you may need to experiment with different planar mappings
to give you the best base to start with.
However, the planar projection isn’t perfect. If you look at the sides of the
torso, from the armpits to the waist, you can see some warping. This is the
ideal place to cut the UV edges for unwrapping.


To cut the UV edges

1 Right-click the vest and select Edge from the marking menu.

2 Select all the edges in a line that runs from under the arm, down the side
of the soldier’s body to the bottom of the vest. You can do this by
double-clicking edges along this path until they are all selected.

3 Shift-select the corresponding edges on the other side.
An edge loop on both sides should be selected now.

4 In the UV Texture Editor, select Polygons > Cut UV Edges.

Now you are ready to unfold the mesh.

To unfold the torso

1 Right-click the torso and select UV.

2 Select one UV at the inside tip of each vest strap, along the unfold line.

Unfolding a UV mesh | 399

3 In the UV Texture Editor, select Polygons > Unfold > .
The Unfold UVs Options window appears.


5 Set Pin UVs to Pin selected UVs.
A pinned UV does not move when a UV mesh is unfolded. In general,
you want at least one pinned UV when unfolding because it gives the
unfold process a point of reference. This is similar to placing a pin in a
piece of fabric so that it does not unfurl out of control as you unfold it.

6 Click Apply and Close.

Maya lays the UV mesh out across the UV space. Parts of it may fall outside
the UV space, but that’s fine for now. More importantly, notice that the pattern
is much more even across the mesh now.


Unfortunately, while you’ve minimized the distortion, you’ve also create a
visible seam where you cut the UV edges. Unfortunately this is unavoidable.
In general it is best to put your seams in the least visible places. In this case,
the seams will be obscured by the arms most of the time and therefore won’t
be as noticeable.

Adjusting the checker pattern
Although not always necessary, it is often helpful to increase the number of
squares in your checker pattern. This can help you to more easily spot
deformities in the pattern.

Adjusting the checker pattern | 401

To increase the number of squares in the checker pattern

1 Right-click the torso and select Object Mode from the marking menu.

2 Select the torso in the perspective view.

3 Open the Attribute Editor and navigate to the checker_pattern tab.


5 In the place2dTexture tab, set Repeat UV to 10, 10.
The number of squares on the torso increases.

Outputting UVs
Now that you have your unfolded UVs, you need to export them so that you
can draw a texture on them. You can do this by taking a snapshot of your UV
layout.

To export a UV snapshot

1 Right-click the torso in the perspective view and select UV from the
marking menu.

2 Drag-select all the UVs on the torso.

3 Select the Scale Tool.


4 In the UV Texture Editor, scale the UV mesh so that it fits inside the
upper-right square of the UV Texture Editor.
This step is necessary because a UV snapshot only captures what is in the
1 x 1 UV texture space (the upper right corner).

5 Right-click the torso in the perspective view and select Object Mode.

6 Select the torso.

7 In the UV Texture Editor, select Subdivs > UV Snapshot.
The UV Snapshot options window appears.

8 Click the Browse button.
A file browser appears.

9 Navigate to GettingStarted/UVMapping and enter the name torso_UVs.

10 Set Image Format to GIF.

11 Click Save.

12 Click OK.

Maya creates a file named torso_UVs.iff in the Getting Started folder. If you
open this file, you can see the exported UV mesh.

Outputting UVs | 403

You can now open this file using an external image editor and paint your
texture using the mesh as a guide.

NOTE If your image editing software does not support Maya .iff images, you can
change the image format in the UV Snapshot options window and then export
the file again.

Unfolding with constraints
Sometimes you only need to unfold a UV mesh in one direction. This is
especially useful when there is only a single seam.
To make things easier, you can use one of Maya’s Saved Layouts to keep both
the Perspective view and the UV Texture Editor in view simultaneously.

To view the perspective view and UV Texture Editor simultaneously

1 Close the UV Texture Editor window.

2 In the panel menu, select Panels > Saved Layouts > Persp/UV Texture
Editor.
The perspective view and UV Texture Editor appear side-by-side in the
viewport.


To unfold the arms

1 Select the soldier’s left arm.

2 Select Create UVs > Planar Mapping.

3 Right-click the arm and select Assign Existing Material > checker_pattern.

4 Right-click the arm and select Edge from the marking menu.

5 Select the edges on the bottom of the arm at the center of the distortion
just under the elbow.

Unfolding with constraints | 405

6 In the UV Texture Editor, select Polygons > Cut UVs.

7 Right-click the arm and select UV from the marking menu.

8 Drag-select all the UVs on the arm and click the Rotate clockwise button

( ).
The UVs rotate so the arm in the UV Texture Editor is vertical.

9 Select one UV at the top of the arm’s tricep and another UV at the tip of
the soldier’s cuff.


The Unfold UVs Options window appears.

11 Set Unfold constraint to Horizontal.


The UV mesh for the arm is unfolded evenly up and down. This is better than
the UV mesh we would get if we unfolded in all directions.


Now you can output these UVs to a file.

To export the UV snapshot

1 Right-click the arm in the UV Texture Editor and select UV from the
marking menu.

2 Drag-select all the UVs on the UV mesh.

3 Select the Scale Tool.

4 In the UV Texture Editor, scale the UV mesh so that it fits inside the
upper-right square of the UV Texture Editor.
This step is necessary because a UV snapshot only captures what is in the
1 x 1 UV texture space (the upper right corner).

5 Right-click the arm in the perspective view and select Object Mode.

6 Select the arm.

7 In the UV Texture Editor, select Subdivs > UV Snapshot.
The UV Snapshot options window appears.

8 Click the Browse button.


9 Navigate to GettingStarted/UVMapping and enter the name left_arm_UVs.

10 Set Image Format to GIF.

11 Click Save.

12 Click OK.
Like the torso you did in the previous step, Maya outputs a .gif file
containing the UV mesh. You can import this file into an image editor
and use it as a template to create a texture.

Now repeat the entire procedure for the right arm. Note that you do not need
to output the UVs for the right arm because it will use the same texture as the
left arm.
Although you could handle the legs the same way you handled the arms
(cutting them into two pieces), you can also treat the entire lower body as a
single mesh. You can follow the same procedure as above, except for the
following:

■ Select the edges down the rear until directly underneath the groin then
select the edges on the inside of each leg. Cut these UV edges.


■ You do not need to pin any UVs for the pants.

■ Like the arms, unfold the UV mesh horizontally.


As with the torso and arms, you can now output these UV meshes to an
external file to paint a texture on them. For information about how to do this,
see Outputting UVs on page 402.

Sewing UV Edges
Depending on the mapping you start with, you may sometimes find that your
UV mesh is broken up in ways that can ruin your final result. In these cases,
you can manually sew UV edges back together.

To map the head to the UV space

1 Select the head and select Create UVs > Cylindrical Mapping.

Sewing UV Edges | 411

2 Right-click the head and select Assign Existing Material > checker_pattern.


Notice that because you started with a cylindrical mapping, the checker
pattern on the sides of the head aren’t warped like in the previous
examples. Unfortunately, if you tumble the camera you can see that the
top of the head is now warped. In this particular case this is preferable
and you will see the reason why later.

If you turn on texture border display by clicking the texture border display

icon ( )in the UV Texture Editor, and re-examine the top of the helmet,
you can see that a few edges that are not on the line of symmetry are colored
thick blue. This indicates that they are on the border of the UV mesh and will
cause a seam. You can fix this by sewing these overlapping UV edges together.

To sew UV edges

1 Right-click the helmet and select Edge from the marking menu.

2 Shift-select the two thick blue edges at the top of the helmet that are not
on the line of symmetry.


3 In the UV Texture Editor, select Polygons > Sew UV Edges.
The thick blue edges change to match the other edges.

Notice that after sewing the UV edges together, the distortion has actually
gotten worse. However, this is only temporary and is fixed when you perform
the unfold.


To unfold the helmet’s UV mesh

1 In the UV Texture Editor, right-click the face mesh and select UV from
the marking menu.

2 Select the UVs down the center of the face starting from the tip of the
helmet’s rim to the bottom of the neck.

The Unfold UVs Options window appears

4 Set Pin UVs to Pin selected UVs.

The face unfolds evenly across the texture space.


Smoothing/Relaxing a mesh interactively
Sometimes you only want to partially unfold a mesh. For this, you can use
the UV Smooth tool to interactively unfold or relax the mesh.

To partially unfold the UV mesh

1 In the UV Texture Editor, select all the UVs.

2 Select Tool > Smooth UV Tool > .
The Smooth UV Tool options window appears.


4 Set Space to UV Space.

Two controls appear over the UV mesh called Unfold and Relax.

6 Click Unfold and drag the mouse to the right.
The UV mesh unfolds as you drag the mouse to the left.

7 Continue to drag until the bottom of the UV mesh until it roughly
resembles the picture below.


If you reach the edge of the screen you can release the mouse button,
click the Unfold control and drag again.

Fixing problem areas
You now have an unfolded UV mesh with no major overlapping faces.
However, there are still a few minor problem areas where the mesh overlaps
itself (particularly the eyes and mouth).
You can use the Smooth UV Tool to fix small imperfections in the shell with
targeted unfolds or relax operations.

To fix the eyes

1 In the perspective view, right-click the soldier’s head and select Edge from
the marking menu.

2 Shift-select the four closest edge loops that surround each eye. You can
do this quickly by Shift + double-clicking one edge in each loop.

Fixing problem areas | 417

3 In the UV Texture Editor, Ctrl + right-click the UV mesh and select To
UV from the marking menu.
The edges selected around the eyes are converted to the UVs selected
around the eyes.


4 Click the Smooth UV Tool icon ( ).

5 Drag the Relax control to the right until the eyes appear round.
As you drag the Relax control, the selected UVs relax until they are round.

Now you can fix the nose and mouth in a similar manner.

To fix the nose

1 Select a group of UVs on and around the nostrils.


2 Drag the Relax control to the right until the UVs stop moving.


To fix the mouth

1 In the perspective view, right-click the head and select Edge from the
marking menu.

2 Shift-select the 4 edge loops around the mouth. You can do this quickly
by Shift + double-clicking one edge in each loop.

3 In the UV Texture Editor, Ctrl + right-click the UV mesh and select To
UV from the marking menu.
The edges selected around the mouth are converted to the UVs selected
around the mouth.


4 Drag the Relax control to the right until the UVs stop moving.
The mouth UVs even out into a circular shape.

5 Select all the UVs on the head.


6 Select the Scale Tool and scale the UVs so that they fit in the upper right
corner of the UV space.

The UV mesh for the soldier’s head now has no UV faces overlapping. This
allows you maximum control over what shows up in each portion of the head
when you create the texture map for the soldier.

As with the rest of the body, you can now output these UV meshes to an
external file to paint a texture on them. For information about how to do this,
see Outputting UVs on page 402.

Applying Textures
Now that you’ve outputted all your UV meshes, you can import them into
an external image editor to create a texture.

Applying Textures | 423

Once you’ve created associated texture files, you need to apply them to your
model. For the purposes of this tutorial, textures have been provided for you
in the sourceimages folder.

To apply the texture for the torso

1 In the perspective view, right-click the torso and select Assign New
Material > Lambert from the marking menu.
The soldier’s torso turns matte grey.

2 Open the Attribute Editor and select the lambert tab.

3 Change the name of the lambert material to Mat_Torso.


5 Click File.

6 Click the file icon next to the Image Name field.

7 Navigate to the Getting Started folder and select
UVMapping/sourceimages/soldier_torso.tif.
The body armor texture is applied to the soldier’s body. If the texture is
not aligned or sized correctly you can adjust the UVs in the UV Texture
Editor using the Scale Tool in the Toolbox. If the texture does not appear
in the scene, press ‘6’.


8 In the Attribute Editor, in the Mat_torso tab, click the box next to Bump
Mapping.

9 Click File.
A file tab appears in the Attribute Editor.

10 Click the browse icon next to Image Name.

11 Navigate to the Getting Started folder and select
UVMapping/sourceimages/soldier_torso_normals.tif.
Normal maps appear on the soldier’s chest. Normal maps give the flat
portions of the texture the illusion of 3D bumps.

Applying Textures | 425

Now you can repeat the process for the other body parts by applying the
following textures:

Appendage Material node name Texture filename Normals filename

Left Arm Mat_Arm soldier_arm.tif soldier_arm_nor-
mals.tif

Right Arm Mat_Arm (reuse from above soldier_arm.tif soldier_arm_nor-
by using Assign Existing Mater- mals.tif
ial)

Legs Mat_Legs soldier_legs.tif soldier_legs_nor-
mals.tif

Left Foot Mat_Feet soldier_foot.tif soldier_foot_nor-
mals.tif

Right Foot Mat_Feet (reuse from above soldier_foot.tif soldier_foot_nor-
by using Assign Existing Mater- mals.tif
ial)

Head Mat_Head soldier_head.tif soldier_head_nor-
mals.tif

Eye Mat_Eye soldier_eye.tif none


NOTE When reusing a texture for a mirrored appendage (Right Arm or Right
Foot), you must flip the UVs in the UV Texture Editor to fit the texture. You can
do this by selecting all the UVs and clicking the Flip UVs in the U Direction button

( ) in the UV Texture Editor.

Beyond the lesson
In this lesson you learned how to unfold a UV mesh so that you can create a
texture for a complex organic mesh.

■ You can divide a mesh into parts for texturing.

■ You can create a planar mapping of UVs.


■ You can apply a basic checker texture to find problem areas.

■ You can cut UV edges in obscure areas to create a seam for unfolding.

■ You can pin a UV and unfold a mesh in all directions or constrained to a
single direction.

■ You can partially unfold a UV mesh with the UV Smooth Tool.

■ You can relax UVs to fix problem areas.

Lesson 3: Normal mapping

Introduction

Normal mapping is a technique in which you use a high resolution mesh to
generate a map for a low resolution mesh. High resolution meshes are made
up of more geometry and can be very taxing in an environment where
resources are at a premium (for example, in a large scene with other high poly
objects, or on a system with limited processing power). As a result, performance
can suffer greatly. Normal mapping is commonly used in these situations to
capture the detail of a high resolution mesh with the geometry of a low
resolution model.


A normal map differs from a texture map in that it produces a multi-channel
image (shown below) based on the normals of the high resolution (source)
mesh. This information is used to light the mapped details on a low resolution
(target) mesh convincingly, even though the surface itself is relatively flat.


■ Create and apply a normal map.

■ Display the poly count for a scene.

■ Set the Search Envelope for a target mesh.

■ Set Default Rendering mode and High Quality Rendering mode.

Lesson setup

1 Make sure you’ve done the steps in Preparing for the lesson on page 362.

2 Select the Rendering menu set.

3 Select Rendering > Default Quality Rendering from the panel menu.

Lesson setup | 429

To create a normal map you need two files, the source and the target. The
source model is generally a higher resolution and more detailed version of
the target model. The target has the geometry you actually want for your
scene.

To open the high resolution model

1 Select File > Open Scene.

2 Navigate to GettingStarted/UVMapping and select Toad_hi_res.mb.

3 Click Open.
A high resolution polygonal toad model appears in the scene.

4 Tumble the view around the toad model.
Maya may respond slowly because the mesh is highly detailed. You can
see exactly how detailed it is by turning on the Poly Count display.

To turn on the Poly Count display

1 Select Display > Heads Up Display > Poly Count.
The Poly Count Options window appears.




Statistics about the scene appear in the top left corner of the main viewport.
This model consists of over a hundred thousand faces just for the head and
upper torso. Loading such a high resolution model into the scene is impractical
for performance purposes.
Now compare the high resolution mesh with the low resolution alternative.

To import the low resolution model

1 Select File > Import.

2 Navigate to GettingStarted/UVMapping and select Toad_lo_res.mb.

3 Click Open.
A low resolution polygon model loads on top of the high resolution toad
model.

4 Select the high resolution model and hide it by pressing Ctrl + H.

The low resolution model is much more manageable in size with just over
1500 faces. However, while it maintains the basic shape of the high resolution
toad, it lacks much of the detail.


Creating a Normal Map
A normal map is a type of transfer map, meaning that it is a texture created
from a polygon object. Different transfer maps handle the conversion from
polygons to textures in different ways. A normal map captures the surface
normal information of the source mesh and uses it to light the target mesh.

To set a base material for the target mesh

1 Right-click the mesh and select Assign New Material > Blinn from the
marking menu.
Maya applies a default Blinn shader to the low resolution mesh.

2 Close the Attribute Editor.

To show the high resolution mesh

1 Open the Outliner (Window > Outliner).

2 In the Outliner, select hi_res_toad.

3 Select Display > Show > Show Selection.
Both meshes appear in the scene overlapping each other.

4 Deselect the high resolution mesh.


To create a normal map

1 Select Lighting/Shading > Transfer Maps.
The Transfer Maps window appears.
The Transfer Maps window lets you create various textures based on
mappings from polygon models. First you need to assign the source and
target meshes for the transfer.

2 In the Outliner, select lo_res_toad.

3 In the Transfer Maps window, in the Target Meshes section, click Add
Selected.

4 In the Outliner, select hi_res_toad.

5 In the Transfer Maps window, in the Source Meshes section, click Add
Selected.

Next you need to set the Search Envelope.
The Search Envelope represents the volume of the target geometry to consider
for the texture. Whatever part of the source mesh between the Search Envelope
and the target mesh is mapped to a texture.
Generally you want the Search Envelope to encompass your entire source
mesh so you don’t miss any detail.

To set the Search Envelope

1 In the Transfer Maps window, set Display to Envelope.
The low resolution toad is replaced by a translucent red mesh.
This red mesh represents the Search Envelope.

2 Drag the slider under Search envelope (%) to the right.
The red mesh grows.
Drag the slider so that the red mesh barely encompasses all of the high
resolution mesh without leaving any white spots (excluding the eyes).
You can also enter a value in the box next to the slider. In this case, a
value of 4.3 yields just enough coverage around the two meshes.

Creating a Normal Map | 433

3 Set Display back to Mesh.

Now you can set the normal map options.

To set the normal map options

1 In the Transfer Maps window, under Output Maps, click Normal.

2 In the Normal Map text field, click the browse icon ( ).

3 Navigate to Getting Started/UVMapping and enter the name toad_texture.

4 Click Save.

5 Set File Format to DDS (dds).


6 In the Transfer Maps window, set the following:
■ Under Connect Output Maps, set Connect maps to to Assigned shader.

■ Under Maya Common Output, set Map width and Map height to
1024 and Sampling quality to Medium (4x4).

7 Click Bake and Close.
Maya generates a normal map.

NOTE It may take a few minutes for Maya to generate the normal map.

Viewing a normal map
Now that Maya has generated the normal map, you need to change the render
mode to High Quality Rendering mode to see it.

To view the normal mapped texture

1 Select the high resolution toad model hide it by pressing Ctrl +
H.

2 In the panel menu, select Renderer > High Quality Rendering.
Now you can see the low resolution model with the detail of the high
resolution model applied as a texture.

3 Tumble the view around the toad.
The light on the surface reacts appropriately to all the details on the
texture, without any loss in performance.

Viewing a normal map | 435

Beyond the lesson
In this lesson you learned how to use a high resolution model to create a
normal map for a low resolution model. You learned how to:

■ Display the poly count for a scene.

■ Set the source and target for a normal map.

■ Set the Search Envelope.

■ Switch between Default Quality Rendering and High Quality Rendering.

You can also try applying other types of transfer maps to a low polygon model.
Each mapping feature gives you slightly different looks on your low polygon
model. For more information about transfer maps, see Lighting/Shading >
Transfer Maps.


Rendering
9
Introduction

In Maya, rendering refers to the process of creating bitmap images of your scene
based on the various shading, lighting, and camera attributes that you set.
When rendering, Maya takes into account all of the various objects and scene
attributes, and performs mathematical calculations to produce the final image
or image sequence. Once you render a sequence of images, you can then play
them back in sequence, producing an animation.
Rendering involves many components to produce an image:

■ Shading materials and textures

437

■ Lighting and shadows

■ Cameras and animation

■ Rendering method

■ Visual effects

In Maya, rendering can be accomplished using software (Maya Software
Renderer, mental ray® for Maya® Renderer, or the Maya® Vector Renderer) or
hardware rendering methods. Each type has its distinct advantages. Which
renderer you decide to use will be determined by your image requirements
(that is, the look you require) and time constraints.
Software rendering generally allows you to create more precise results but can
take longer to produce each frame or image. The Maya software render type
uses a process for scene illumination that directly illuminates objects in the
scene or simulates illumination by reflecting neighboring objects in the scene
or via texture mapping the effect on the object.

The mental ray® for Maya® software render type additionally provides a feature
called Global Illumination: a process that simulates the effect of indirectly
illuminating objects that are not receiving direct illumination. It can also
simulate light effects known as caustics. Hardware rendering is generally faster
but is less capable of producing detailed results. In addition, some visual effects
can only be produced via one method; at times, a combination of more than
one type of rendering method may be required.
Rendering usually requires several iterations to achieve the final image that
meets your requirements. The key is to strike the balance between producing
the image that meets your requirements and producing it in the time required.
This is particularly important if you are using Maya in a production setting.
This chapter introduces you to some of the fundamental concepts and skills
related to rendering. This chapter includes the following lessons:

■ Lesson 1 Rendering a scene: Introduction on page 439

■ Lesson 2 Shading surfaces: Introduction on page 465

■ Lesson 3 Lights, shadows, and cameras: Introduction on page 484

■ Lesson 4 Global Illumination: Introduction on page 501

■ Lesson 5 Caustics: Introduction on page 519

438 | Chapter 9 Rendering


2 To ensure the lessons work as described, select the Rendering menu set.
selections assume you’ve already selected the Rendering menu set.

Lesson 1: Rendering a scene

Introduction

This lesson provides a brief introduction to rendering in Maya. In this lesson,
you learn how to:

■ Assign shading materials to surfaces in the scene.

■ Edit the color of shading materials.

■ Apply simple textures to shading materials.

■ Render both a single image and a sequence of images for an animation.

■ Use Interactive Photorealistic Rendering (IPR) to perform test renders of
the scene.

■ Edit the Render Settings attributes to change the quality of the final results
of an image.

■ View a sequence of rendered frames for an animation.

Preparing for the lessons | 439

In this lesson, you render a scene we’ve created for your use.


2 Open the scene file named apple.mb.
your Maya project:
GettingStartedRenderingapple.mb

The scene contains an apple sitting on a plane, with another plane as the
background. A camera in the scene is animated to revolve around the
apple at varying distances. (As an alternative to using the scene apple.mb,
you can create a similar scene with your own objects.)


4 Click the Time Slider category and make sure the Playback Speed option
is set to Real-time (24 fps) so your animation will playback at the default
rate of 24 frames per second.

5 Close the Preferences window.
You won’t use the animated camera until later in the lesson. In the next
steps, you color the apple and the planes by creating shading materials.


Creating shading materials for objects
A shading material is a collection of attributes that you apply to a surface to
control how the surface appears when it is rendered. Shading materials include
such attributes as color, shininess, and texture. The following table outlines
the materials you’ll be working with:

Material Description

Lambert Creates a matte surface without specular
highlights. Lambert is the default shading
material.

Blinn Creates a shiny surface with specular
highlights, often used to simulate metallic
surfaces.

When you open the apple.mb file, it initially displays the apple and the planes
as wireframes (Shading > Wireframe). This is the default display mode for
objects in a scene view.

To create materials for the apple stem

1 In the perspective view, select Shading > Smooth Shade All (hotkey: 5).

Creating shading materials for objects | 441

The apple and the other surfaces appear with a default gray, smooth
shading material, lit using default lighting. Default lighting occurs when
no other lights have been placed in the scene.

2 In the perspective view, select the apple stem by clicking its geometry.
(Be sure that only the apple stem is selected.)

3 From the Rendering menu set, select Lighting/shading > Assign New
Material > Lambert.
The Attribute Editor appears for the Lambert material.
A Lambert material creates a matte surface without shiny highlights. You
will learn more about materials and their attributes in a later lesson.

4 Click the gray box to the right of Color.

The Color Chooser window appears.

5 Click inside the color wheel and drag to a brown color.
The color you select in the Color Chooser is applied to the apple stem.


6 Click Accept to close the window.

7 In the Attribute Editor, rename the lambert shading material to
appleStem_lambert.

To create materials for the apple

1 Right-click the apple and select Assign New Material > Blinn from the
marking menu.
The Attribute Editor updates to display the attributes for the Blinn
material.
A Blinn material gives the apple a shiny appearance.

The Color Chooser window appears.

3 Click inside the color wheel and drag to a red color.
The apple’s surface updates to the same color you select in the Color
Chooser.


5 In the Attribute Editor, rename the Blinn shading material to
appleSkin_blinn.

Creating shading materials for objects | 443

To create materials for the counter and wall

1 Right-click the background plane and select Assign New Material >
Lambert from the marking menu.
The Attribute Editor displays the attributes for the Lambert material.


3 In the Color Chooser window, click inside the color wheel and drag to
a light blue color.
The color you select in the Color Chooser is applied to the plane.


5 In the Attribute Editor, rename the Lambert shading material to
wall_lambert.

6 Right-click the surface that the apple is resting on and select Assign New
Material > Lambert.
The Attribute Editor displays the attributes for the Lambert material.


8 In the Color Chooser window, click inside the color wheel and drag to
a beige color.
The color you select in the Color Chooser is applied to the plane.


10 In the Attribute Editor, rename the Lambert shading material to
counter_lambert.


The counter, wall, and apple stem all have a matte Lambert surface, while
the apple has a shiny Blinn surface. There are many other attributes you
can set to change the appearance of these objects, which you’ll explore
in the next section.

Refining shading materials for objects
You can refine the shading materials in the scene to make the objects appear
more realistic. In the next steps you connect (or apply) a procedural texture to
the counter, and a ramp texture to the apple. These textures are connected to
the color attribute of the shading material for each surface to provide natural
surface variation. When you connect textures, you create shading networks.
You’ll learn more about shading networks in a later lesson.
A procedural texture is a 2D or 3D texture calculated based on an algorithm
or mathematical formula. It can be useful for creating random patterning. A
ramp texture is a 2D texture or color gradient in which the color or grayscale
value changes across the image.

To connect a procedural texture to the counter surface

1 In the perspective view, right-click the counter surface and select Material
Attributes.
The Attribute Editor for the counter_lambert material appears.

Refining shading materials for objects | 445

2 To the right of the Color slider, click the Map button

The Create Render Node window appears and lists the various textures
you can connect to the color attribute of the Lambert material assigned
to the counter surface.

3 In the Create Render Node window, scroll through the list of textures,
and from the list of 3D Textures, click Granite.

The procedural texture gives the counter the look of a stone granite
counter top when it is rendered, and provides the context for the scene.

4 Press 6 to see a shaded and textured display of the granite texture on the
counter top surface.

5 In the Attribute Editor, under Granite Attributes change the Filler Color
from the default reddish-brown to a beige color as follows:
■ Click the color box to the right of Filler Color.


■ In the Color Chooser window, select a beige color and click Accept.

NOTE Materials and textures displayed in the perspective view do not
show their true appearance. To see the accurate appearance of the texture
you must render the scene.

To connect a ramp texture to the apple surface

1 Right-click the apple and select Material Attributes from the marking
menu.
The Attribute Editor updates to display the appleSkin_blinn material
properties.

2 To the right of the Color slider, click the Map button.

The Create Render Node window appears and lists the various texture
patterns you can connect to the Color attribute of the Blinn material
assigned to the apple.

3 From the list of 2D textures, click Ramp.


This texture creates a gradation through a series of selected colors.
Applying the ramp texture provides the apple with a realistic variation
in surface color.

4 In the Attribute Editor, under Ramp Attributes, change the Type to U
Ramp.
The Ramp Type indicates the direction of the color gradient. A U ramp
applies the gradient in a linear, vertical direction across the object.

5 Add another color component by clicking within the ramp.
A new set of color handles appears in the ramp, for a total of four color
components.


6 To change the ramp colors, click the top circular color handle (to indicate
which color you want to modify), then click the color box to the right
of Selected Color to display the Color Chooser window.

7 Click inside the color wheel and drag to a very dark brown for the first
ramp color. Click Accept to close the window.

8 Repeat steps 6 and 7 for the other three ramp colors. For the two middle
ramp colors, select a dark red. For the last ramp color, select a deep olive
green.


10 Use the circular color handles to reposition each component as shown
below:


The position of these handles and the corresponding colors affect the
location and breadth of the color within the gradient on the apple’s
surface.

11 Save your work.
In the next section you render your scene to view the textures and
materials you’ve assigned to the objects.

Maya renderers
So far, you’ve seen the results of shading the apple and other surfaces in the
scene view. In this view, Maya uses your computer’s graphics hardware to
display the shading and textures quickly but with low quality.
To view the shading results of the colors and textures in a more realistic
fashion, you must use a renderer. In this lesson you use a process called software
rendering.
Software rendering can take seconds or minutes to render a single frame of
animation from your scene, depending on the complexity of surface geometry,
shaders, lighting and other visual elements present in the scene.
The following table outlines the different types of renderers in Maya and what
each is used for:

Renderer Use

Maya’s Software renderer A general purpose renderer with broad
capabilities. You can produce high-quality
images with complex shading networks,
including procedural textures and ramps.
Software rendering is computed through
your machine’s processor.


Renderer Use

Interactive Photorealistic Rendering (IPR) A feature of Maya’s software renderer, used
to make interactive adjustments to the final
rendered image. You can adjust shading
and lighting attributes in real-time, and IPR
automatically updates the rendered image
to show the effects of your changes. IPR is
useful for tweaking an image before render-
ing to disk.

mental ray® for Maya® renderer A general purpose renderer that includes
exclusive, advanced rendering functional-
ity, such as host and network parallel ren-
dering, area light sources for soft shadows,
global illumination, and caustics (light
patterns).

Maya Vector renderer A specialized renderer used to produce
stylized renderings (for example, cartoon,
tonal art, line art, hidden line, wireframe)
in various bitmap image formats (IFF, TIFF)
or in 2D vector formats (SWF, AI, EPS,
SVG). The Maya Vector renderer is often
used to render web-ready images.

Maya’s Hardware renderer A general purpose renderer that uses your
machine’s graphics card for computation.
You can produce broadcast resolution im-
ages in less time than with software render-
ing, and in some cases, the quality may be
good enough for final delivery.

The Render View window
When you render your scene the rendered image appears in its own window
called the Render View. By default, the Render View uses the same camera as
the Scene View (persp), but includes particular rendering capabilities.

Maya renderers | 451

The following table shows the differences between the Render View and the
Scene View:

Scene View Render View

Display 3D object scene 2D rendered image

Surfaces modeled surfaces, the grid, shaded surfaces only
vertices, curves, and object
manipulators

Background default gray background black background by de-
fault because only objects
with materials that are lit
can be seen

Quality low-quality, colors and tex- high-quality, colors and
tures do not appear in their textures appear in their fi-
final display form nal rendered form

Rendering a single frame using IPR
In this section, you work with IPR (Interactive Photorealistic Rendering), a
type of software rendering.
The advantage of rendering with IPR is that, after you render an image, you
can adjust the shading and lighting attributes of the scene and then quickly
update part or all of the rendered image to review the effect of your changes.
IPR is useful for iterations when you need to fine-tune specific attributes.
Updates to the image are not always instantaneous, but they are full quality.

To render the scene using IPR

1 In the perspective view, select View > Camera Attribute Editor to display
the attributes for the camera.
You need to specify the exact region of the perspective view you want to
render.

2 In the Attribute Editor, open the Display Options section and turn on
Display Resolution.
A dark green rectangular border shows the region to be rendered. This
region defines the area of the final image, and allows you to decide what


appears or does not appear in the final image. (The left and right borders
of the rectangle may be positioned at the edge of the window.)

3 Select Render > IPR Render Current Frame (or select the IPR render current
frame button on the Status Line). (By default, Maya uses the Software
renderer as indicated on the Render View window’s toolbar.)
The Render View appears and displays the rendered image.

The rendered image shows the appearance of the apple based on the
lighting, and shows the more realistic texture of the counter.

Rendering a single frame using IPR | 453

The message displayed at the bottom of the IPR Render View window
states “Select a region to begin tuning”. In the next step, you create a
subregion of the image to render using IPR.

4 In the Render View, select View > Frame Image to resize the Render View
window so it fits closely to the rendered image.

To select a subregion to render using IPR

1 In the Render View, drag a selection box around the small area
surrounding the apple, counter, and wall as shown:

When using IPR, this selected region updates as you alter any shading,
texture, or lighting attributes. Selecting a smaller region quickens the
update. You can select regions throughout the image to see those areas
update.

2 In the scene view, right-click the wall and select Material Attributes to
display the Attribute Editor for the Lambert shader you applied to the
wall.

3 Click the Color box and change the color to green.
The area within the selected region of the Render View updates
immediately as you alter the color; the wall turns green.
When you drag within the color wheel of the Color Chooser window,
the selected region updates occur immediately.


NOTE If the region does not update, in the Render Settings window, turn
the Raytracing option off.

(You won’t alter any other attributes in this lesson. The purpose of the
lesson is to learn the process of rendering, not to perfect the results at
this point.)

4 From the Render View menu, select IPR > Redo Previous IPR Render.
The rendered image updates to the full resolution.

By default, the resolution of the IPR window is 320 by 240 pixels. The
advantage of this relatively small resolution is that it renders quickly. However,
if you want a larger image, you can increase the image resolution.

To increase the size of the rendered image

1 In the Render View menu, select Options > Render Settings (or click the
Render Settings button in the Render View window).

The Render Settings window appears.

Rendering a single frame using IPR | 455

2 Click the Common tab, open the Image Size section, and select 640x480
from the Presets drop-down list.

(An image size of 640 by 480 is four times as large as the 320 by 240 image
size.)

3 Close the Render Settings window.


4 Close the Render View window.

5 Select Render > IPR Render Current Frame (or select the IPR render current
frame button on the Status Line).
The Render View window opens and renders an image with an image
size of 640 by 480 pixels.

NOTE If you are using Maya on Windows or Linux, rendering the scene
displays another window called the Output window, typically behind other
windows on your desktop. The Output window lists statistics about the image
just rendered. For now, you can ignore and close the Output window. It
contains information that you will appreciate more as you gain experience
using Maya.

So far, you’ve used IPR to see changes you made to a shader. If you add lights
to the scene rather than using default lighting, you can also use IPR to help
adjust the lighting.

Rendering using the Maya software renderer
You are nearly ready to render the entire animation to disk. You must first
switch camera views so you can render the scene from the point of view of
the camera that was animated for this lesson. When animating a camera it’s
a good practice to create a second camera to animate, rather than animating
the default persp camera. In that way you can return to the default perspective
view should it become necessary.
Rendering the entire animation can take a lot of time, so it is useful to first
use Maya’s software renderer to test render a few frames to your monitor and
examine the results.
Once you are satisfied with the quality of a few rendered frames, you can
render the entire animation to disk.

To switch camera views and playback the animation

1 In the perspective view, select Panels > Perspective > apple_camera.
The view updates to display the scene as seen through the lens of the
apple_camera.

2 Click the Play button in the Timeslider playback controls.
During playback, the animated camera tracks and tumbles about the
apple.

Rendering using the Maya software renderer | 457

3 Stop the animation at a frame you want to test render.

To test render the current frame of animation

1 In the Render View window, select Options > Render Settings.

2 In the Render Settings window, ensure that Maya Software is selected
from the Render Using drop-down list.

3 In the Render Settings window, select the Maya Software tab.

4 In the Anti-aliasing Quality section, select Production quality from the
Quality drop-down list.

This setting provides high quality results by smoothing any jagged surface
edges in the rendered image.


6 In the Render View window, select Render > Render > Current
(apple_camera).
This menu item uses the software renderer to render a single frame of
the scene that you rendered with IPR previously but from the point of
view of the animated apple_camera.
You might not see a big improvement in quality as compared to the
IPR-rendered image. If you dolly the camera closer to the apple and render
once with IPR and once with the software renderer, you will see an
improvement at the edges of the apple as shown below:


7 Go to frame 120 of the animation, where the apple is viewed in a different
position.

8 In the Render View, select Render > Render > Current (apple_camera).
Ensure that the rendered image looks good at this frame also.

Now that you’ve checked a pair of rendered frames that represent the entire
animation, you are ready to render the entire animation sequence. In your
own projects, you might want to test render several frames, particularly where
new shading and lighting elements occur in the animation.

Batch rendering a sequence of animation frames
After you model, animate, and color your scene, you set several Render Settings
options and then use the software renderer to batch render part or all of the
animation’s range of frames to files on disk. Each file represents a single frame
(image) of the animation.

To set the Render Settings for batch rendering

1 In the Render View window, select Options > Render Settings to display
the Render Settings window.

2 In the Render Settings window, select the Common tab, and then open
the File Output section.

3 In the File Output section, set the following options:
■ File Name Prefix: Type the name Apple. This name will be the base
of the filenames created by batch rendering.

■ Image Format: Select Maya IFF (.iff), Maya’s standard image file format.
You can use the .iff format for any further work you need to do,

Batch rendering a sequence of animation frames | 459

including previewing and compositing the animation. If you require
a different format, you can specify it instead of .iff in the Render
Settings.

■ Frame/Animation Ext: Select name.#.ext. This specifies that the
filenames will have the format prefix.frameNumber.fileFormat. For
example, batch rendering the entire 200-frame animation will create
Apple.0001.iff, Apple.0002.iff, and so on through Apple.00200.iff.

■ Frame padding: Enter 4. This causes the frameNumber part of the
filenames to be four digits prefixed with 0s. For example, the filenames
will be Apple.0001.iff through Apple.0050.iff.

■ Start frame: Enter 1, the first frame of the animation sequence to be
batch rendered.

■ End frame: Enter 60, the last frame to be batch rendered. (Rendering
all 200 frames may be time-consuming.)

■ Renderable Camera: Select apple_camera from the drop-down list to
indicate which camera view to render.

The four-digit padded filename is compatible with many image playback
programs, for example, Maya’s FCheck utility. Image playback programs
let you view rendered animation sequences on your monitor at real-time
speed.
For the remaining options in the Render Settings window, you’ll use the
default settings. Maya will render using the image size (640x480), and
anti-aliasing quality (Production Quality) that you specified earlier in the
lesson.
After you set the Render Settings, the top portion of the Common tab
shows the correct path and filenames for the files to be created during
batch rendering. Check that this information is correct.



To batch render animation frames

1 Save the scene.
It’s a good practice to save the scene before batch rendering. This is useful
if, after batch rendering, you need to change any display settings and
render again. By saving the scene prior to batch rendering, you can
examine the scene to learn which option settings were in effect at the
time you batch rendered.

2 From the Rendering menu set, select Render > Batch Render > .
The Batch Render Frame window appears.

3 Turn on Use all available processors, then click Batch Render and close
to start batch rendering.
(The Use all available processors option allows Maya to use all the
processors available on the local machine to complete the render.)

Batch rendering a sequence of animation frames | 461

NOTE For users of Maya Personal Learning Edition, the Use all Available
Processors option is disabled. Use the default settings.

Batch rendering 50 frames of a simple scene takes a few minutes. A
complex scene may take hours per frame, depending on the speed of
your computer.

To check the status of the batch render

1 While Maya is rendering, select Window > General Editors > Script Editor.
Expand the size of the Script Editor window. The window shows a
completion log for the frames being rendered.
Maya puts the resulting files in a default images directory. The files have
the following names:
Apple.0001.iff
Apple.0002.iff
Apple.0003.iff
...
...
Apple.0050.iff
The images directory is located in the same path as the scenes directory.
You can have Maya save to a different path by changing the project
setting. See the Maya Help for further information on projects.

2 Close the Script Editor when the following message appears:
// Result: Rendering Completed. See mayaRenderLog.txt for inform
ation. //
The mayaRenderLog.txt file contains rendering statistics for advanced
users.

Viewing a sequence of rendered frames
You can use Maya’s FCheck image viewing utility to view the batch-rendered
images at a speed that approximates video or film.

To use FCheck to view a sequence of rendered frames

1 Select File > View Sequence.
The File Browser window appears.


2 Using the File Browser, navigate to the images directory for your current
project (or wherever you saved the rendered sequence of images for the
Apple).

3 Click the image file Apple.0001.iff to select the first image in the
sequence and then click Open.
The FCheck image viewing utility appears and the rendered sequence of
60 frames plays back as an animated loop.

4 Close the window after viewing the animation.

NOTE The FCheck rendering utility has playback, display, and other options
you can select from your keyboard. Details are available from the FCheck
Help menu.

Beyond the lesson
In this lesson, you were introduced to some of the basic concepts for rendering
an image. In this lesson you learned that:

■ Surfaces are assigned shading materials to provide basic attributes such as
color, shininess, reflectivity, and so on. Each shading material has unique
characteristics that can be modified to suit your requirements.

■ You can additionally assign a texture map to some of the shading material
attributes so that your objects appear more realistic.

■ Maya provides several methods for rendering an image. You can render
using the Maya Software renderer, the Maya Hardware renderer, the Maya
Vector renderer or the mental ray® for Maya® renderer. Each type of
renderer has specific advantages and uses.

■ You can choose the size and quality for a rendered image prior to rendering
based on your specific needs and requirements.

■ You can render a single image or a sequence of images from an animation.

■ You can view one image, or a sequence of rendered frames using the FCheck
utility.

As you render scenes, consider the following issues:


Using IPR
There are a few limitations to using IPR for fast visual feedback as you adjust
shading and lighting. Besides being unable to provide production-quality
anti-aliasing, IPR cannot display several other advanced display characteristics,
for example, true surface reflections (raytracing) and 3D motion blur. If an
advanced display characteristic seems to be missing from an IPR-rendered
frame, try rendering the frame with the software renderer.
If you change the camera view, turn Depth Map Shadows on or off, or
reposition shadows, IPR does not update the rendered image automatically.
You must refresh the image. From the Render View window, select IPR >
Refresh IPR Image.

Batch rendering
In this lesson, you used the Maya software renderer to check the image quality
of two frames before you started to batch render. When you create scenes with
sophisticated animation, it’s useful to batch render with low-quality resolution
to check the animation accuracy before batch rendering with
production-quality resolution. For instance, you might preview your animation
with the frames resulting from batch rendering at a small image size (320 by
240) with Preview Quality anti-aliasing.
You don’t need to use the batch renderer to render single frames from your
scene to disk. From the Render View window, select File > Save Image.

Hardware rendering
Hardware rendering leverages the power provided by hardware graphics cards
to render your images. The benefits of hardware rendering include the ability
to batch render frames more quickly than with software rendering, and
rendering specific particle effects not possible through software rendering. In
some cases, the image quality may be good enough for final use. You access
the hardware renderer by selecting Render > Render Using > Maya Hardware.
Hardware rendering has its own limitations when compared to software
rendering. For more information on hardware rendering, see the Maya Help.

Rendering in layers
It’s often useful to render objects in your scene in different layers and combine
them using compositing software. In some cases, you must render some optical
effects and then composite them afterwards. Rendering in layers can end up
being faster than rendering an entire scene, and it lets you replace individual
objects quickly if the need arises. To set up layers, use the Layer Editor, which


appears below the Channel Box by default. For more information, see “Render
layers” in the Maya Help.

Lesson 2: Shading surfaces

Introduction

In the real world, objects are seen in specific ways based on the following:

■ The materials they are made of.

■ Their surface textures.

■ How they are lit and reflect light.

■ The environment surrounding them.

In Maya, you provide your surfaces and objects with these characteristics by
assigning shading materials to them.
Shading Materials provide instructions to the renderer so it can simulate how
the surfaces in your scene react to light and appear in the final image. Shading

Lesson 2: Shading surfaces | 465

involves such attributes as color, transparency, shininess, and many others
to create a realistic look.
Editing the material attributes associated with shading materials affects how
they appear in the rendered image. In this way, Maya provides the option of
allowing you to create images as they would appear in the real world or in
your imagination.
In this lesson, you learn to use basic shading features to render a sphere so it
appears like an orange in the final image.

■ Assign a shading material with specific color and surface attributes.

■ Differentiate between shading material types (Lambert, Blinn, Phong, and
so on) to achieve a specific material appearance.

■ Assign a label texture map to a surface.

■ Use the Hypershade editor to view and work with shading materials.

■ Create a bump texture map to simulate the orange’s pebbled skin.

■ Control the placement of a 3D texture using a 3D manipulator.



2 Open the scene file named ShadeOrange.mb.
your Maya project:
GettingStartedRenderingShadeOrange.mb
This scene contains a sphere modeled to resemble an orange.


The scene’s perspective view also has two settings turned on—Shading >
Smooth Shade All and Shading > Hardware Texturing (Hotkey: 6)—which
let you see the shading changes you are about to make.

Assigning a shading material
In the next steps, you create a material and assign it to the surface. A material
is a collection of attributes that define color, shininess, and other surface
characteristics.

To assign a material to an object

1 Before you create a new material, right-click the sphere and select Material
Attributes.
The default material attributes appear in the Attribute Editor.
The default material assigned to the sphere (and all other surfaces) is a
type of material called Lambert. The material displays the surface with
gray shading. You should not edit the default shading material.

2 Right-click the sphere and select Assign New Material > Blinn to create a
new material for the sphere.
The new material’s attributes appear in the Attribute Editor.
A Blinn material gives a surface a shinier look than a Lambert material.
Blinn is a good choice for creating a variety of surface appearances.
Knowing which material type to use for a particular surface comes with
practice. Fortunately, you can change the material type later on, so you
do not need to make a decision now. You will learn more about material
types later in the lesson.

3 In the Attribute Editor, click the gray box to the right of Color to open
the Color Chooser.

Assigning a shading material | 467

4 In the Color Chooser, click inside the color wheel (hexagon) and drag
the pointer to an orange-colored area, as illustrated.
The sphere becomes the same color you select in the Color Chooser. Also
drag up the slider to the left of the hexagon to get a brighter shade.

5 Click Accept to close the Color Chooser.
If you compare the color in the Color attribute box with the sphere’s
color in the scene view, you’ll notice a difference.
The color you assigned is only one aspect of surface appearance. The
appearance also depends on how the surface reacts with light. The main
attributes that control the reaction to light are under the Common
Material Attributes heading. As an example of these attributes, you will
change the Diffuse setting.

6 In the Attribute Editor, drag the Diffuse slider to its right to increase the
color brightness as viewed in the scene view.
This will help create the illusion of a bright orange.


In practical usage, the Diffuse setting makes a surface appear brighter.
The name diffuse comes from a property in physics that describes how
light spreads after it strikes a surface. A surface with a high diffuse property
spreads the light that strikes it, making the object appear brighter.
Like the Diffuse attribute, the other Common Material Attributes also
refer to general characteristics of light and the way a surface reacts to
light.
The next section in the Attribute Editor, Specular Shading, contains
attributes that control the appearance of shiny highlights on the surface.

Next, you’ll alter the surface specularity—the amount of light that reflects off
a surface, resulting in shiny highlights.

Modifying surface specularity
When light reflects in a concentrated manner off of a surface, a specular
highlight results. Specular highlights can be thought of as “pseudo” reflections
of bright areas in the scene (sunlight, bright lights, and so on). Modifying the
specular attributes affects the perceived reflectivity for a surface. When you
reduce the specularity, you in turn reduce the perceived reflectivity.

To modify the specularity of a material

1 In the Specular Shading section of the Attribute Editor, move the
Eccentricity slider back and forth to change the size of the shiny
highlights.

2 Move the Specular Roll Off slider to change the blend between highlighted
and other areas of the surface.
Changes to this attribute do not alter the surface in the scene view, so
you need to check the Material Sample in the Attribute Editor (see the
following illustration). You can also render a test image (Render > IPR
Render Current Frame).

Modifying surface specularity | 469

As you work with shading, you’ll find many attributes that have no effect
in the scene view, for instance, Ambient Color and Translucence.
Generally, the scene view is a rough approximation of how the scene will
render.
The IPR renderer is ideal for testing shading. It shows the results of all
changes you make to shading and shows them immediately. There is
only one attribute change the IPR renderer does not show—reflectivity.
See the next step for details.
Some attribute changes such as reflectivity and reflections are not
displayed by the Material Sample.

Material types
A material type (also referred to as a shading model) defines how a particular
shading material on a surface simulates a natural reaction to light. Blinn,
Phong, and Lambert are a few examples of material types available in Maya.
Each of these material types provide distinct shading characteristics based on
the mathematical algorithms that define them.
From the settings you’ve made so far, you may decide you want to give the
orange a different look than possible with the Blinn material. You will now
change to a different material for comparison.

To set the material type

1 Next to the Type attribute near the top of the Attribute Editor, pull down
the menu and select Phong E.
Phong and Phong E are variations of the Lambert material type, with
specular highlights added. The main difference between materials is the
way each handles specularity. By switching between the material types,
you can compare which material gives you the specularity you need.


Your settings for the Color and Diffuse attributes are maintained because
they are common to all material types. The Specular Shading and all other
attribute settings do not convert when you change the material, so it’s
best to choose your material before you make many changes.

2 In the Specular Shading section, you can leave Roughness and Highlight
Size at the default settings. The default highlight settings give the orange
a waxy look.

These attributes are similar to the Blinn attributes, Eccentricity and
Specular Roll Off. Unlike the Blinn counterparts, these highlights do not
appear in the scene view. You can see the highlights only in a rendered
image and in the Material Sample.

3 The Phong E material type has a Whiteness attribute not available with
Blinn. Change Whiteness to a light gray to accentuate the highlights.
This change is subtle, so drag the slider back and forth while watching
the effect in the Material Sample or in an IPR region. Look for the entire
highlighted area to become whiter. Again, a strong highlight will create
a waxy look.

Assigning textures
For an orange, one color may be all that you need. In this section, you will
go a step further by making a logo stamp appear on the orange skin. For this
and other color effects, you need to apply a texture to your material.
In visual arts, a texture is any kind of surface detail, both visual and tactile.
In Maya, a texture is a collection of attributes that creates surface detail.
Textures have a more specialized display purpose than materials. For example,
you can use textures to create the appearance of a marbled pattern, bumps,
or a logo image on the side of a can.

Assigning textures | 471

In the Maya Help, a texture is also referred to as a texture node. A node is a
collection of attributes (or actions) with a common purpose. A shader is
sometimes called a shader node or material node.
To display a texture on a surface, you apply a texture node to an attribute of
the surface material. In the next steps, you apply a texture to the Color attribute
of the Phong E material.

To apply a texture to a material

1 Click the Map button next to the Color slider. This is a quick way of
applying a texture to an attribute. This is also called mapping a texture.

The Create Render Node window displays a list of the textures you can
apply. The texture names and their icons help you to decide which texture
is appropriate for the effect you want.

To create the logo stamp effect, you will use the File texture. A File texture
uses an image file that you or someone else created separately, such as a
drawing from a paint program. For this lesson, you’ll use an image we
created for you.

2 Before you create the texture, make sure Normal is selected in the options
above the texture swatches.


The Normal option means Maya will stretch the texture evenly around
the surface. The other settings—Projection and Stencil—are other ways
you can apply a texture. You will learn about these settings at the end of
the lesson.

3 In the 2D Textures list, click the File button once.
At this point the system may prompt you with the warning that “The
IPR file does not have enough information to support your most recent
change”. Select “Close the IPR file and stop tuning”. The file1 node
appears in the Attribute Editor.
The file texture also causes the sphere to turn white in the scene view
and black in a rendered view. This is a temporary color until you specify
the actual file name of the file texture.

4 Click the folder icon to the right of the Image Name attribute. A browser
window opens with the path set to a default directory called sourceimages.
Maya looks for source images in a default sourceimages directory.
However, Maya can use file texture images anywhere on your workstation
or local network. For example, you could have them on a central disk
drive that is shared among your coworkers.

5 Navigate to the GettingStartedRenderingsourceimages directory and
open Render_Mayakist.iff.

6 In the Render View window select IPR > Redo Previous IPR Render.
The file texture with a Mayakist logo now appears on the sphere. The
logo is somewhat jagged, which will simulate the look of an ink stamp
on rough orange skin.

7 In the Attribute Editor, click the place2dTexture1 tab.

The place2dTexture1 tab is a node with attributes that control the texture’s
position on the surface.

Assigning textures | 473

If you select another object and the Attribute Editor no longer displays
the file texture attributes, it’s easy to restore the display. Right-click the
sphere, select Material Attributes, and click the texture map icon next to
the Color attribute.

8 As an example of the place2dTexture1 placement controls, move the
Rotate UV slider slightly to the right, to a value about 5.9. This rotates
the Mayakist logo on the surface.
In this case, the texture placement needs almost no adjustment. For the
ease of this lesson, we created a file texture that conforms to the sphere’s
shape by default. In practice, placing file textures requires more
adjustment. For details, see Preparing for the lessons on page 439.

Using the Hypershade editor
After you create a texture node, you will often want to return to the associated
material node to make changes. Because material and texture nodes do not
have icons that represent them in your scene view, you need a special editor,
called Hypershade, to select them and edit their attributes. In this section,
you learn how to work with Hypershade.

To view and edit material attributes using Hypershade

1 In the perspective view, select Panels > Saved Layouts > Hypershade/Persp.
This layout is convenient because it’s common practice to drag and drop
items from Hypershade (using the middle mouse button) onto objects in
the perspective view. You can also open Hypershade as a separate window
(Window > Rendering Editors > Hypershade).

2 At the top of Hypershade, click the Materials tab to make sure the tab is
displayed. If the material swatches are too small to see clearly, dolly into
the view using the same keyboard and mouse shortcuts you would use
in the scene view.


This tab shows all the materials currently in your scene. It is especially
useful when you have a complex scene and you need to locate a material
to edit it. The materials you will recognize are the default Lambert material
and the Phong E material. You can ignore the others. They exist in all
scenes, by default, for use with other Maya features.
In addition to the Materials tab, Hypershade includes other tabs to help
you keep track of textures, lights, and other nodes related to rendering.

3 With the middle mouse button, drag the lambert1 swatch into the scene
view and over the sphere. When you release the mouse, the Lambert
material appears on the sphere instead of the Phong E material you
previously created.

4 Drag the phongE1 swatch onto the sphere to reapply that material.
Hypershade is designed for quick, drag-and-drop operations such as this.

5 Select the sphere.

6 From the menus in Hypershade, select Graph > Graph Materials on
Selected Objects.
A graph appears in the Work Area tab in the bottom section.

Using the Hypershade editor | 475

This graph shows all material and texture nodes applied to this object.
While the Materials tab shows a catalog of the materials in the scene, the
Work Area tab shows whatever material, texture, or other node you are
currently working on. The Graph menu has several menu items that
change the contents of the Work Area display.
The Shader Library tab shown in the above illustration might not be a
part of your Maya installation. It is an optional feature, discussed at the
end of this lesson.
The Work Area shows connection lines between the nodes. The lines
have arrows that all point in one direction. For a closer look at these
arrows, dolly into the view using the same keyboard and mouse shortcuts
you would use in the scene view.

The arrows depict Maya’s internal information input and output, called
a stream. The next step shows the importance of this connection stream.

7 Click the line between the file1 and phongE1 nodes (it turns yellow) and
press the Delete key.
The sphere reverts to the default gray color because you have broken the
connection between these nodes and the texture is no longer assigned
to it. This is a simple illustration of how the connection stream works.
The file1 texture node is upstream from the connection you deleted, so
it no longer inputs data into the material; Maya ignores it.
In practical terms, this is an example of how you can disconnect a texture
from a material without actually deleting the texture. For example, you
may want to remove the file texture from this material and connect it to
another material instead. In a later step, you will learn about using
Hypershade to make connections between textures and materials.


8 Select Edit > Undo (see Edit > Undo, Redo, Repeat) to restore the file
texture connection you deleted.

9 In Hypershade, right-click the center of the phongE1 swatch and select
Rename.

10 Type: Orange.
Renaming is not as important in this scene as it would be in more complex
scenes with several materials.
The Rename operation is one of several useful menu items that appear
when you right-click a material swatch. Another handy menu item is
Assign Material to Selection. You can use this operation to assign a
material to multiple selected objects rather than assign it one object at a
time.

Creating a texture within the Hypershade editor
To mimic the skin of an orange, you will add a bump map texture. A bump
map creates the illusion that the surface has bumps or other types of surface
relief. You will map the texture using the Create Bar in Hypershade.

The Create Bar is similar to the Create Render Node window you have used
already. It is built into Hypershade for greater convenience.
Create Render Node appears at the top, by default. Next to the heading is an
arrow icon. If you click this icon, you switch to the Create mental ray Nodes
mode. In this case, leave the Create Maya Nodes selection turned on.
The Mayakist logo file texture is a 2D texture, which wraps evenly around the
surface. Next, you create a 3D texture. A 3D texture is for making objects
appear to have been carved out of a solid substance, such as marble or wood.

Creating a texture within the Hypershade editor | 477

To create a bump texture within the Hypershade Editor

1 In the Create bar, scroll down to the 3D Textures heading.
For this bump effect, you use a Brownian 3D texture. Experience has
shown that a Brownian texture is the best texture for approximating the
bumps on an orange skin. Becoming skillful with textures is a matter of
observation, experimentation, and experience.

2 With the middle mouse button, drag the Brownian texture (under 3D
Textures) onto the Orange material swatch in the Work Area tab and
release the mouse button.

3 From the menu that appears, choose bump map.
Maya connects or applies Brownian to the Orange material’s bump map
attribute.

The pop-up menu shows a list of common material attributes. Although
you can map textures to any material attribute, these are the most
commonly mapped attributes.
By default, you can assign only one texture per attribute. Attributes that
already have an assigned texture appear in italics. (For a discussion about
assigning multiple textures to an attribute, see Layered textures on page
483.)
This drag-and-drop method of applying a texture is essentially the same
as clicking the map icon next to a material’s attribute slider. Using
Hypershade offers a faster, more graphical alternative to using the
Attribute Editor.

4 Select Graph > Input and Output Connections to view the node
connections for the new texture you created.


Also notice that bumps from the bump map appear in the Orange
material’s swatch. The Orange material swatch is the same as the Material
Sample that appears in the Attribute Editor for the material node. (The
bumps also appear in a rendered image, but not in the scene view.)

5 Double-click the bump3d1 swatch (the checkered cube) to display its
attributes in the Attribute Editor.
This node is the link between the texture and the material. It converts
visual information, such as the mottled Brownian pattern, into the
appearance of surface relief.
The most important attribute in the bump3d1 node is Bump Depth,
which controls the intensity of the bumps.

6 Change Bump Depth to 0.15. In the Orange swatch or a rendered image,
you’ll see that this diminishes the bumps as compared to the default
value 1.0.

NOTE If you select Render > IPR Render Current Frame while Hypershade is
selected, a message appears: Please select the view you want to render. Either
select the perspective view before choosing IPR Render Current Frame, or,
in the Render View window, select IPR > Redo Previous IPR Renderer.

7 In the Hypershade panel, click the brownian1 texture swatch to reveal
its attributes. Set the following:
■ Increment: 0.3

■ Octaves: 4.0

These values produce a rendered image closer to real orange skin.

Creating a texture within the Hypershade editor | 479

Our recommendation for these values is based on experimentation. For
Brownian and some other textures, it’s usually faster to get desirable
results by experimenting with the settings rather than trying to
understand the definition of each attribute.

Modifying a bump texture
The bump texture is too crater-like to be a convincing orange. The bumps are
too numerous and too deep. A quick way to fix this problem is to scale up the
entire texture.

To interactively position a 3D texture

1 Double click the place3dTexture1 swatch, to the left of the Brownian
color swatch.
This node controls the 3D texture’s position, scale, and rotation. The
visual display of this node is a large cube that surrounds the sphere in
the scene view. This is the texture placement cube.

2 Click the Interactive Placement button in the Attribute Editor. A
manipulator appears for the texture placement cube.


3 In the scene view, click on the center scale box to activate the center
scale option. Scale the whole texture placement cube to about twice the
original size (until the Scale attribute values are about 2).

Now when you render, the bumps on the surface appear wider and
smoother, like the bumps on an orange skin. For example, the bumps in
the area surrounding the highlight do not appear to be as deep as they
were before you scaled the texture.

Scaling a texture placement cube is a common way to tune the texture’s
display. Scaling does not actually change the pattern, but enlarges or
shrinks it relative to the surface.

4 Now that you’ve changed the surface texture through scaling, move the
texture placement cube above the sphere (drag the green arrow up), to
see how that affects the texture.

Modifying a bump texture | 481

NOTE If you have tumbled the camera for a different view of the orange or
the texture placement cube, ensure you reposition the camera so that the
orange’s Mayakist logo is visible before rendering again. Otherwise, the
rendered image will appear incorrect.

In the rendered image, notice that the bumps still remain on the sphere.
Objects do not need to be within the texture placement cube, because it
represents an imaginary texture volume, which is infinite.
However, movement of the texture placement cube does shift the surface
texture pattern. The difference is hard to notice on a uniform texture like
Brownian. Transforming the cube would be more noticeable with a texture
such as Marble, where the veins within the pattern would be repositioned.
Movement of the object itself also shifts the surface texture. For example,
if you were to animate the orange rolling and then render an image
sequence, the texture would shift each frame rather than roll with the
surface. To prevent this undesirable effect, you need to make sure that
the texture moves in the same way the object moves. One way to do this
is to parent the texture placement cube (also called the place3dTexture
node) to the object. For more information on parenting, refer to the Maya
Help.

Beyond the lesson
In this lesson, you were introduced to some of the features available for shading
surfaces. You learned that:

■ Shading materials can employ a variety of material types that can be used
to achieve specific surface characteristics (Shininess, Matte, and so on).


■ Textures can be applied to a shading material to enhance the realism of
the final image. For example, logo graphics, bumps, and so on, can be
added to enhance the detail on the surface.

■ Textures can be 2D or 3D in nature. Each has its unique techniques for
application and placement.

Placement of textures

When you put the Mayakist logo on the surface, the letters appeared straight.
The letters are actually skewed in the texture. We skewed the logo for your
use in this lesson so that it looks straight when stretched onto the surface.
In your own work, skewing texture images is usually too difficult and
impractical. A more practical Maya technique for assigning and positioning
file textures is to use texture projection. With this feature, you project the
texture onto the surface as if you are projecting a slide image onto a screen.
The texture is positioned where the projection strikes the surface. Instead of
a skewed Mayakist logo, you could use a straight logo and project it onto the
sphere. You could tune the angle of projection so that the curvature of the
surface skews the logo just as in the lesson. To assign textures as projections,
you turn on the As Projection option at the top of the 2D Textures section of
the Create Render Node window.
The placement of texture projections is similar to the placement you performed
for the bump map (3D) texture. Like the bump map texture, you need to
parent the texture projection (the place3dTexture node) to the object in order
to avoid the texture placement changing when the object moves.

Layered textures
Suppose you want to add a scarred pattern to the orange skin. Because you
can only have one texture assigned to the Color attribute you can use a Layered
Texture to combine two or more texture maps.
The Layered Texture is a texture node that lets you composite or layer several
textures on top of each other. You assign it to a material’s attribute just like
other textures. Within the Layered Texture’s attribute controls, you can connect


other textures and control how they blend together. For example, the bottom
layer could be the logo image you used in the lesson, and a top layer could
be an image of streaking lines that resemble scars. The combined logo and
scars would give the orange the final aged look that you wanted.

Shader Library
As an option, you can install a Shader Library with Maya to help you quickly
create common materials, such as bricks, fabrics, foods, and many other surface
types. When installed, a Shader Library tab appears in Hypershade. To use a
material, find the type of shading you want, drag and drop it into Hypershade,
then drag and drop it onto a surface in your scene using the middle mouse
button.

Lesson 3: Lights, shadows, and cameras

Introduction

Directors of live-action film use camera and lighting techniques to enhance
the visual impact of a scene. Wide, medium, and close up views of the subject,
depth of field, high or low key lighting all communicate something about the
subject and the scene to the viewer.


Lighting and camera techniques are one of the most crucial aspects to consider
when working with artificial characters and objects. The more realistic the
lighting and shading appear, the more convincing the scene will appear to
the viewer.
A prerequisite to creating effective 3D rendered animation is to study the
lighting and camera effects used in live-action film. Your goal is to create the
desired scene ambience while keeping the lights and camera view as
unobtrusive as possible.
In Maya, it is possible to simulate both realistic and unrealistic lighting and
shadow effects for your final images and animations. In this lesson, you learn
basic techniques for working with lights, shadows, and cameras. In this lesson,
you learn how to:

■ Create and position various types of lights in the scene.

■ Edit the attributes of lights and experiment with their effect in the scene.

■ Cast shadows on your surfaces using the lights and objects in the scene.

■ Create and animate an additional camera in the scene.

In this lesson, you work with a scene we created for your use. In the first steps,
you open the scene, create a directional light, and compare the directional
light’s effect to the scene’s default lighting.


2 Open the scene file named Lights.mb.
your Maya project:
GettingStartedRenderingLights.mb
The scene contains a room with two walls and a floor. Sitting in the room
is a drafting table and lamp, grouped under the name tableGroup. All
objects have a default gray shading.


When you open the scene, Maya lights the scene with default lighting
provided by an imaginary light fixture. It emanates light infinitely from
a point above and behind the active scene view camera. There is no icon
that represents the default light in the scene view.

Directional lights
Maya has many types of lights that simulate natural and artificial lighting. In
the next steps, you create a light for the scene using a directional light. A
directional light uses parallel rays of light, as if illuminating from a very far
distance, to illuminate the scene. A directional light is often used to simulate
sunlight.

To create a directional light

1 Select Create > Lights > Directional light > .

2 Turn off Interactive Placement, then click Create.
A directional light is created at the center of the scene.

Because a directional light is similar to sunlight. Its parallel rays strike all
objects in the scene from a single direction as indicated by the arrow icon
representing the light. The position of the light is not so much important
as the direction that the arrow icon points.


When you create a light, the scene view does not display its effect, by
default. The scene view instead uses default lighting.

3 Select Lighting > Use All Lights (Hotkey: 7). This lights up the scene view
only with lights you’ve created, not with default lighting. If you later
want to see the scene view with default lighting again, select Lighting >
Use Default Lighting (Hotkey: 6).
When you render the scene, by default, Maya uses all lights you’ve created.
If you don’t create any lights, Maya creates a temporary default directional
light for you and then deletes it when the render is complete.

Next, you aim the directional light and edit its attributes.

To edit the directional light

1 With the directional light selected, rotate the light in various directions.
The shading of surfaces changes as you rotate the light. The more directly
the light points at a surface, the brighter the shading. A directional light
is affected by its rotation, not its position. As you’ll see later, the position
of other lights affects the lighting.

2 Rotate the light as follows:
■ Rotate X: -40

■ Rotate Y: 25

■ Rotate Z: -20

With this orientation, all object surfaces in the scene show the effect of
the light in the current camera view.

3 With the light still selected, open the Attribute Editor (under the Window
menu). Drag the Intensity slider to various values to see the effects of
intensity.
Higher values brighten the surfaces. For example, an Intensity of 1.6
brightens the lighting so much that the gray default shading of some
surfaces are bleached to white.

NOTE Several of the following illustrations in this lesson are snapshots of the
scene after rendering. To render the scene, select Render > Render Current
Frame. Do not use IPR rendering for this lesson because it doesn’t
automatically update the image for some of the changes you make to the
scene.

Directional lights | 487

4 In the Attribute Editor, click the white Color box above the Intensity
box. This displays the Color Chooser.

5 Click inside the color wheel (hexagon) and drag the pointer to a red color.
The lighting imparts a red hue to the surfaces in the scene.

6 Change the color back to white and set the Intensity to 1.2 or so.
You’ll use these settings for the basic lighting of the scene.

Spotlights
In the next steps, you light part of the desk by creating a spotlight and
positioning it within the desk lamp. A spotlight emits light from a single point
within a limited cone angle. You can aim a spot light in the direction you
want the light to illuminate.

To create a spotlight

1 Select Create > Lights > Spot Light > .

2 Turn off Interactive Placement, then click Create.
This creates the spotlight’s icon at the center of the grid. The light points
toward the back wall.

3 Move the spotlight above the lamp. (Drag the light up along its local
Y-axis.)


If you look at the spotlight icon from several angles, you’ll notice that it
is shaped like a cone with an arrow pointing out of it.
The cone symbolizes that a spotlight emits a beam of light that gradually
widens with distance.

4 Select Modify > Transformation Tools > Show Manipulator Tool (see
Modify > Transformation Tools > Move Tool, Rotate Tool, Scale Tool,
Show Manipulator Tool).
With the spotlight selected, this tool provides two manipulators that you
can move to position and aim the light precisely.

The look-at point specifies where the light focuses. The eye point defines
the position of the light source. All types of lights have an eye point, but
not necessarily a look-at point.

5 Move the look-at point to the top of the table, and move the eye point
roughly to the center of the lamp housing.

Spotlights | 489

You can also use the Rotate tool to center the eye-point more accurately
in the lamp housing.
An alternative way to position a spotlight is to select the light and then
select Panels > Look Through Selected. You can then dolly and pan the
view to focus on the desired surface. The area of focus is where the light
strikes the surface. To return to the perspective view select Panels >
Perspective > persp.

6 If you render the scene, you’ll notice that the spotlight lights up a circular
region on both the desk and the floor.

By default, light passes through and lights up each surface in its path.
The circular region of light is wider on the floor than the desk because a
spotlight emits a beam of light that widens with distance.
Only the floor, not the desk, will be lit by the spotlight in the scene view.
You’ll see the desk lit up only if you render the scene.

7 You can prevent the light from passing through the table. With the light
selected, display the Attribute Editor. Open its Shadows section and then
the Depth Map Shadow Attributes section, then turn on Use Depth Map
Shadows. Rendering creates this result:


By turning on Use Depth Map Shadows, the spotlight’s lighting is blocked
by the first surface it hits (the desk). The floor is in the shadow of the
desk so it receives no light. You’ll learn more about Depth Map Shadows
later in the lesson.
If you were to render the scene with IPR rather than the software renderer,
the image would not automatically remove the lighting of the spotlighting
from the floor when you turn on Use Depth Map Shadows. You would
need to refresh the image again in the Render View window by selecting
IPR > Refresh IPR Image.)

Editing light attributes
Spot lights, directional lights, and other light types have several unique
attributes (for example, Intensity, Dropoff, Color, etc.). In the next steps, you
modify some of the attributes for the spotlight.

To modify the attributes of a spotlight

1 The spotlight’s default Cone Angle is 40 degrees. In the Attribute Editor,
open the Spotlight Attributes section and set Cone Angle to 20.
The circle of light narrows.

2 Set Cone Angle to 60.
The circle of light widens. Rendering creates this result:

Editing light attributes | 491

3 Set Dropoff to 10.

This attribute sets how much the light intensity diminishes from the
center of the circular region out to the edge. Finding the right value is a
matter of experimentation. When you increase the Dropoff, the light’s
intensity diminishes, so you need to increase the Intensity. For example,
increase the Intensity to 1.6. Rendering creates this result:
To mimic the way a light source’s intensity naturally decreases with
distance, you might want to select a Decay Rate to diminish the light’s
intensity. The Linear setting diminishes light with the least abruptness,
Quadratic with the most abruptness. Cubic is between the two other
settings.
The default setting is No Decay, which means the light remains at full
intensity regardless of distance. If you use a setting other than No Decay,
you likely will need to increase the Intensity. For this lesson, leave the
Decay Rate set to No Decay.

4 Set the Penumbra Angle to 10.
This attribute controls the softness along the edge of the area of
illumination provided by the light. Again, finding the right value is a
matter of experimentation. You can also use negative numbers to fade


inward from the circle’s edge. The viewing angle of the camera influences
the appearance of the fading at the edge. Rendering creates this result:

5 In the Light Effects section of the Attribute Editor, click the map button
to the right of the Light Fog box.

This gives the appearance of the light beams illuminating fog or dust in
the air. Rendering creates this result:

Fog is more noticeable when you view (render) the light beam from a
side angle rather than from above the light fixture.
When you click the Light Fog map button, Maya creates a light fog node
and displays its attributes in the Attribute Editor.
The Color and Density attributes are useful for altering the fog’s hue and
transparency. These attributes affect only the light on its way to the
surface, not the light on the surface.
In the scene view, you’ll also notice a Light Fog icon extending from the
spotlight icon. When highlighted, it looks like this:

Editing light attributes | 493

The icon displays the region of the potential illumination. You won’t see
light fog under the table. The table blocks the light fog because you
previously turned on spotlight’s Depth Map Shadows attribute. You can
use the Scale tool on the icon to expand or contract the region of the
illumination effect.

Shadows
Shadows are the darkened areas that appear on a surface when an object gets
in the path of a light source. Shadows are cast onto the area of a surface that
doesn’t directly receive light. Shadows ground the objects in your scene and
aid in defining their three-dimensional appearance. Shadows can add drama
to your scene.
Next, you create a shadow on the floor from the light cast by the spotlight.
To do this, you must edit a few of the spotlight’s attributes.

To create shadows using a spotlight

1 Select the spotlight and click the spotLightShape1 tab in the Attribute
Editor.

2 Set the Cone Angle to 105.
When you render the scene, you’ll see the spotlight has widened its beam
to light up a small part of the back wall. The table and light fixture block
light and create shadows.
The shadows occur because you turned on Use Depth Map Shadows for
the spotlight earlier in the lesson.


Depth Map Shadows refers to the algorithm Maya uses to produce shadows.
For basic shadowing, you don’t need to know about the algorithm, but
you do need to make sure you turn on Use Depth Map Shadows.

3 To sharpen the shadow’s edges, open the Attribute Editor’s Shadows
section and then the Depth Map Shadow Attributes section. Set the
Resolution to 1024.
Rendering creates this result:

Increasing the shadow’s resolution increases rendering time. Use a higher
value only if it makes a noticeable difference on the shadows. In this case,
the difference is so subtle that you might prefer to use the default value
512. In your future projects, keep in mind that higher shadow resolution
values can make a big difference in the quality, but also affect rendering
time.
A related attribute, Filter Size, is useful for blurring or softening shadow
edges that seem too sharp. Increase the value to increase the blur. Again,
higher values increase rendering time.

Shadows | 495

If you are intent on perfecting shadows in your future projects, try various
combinations of values for Resolution and Filter Size. For this lesson, the
default values are satisfactory because the shadow edge has minimal
contrast. If you create shadows with sharp contrast at the edges, altering
the default values will be more desirable.

Creating additional cameras in a scene
Elsewhere in this book, you’ve used the default perspective camera to examine
and render your modeling and animation work in progress. In some situations,
it is convenient to create and use additional cameras.
For example, you might want to render the scene from two different camera
views to compare the results. Alternatively, you might want to use the default
camera for interactive modeling and animation and the second camera strictly
for rendering the scene. In the next steps, you create an additional camera
and manipulate its view of the scene.

To create a second camera for the scene

1 Select Create > Cameras > Camera. This creates a perspective camera with
an icon representing it at the center of the grid.

2 In the Channel Box, change the name of the camera to myCamera.
Even though you’ve created a new camera, you are still looking at the
scene through the default perspective camera named persp. You will view
the scene through myCamera after you position it in the next step. If
you were to view the scene through myCamera now, you would see a
disorienting view of the back wall and floor. The camera’s icon points in
the direction of the camera’s view.
The scene’s default persp camera has no icon. An icon is displayed only
for a camera you create.

3 Use the Show Manipulator Tool (select Modify > Transformation Tools
> Show Manipulator Tool) to position myCamera roughly in this position:


With a camera selected, the Show Manipulator Tool provides the same
two manipulators that you used to position the spotlight: eye point and
look-at point. The look-at point sets where the camera aims. The eye
point sets the position of the camera.
You can select the current camera by selecting View > Select Camera.

4 Select Panels > Perspective > myCamera to view the scene from myCamera.

If your camera view is not similar to the above illustration, select
tableGroup in the Outliner (Window > Outliner) and select View > Frame
Selection from the panel menu. This centers the view of myCamera on
the table.
The dolly, track, and tumble movements work the same for myCamera
as they do for the default persp camera.
You can return to the view of the persp camera by selecting Panels >
Perspective > persp.

5 While working with a camera, it’s useful to know the exact region of the
myCamera view that is displayed in rendered images. To see the border
of the render region, select View > Camera Attribute Editor. In the
Attribute Editor, open the Display Options section and turn on Display
Resolution. A rectangular border shows the region that will be rendered.

6 In the Film Back section of the Attribute Editor, set the Fit Resolution
Gate setting to Overscan.
By enabling the Overscan, the view displays more of the region outside
the area that will be rendered.
By displaying a small part of the scene that lies outside the rendered area,
you can plan future camera movement more easily, especially if the scene
has objects that move in and out of view.

Creating additional cameras in a scene | 497

Animating camera moves
In Maya, the camera can be animated. You can set keyframes for the camera
moves the same as for other objects in your scene. In the next steps, you set
keys to do a simple animation of the camera’s movement.

To animate the camera


2 Dolly, tumble, and track myCamera to create a view similar to this:

3 With myCamera selected, set a key for the camera’s current view at the
first frame. To set a key, select the Animation menu set, and then select
Animate > Set Key. (For details on setting keys and animation technique,
see Lesson 1: Keyframes and the Graph Editor on page 200.)

TIP You can undo and redo view changes such as dolly, track, and tumble
by selecting either the [ or ] bracket respectively. You can press these keys
repeatedly to undo or return to a particular view orientation.


4 Go to frame 150.

5 Dolly myCamera to create a view similar to this:

6 Set another key.

7 Play the animation to see the camera dolly toward the table for the first
150 frames.
At this point, feel free to experiment with keying changes in the view
resulting from tumbling and tracking the camera. Excessive animation
of tumbling and tracking creates a dizzying effect that is a common
mistake of inexperienced artists. In general, it’s best to keep camera
animation simple except when you are striving for an unusual effect.

Beyond the lesson
In this lesson, you were introduced to some basic techniques related to lights
and cameras in Maya. You learned how to:

■ Place two types of lights in your scene and edit their attributes.
In addition to the directional light and spotlight you created in this lesson,
Maya has several other types of lights for creating nearly any type of natural
or artificial lighting. You might use as few as two lights or as many as 10
to get the look you want. Generally, the more lights you create, the longer
the rendering will take.
In addition to the light fog effect you created in this lesson, you can also
create Glow, Halo, and Lens Flare light effects with a similar workflow. To
see these effects, the light must point toward the camera view.
In some situations, you might want to prevent a light from striking a
surface in its path. For example, your scene shows a person leaning against
a wall in an outdoor night setting. You might want to light the wall with
dark, shadowy spotlights, and the person’s face only with a brighter, soft


spotlight. Because the face and the wall are near each other, all the
spotlights currently strike both objects. You can use Maya’s light-linking
capability to isolate the lighting.

■ Create shadows in the scene by having the lights cast shadows.
The Maya software renderer has two types of shadows: Depth Map Shadows
and Ray Traced Shadows. In this lesson, you created Depth Map Shadows,
which are less realistic than Ray Trace shadows but much faster to render.
Ray Traced Shadows are mainly useful in scenes where the audience is
focusing on the shadow region, for instance, a close-up of a still setting.
Ray Traced Shadows are also useful if you want to cast shadows more
accurately for transparent objects. To reduce rendering time, use Ray Traced
Shadows only when necessary.

■ Create and animate an additional camera from which to view the scene.
If you have previous experience with photography, you’ll recognize the
names of various camera attributes displayed in the Attribute Editor while
a camera is selected. You can modify the attribute values to suit your
requirements.
The values for certain camera attributes (for example, Film Aspect Ratio)
might cause a rendered image to not match the region bounded by the
Resolution Gate. In such cases, you can display the Film Gate (View >
Camera Settings > Film Gate) to see the region that will be rendered.
You can animate a camera along a path; for example, to create the illusion
of flying through mountainous terrain. This type of animation involves
the use of Animate > Motion Paths > Attach to Motion Path (from the
Animation menu set). If you additionally want the motion path-animated
camera to focus on a stationary or moving object, you need to use Create
> Cameras > Camera and Aim. If you want the camera to move in a looping
path, (for example, a roller coaster) you need to use Create > Cameras >
Camera, Aim, and Up.
Before you batch render a scene, you must select the camera you want to
use for rendering. Select Window > Rendering Editors > Render Settings
to display the Render Settings window. In the File Output section, select
the camera from the Camera option.


Lesson 4: Global Illumination

Introduction

The mental ray® for Maya® renderer can render using a feature called Global
Illumination. Global Illumination simulates the effect of all lighting and
inter-reflection in the scene, whether the items are lit directly by a light source
or indirectly illuminated by other objects (and diffuse sources of illumination
in the scene).
For example, when a photographer lights an object in a studio, some of the
lighting for the object in the final image comes directly from the lights that
are used, while additional illumination comes from objects that are placed
near the subject to act as light reflectors. These are referred to as fill cards.
Light bounces off the fill cards, indirectly lighting nearby objects with a
secondary source of diffuse light. The color of the fill card colors the light that
gets reflected onto the object. The final illumination of the object comes from
this combination of multiple sources (direct light, specular reflections, and
diffuse light).

Lesson 4: Global Illumination | 501

The Global Illumination feature in the mental ray® for Maya® renderer
simulates this effect and provides for a realistic illumination simulation in
your Maya scenes.

■ Differentiate between images made with Global Illumination compared
to other lighting types.

■ Render an image using Global Illumination by performing repeated test
renders to achieve a final result which includes:
■ Lighting a scene using the mental ray Global Illumination attributes.

■ Adjusting the Global Illumination attributes and quality settings in a
systematic manner to achieve a high quality image.

■ Visualize photon maps for the scene.



2 Open the scene file named GlobalIllum.mb.
your Maya project:
GettingStartedRenderingGlobalIllum.mb


The scene contains a still life with a fruit bowl. Other surfaces act as the floor
and walls for the scene. The primary light source is a spotlight. The spotlight
casts light through a vertical opening in the wall. Some areas in the scene are
directly lit and other areas are not.
Shading materials have already been assigned to the bowl, fruit, and other
surfaces. The apple and orange models are from the previous lessons. If you
want to see what other shaders and textures are in the scene, you can view
them by opening the Hypershade editor.
When you render this scene using Global Illumination, the effect you want
to achieve is to have the upper and lower regions of the scene receive indirect
light: you want to be able to view more detail in the shadow areas as a result
of the Global Illumination.

Render the scene using raytracing
To better understand the differences in a rendering performed using direct
lighting methods vs. global illumination, you begin by rendering the scene
using the mental ray for Maya renderer without using Global Illumination.
You start by performing some preparatory setup and then render the scene.
In this section you:

■ Select the mental ray for Maya renderer.

■ Set the quality setting for your rendering.

■ Set the image size for your rendering using the Image Size settings.
When performing repeated test renders, a good practice is to render small
images so the tests render quickly.

■ Turn on shadows for the spotlight in the scene.

■ Render an image using the mental ray for Maya renderer using raytracing.

Using the mental ray for Maya renderer
To use the Global Illumination feature in Maya you must render using the
mental ray for Maya renderer.
To render using the mental ray for Maya renderer you need to change the
rendering type from Maya to mental ray for Maya. You initially render the
scene without using Global Illumination.

Render the scene using raytracing | 503

To change the renderer to mental ray for Maya

1 In the main menu, select Window > Rendering Editors > Render Settings
(or click the Render Settings icon on the Status Line) to display the Render
Settings window.

2 In the Render Settings window, set the Render Using setting to mental
ray.

When you render an image it will now use the mental ray for Maya
renderer.

NOTE When you switch between renderers in Maya (for example, Maya
Software, Maya Hardware, and mental ray for Maya), the common Render
Settings do not require re-setting.

When you perform repeated test renderings for a particular scene, consider
the time it takes for each render to complete. If you reduce the time it takes
to render each test image, the testing process proceeds much faster.

Setting render settings for raytracing
For the first rendering test, you render the scene to see how the scene appears
without Global Illumination. The testing process proceeds faster if the quality
level for the image is initially set low.

To set presets for rendering

➤ At the top of the Render Settings window, select mental ray as your
renderer. Click on the Quality tab and set the Quality Presets setting to
Draft.


The Draft setting ensures low anti-aliasing settings are used and reduces
the rendering time compared to other preset settings. This is a good
practice when evaluating the lighting and basic material properties in
your test renderings.

Setting the image size for rendering
You set the size that an image is rendered in the Render Settings window. For
this lesson, you render the image at a size that allows you to evaluate the
Global Illumination effect.

To set the image size for rendering

1 At the top of the Render Settings window, select the Common tab and
open the Image Size settings.

2 Set the Preset to 320 X 240.
This sets a small image size for your rendering tests. The smaller image
size renders in less time when compared to a larger image size.



Turning on shadows
Shadows add realism to a scene, and in this lesson, help to demonstrate how
a scene rendered using Global Illumination differs from a scene rendered using
direct illumination.

To turn on shadows for the spotlight

1 Open the Hypershade window (Window > Rendering Editors >
Hypershade) and click on the Lights tab to display the lights in the scene.

The scene is lit with one spotlight named spotLightShape1.

2 In the Hypershade window, double-click the icon for spotLightShape1
to display the attributes for the spotlight.

3 In the Attribute Editor, click the spotLightShape1 tab to display the
lighting attributes for the spotlight. (You may need to minimize the
Hypershade window to see all of the Attribute Editor.)

4 In the Shadows section, open the Raytrace Shadow Attributes turn on
Use RayTrace Shadows. This turns on shadows for the spotlight.

5 Close the Attribute Editor and Hypershade window.

Rendering the image
When you render an image, all of the objects, lighting, shading materials, and
image quality settings are used to calculate the image, based on the particular
camera view that is set.


To render an image using mental ray for Maya

1 Click in the perspective window. This indicates which camera view you
want Maya to render.

2 On the Status Line, click the Render Current Frame icon to launch the
renderer to produce an image.

The Render View window appears and the fruit bowl scene renders using
the mental ray for Maya renderer.

3 Once the render is complete, click the Keep Image icon in the Render
View window to save this image.

Keeping the image allows you to compare it to any subsequent test renders
you produce. In this lesson you compare each rendered image to the
previous ones to understand how the changes you make in various settings
affect the rendered image.

The rendered image shows the fruit bowl lit from the right of the frame.
The upper and lower portions of the image are in shadow where the edges
of the wall prevented the spotlight from lighting those portions of the
scene. The shadow areas appear dark and do not show any detail of the
floor or walls. This illumination effect is typical of an image produced
with a single light source and direct illumination.


Render the scene using Global Illumination
To render using Global Illumination you need to turn on specific settings or
attributes. There are two areas that you must initially set.

■ Turn on the Global Illumination rendering attributes using the Render
Settings Window.

■ Turn on the Global Illumination lighting attributes using the Attribute
Editor.

You initially render the scene using the attributes at their default settings to
see how they affect the rendered image and then compare it to the previous
raytrace rendering. As you gain more experience rendering with Global
Illumination you will better understand what settings to initially use.

To turn on Global Illumination rendering attributes

1 Open the Render Settings window.

2 In the Render Settings window, click on the Quality tab and set the
Quality Presets setting to Preview: Global Illumination.

This turns on preset attribute settings that enable and control the quality
of the Global Illumination. You initially render the scene using the default
settings. Once you’ve rendered an image and observed their effect, you
return to the Render Settings window and modify the settings accordingly.


Global Illumination uses photons to simulate the light inter-reflection effects
in a scene. Photons are small packets of energy emitted from a light source
into the scene that bounce off surfaces to determine the intensity of light for
those areas not receiving direct illumination. The renderer keeps track of the
illumination that results from this photon emission in a file called a photon
map.
In addition to having the spotlight emit light you need to set the spotlight to
also emit photons for the Global Illumination simulation to occur. The overall
illumination for the scene will be determined from a combination of the light’s
intensity and photon illumination from this single spotlight.


To turn on Global Illumination lighting attributes

1 Open the Hypershade window (Window > Rendering Editors >
Hypershade) and click on the Lights tab to display the lights in the scene.

2 In the Hypershade, double-click on the icon for spotLightShape1 to
display the attributes for the spotlight.

lighting attributes for the spotlight.

4 Open the mental ray section, and in the Caustic and Global Illumination
attributes set the following settings:

■ Emit Photons: On

■ Photon Intensity: 8000

■ Global Illum Photons: 10000

The spotlight emits photons into the scene when you next render an
image. Photon Intensity sets the brightness of the Global Illumination.
Global Illum Photons sets the number of photons that get emitted into
the scene.

Setting a panel layout for rendering
The process of producing a rendered image usually involves rendering and
evaluating successive test images to achieve the desired final image. This
process involves adjusting many render quality, shading, and lighting settings
in specific windows and panels. Opening and closing the various windows
can become tedious.
Displaying the most frequently used windows and panels for rendering allows
you to work more efficiently without having to open and close them
repeatedly.

To set a panel layout for rendering


Render the scene using Global Illumination | 509

2 From the perspective view’s panel menu, select Panels > Saved Layouts
> Hypershade/Render/Persp.

The panel layouts update to display the Hypershade window, Render
View window, and Perspective view simultaneously. This allows you to
easily work with these windows without having to open and close them
repeatedly.
If the image in the Render View window appears pixelated as a result of
the new panel layout, do the following:

■ In the Render View window menu, select View > Real Size. This resizes the
rendered image to its actual size.

TIP You can resize the panels in a preset layout by dragging the border
between neighboring panels using your left mouse button.

Rendering the scene with Global Illumination
Now that the lights are set to emit photons and the Global Illumination preset
is selected, you’re ready to render an a test image using Global Illumination.

To render the scene using Global Illumination

1 In the Render View window, click the Redo Previous Render icon to render
the image with the default Global Illumination settings.

2 When the image has completed rendering, click the Keep Image icon to
save the image.


3 Visually compare this rendered image with the previously rendered
images.

In this rendering, the shadow areas of the scene appear less dark as a
result of Global Illumination. The bowl also appears more transparent
than in the previous rendering.
The effect you want to achieve is to have the shadow regions receive
indirect light; that is, you want to be able to view more detail in the
shadow areas as a result of the Global Illumination. To do this, you must
adjust the Global Illumination photon attributes. After you change an
attribute, test render the scene to see the effect of this change in the
rendered image. These repeated test renderings or iterations allow you to
work systematically towards the goal of creating the desired final image.

In the next steps you use the Attribute Editor to increase the Photon Intensity
to increase the overall Global Illumination for the scene.

Increasing the brightness of Global Illumination
Increasing the Photon Intensity setting increases the brightness of Global
Illumination. The goal is to provide more visible detail and brightness in the
shadow areas of the scene in the next test image.

To increase the Global Illumination lighting

1 In the Hypershade window, double-click on the icon for spotLightShape1



3 In the Caustic and Global Illumination attributes adjust the settings to
the following:

Increasing the Photon Intensity increases the illumination in the areas
affected by Global Illumination.

To render the scene

the image.

save the image.

3 Compare this rendered image with the previously rendered images.

The brightness of the illumination in this image has increased as a result
of increasing the Photon Intensity. This is indicated by the increased
brightness and details seen in the shadow areas of the scene. However,
some circular spots have also appeared in the image along the dark wall
behind the bowl. These spots are the result of low photon quality settings.

Adjusting the quality of Global Illumination
The quality of Global Illumination is primarily affected by three attributes:

■ The accuracy of sampling (Accuracy)

■ The radius size that determines the size of the region surrounding a
particular sampling point (Radius).

■ The number of photons (Global Illum Photons).


In the next steps, you return to the Render Settings window and the Attribute
Editor to increase the quality attributes that affect the Global Illumination
effect.

To increase the Global Illumination quality settings

1 In the Render Settings window, click on the Indirect Lighting tab and
expand the Global Illumination section. Change the following Global
Illumination attributes to:
■ Accuracy: 900

■ Radius: 2.5

The Accuracy setting determines how many photons will be evaluated to
determine the Global Illumination intensity at a given sampling point.
Radius determines the size of the region surrounding the particular
sampling point. The more photons that get sampled, the more even the
Global Illumination will appear in the final image.

NOTE As you increase the Global Illumination related quality and photon
settings, the time to render the image also increases. Your goal should be to
increase these settings just enough to achieve the desired image quality,
without increasing them beyond what is required so that your rendering
times are not adversely affected.

the image.

save the image and then compare this rendered image with the previously
rendered images.


When the Accuracy and Radius values are increased, the resulting rendered
image shows the circular spots have almost fully disappeared and the
Global Illumination is much more uniform when compared to the
previous rendering. Increasing the number of Global Illumination photons
should aid in making the Global Illumination more uniform.

In the next steps, you increase the number of photons to provide a more
uniform Global Illumination in the scene.

To increase the Global Illumination photons

1 In the Hypershade, double-click on the icon for spotLightShape1 to
display the attributes for the spotlight.


3 In the Caustic and Global Illumination attributes adjust the settings to
the following:
■ Global Illum Photons: 80000

When you increase the number of Global Illumination Photons you are
increasing the resulting density of the photon map that gets produced
at the beginning of the render process. The more photons, the smoother
the resulting Global Illumination. Increasing the number of photons also
increases the rendering time.

To render the image

the image.


save the image and compare this rendered image with the previously
rendered images.

In this image, the circular spots that were seen in the previous renderings
have disappeared. You can observe other Global Illumination effects
compared to the original raytrace rendering:
■ Many of the objects have received some additional color from
neighboring objects in the scene as a result of the Global Illumination,
an effect known as color bleeding. When color bleeding occurs, objects
take on some of the color from neighboring objects as a result of the
reflected and transmitted light.

Now that you’ve tested and refined the Global Illumination for a small image
you can render a final image for the scene at a larger image size and increase
the rendering quality settings.

To increase the image size and antialiasing

1 In the Render Settings window, select the Common tab and open the
Image Size settings.

2 Set the preset to 640 X 480 to render a larger sized image.

3 In the Render Settings window, select the Quality tab.

4 Open the Anti-Aliasing Quality attributes. Leave the Sampling Mode as
the default (Adaptive Sampling) and set the following:


■ Number of Samples - Max sample level: 1

Sampling is the process for determining the amount of anti-aliasing that
occurs. The Sample Level attribute sets minimum and maximum limits
for the amount of sampling that will occur for a given pixel area in the
image. Modifying the anti-aliasing Sample Level settings will ensure that
the surfaces in the rendered image appear smooth.
A Max value of 1 should provide the correct amount of anti-aliasing
sampling for this particular image at this image size.

To render a final image of the scene

➤ In the Render View window, click the Redo Previous Render icon to render
the image.


Beyond the Lesson
In this lesson you were introduced to the Global Illumination features provided
by the mental ray® for Maya® renderer. You learned that:

■ The mental ray for Maya renderer provides a feature that simulates indirect
illumination in the Maya scene called Global Illumination.

■ Global Illumination allows you to achieve realistic lighting effects for
objects and areas of the scene that do not receive direct lighting.

■ Photons are used to measure the Global Illumination of the scene via the
creation of a photon map.

■ The brightness of the Global Illumination in a scene is controlled by the
Photon Intensity.

■ The quality of the Global Illumination effect is dependent on the number
of photons emitted into the scene, the Accuracy, and the Radius attribute
settings.

■ Multiple test renders are often required to achieve the desired final image.

Light sources for Global Illumination
Point, spot, and mental ray area lights can be used as light types for Global
Illumination with the mental ray for Maya renderer. A Directional light does
not work as a source for Global Illumination because this light type does not
have a defined point of origin (that is, the rays emit in a parallel manner).

Photon maps
You can visualize the photon mapping that occurs at the beginning of the
rendering process provided you turn on the Enable Map Visualizer option in
the Caustics and Global Illumination > Photon Tracing section of the Render
Settings window. To view a visualization of the photon mapping, select
Window > Rendering Editors > mental ray > Map Visualizer.

Beyond the Lesson | 517

Visualizing the photon mapping can aid in determining whether the coverage
and density of photons for the scene is appropriate for the resulting final
image.
By default, the mental ray for Maya renderer rebuilds the photon map each
time you render a scene using Global Illumination. If you are rendering a
scene containing camera animation in which the objects and lights remain
static, or rendering several iterations of a single image, you may consider
turning off the Rebuild Photon Map setting in order to reduce the rendering
times for each frame.


Lesson 5: Caustics

Introduction

Caustics are the light effects and specular patterns that are cast on surfaces as
a result of focused light reflecting off highly reflective surfaces or refracting
through translucent surfaces.
The light patterns that occur on the bottom of a swimming pool on a sunny
day, or the bright areas that occur in the shadow of a glass object as light
shines through it are examples of caustics.

The Caustic feature in the mental ray® for Maya® renderer simulates caustic
effects in your Maya scenes. Caustics are similar to Global Illumination in that
they are an indirect illumination effect.

■ Create the shadow effect that results from the refraction and concentration
of light through a transparent object, using the Caustic feature provided
in the mental ray for Maya renderer.

■ Adjust refraction level limits in order to achieve desired refractive effects
with transparent objects.

Lesson 5: Caustics | 519

■ Systematically perform test renders and adjust the render and caustic
quality settings in order to achieve a high quality image.

In this lesson, you work with a scene we created for your use. In the first steps
of this lesson, you open the scene and view the various elements that have
been preset for your use.


2 Open the scene file named CausticStart.mb.
your Maya project:
GettingStartedRenderingCausticStart.mb

The scene contains a still life with a translucent bottle and apples. Other
surfaces act as the floor and walls for the scene. (The bottle appears opaque
when viewed in shaded and textured display mode.)
Two lights illuminate the scene: a spotlight and a point light.
Shading materials have already been assigned to the models and surfaces.
You can view the shaders and textures by opening the Hypershade editor.
When you initially render this scene, the objects cast shadows onto the
floor surface. Caustics are added to the lighting of the scene to create a
more realistic shadow for the translucent bottle.


Render the scene using raytracing
To better understand the differences between caustics versus other lighting,
you begin by rendering the scene using the mental ray for Maya renderer
without using Caustics.
You start by preparing the scene and then rendering. In this section you:

■ Set a panel layout for rendering

■ Turn on shadows for the spotlight

■ Turn on the mental ray for Maya renderer

■ Set the image size for your rendering

■ Set the image quality preset

■ Render the image using raytracing

Setting a panel layout for rendering
Producing a rendered image usually requires that you render test images to
achieve the final result. This may involve adjusting many render quality,
shading, and lighting settings. Opening and closing the various windows can
become tedious.
Keeping the most frequently used windows and panels open allows you to
work more efficiently.
In the following steps, you select a panel layout to work more efficiently with
the various panels and windows.

To set a panel layout for rendering

➤ From the perspective view’s panel menu, select Panels > Saved Layouts
> Hypershade/Render/Persp.


The panel layouts update to display the Hypershade window, Render
View window, and Perspective view simultaneously.
When you render an image, it appears in the Render View window.

TIP You can resize the panels in a preset layout by dragging the border
between neighboring panels using your left mouse button.

Turning on shadows
In this lesson, you learn how the bottle’s shadow can be made to appear more
realistic as a result of the caustics.

To turn on shadows for the spotlight

1 In the Hypershade window, click the Lights tab.

The Hypershade displays icons for the two lights in the scene.

2 In the Hypershade window, double-click the icon for spotLightShape1.
The Attribute Editor appears.



4 In the Shadows section, open the Raytrace Shadow Attributes and turn
on Use RayTrace Shadows.

When you render the scene, shadows are cast by the spotlight.

5 Hide the Attribute Editor by clicking the Show/Hide Attribute Editor icon
on the Status Line.

Using the mental ray for Maya renderer
To use the Caustics feature in Maya you must render using the mental ray for
Maya renderer.

To turn on the mental ray for Maya renderer

1 In the main menu, select Window > Rendering Editors > Render Settings
(or click the Render Settings icon in the Render View window).

2 In the Render Settings window, set the Render Using setting to mental
ray.


Setting the image size for rendering
You set the size that an image will be rendered in the Render Settings window.
For this lesson, you render the image at a size that allows you to evaluate the
caustic effect.

To set the image size for rendering

1 At the top of the Render Settings window, select the Common tab and
open the Image Size settings.

2 Choose the 640 X 480 preset from the Presets drop-down list.

Setting render presets for raytracing
For the first rendering, you render the scene to see how the shadows appear
without using caustics.

To set Render options for raytracing

1 In the Render Settings window, select the Quality tab and set the Quality
Presets setting to Production.

The Production preset ensures that the refraction level settings (found in
Raytracing Quality section) are at a level high enough to render objects
with translucency (for example, the bottle). The Production preset also
sets the anti-aliasing level for the image.

2 Close the Render Settings Window.


Rendering the image
When you render an image, all of the objects, lighting, shading materials, and
image quality settings are used to calculate the image, from the camera’s view.

To render an image using mental ray for Maya

1 Click in the perspective window to indicate which view you want to
render.

2 In the Render View window, click the Render Current Frame icon.

The bottle scene renders using the mental ray for Maya renderer and the
image appears in the Render View window.
.

TIP If the rendered image appears either too small or too large in the Render
View window, select View > Frame Image from the Render View menu to fit
the image to the Render View.

View window.

Keeping the image allows you to compare it to any subsequent test
renders. In this lesson you compare each successive rendered image to
the previous one to observe how the changes you make to render settings
affect the rendered image.


The rendered image shows the following:
■ A translucent bottle with apples beside it casting shadows towards
the rear of the scene. Notice how the shadows appear when raytrace
rendered.

■ The distortion of the table surface in the translucent glass effect based
on the refractions and reflections.

■ A dark region on the surface of the bottle. This results from the bottle
reflecting the empty black area of the scene in front of it.

In the next section, you turn on the caustics rendering attributes and render
the scene.

Render the scene using caustics
To render using caustics you need to turn on specific settings or attributes.
There are two sets of caustic-related attributes that you must initially set.

■ Turn on the caustics-related rendering attributes using the Render Settings
window.

■ Turn on the caustics-related lighting attributes using the Attribute Editor.

You initially render the scene using these attributes at their default settings
to see how they affect the rendered image and then compare it to the previous
raytrace rendering. As you gain more experience rendering with Caustics you
will better understand what settings to initially use.

To turn on the caustics preset settings

1 In the Render Settings window, select the Quality tab and set the Quality
presets setting to PreviewCaustics.

This turns on the presets that control the quality of the caustics.


Mental ray for Maya uses photons to simulate the caustic effects in a scene.
Photons are small packets of energy emitted from a light source into the scene.
The photons travel throughout the scene, refracting through transparent
objects or reflecting off reflective surfaces. The renderer keeps track of the


illumination that results from this photon emission in a file called a photon
map. The overall caustic simulation is determined from the photon calculations
that result.
In addition to having the spotlight emit light into the scene you set the light
to also emit caustic photons. The overall caustic effect is determined from the
photon calculations that result.

To turn on the caustics lighting settings

1 In the Hypershade, double-click on the icon for spotLightShape1.


3 Open the mental ray section, and in the Caustic and Global Illumination
attributes set:
■ Emit Photons: On


■ Caustic Photons: 10000

4 Hide the Attribute Editor.

Rendering the scene with caustics
Now that the lights are set to emit caustic photons and the caustics preset is
turned on, you’re ready to render an image using caustics.

Render the scene using caustics | 527

To render the scene using caustics

1 In the Render View window, click the Redo Previous Render icon.

2 When the image has completed rendering, click the Keep Image icon.

3 Compare this rendered image with the previously rendered image by
dragging the scroll bar at the bottom of the Render View window left and
right.

This image differs from the previous one in the following ways:
■ The bottle appears more opaque. This indicates that the correct
number of refractions may not be occurring. The Raytracing Refraction
Level setting may need to be increased. When a different preset was
selected (Production to Preview), the refraction levels changed.

■ There are spotted areas on the table surface directly in front of the
bottle. This can be corrected by adjusting the photon quality settings.

■ The desired caustic effect in the shadow has appeared but is not very
pronounced. You want to achieve an effect where the shadow has
brighter regions as a result of light being refracted through the surfaces
of the bottle.

Adjusting the refraction levels
When the refraction levels are set too low, light rays do not refract through
all of the surfaces enough to provide a realistic indication of a translucent
surface when raytraced. This results in the object appearing opaque when it
should appear translucent.


Increasing the Refractions setting allows the renderer to calculate what is seen
through the surfaces of the glass by allowing the light rays to refract the correct
number of times.
In the next step, you change the Refraction settings so that the bottle will
appear translucent when rendered.

To increase the refraction levels

1 In the Render Settings window, select the Quality tab and then open the
Raytracing attributes.

2 In the Raytracing section set the following:
■ Refractions: 6

■ Max trace depth: 8

The Refractions setting sets the number of times a light ray can be refracted.
When the setting is too low the ray does not penetrate through all of the
surfaces. The Max Trace Depth setting limits the total Refraction and
Reflection settings. By setting it to 8, you ensure that two reflection and
six refraction calculations can occur.

Photons refract in a manner similar to light rays when rendering. Increasing
the Refractions setting for the Caustic Photons ensures that the renderer can
correctly calculate the caustics that should occur with the bottle. In this case,
matching the Caustic Photon refraction settings with the Raytracing refractions
is a good practice.

To increase the photon refraction settings

1 In the Render Settings window, select the Indirect Lighting tab.

2 In the Photon Tracing section set the following:
■ Max Photon Depth: 6

■ Photon Refractions: 6

The Max Photon Depth setting limits the Refraction and Reflection
calculations for the Caustic Photons to the limit set. The Photon Refractions
setting is similar to the Refractions setting for raytracing but sets the
refractions for the Caustic photons. Close the Render Settings window.


Increasing the brightness of caustics
Increasing the Photon Intensity setting increases the brightness of the refracted
caustic that appears in the shadow of the bottle.

To increase the Photon Intensity

1 In the Hypershade window, double-click the icon for spotLightShape1

2 In the Caustic and Global Illumination attributes for the light adjust the
settings to the following:

To render the scene

the image.

View window to save this image.

3 Compare this rendered image with the previously rendered images.

The translucency of the glass now appears more realistic. The caustic
effect is more evident in the shadow of the bottle. However, the spotted
effect, that appeared on the surface in front of the bottle, is more
pronounced. These spots are the result of a low caustics quality setting.

Adjusting the quality of caustics
The quality of the caustic effects in a scene is primarily affected by the number
of photons, the accuracy of sampling, and the radius surrounding the sampled


area of illumination. (If you have previously completed the Global Illumination
tutorial, you may notice similarities in this area.)
In the next steps, you return to the Render Settings window and the Attribute
editor to increase the quality attributes that affect the caustics effect.

To increase the caustics quality settings

1 In the Render Settings window, open the Caustics and Global Illumination
attributes and change the following Caustics attributes to:
■ Accuracy: 900

■ Radius: 1.5

The Accuracy determines how many photons will be evaluated to
determine the Caustic intensity at a given sampling point. Radius
determines the size of the region surrounding the particular sampling
point. The more photons that get sampled, the more realistic the caustic
effect appears in the final image.


Increasing the number of caustic photons that get emitted into the scene also
increases the quality of the caustic effect. When you increase the number of
caustic photons you increase the density of the resulting photon map that
gets produced at the beginning of the render process. The more photons, the
smoother the resulting caustics effect.

NOTE As you increase the caustic quality and photon settings so will the render
time. Your goal should be to increase these settings just enough to achieve the
desired image quality, without increasing them beyond what is required so that
your rendering times are not adversely affected. Performing test renderings is the
best method to determine these settings.

To increase the number of caustic photons

1 In the Hypershade window, double-click the icon for spotLightShape1.


2 In the Caustic and Global Illumination attributes, adjust the following
settings:
■ Caustic Photons: 50000

3 In the Render View window, click the Redo Previous Render icon.

4 When the image has completed rendering, click the Keep Image icon and
compare this rendered image with the previously rendered images.

In this image the bright spots in front of the bottle should be reduced
when compared to the previous images. The caustic in the bottle’s shadow
should also appear more pronounced and more evenly illuminated.

Beyond the Lesson
In this lesson you were introduced to the caustic features provided by the
mental ray® for Maya® renderer. You learned that:

■ Caustics provide additional realism in a rendered image by simulating the
focusing of light on diffuse surfaces as a result of the light reflecting off
specular surfaces or via the refraction of light through translucent surfaces.

■ Photons are used to determine the caustic effect in a scene via the creation
of a photon map.

■ The brightness of the caustic is controlled by the Photon Intensity attribute.


■ The quality of the caustic effect is controlled by the number of photons
emitted into the scene, the Accuracy, and the Radius attributes.

■ Multiple test renders are often required to achieve the desired final image.

Light sources for caustics
Point, spot, and mental ray area lights can be used as light types for caustics
with the mental ray for Maya renderer. A Directional light does not work as
a source for Caustics because this light type does not have a defined point of
origin (that is, the rays emit in a parallel manner).

Photon maps
You can visualize the photon mapping that occurs at the beginning of the
rendering process provided you turn on the Enable Map Visualizer option in
the Caustics and Global Illumination section of the Render Settings window.
To view a visualization of the photon mapping, select Window > Rendering
Editors > mental ray > Map Visualizer.

Visualizing the photon mapping can aid in determining whether the coverage
and density of photons for the scene is appropriate for the resulting final
image.
By default, the mental ray for Maya renderer rebuilds the photon map each
time you render a scene using Caustics. If you are rendering a scene containing
camera animation in which the objects and lights remain static, or rendering
several iterations of a single image, you may consider turning off the Rebuild
Photon Map setting in order to reduce the rendering times for each frame.


Dynamics
10
Introduction
Dynamics is a branch of physics that describes how objects move using physical
rules to simulate the natural forces that act upon them. Dynamic simulations
are difficult to achieve with traditional keyframe animation techniques.
Maya provides a means to do this type of computer animation where you set
up the conditions that you want to occur, then let the software solve how to
animate the objects in the scene. Maya® Dynamics™ provides the tools for
creating effects that will enhance your final images and animations.
With Particle Effects, you can create the illusions of smoke, fireworks, rain, fire,
and explosions.
With Rigid Body Dynamics, you can simulate real-world physical interactions
between objects, such as collisions between surfaces. For example, you can
simulate a bowling ball crashing through pins or simulate the effects of gravity
when a ball falls to the ground. You can also simulate natural forces, such as
wind.
This chapter contains the following lessons:

■ Lesson 1 Particles, emitters, and fields: Introduction on page 536

■ Lesson 2 Rigid bodies and constraints: Introduction on page 554

Do these steps to ensure the lessons in this chapter work as described:

1 Select File > New Scene to create a new scene before you start each lesson.

535


3 Select Window > Settings/Preferences > Preferences. Click Timeline under
Categories and make sure the Playback Speed is set to Play every frame.
Dynamic animation plays more accurately with this setting.

4 Select the Dynamics menu set. Unless otherwise noted, the directions in
the Dynamics menu set.

Creation option for primitives is turned off by selecting Create > NURBS

Lesson 1: Particles, emitters, and fields

Introduction
Particles are points that display as dots, streaks, spheres, or other shapes.
Particles can have attributes applied to them so they animate and render to
simulate natural phenomena.
You can create particles by clicking positions in the scene view, or you can
create them with an emitter that shoots particles into view.
To animate particles, you typically apply fields such as gravity or wind. By
combining emitters, particles, and fields, you can create natural phenomena
such as smoke, fireworks, or rain.
In this lesson, you will be introduced to some of the basic concepts of particles
and use particles, emitters, and volume fields to create a fountain-like effect.

■ Create a particle emitter in your scene.

■ Create a field to direct the movement of particles.

■ Use a volume shape to control the movement of particles.

536 | Chapter 10 Dynamics

■ Work with particle attributes.

■ Color particles.

■ Use a color ramp to add colors to the particles.

■ Render the particles using hardware rendering.

Creating an emitter
Emitters create particles as an animation plays. The emitter controls the
position, direction, quantity, and initial velocity of the emitted particles when
they are born. After particles are born, the attributes of the particle object
control their appearance.
You can make a standalone emitter, or you can make a surface, curve, and
even another particle an emitter. You move an emitter the same way you
move any geometry, such as setting keys or parenting it to a moving object.
In the next steps, you create a circle and emit particles from it.

To create a particle emitter


2 Set the start frame to 1 and end frame to 120.

3 Select Create > NURBS Primitives > Circle > . In the options window,
set the following options and click Create:
■ Radius: 4


Creating an emitter | 537

With Radius set to 4, the circle will be wide enough to see the particle
emission clearly. With Number of Sections set to 25, the emission will
be distributed evenly from points around the circle.
Note that the illustrations in this chapter show the grid with a custom
blue color and numbered lines so that the shape and size of the objects
you create are easier to distinguish. (If you want to change the grid color
in your scene, select Display > Grid > .)

4 With the circle selected, select Particles > Emit from Object.
By default, this creates an Omni emitter. If you dolly toward the center
of the grid, you can see a tiny icon that represents the emitter. When
you create an Omni emitter on a NURBS object, for instance, a circle,
each control vertex (CV) of the object emits particles in all directions.

5 Play the animation for a few seconds to see the emission.

The particles begin to emit from the object. When you create any type
of emitter, a particle object is automatically created and connected to it.
The connected particle object originally has no particles and is therefore
invisible. As the animation plays and the emitter generates particles, the
particle count of the connected particle object increases. When you go
to the start of the animation, the particle count returns to 0.
Note that if you had created the circle with a smaller Number of Sections,
there would be fewer CVs for the circle and therefore bigger gaps between
the emission points on the circles.


6 Display the Outliner (Window > Outliner).

7 In the Outliner, select particle1.
This is the particle object. A particle object is a collection of particles that
share the same attributes. You can create particle objects containing a
single particle or millions of particles. Each particle in a scene belongs to
some particle object.
The particle object’s attributes define the appearance and other
characteristics of the emitted particles. The emitter’s attributes control
the initial position, direction, quantity, and velocity of the emitted
particles.

Creating volume axis fields
Fields are forces that you use to animate the motion of particles. With a Volume
Axis field, you can move particles in various directions within the volume of
a cube, sphere, cylinder, cone, or torus. With clever use of this type of field,
you can create effects such as particles flowing around obstacles, solar flares,
explosions, tornadoes, and rocket exhaust.
In the next steps, you’ll use a volume axis field to move the particles up a
conical path. When the particles exit the top of a conical region, you’ll use
another volume axis field to give them a downward arcing motion within a
torus. The result resembles a fountain of light.

To create a cone volume axis field

1 With the particle object still selected, select Fields > Volume Axis > .

2 Set the following Volume Axis Options and click Create:
■ Magnitude: 50

■ Volume Shape: Cone

■ Away From Axis: 0

■ Along Axis: -1

NOTE If any of these options are not visible, enlarge the Volume Axis
Options window.

This creates a conical Volume Axis field that affects the motion of particles
that enter or exist within its volume. Particles move in relation to a central

Creating volume axis fields | 539

axis within the volume. For a Cone Volume Shape, the central axis is the
positive Y axis:

Using the axis attributes, you can specify that the particles:

■ move in a direction roughly parallel to the axis toward or away from the
point of the cone (Along Axis)

■ radiate outward or inward relative to the axis (Away From Axis)

■ swirl around the axis (Around Axis)

■ move in a direction based on a combination of these directions
By setting Along Axis to -1, the particles move toward the point of the
cone. (A positive value would move particles in the opposite direction.)
In the next step, you’ll flip the cone 180 degrees so the aim of the cone
and particles is upward.
By using 0 for the Away From Axis value rather than the default value of
1, the particles will not radiate away from the axis.
Note that you can use larger or smaller values for the Axis attributes to
intensify or diminish movement.
Magnitude specifies the strength of the volume axis field. The greater the
value, the more force is exerted on the particles.


You’ll typically need to experiment with various Volume Axis field attribute
values to achieve a desirable motion for particles. Be aware that small
arrow-shaped icons within the Axis Field icon show which direction the
particles will go.

1 With the Volume Axis field still selected, set the following values in the
Channel Box:
■ TranslateY: 13

■ RotateZ: 180

■ ScaleX: 5

■ ScaleY: 13

■ ScaleZ: 5

This positions, rotates, and scales the volume axis field so that its base
lies on the same plane as the circle emitter. Even though the circle emits
particles in random directions, the volume axis field will redirect their
motion up the cone.

2 Go to the start of the playback range and play the animation for a few
seconds.


When the particles move out of the conical region, they continue in the
same direction, mirroring the pattern of movement within the conical
region. The volume axis field no longer controls the motion, but the
particles continue with the same speed and direction they had at the
moment they exit.

To create a torus volume axis field

1 In the Outliner, select the particle object

2 From the main menu, select Fields > Volume Axis > .

3 Set the following Volume Axis Options and click Create:
■ Magnitude: 25

■ Volume Shape: Torus

■ Section Radius: 1.5

■ Away From Axis: - 0.7

■ Along Axis : 0.0

■ Around Axis: 2

The Torus Volume Shape creates a volume shaped like a doughnut.


Section Radius defines the thickness of the torus.

A value of 2 for Around Axis causes the particles to swirl around the
central axis. For a torus, the central axis is the ring in the center of the
solid part of the torus.
A value of -0.7 for Away From Axis causes the particles to move radially
toward the central axis.
When you later play the animation, the combination of these values
cause the particles to loop up then down as if guided along the inner
walls of a torus.
Again, achieving the desired motion for particles within a volume axis
field requires experimentation with attribute values. Examine the arrows


and other small icons within the axis volume field to help get the desired
results.
Note that the field’s effect is pervasive enough that all particles passing
through the hole of the torus are influenced by the field. You can cause
particles to pass through the hole by altering the Max Distance and
Attenuation.

4 With the torus volume field still selected, enter the following values in
the Channel Box:
■ TranslateY: 15

■ ScaleX: 3.6

■ ScaleY: 3.6

■ ScaleZ: 3.6

This moves the torus volume field up 15 units and scales it larger. Finding
the appropriate position for the volume axis field is a matter of
experimentation.

5 Go to the start of the playback range and play the animation.

When the particles move through the top of the cone region, they spread
outward somewhat but do not follow the shape of the torus volume field
as specified in the prior steps. You’ll correct this situation in the next
steps.


Adjusting the velocity of moving particles
The torus volume axis field doesn’t guide the motion of the particles as
expected because the initial emission velocity of the particles dominates the
motion of the particles rather than the field. You can use a particle object’s
Conserve attribute to scale down the emission velocity’s influence and increase
the field’s influence.

To adjust the velocity of moving particles

1 Select the particle object and set the Conserve attribute to 0.8 in the
Channel Box.
By changing the Conserve value from the default value, 1, to 0.8, the
emission velocity’s influence on the particle motion decreases and the
field’s influence increases.

2 Go to the start of the playback range and play the animation. Notice how
the particle movement now conforms to the shape of the torus volume
field.

Setting the particle render type
The particle render type of a particle object determines how the particles look
when rendered. For example, you can display particles as small spheres, streaks,
or 2D images (known as sprites) of your favorite snapshot. Once you select

Adjusting the velocity of moving particles | 545

the particle render type, you can add attributes specific to the render type to
adjust the appearance.

To set the particle render type

1 With the particle object still selected, display the Attribute Editor, and
select the particleShape1 tab.

2 Scroll down to the Render Attributes section, and set the Particle Render
Type to Streak.


The Streak render type displays moving particles with an elongated tail.
This render type enhances the display of objects such as meteors, and it’s
often used to create rain. The streak length is based on the velocity of
the particle, so if the particles are stationary or moving slowly and the
render type is set to streak, you won’t see the particles.

Adding dynamic attributes
To maximize the display versatility of particle render types, you need to add
built-in dynamic attributes to the particle object. When you add a dynamic
attribute to an object, the attribute appears in the Attribute Editor for the
selected object.


To add dynamic attributes

1 In the Attribute Editor, under the Render Attributes section, click the
Current Render Type button next to Add Attributes.

2 Observe the attributes that are added.

3 Set the following attributes:
Line Width 2 This sets the width of each
streak.

Tail Fade 0.5 This sets the opacity of the
tail fade; it can range from
0 to 1. A value of 1 makes
the tail completely opaque;
a value of 0 makes the tail
transparent.

Tail Size 2 This scales the length of the
tail. A value of 1 is the de-
fault length. Values less
than 1 shorten the tail; val-
ues greater than 1 lengthen
the tail.

You can experiment with these settings to change the look of the particles.

Adding dynamic attributes | 547

Adding per particle attributes
Particle objects have two different kinds of attributes: per object and per
particle.
A per object attribute lets you set the attribute value for all particles of the
object collectively with a single value. For instance, the per object color
attribute lets you set a single color for all the particles in the object.
A per particle attribute lets you set the value of the attribute individually for
each particle of the object. For example, the per particle rgbPP attribute lets
you set a unique color for each particle. Though there is only one rgbPP
attribute in a particle object, the attribute holds the value for each particle’s
color value. The attribute holds the values in an array. An array is similar to
a list. Arrays are appropriate for storing data which must be accessed in an
unpredictable order, in contrast to lists which are best when accessed
sequentially.
Although per particle attributes are best for creating complex effects, you can’t
keyframe them. You can keyframe per object attributes. In this lesson, you
add a per particle color attribute so you can give different particles different
colors.

To add a per particle color attribute

1 In the Attribute Editor, expand the Add Dynamic Attributes section, if
necessary.

2 Click the Color button. The Particle Color box is displayed,

3 Turn on the Add Per Particle Attribute and click Add Attribute. Notice
the rgbPP attribute that is added to the Per Particle (Array) Attributes
section of the Attribute Editor.


Adding color to particles with a color ramp
A ramp texture is a patterned 2D image in which the color blends from one
shade to another. In the next steps, you use a color ramp to color the particles
as they age.

To add color to particles using a color ramp

1 In the Attribute Editor, right-click the rgbPP data box and select Create
Ramp from the drop-down menu.
This causes a default color ramp to color the particles as follows:

As each particle ages from its time of birth (emission), its color changes
according to the ramp’s color in an upward vertical (V) direction. The
horizontal (U) direction of the ramp’s color is unused in this lesson.
When you create the ramp, Maya adds a lifespan attribute and sets it to
1 second, by default. Each particle changes from red to green to blue over
its lifespan of 1 second. The particle then disappears (dies).

2 From the perspective window menu, select Shading > Smooth Shade All.
This enables you to see the colors of the particles the next time you play
the animation.

3 Go to the start of the playback range and play the animation. Notice the
particles never reach the end of the cone volume.

Adding color to particles with a color ramp | 549

This is because the Lifespan is set to the default of 1, which is the number
of seconds the particles exist in the animation.

4 In the Channel Box, set Lifespan to 3. Go to the start of the playback
range and play the animation.

Because the particles live longer, they pass all the way through the cone
and part of the way through the torus. The particles change from red to
green to blue and disappear as they are born, age, and die.


Hardware rendering particles
In 3D animation, rendering typically refers to the act of creating a sequence
of high-quality image snapshots for each frame of an animation sequence.
After rendering the images, you play them in sequence to create a film or
video clip. If the concept of 3D animation rendering is new to you, consider
doing the lesson Lesson 1: Rendering a scene on page 439 before completing
this section.
You cannot render most particle render types, including streaks, with Maya’s
software renderer. You must hardware render the particles.
Hardware rendering uses your computer’s graphics hardware to render a scene
to disk and monitor faster than software rendering. Hardware rendering
generally displays surface shading and textures less accurately than software
rendering, so most people use it only to render particle effects.
In the following steps, you test render the last frame of the scene to make sure
the particles look satisfactory. Next, you render the entire frame sequence to
disk and then play the rendered images with the flipbook feature.

To test render the scene

1 Select Window > Rendering Editors > Hardware Render Buffer. This
displays a window from which you hardware render the scene.

2 In the Hardware Render Buffer, go to the start frame and click the play
button. Stop the animation at frame 75.
You must play the particle animation from the beginning in order for
particle effects to be displayed correctly at each frame. You cannot go
directly to an arbitrary frame in the Time Slider and see correct results.
Maya calculates particle animation sequentially frame-by-frame.

3 In the Hardware Render Buffer, select Render > Test Render.

The streaks look smoother than they do in the scene view. You can
improve the streaks even more as shown in the next steps.

Hardware rendering particles | 551

4 In the Hardware Render Buffer window, select Render > Attributes.
The Attribute Editor appears.

5 In the Attribute Editor, under the Render Modes section, turn on Line
Smoothing. This softens jagged edges when you hardware render Streak
or MultiStreak render types.

6 To see the softened edges, select Render > Test Render.
If you click in the Hardware Render Buffer window, the rendered image
disappears. If this occurs, select Render > Test Render again to redisplay
the image.

To render the sequence and playback the results

1 In the Hardware Render Buffer window, select Render > Attributes to
display the Attribute Editor.

2 Set the Hardware Render Buffer settings as follows:
Filename Emit This name will be the base
of the filenames created
when you render all frames
to images on disk.

Start Frame 1 This specifies the first frame
of the animation sequence
to be hardware rendered.

End Frame 75 This specifies the last frame
to be hardware rendered.

Other attributes in the Attribute Editor specify the image resolution, file
format, lighting, and other display characteristics.

3 Make sure that no other windows overlap the Hardware Render Buffer
or that your screensaver may accidentally launch while you use this
feature. When you hardware render a frame sequence to disk, Maya
renders whatever exists within the borders of the Hardware Render Buffer
window.

4 In the Hardware Render Buffer window, select Render > Render Sequence.
This creates a series of files named Emit.0001, Emit.0002, and so on,
through Emit.0075. These files are the rendered frames 1 through 75.
Maya puts the files in your current project’s images directory.


5 To play the hardware-rendered sequence, select Flipbooks > Emit.1-75.

6 Close the FCheck image viewing window when you are finished
examining the animation.

Beyond the lesson
In this lesson you were introduced to a few of the basic concepts when using
particles. You learned how to:

■ Create particles from a source object called an emitter.
When you create any type of emitter, a particle object is also automatically
created and connected to it. Emitters can be points (CVs, vertices), surfaces
(NURBS, polygons), curves (NURBS curves) or volumes (spheres, cylinders).

■ Control particles using fields, and volume objects.
With volume axis fields, you can funnel or swirl particles within the
boundaries of common volumetric shapes. Although this lesson showed
how to use a pair of volume axis fields to control the motion of particles,
Maya has several other types of fields such as Gravity and Turbulence for
simulating natural phenomena. You can use the fields to animate the
motion of curves and surfaces in addition to particles.

■ Change the color of particles using a ramp texture.
You can also change ramp colors by editing other ramp attributes, such as
Noise and Noise Frequency. To do so, right-click the attribute box for rgbPP,
then select arrayMapper1.outColorPP > Edit Ramp. See the Maya Help for
details on ramp attributes. You can also control other particle attributes
with ramps; for example, opacity. See the Maya Help for more information.

■ Render particles using the hardware renderer.
The majority of particle rendering types are visible only when using the
hardware render. Software rendering does not display them. However, if
you use a particle render type of Blobby Surface, Cloud, or Tube, you must
render the particles using the software renderer as hardware rendering does
not display those types.
If you create a scene that includes both particles and geometric surfaces,
you may need to render the scene twice, once with hardware rendering
and once with software rendering. In such cases, you’ll need to composite
the two sets of rendered images using a compositing software package.


Lesson 2: Rigid bodies and constraints

Introduction
In Maya, a rigid body is a surface which has the attributes of an unyielding
shape. Unlike conventional computer surfaces, rigid bodies collide rather than
pass through each other during animation and are used for creating dynamic
simulations. As well, rigid surfaces do not deform when they collide with
other objects in Maya.
Rigid bodies can be created from polygonal or NURBS surfaces. Rigid body
attributes can be assigned to the surfaces so they act and react in a simulation
in specific ways. Examples of rigid body attributes are velocity, mass, and
bounce.
To animate rigid body motion, you can use fields, keyframes, expressions,
rigid body constraints, or collisions with particles or other rigid bodies.
Rigid body constraints restrict the motion of rigid bodies. The constraints
simulate the behavior of real-world items you’re familiar with, such as pins,
nails, barriers, hinges, and springs.
In this lesson, you create a rigid body dynamic simulation in which you drop
a ball on some planks and watch the simulation in action. In this lesson you
learn how to:

■ Create objects with physical properties.

■ Apply hinge constraints to objects so they react in specific ways.

■ Set attributes for the rigid bodies to be either active or passive for the
simulation.

■ Play back a rigid body dynamic simulation.

Lesson setup
You can create rigid bodies from NURBS surfaces and polygonal surfaces. In
the following steps, you create some polygonal surfaces to be used for the
rigid bodies.

To create polygonal objects for the rigid body simulation



2 In the Time and Range Slider, set the start frame to 1 and end frame to
200.


4 In the Polygon Cube Options window, select Edit > Reset Settings (to
make sure the tool is set to its default, and then set the following options
and click Create:
■ Width : 2

■ Height: 4

■ Depth: 0.25

■ Axis: Z

5 With the polygon still selected, select Edit > Duplicate Special > .

6 In the Duplicate Special Options window, select Edit Reset Settings. Set
the following options and then click Duplicate Special:

■ Number of copies: 5

This creates five copies of the polygon, each one placed 3 units above
the lower one.

To position the objects for the rigid body simulation

➤ Position the objects as shown in the side view in the following illustration.
To position the planks precisely, select each plank individually and use
the Channel Box to enter the appropriate value from this list:
■ pCube1 - Translate Z: 0

Lesson setup | 555




■ pCube5 - Translate Z: -1


Creating hinge constraints
A Hinge constraint constrains rigid bodies along a specified axis. You can use
a Hinge constraint to create effects such as a door on a hinge, a link connecting
train cars, or a pendulum of a clock. In this example, the Hinge constraint
constrains the plank to a position in the scene view.
In the following steps, you’ll add Hinge constraints to the center of the planks,
which automatically turns the plank into a rigid body. You will do this for
each plank. By default, Maya automatically creates a rigid body when you use
a field or rigid body constraint to control its motion.

To create a hinge constraint

1 Select Soft/Rigid Bodies > Create Hinge Constraint > .

2 In the Constraint Options window, set the following options:
■ Initial Orientation X, Y, Z: 0 90 0

■ Leave the options window open.


By default, the initial orientation is set to 0, 0, 0, which orients the hinge
constraint to lie parallel to the Z-axis in world space. By setting the
orientation to 90 in the Y-axis, the hinge constraint is rotated 90 degrees
around the Y-axis, which orients the constraint parallel to the X-axis.

By leaving the Set Initial Position at its default setting, the hinge
constraint is created at the rigid body’s center of mass.

3 Select pCube1 and click Apply in the Constraint Options.

4 Select pCube2 and click Apply in the Constraint Options.

5 Repeat this until each of the six planks has a constraint applied to it.

6 Close the Constraint options window.

Running a dynamics simulation
In the next steps, you create a ball and add gravity to make the ball drop and
hit the planks and then playback the simulation.

To create a ball for the simulation

1 Select Create > Polygon Primitives > Sphere > .

2 Set Radius to 0.2 and click Create.

3 In the Channel Box, set the Sphere’s Translate Y value to 18.

To add gravity attributes to the ball

➤ With the sphere still selected, select Fields > Gravity.
When you connect Gravity to the sphere, it automatically makes the
sphere an active rigid body. Gravity affects only the object that was
selected when you add the Gravity field.

To run the dynamics simulation

➤ In the Time and Range slider, play the animation.

Running a dynamics simulation | 557

The ball falls and collides with the planks, which rotate about the hinge
constraint.

Changing an active rigid body to passive
Maya has two kinds of rigid bodies—active and passive. An active rigid body
is animated by dynamics—fields, collisions, and springs—not by keys.
Because the ball and planks are all active rigid bodies, gravity pushes it down
and it rebounds after colliding with the planks.
A passive rigid body can have active rigid bodies collide with it. You can key
its Translate and Rotate attributes, but dynamics have no effect on it.
In the previous steps, all the planks were active rigid bodies and reacted to
the collision of the ball. In the following steps, you’ll change the bottom plank
to be a passive rigid body so the ball bounces off the plank but the plank
doesn’t react to the collision.

To change an active rigid body to a passive rigid body

1 Select pCube1 and display the Attribute Editor.

2 Click the rigidBody1 tab to display the rigid body attributes.

3 In the Rigid Body Attributes section, turn off Active to make pCube1 a
passive rigid body. Hide the Attribute Editor.

Observe how pCube1 no longer reacts to the impact of the ball, but the
ball continues to bounce off it.


Beyond the lesson
In this lesson you learned some fundamental concepts with respect to rigid
body dynamics.

■ There are differences between active and passive rigid bodies.
When a rigid body is passive, active rigid bodies can collide with it but
will not move it. You can control its movement by setting keys.
When a rigid body is active, you control its movement using dynamic
forces, specifically fields and collisions. You can change the active and
passive state of the rigid body to achieve various effects. For example, you
can roll a ball off a table using keys (passive rigid body) then cause the ball
to fall using gravity (active rigid body).

■ A hinge constraint can be used between an active rigid body and a position
in the scene view.
You can also create a hinge constraint between a passive rigid body and a
position in the scene view, two rigid bodies, and an active and passive
rigid body.
Other types of constraints include pin, nail, spring and barrier constraints.
For additional information on the types of constraints and their usage,
please refer to the Maya Help.


Painting
11
Introduction

Maya provides painting tools that go above and beyond what many 3D creative
artists might normally envision. These tools allow you to accomplish a wide
range of modeling, animation, texturing, and effects work.

The painting tools are separated into three categories: Maya® Artisan™ brush
tools, Maya® Paint Effects™ tools, and 3D Paint. If you completed the previous
lessons in Getting Started with Maya, you already have experience with a few
of these tools.
The Artisan brush tools have a variety of applications and allow you to directly
modify attribute values interactively:

■ In the NURBS modeling lesson, you used the brush tools to sculpt a simple
face from a sphere.

561

■ In the Character Setup chapter, you used Artisan brush tools to modify
the skin weights on a surface mesh to ensure the character’s joint deformed
properly.

■ In the Character Setup chapter, you used the Artisan brush tools to modify
the cluster weights for Control Vertices to ensure a blend shape deformer
worked predictably.

As you have seen, Artisan brush tools can also be used to select surface
components. This selection method can dramatically improve the speed of
your workflow.
Maya Paint Effects allows the user to create natural and fantastic effects either
on a 2D canvas or as actual 3D objects in the scene.

■ Paint Effects enables you to create a 2D backdrop for your scene, or a
dynamic 3D paint effect such as a field of grass, with flowers and a
wind-blown tree—all at the drag of your mouse or tablet pen.

■ Paint Effects comes with a suite of preset brushes to enable you to create
many types of 2D and 3D effects.

With 3D paint, you can paint and modify textures directly onto 3D surfaces
using both the Artisan and Paint Effects tools. You can paint texture attributes
such as color, transparency, and bump, to name but a few.
As you have already gained some experience with the Artisan brush tools, this
chapter focuses on Paint Effects and 3D Paint. It includes the following lessons:

■ Lesson 1 Painting in 2D using Paint Effects: Introduction on page 563

■ Lesson 2 Painting in 3D using Paint Effects: Introduction on page 575

■ Lesson 3 Painting textures on surfaces: Introduction on page 608

To ensure the lessons work as described, do the following:

1 Consider doing the lessons in the Rendering section of this guide.
Familiarity with Maya rendering concepts is important to understanding
the following lessons.


562 | Chapter 11 Painting



4 To use all available screen space, maximize the Maya window.

5 From a panel menu bar, select Panels > Layouts > Single Pane.

6 Select the Rendering menu set. Unless otherwise noted, the directions in
this chapter assume the Rendering menu set is selected.

Lesson 1: Painting in 2D using Paint Effects

Introduction
One of the features of the Paint Effects Tool is the ability to paint colors,
patterns, and textures on a 2D canvas image. You can use the image as an
independent piece of art, a background image in your scene, or a texture to
be applied to a 3D surface.

■ Display the 2D canvas.

■ Paint strokes on the canvas, and modify your paint brush.

■ Use the Visor to access the many pre-defined paint brushes.

■ Modify brush settings such as brush size, color, and transparency.

■ Modify the canvas size.

■ Smear, blur, and erase brush strokes from the 2D canvas.

■ Use the pre-defined Paint Effects brushes to paint flowers and foliage.

■ Save modified brush settings to the Shelf.

■ View the alpha channel for your 2D image.

Lesson 1: Painting in 2D using Paint Effects | 563

Painting strokes
In the following steps, you display the 2D canvas and use preset brushes to
paint a few strokes.
Although not covered in this lesson, you can use a tablet and stylus to paint
with pressure sensitivity. The harder you press down, the more paint is applied.

To paint strokes on the 2D canvas

1 Do the steps in Preparing for the lessons on page 562.

2 If you want to create maximum space in the Maya window, turn off
Display > UI Elements > Channel Box/Layer Editor, Tool Settings, and
Attribute Editor.

3 On the panel menu bar, select Panels > Panel > Paint Effects (hotkey 8).
The panel displays a Paint Effects toolbar and menus.

4 From the Paint Effects menus, select Paint > Paint Canvas to display the
2D canvas.
You’re ready to start painting. It is not possible to display a grid on the
canvas.

5 Paint a stroke by dragging across the canvas.

When you first display the Paint Effects panel, your strokes use the default
brush—a solid black stroke similar to an airbrush.


TIP You can dolly and track the canvas using Maya’s standard mouse and
keyboard conventions.

6 Now paint with various preset brushes. To select a preset brush, select
Brush > Get Brush or click the following button in the toolbar:

The Visor window opens.

The Visor organizes the hundreds of Paint Effects brushes into category folders.
In the Visor, click a folder, then click a brush icon in the area to the right of
the folders. (The name of each preset brush has the extension .mel because
each is a MEL script that establishes the brush’s operation characteristics.) You
can dolly within the Visor window to enlarge the viewable size of the brush
icons and read the names more clearly.
You can copy a brush or all brushes within a folder to the Shelf. Use the middle
mouse button to drag the brush or folder to the Shelf. Use the shelf editor
(available from the arrow menu at the left of the shelf) to remove items from
the shelf.

Some brushes apply paint directly along the paint path, while others produce
added effects. For example, the pens folder includes brushes such as
ballpointRed.mel that work like pens, while the flowers folder includes brushes
such as dahliaPink.mel that grow flowers as you drag the mouse. Brushes like
dahliaPink.mel use Paint Effects tubes.

1 Select the dahliaPink.mel brush and drag the mouse slowly for one stroke,
then quickly for the next stroke.

Painting strokes | 565

When you paint a stroke slowly, the density of flowers is higher than
when you paint quickly. The effect of stroke speed on density works the
same for all brushes that use tubes.

2 To erase your last stroke, select Canvas > Canvas Undo.
When displaying the 2D canvas, you can undo only a single stroke. Edit
> Undo, Redo, Repeat (on the main menu) doesn’t undo strokes.

3 To erase the entire canvas, select Canvas > Clear or click the Canvas Clear

button on the toolbar:

Modifying the default brush settings
When you select a preset brush, Maya copies its brush settings to a template
brush. A template brush is a holder for the attribute settings of the next strokes
you paint. When you change the settings of the template brush, they affect
only the next strokes, not previous strokes.

To edit the template brush settings

1 Select Brush > Reset Template Brush to select the default brush, then
paint on the canvas so you remember the brush effect.

2 Select Brush > Edit Template Brush or click the following button in the

toolbar:
You can edit various brush settings, for example, the brush width, in the
window that appears.

3 To resize the brush, change the Global Scale value. Alternatively, you can
move the brush over the canvas, press and hold the b Hotkey and drag
left or right. The circle on the canvas represents the size of your brush.

4 Paint on the canvas to try out a new size.


5 Close the Paint Effects Brush Settings window.

6 On the toolbar, click the swatch to the right of C (color) to display the
Color Chooser.

7 Select a color from the Color Chooser and paint on the canvas.

8 On the toolbar, slide the T (transparency) slider to the right until the T
box is a light gray. Paint on the canvas.
When you paint over existing paint strokes you will notice that your
paint is transparent allowing the previous strokes to show through.

NOTE The Toolbar color boxes, for example, C and T, are also available in
the Paint Effects Brush Settings window. (Select Brush > Edit Template Brush
> Shading.)

Modifying the default brush settings | 567

Modifying the canvas
In the next steps you change a few canvas options, including color and size.

To modify canvas settings

1 Clear the canvas (Canvas > Clear).

2 Select Canvas > Set Size and set the canvas size to 512 x 512—the width
and height in pixels. When you are prompted to save, click No, then
close the Set Canvas size window.
Although you’ll often use the default maximum canvas size to take
advantage of the available screen space, you might need to use a smaller
or larger size in many circumstances. For instance, if you plan to use the
image as a background in a computer game, you might need to use a
small canvas size such as 256 by 256.

3 Turn on the wrap buttons on the toolbar:

4 Paint strokes past the edges of the canvas.
The strokes wrap around to the opposing side. This feature is useful for
creating patterned texture images to be applied to surfaces. When you
tile or repeat the image on the surface, the wrapped strokes help make
the borders between the images unnoticeable.
If you want to display the area of the canvas where the edges join, you
can do this using the roll feature (Canvas > Roll).

5 Select Canvas > Clear > . In the options window, slide the Clear Color
slider all the way to the left. Click Apply.
This clears existing strokes and turns the canvas black. Before you paint
strokes on the black canvas, you may notice that some brushes seem to
have no effect. If this occurs, it’s because the paint is black or because it
is transparent enough to prevent the color from showing.

Modifying the colors of a preset brush
In the following steps, you alter leaf and bud colors of a preset brush; fern.mel.


TIP When using the fern.mel brush, if any of the sliders do not appear, or appear
cut off on the right, you need to increase the screen display resolution setting on
your monitor to 1280 X 1024.

To change the color of a brush

1 In the Visor (Brush > Get Brush), click the fern.mel preset brush in the
plants folder.

2 Paint on the canvas to see the default display.
Because fern.mel uses tubes, ferns grow along the path of your stroke.

3 Resize the brush to a Global Scale of about 0.5 (Brush > Edit Template
Brush) and paint on the canvas.

4 On the toolbar, click the L1 color box (Leaf Color 1), select a shade of
blue from the Color Chooser, and leave the Color Chooser open.
L1 sets the color of the tips of the leaves.

5 Click the L2 color box (Leaf Color 2) and select a shade of red from the
Color Chooser.
L2 sets the color of the base of the leaves.

6 Click the B color box (Bud Color) and select a shade of yellow from the
Color Chooser. B sets the color of the flower buds.

7 Paint on the canvas and observe how the changes you’ve made to the
settings affect the final paint effect.

TIP You can change the path width of fern.mel without changing the width
of the leaves and stems. Select Brush > Edit Template Brush to display the
Brush Settings window, then in the Brush Profile section, change the value
of Brush Width. Similarly, you can alter the path width for any other preset
strokes with tubes.

Modifying the colors of a preset brush | 569

8 Clear the canvas (Canvas > Clear).

Editing strokes with tubes attributes
Now you’ll edit the attributes that specify the foliage that grows along the
path with fern.mel.

To edit tube attributes

1 To edit brush settings, select Brush > Edit Template Brush.

2 Open the Tubes section, then open Growth.
By default, only Leaves and Buds are created as you paint. You can also
create Branches, Twigs, and Flowers to simulate a fern in various stages
of its natural life cycle.

3 Turn on Flowers. Paint on the canvas to see the result.

4 Open the Leaves section, change Leaves in Cluster to 4, then paint on
the canvas.
Leaves are created in radial clusters around a branch or twig. This setting
defines how many leaves are in each cluster. The higher the number, the
denser the foliage.


5 To make the flowers point in a different direction, open the Behavior
section and then the Forces section. Set Path Follow to 0.1.

6 Paint to see the result.

Saving brush settings for future use
When you first selected the preset brush fern.mel previously, Maya copied it
to the template brush. You then edited the color and various other attributes
of the template brush to create a unique ferns brush. The next steps show how
to save the current settings of the template brush for future use.

To save a brush to the Shelf

1 On the main menu bar, select Paint Effects > Save Brush Preset. This is
the menu item you use to save the template brush as a preset brush.

2 Type the name blueFern in the Label box as well as the Overlay Label
box.
This name appears in icons on the Shelf or Visor after you save the brush.

3 For the Save Preset option, turn on To Shelf. This means you’ll put the
brush on the Shelf but not in the Visor.

Saving brush settings for future use | 571

4 Click Grab Icon and drag a selection box around a part of the image that
is representative of the brush’s result.
A swatch appears in the window for the selected region. Repeat this step
until you are satisfied with the icon.

5 Click Save Brush Preset. An icon for the new preset brush appears on the
Shelf.

6 To check that the blueFern brush works, select a different preset brush
and paint on the canvas, then select the blueFern from the Shelf and
paint on the canvas.

7 Clear the canvas and close the Save Brush Preset window.

Blending brushes
You can blend brushes. Before beginning, display the Visor, click gold.mel in
the metal folder, and paint on the canvas so you know gold’s effect. Do the
same for grassOrnament.mel from the grasses folder.

To blend brushes

1 Click grassOrnament.mel in the grasses folder.

2 From the menu, select Paint Effects > Preset Blending > .
The Preset Blending options window appears.
The brush preset blending is toggled on and the options in this window
set how much the template brush is influenced by the next preset brush
you select. This affects only the subsequent painting, not the preset
brushes in the Visor.

3 Change the Shading value to 80 and the Shape value to 0.
When you select the next brush (gold.mel), Maya uses 80% of its shading
and 0% of its shape. Conversely, the stroke uses 20% of the
grassOrnament.mel brush’s shading and 100% of its shape.

4 To confirm the effect, select gold.mel (in the metal folder), then paint
on the canvas.

5 Repeat the preceding steps, experimenting with different preset brushes,
Shading, and Shape values. As a first try, blend flameCoarse.mel from
the fire folder with the existing template brush. Set Shading to 60 and
Shape to 30.


If the Brush Preset Blend window is open, each time you select a preset
brush, its Shading and Shape values will be blended with the template
brush.

6 Close the Brush Preset Blend window when you are done blending
brushes.

7 Do not clear the canvas. You’ll use your existing strokes in the next steps.

Smearing, blurring, and erasing paint
Now you’ll work with brush types that smear, blur, and erase paint.

To smear, blur, and erase paint

1 Select Brush > Reset Template Brush to select the default brush.

2 On the Brush menu, try the Smear, Blur, and Erase menu items and paint
on the strokes already on the canvas. You can also change these settings
using the Brush Type setting in the Paint Effects Brush Settings window
(Brush > Edit Template Brush).

3 If you need to perform compositing work, you can view the image’s alpha

channel by clicking this button: .

Smearing, blurring, and erasing paint | 573

White regions represent full opacity. Black represents full transparency.

4 If you turned on the alpha channel (Display > Alpha Channel), return
to the display of full color by selecting Display > All Channels.

5 Clear the canvas and restore the canvas color to white (Canvas > Clear >
).

6 To quit the canvas display and return to a scene view, select Panels >
Perspective > persp (Hotkey 8).

7 In the Toolbox, click the Select Tool.
Clicking the Select Tool quits the Paint Effects Tool, and the mouse cursor
displays as an arrow.

8 Select Paint Effects > Preset Blending to turn off Preset Blending before
you proceed to the next lesson.

Beyond the lesson

■ Use Paint Effects to paint on the 2D canvas.

■ Use the preset Paint Effects brushes from the Visor.


■ Edit, blend, and save preset brushes for later use.
Painting on the 2D canvas is useful when you need to create a texture to
be applied to a surface. For example, suppose you paint a repeating brick
pattern on the canvas and save the canvas as an image file. You can create
a material, for instance, a Blinn material, then apply the image file as a
file texture to the color of the Blinn material. You can then apply the Blinn
material to a 3D wall you’ve modeled, which creates the illusion of a brick
wall.

Painting a 2D canvas is also useful for creating a background image for a scene.
For instance, you might create lush foliage on the canvas, put it on a camera’s
image plane, then use it as the backdrop for animated jungle animals in the
foreground.
Although not covered in this lesson, you can use a tablet and stylus to paint
with pressure sensitivity. Pressure sensitivity allows you to more realistically
simulate the effects of traditional drawing media (pens, pencils, markers, etc.)

Lesson 2: Painting in 3D using Paint Effects

Introduction

The Paint Effects Tool goes beyond traditional paint software by allowing you
to paint directly in 3D space, either on the ground plane or on an object’s
surface. When you use Paint Effects for 3D work, the paint strokes are
three-dimensional and editable.
With Paint Effects, all of the hundreds of preset brushes found in the Visor
under the Paint Effects tab (airbrushes, pens, markers, watercolors, plants, fire,

Lesson 2: Painting in 3D using Paint Effects | 575

metal, flowers, trees, and underwater etc.) can be used to create 3D objects in
your scene. For example, you can use the preset plant brushes to paint a 3D
tropical fern garden around a walking character in your scene.
You can animate brush strokes to create dynamic effects. For example, you
can animate the ferns to shake in the wind or have them move when a
character walks near them.
An electronic tablet with stylus is an ideal tool for painting with Paint Effects.
With a real paint brush, pressing harder makes the brush wider and applies
the paint more thickly. You can achieve the same effect with Paint Effects by
specifying the effect of pressure on the stylus for each stroke and the threshold
of response to pressure. You can map up to three attribute values to stylus
pressure and edit them as you work.
When you use Paint Effects to paint 3D strokes, you can edit the brush and
stroke attributes to create a variety of effects.
In this lesson, you begin to explore what is possible with painting in 3D using
the Paint Effects Tool by learning how to:

■ Paint directly in the 3D scene view.

■ Choose brushes from the Visor and the Shelf and modify their brush
attributes.

■ Paint in 3D using the Paint Effects panel.

■ Differentiate between paint brushes and paint strokes.

■ Make surfaces paintable so paint strokes can be applied to them.

■ Select brush strokes and modify their attributes.

■ View strokes in wireframe and rendered mode.

■ Apply various effects to stroke attributes.


1 If you have not done so already, consider doing the lessons in the
Rendering section of this guide. Familiarity with Maya rendering concepts
is important to understanding the lessons.



If you just finished Lesson 1 in this chapter you may be presented with
a window asking if you wish to Save previous paint effects. Select No.

3 To use all available screen space, maximize the Maya window.

4 From a panel menu bar, select Panels > Layouts > Single Pane.

this chapter assume the Rendering menu set is selected.

6 From the Shelf, select the Paint Effects tab to display the various preset
brushes.
If the Paint Effects Shelf tab does not appear as part of the shelf set, see
the Maya Help for Shelves. (For Linux users, any new shelves do not load
by default.)
Regardless of your operating system, the Paint Effects preset brushes are
accessible from the Visor panel. (From a view panel, select Panels > Panel
> Visor.)

Brushes and strokes
Like a traditional paint program, Paint Effects allows you to use a brush and
paint strokes. In Paint Effects, the brush and stroke have unique qualities and
characteristics.
A brush contains the various attributes that define the appearance and behavior
of the paint. The template brush settings define the initial settings for a brush.
When you drag the Paint Effects brush, you create a path for the brush called
the paint stroke.
A stroke is a 3D curve (or collection of curves) with attributes that define how
the paint is applied along the stroke path. You can paint strokes directly in
the 3D scene or on objects.
When you select a brush preset from the shelf or from the Visor, that brush
is copied to the template brush. Any changes you make to the template brush
settings affect what the next stroke looks like, but they do not affect any
previously painted strokes.

To select a Paint Effects preset brush from the Shelf

1 From the Toolbox panel layout shortcuts, select the Single Perspective
View.

Brushes and strokes | 577

2 From the Shelf, select the Paint Effects tab to display the Paint Effects
preset brushes.

3 From the Paint Effects shelf, select the Daisy Large Brush.

In the scene view, the cursor changes to a red circle with a vertical line
indicating it is set to paint a stroke. The circle indicates the width of the
brush path. With some types of strokes, this path will appear as the width
of the actual paint; with other stroke types, it indicates the width of the
tube seeding path, for example, plants, trees, etc.

The settings of the preset brush you select are copied to the template
brush. The template brush settings are used when a paint stroke is drawn.
If you want to modify the brush presets before you begin to paint, you
must edit the template brush after you’ve chosen the preset brush (Paint
Effects > Template Brush Settings).


By default, the brush cursor moves along the ground plane. The ground
plane lies in the X, Z dimension. This is the default behavior for the brush
cursor. If you draw a paint stroke, it is applied to the ground plane (X,
Z).

To paint 3D strokes in the scene view

1 With the Daisy Brush selected, draw one short paint stroke on the ground
plane using one of the following methods:
■ Drag the stylus across the tablet while exerting slight pressure on the
stylus as you move it.

■ Drag the mouse while pressing the left mouse button.

One or more wireframe daisy stalks appear in the scene view along the
path of the paint stroke. When you paint a stroke in the scene view it
initially appears as a wireframe. Paint is not applied to the stroke until it
is rendered.


The stalks that extend out of the curve or stroke are called tubes. In Paint
Effects, strokes are either simple strokes or strokes with tubes.
Because the stroke has a curve associated with it, you can move, scale, or
rotate the stroke like other objects in the scene. You can edit the curve
to modify the shape of the stroke path.

2 Dolly and tumble the scene to better view these strokes with tubes in 3D.

A move manipulator icon appears at the X, Y, Z origin. (If the move
manipulator does not appear, you can click on the stroke to reselect it
with the Move Tool.)

4 In the scene view, drag any of the Move Tool manipulator arrows to
reposition the stroke.

Each time you paint a stroke, Paint Effects creates a new brush and stroke
node and attaches them to the stroke that is created. You can modify these
brush and stroke nodes once they’ve been created. To edit these brush or
stroke attributes, you use the Attribute Editor.


To modify the attributes of an existing paint stroke

1 To view the Attribute Editor, click the Show/Hide icon on the Status Line.

The Attribute Editor displays.

2 In the scene view, select the paint stroke associated with the daisies. You
can select a stroke by one of the following methods:
■ Select the curve associated with the stroke path.

■ Select the tubes associated with the stroke path.

The Attribute Editor updates to display the nodes associated with the
selected daisy stroke. The various attributes for the stroke appear under
different tabs. Each tab represents a node associated with a specific set of
attributes.

3 Click on the strokeDaisyLarge1 tab to see its attributes.
This tab contains information related to the transform node, because the
most important attributes on this tab control the stroke’s curve
transformation.

4 Under Transform Attributes, set Rotate to be 0, 90, 0.


The stroke is rotated 90 degrees about the Y axis.

5 Click the strokeShapeDaisyLarge1 tab to see its attributes.
This tab is called the stroke attribute node because the attributes establish
the paint stroke’s properties when the stroke is first created.

6 Expand the End Bounds section by clicking the arrow to see the Min and
Max Clip attributes.

Min Clip specifies the start of the stroke along the path. Max Clip specifies
the end of the stroke along the path.

7 Drag the Max Clip slider from its present value of 1.0 to a value of 0.1.
The stroke path is shortened.
Min and Max Clip can be animated to create the effect of the paint
advancing along a path.


8 Drag the Max Clip slider back to its original value of 1.0.

9 Click the daisyLarge1 attribute tab to see its attributes.
This is the node that contains attributes related to the paint brush
associated with the stroke.

10 Set the Global Scale attribute to 6.0.
The daisies scale larger along the stroke’s path.

11 In the daisyLarge1 node, expand the Tubes attributes, then Behavior and
Forces.


12 Drag the Gravity slider to the right so that the value of gravity increases
to a value of 1.0.
The daisies lay on the ground plane, as if wilting, with the increased
gravity.

Drag the Gravity slider back to its original position approximately so that
the stalks appear upright.
The last tab in the Attribute Editor is the time node. The time node is
used for animation and dynamics. You do not use this node in this lesson.

Rendering Paint Effects strokes
The paint strokes display in wireframe mode when you paint in the scene
view. Working in wireframe mode is very efficient in terms of interactive


performance but you don’t see how the paint actually appears. To view the
paint strokes in a rendered mode you can either:

■ Render the scene view using the software renderer.

■ Switch to painting in the scene painting view using the Paint Effects panel.

To render the paint strokes in the scene view

1 Dolly or tumble the scene so the view of the daisies appears roughly
similar to the image below.

2 From the Status Line, click the Render Current Frame button.

The Render View window opens, renders the image, and then displays
it.

Rendering Paint Effects strokes | 585

The daisies may initially appear a bit dark in the image.
The Maya renderer creates a temporary light with a default brightness
level in order to render the image when no lights are present in the scene.
This ensures that you don’t produce an image that is totally black;
however it may not produce the correct illumination for your scene. If
you want to obtain more control over the illumination of the daisies,
you can create a light for the scene and adjust its brightness.

3 From the main menu, select Create > Lights > Directional Light.
A directional light is created at the X,Y,Z origin of the scene.

The Attribute Editor updates to display the attributes for the active
directional light.

4 In the Attribute Editor, set the Intensity for the directional light to be
1.5.

5 From the Status Line, click the Render Current Frame button to render
the scene again.
The image renders and the Render View window image is refreshed.
The daisies appear brighter in this version of the rendered image.



Sometimes you may want to view your painted strokes as you paint. To do
this, you can paint in the Paint Effects panel view and use the scene painting
view mode.

To display rendered paint strokes as you paint

1 Press 8 to switch to the Paint Effects panel.

NOTE If the 2D Paint Canvas appears instead (i.e.: panel appears white),
select Paint > Paint Scene, from the panel menu.

The Paint Effects panel menu and toolbar displays as well as the scene
painting view. This panel allows you to paint in scene painting view
mode.

Rendering Paint Effects strokes | 587

The scene painting view is a snapshot of the modeling view. In this view
you can both paint and view your strokes in a rendered fashion to see
what they will really look like as you work.
You can dolly, track, and tumble in the scene painting view. You can
select objects by pressing the Ctrl key and clicking on them. If you want
to move, or otherwise manipulate 3D objects in the scene view, you must
exit the Paint Effects panel by pressing the 8 key again.

2 With the Daisy Brush selected, paint a stroke in the scene painting view.
The new stroke displays in rendered mode. If you dolly or track the scene
painting view, any rendered strokes will revert back to wireframe display
until you refresh the rendered display.

3 To automatically update the paint strokes so they display in rendered
mode, select Stroke Refresh > Rendered.
It will take a few moments for the rendering of all of the paint strokes to
be calculated and then displayed.
Each time you adjust the camera view while working in scene painting
mode with Refresh > Rendered turned on, the system will automatically
update the rendering based on the new view.
Automatically refreshing the rendering can be time-consuming depending
on the complexity of paint strokes in your scene. Alternatively, you can
set the rendering to refresh only when you manually choose to do so.

4 From the Paint Effects panel menu, select Stroke Refresh > Off.


Now you must manually refresh the Paint Effects rendered view using
the Redraw Paint Effects view button in order to see the paint strokes
rendered.

5 Dolly the view to obtain a closer view of the daisies.

6 Manually refresh the rendering of the daisies by clicking the Redraw Paint
Effects view button.

7 Exit the scene painting view mode by pressing the 8 key.

Paint Effects on 3D objects

With Paint Effects, you can paint 3D strokes directly on 3D objects in a Maya
scene.

Paint Effects on 3D objects | 589

In this section, you create a surface for an underwater terrain and sculpt it to
the desired form using the Sculpt Geometry tool. You use the underwater
preset Paint Effects brushes found in the Visor to begin the underwater scene.

Creating a surface to paint on
In Paint Effects, NURBS surfaces are the only surface type you can paint on.
You will create a NURBS plane, and sculpt it to make its surface appear like
an underwater terrain.

To create a surface terrain for the underwater scene

A new empty scene is created.

2 From the main menu, select Create > NURBS Primitives > Plane > .
The NURBS plane options window appears.

3 In the NURBS Plane Options window, select Edit > Reset settings and
■ Width: 15

■ Length: 15

■ U Patches: 10

■ V Patches: 10

4 In the NURBS Plane Options window, click Create.
Maya creates a plane primitive and positions it at the origin. The plane
is 15 units by 15 units in dimension with 10 subdivisions along each side.


This surface will become the seabed terrain for your scene.

To sculpt a terrain using the Sculpt Geometry Tool

1 Select the plane surface.

2 On the Status line, select Surfaces from the drop-down menu.
The Main Menu changes to display Surfaces menu set.

3 From the Main menu, select Edit NURBS > Sculpt Geometry Tool.
The cursor display changes to the brush cursor for the Sculpt Geometry
tool.

4 On the Status Line, click the Show/Hide Tool Settings button to display
the tool settings for the Sculpt Geometry tool.

5 In the Brush section, set the Radius (U) to 2. and set the sculpt Operation
to Pull.

Creating a surface to paint on | 591

6 Drag the cursor along the back right edge of the plane to pull it upwards
as shown.

7 Drag the cursor along the back left edge of the plane to pull it upwards.

8 Dolly and track the view as required so you can easily view the areas you
need to sculpt.

9 Sculpt along the front and middle of the plane to make some bumpy
areas.

10 Repeat steps 7 through 10 until you have your 3D terrain looking roughly
as shown in the image below.

TIP If you want to undo a particular sculpt operation, click Ctrl + z to undo
the sculpt stroke. You can click Ctrl + z repeatedly to undo a number of sculpt
operations.


11 When you complete your terrain, return to the Rendering Menu set by
selecting Rendering from the drop-down menu on the Status Line.

12 Hide the Sculpt Geometry Tool settings window before proceeding.

To select preset brushes from the Visor

1 From the main menu, select Paint Effects > Get Brush.
The Visor panel appears.

2 In the Visor, click the Paint Effects tab to display the various brush folders.

3 Scroll down the brush folders list to the underwater folder, and click it
to view its contents.

Painting on objects
To paint on a 3D object, you must first make the object paintable. When you
paint directly on a paintable object, Paint Effects creates a curve on the surface
along the stroke path and attaches the stroke and new brush to it.

Painting on objects | 593

If you make an object paintable and then try to paint on one that is not
paintable, no stroke occurs. If you don’t make any objects in your scene
paintable, your strokes are placed on the ground plane.

To paint on a 3D object

1 With the terrain surface selected, select Paint Effects > Make Paintable.

2 From the Visor, select the brush named kelp.mel.

3 Paint a short stroke onto your 3D terrain surface.
When you paint directly on a paintable object, Paint Effects creates a
curve on the surface along the stroke path and attaches the stroke and
new brush to it. If you move the plane, the paint stroke moves with it.

4 Paint a few more kelp strands throughout the scene as shown.

The kelp brush orients the tubes to point along the normal of the surface
you paint on. In the ocean, kelp grows towards the surface of the water
in a vertical manner. If you want your kelp to appear realistic, it should
point vertically upwards. If you paint the kelp on an angled part of the
surface, the kelp tube will not point in a vertical direction.

TIP If you want to change the scale of the Paint Effects stroke to obtain larger
plants or animals, press the b key and drag your stylus or mouse to the left
or right to make the global scale for the current brush smaller or larger.
If you want to change the width of the brush stroke, to paint a narrower or
wider tube path, for example, a wider swath of kelp plants, press the shift
and b key and drag to the left or right.


Using turbulence with brush stroke tubes
In the ocean, kelp would react to the turbulence created by ocean currents.
The tube attributes associated with many preset brushes have turbulence
attributes turned on for interesting visual effects. Turbulence attributes can
be increased from their default settings to make the kelp sway back and forth,
providing additional realism when used in an animation.

To increase the turbulence on the kelp brush tube

1 In the scene view, select the kelp stroke.

2 Open the Attribute Editor, select the Kelp tab, and expand the Tubes >
Behavior > Turbulence section.

3 In the Turbulence section, set the options as follows:
■ Turbulence Type: World Force

■ Interpolation: Smooth over Time and Space

■ Turbulence: 0.5

■ Frequency: 0.5

4 Click the Play Forward button on the Animation Time Slider to see the
turbulence effect on the kelp (You don’t need to set specific keyframes).
The kelp animates as if it were affected by ocean currents.

5 Press the Stop button to cancel the animation playback.

Using turbulence with brush stroke tubes | 595

You can adjust the turbulence settings while viewing the playback. If the
frame range is too short, you can modify it to suit your needs.

Using additional preset brushes
1 From the Visor, select the brush named fanCoral.mel.

2 Paint a few fan coral strokes in your scene near the back edges of the
plane.

TIP If you paint a stroke in your scene and want to delete it you can do so
by one of the following methods:
■ Press Ctrl + z to immediately undo the stroke.

■ Click on the stroke to select it and then press the Delete key.

■ Marquee-select a tube associated with the stroke and then press the
Delete key.

■ Marquee-select multiple tubes and strokes and then press the Delete
key.

If you want to delete all the paint strokes in your scene you can select Edit >
Delete All by Type.

3 Paint additional strokes in your underwater scene using a few using the
following brushes found in the underwater folder in the Visor:
■ sea urchins, starfish, seashells, and anemones

4 Dolly and track the scene for a closer view so it appears approximately
as shown.



6 The renderer executes, renders the image, and then displays it in the
Render View window.

You can create a seabed texture for the plane primitive, a few rocks, and some
animated fish swimming to complete your scene.
You can spend additional time to further refine this scene, but this example
gives you an idea of how a scene with various 3D props can be quickly
established using Paint Effects and the various preset brushes found in the
Visor.

Using additional preset brushes | 597

Mesh brushes

Mesh brushes are a brush type that provide special features not available with
other Paint Effect brush types. Mesh brushes render using polygonal triangles
rather than brush stamps. As a result, mesh strokes can be more accurately
texture-mapped for realistic results. They also appear more realistic compared
to other brush types whether they are viewed close-up or from a distance.
The mesh brush stroke can also be converted to a polygonal surface in the
Maya scene. Once the stroke is converted to polygons, the resulting polygons
can be modified using any of the Maya polygonal modification tools and
utilized like any other polygonal surface (animation, rendering, and so on)
In this section, you are introduced to mesh brushes and learn additional
techniques related to the various brush and stroke attributes. You learn how
to:

■ Understand the structure of strokes with tubes.

■ Modify a variety brush tube attributes.

■ Convert the mesh brush stroke to polygons.

■ Modify the converted mesh using construction history.

■ Render the polygonal meshes.

To select a mesh brush preset from the Shelf

A new empty scene is created.

2 From the Toolbox panel layout shortcuts, select the Single Perspective
View.


3 From the Shelf, select the Paint Effects tab to display the Paint Effects
preset brushes.

4 From the Paint Effects shelf, select the Teapot Brush.

In the scene view, the cursor changes to a sphere icon indicating it is set
to paint a stroke. The Teapot Brush is a mesh brush type.

5 In the scene view, drag your mouse or stylus along the ground plane to
create one short stroke.

6 Dolly and tumble the view to see the wireframe version of the stroke.
The teapot stroke displays three wireframe tubes to represent the teapot.
These tubes represent the body, spout, and handle for the teapot.
Paint Effects uses a plant or tree archetype to represent the various tube
attributes. If you envision how a plant or tree has a trunk, out from which
branches, leaves, flowers, and buds grow, you understand how each
attribute is controlled in the attribute editor.

The center vertical line represents the main tube, whose attributes are
found in the Creation tab of the attribute editor. The diagonal and
semicircular lines represent the Leaves and Flowers tube attributes for the
spout and handle of the teapot.

Mesh brushes | 599

To render the paint effects stroke


The renderer executes, renders the paint stroke, and then displays the
image in a Render View window.


Mesh brush types are useful for representing hard surfaces compared to other
brush types (the teapot is one example).

Converting mesh strokes to polygons
Mesh strokes can be converted to polygons. Converting the mesh stroke to
polygons allows you to visualize any brush modifications you make in the
Attribute Editor without having to render the stroke. It is possible to edit,
animate, and render the converted polygon mesh the same way you would
any other polygonal surface types.

To convert a mesh stroke to polygons

1 Press the q key (Hotkey) to choose the Select Tool.
The cursor changes to an arrow icon indicating the change to selection
mode.


2 Select the teapot stroke, if it is not already selected.

3 Select Modify > Convert > Paint Effects to Polygons > .

4 In the Convert Paint Effects to Polygons Options window, ensure that
the Hide Strokes option is set to On.

Setting the Hide Strokes option to On ensures that after the conversion,
only the converted polygon mesh will be displayed.

5 In the Convert Paint Effects to Polygons Options window, click Convert.
The mesh brush stroke is converted to a polygonal surface. A teapot model
made of polygons results.

The original mesh brush stroke still remains but is now hidden.

6 Click anywhere in the scene view away from the teapot surface to de-select
the teapot surface.

7 In the scene view, press 5 to smooth shade the display of the polygonal
teapot.

Converting mesh strokes to polygons | 601

Modifying a converted polygonal mesh
By default the original brush stroke is linked to the new polygonal surface via
construction history. If you modify the original brush stroke attributes, the
polygonal surface will update so long as the construction history link exists.
This construction history link allows you to easily modify the polygonal mesh
surfaces in a variety of ways. You modify the brush stroke attributes using the
attribute editor.
To modify the teapot brush attributes

1 Marquee-select the polygonal teapot.

2 To view the Attribute Editor, click the Show/Hide button on the Status
Line.

The Attribute Editor displays.

3 In the Attribute Editor, click on the teapot1 tab to display the brush
attributes for the teapot stroke. (You may need to click the display arrow
(Windows, Mac OS X) or select the tab from the pop-up list (Linux) in
order to see the tab.)


4 In the Attribute Editor, expand the Mesh attributes section to display its
attributes.

5 In the Mesh attributes, drag the Tubes Sections slider to the left to a value
of 3.

The body, spout, and handle of the teapot update to display as 3 sided
surfaces.

Modifying a converted polygonal mesh | 603

Tube Sections defines the number of sides around the width of the tubes
in a mesh stroke. Changing the Tubes Sections gives a range of results
depending on the brush type you choose.

6 Set the Tubes Sections to a value of 18.

7 In the Attribute Editor, close the Mesh attributes, and then expand the
Tubes attributes, then the Creation attributes.

The Creation attributes control the main body of the teapot; the “trunk”
or “stalk” of your paint effect mesh type.

8 Scroll down to the Width Scale attributes.

9 In the Width Scale attributes, drag an index point handle (as shown
below) to change the profile shape of the teapot.
The profile of the teapot body is modified.


The Width Scale graph allows you to control the width of a tube by
interpolating the shape between the index points. (If you look closely at
the graph, you’ll see the profile of the teapot laying on its side.)

10 Drag the index marker back to its original position.

11 Close the Creation attribute section in the Attribute Editor, and open the
Growth attributes, followed by the Leaves attributes.

12 In the Leaves attributes, drag the sliders for the Leaves In Cluster, Leaf
Length, Leaf Base Width, and Leaf Tip Width attributes to experiment
with the spout of the teapot.

Modifying a converted polygonal mesh | 605

If you want to adjust the attributes of the teapot handle, you can edit
the Flower attributes.

Using this converted poly mesh is one example of how the attributes of the
paint stroke can be modified to affect the shape of another object through
construction history.
If you delete the paint stroke, the construction history between the stroke and
the polygonal teapot will be removed. If you then want to make further
changes to the teapot, you must use the Edit Polygon tools.

To render the polygonal mesh teapot

➤ Render the teapot by clicking the Render Current Frame button on the
Status Line.

Beyond the lesson
In this lesson with Paint Effects, you learned how to:

■ Use preset brushes from the Shelf and the Visor.


■ Paint directly in 3D space onto the ground plane or onto 3D objects.

■ Select and move strokes in the scene.

■ Edit brush and stroke attributes using the Attribute Editor.

■ Render paint strokes.

■ Use the Paint Effects Panel to paint fully-rendered paint strokes.

■ Create a terrain to paint on using the Sculpt Geometry tool.

■ Understand the structure and archetype for strokes with tubes.

■ Use mesh brush types to paint hard-surface objects.

■ Convert mesh brush strokes to polygonal surfaces.

You can use Paint Effects to create natural or fantastic scenery, backdrops, and
atmospheres. Mesh Brush types are particularly useful for creating polygonal
trees that appear strikingly convincing, whether they are viewed close-up or
from a distance.
Paint Effects has many other useful techniques not covered in this lesson.
With Paint Effects you can:

■ Modify strokes to share a single brush, make strokes glow, and animate
the movement of strokes.

■ Attach a brush to an existing curve (you don’t need to paint a curve).

■ Add spring-like behavior to strokes with tubes, or you can make the tubes
react to dynamic forces such as wind.

■ Create animated textures; for example, falling rain.


■ Paint using a Thin Line brush type which allows you to render large
numbers of fine tubes much more quickly than the Paint Brush type. This
brush type is useful for painting hair.

Lesson 3: Painting textures on surfaces

Introduction
The 3D Paint Tool allows you to paint textures directly onto a model’s surface.
In this lesson, you paint colors, patterns, and textures on a dinosaur model.

■ Prepare a surface model for painting.

■ Paint on a surface using both Artisan and Paint Effects brushes.

■ Use reflected paint strokes for symmetrical effects.

■ Flood fill an entire 3D model with paint.

■ Modify brush shapes and stamp settings.

■ Paint a bump map texture directly on a surface.

You will paint a dinosaur model we prepared for this lesson.

1 Do the steps outlined in Preparing for the lessons on page 562.

2 Open the scene file named 3DPaint.mb.
your Maya project:
GettingStarted/Paint/3DPaint.mb


The scene contains a model named Dino. Although Dino is a polygonal
model, the 3D Paint Tool works on all surface types: polygonal, NURBS,
and subdivision surfaces.
To prepare for this lesson, we assigned a Blinn material named DinoSkin
to the model. In Maya, you can paint a surface only if it has a material
assigned to it. We also gave the Blinn material a green color. A color is
optional, but it provides a base color for the texture you will paint.
Finally, we made other preparations to Dino so you can use the 3D Paint
Tool successfully. You’ll learn about the preparations in Preparing UVs
for painting on page 621.

3 Save the scene in your default scenes directory (File > Save Scene As).
This lesson works best when you start with a saved scene. When you use
the 3D Paint Tool, Maya automatically creates a directory to store the file
texture that will be created from your painting. By saving the scene, you
ensure that Maya can locate the directory and file texture that it creates
automatically.

4 Select Display > UI Elements > Tool Settings. This displays a Tool Settings
panel where the Channel Box is normally located. You will be working
with this panel throughout the lesson.

Preparing for painting
1 Select Dino. You can paint only on selected objects. When you actually
use the 3D Paint Tool, the wireframe of a selected object is not
highlighted. You can check the Outliner to be sure the object is selected.

2 Select Texturing > 3D Paint Tool. The following warning appears on the
Command Feedback line:
Warning: Some surfaces have no file texture assigned to the
current attribute.

Preparing for painting | 609

The 3D Paint Tool requires that the material assigned to your model has
a file texture applied to it. Because there is no file texture yet assigned,
the warning appears.
When you move the cursor over Dino, you see a circle-X icon that
indicates you cannot paint on the model.

3 To make sure you have the default settings for the 3D Paint Tool, click
Reset Tool at the top of the 3D Paint Tool settings panel.

4 In the File Textures section of the 3D Paint Tool settings panel, set the
Attribute to Paint setting to Color, then click Assign/Edit Textures.
This step and the next two steps assign a texture to Dino. (Note that you
can also paint over an existing texture that you assigned from
Hypershade.)

5 Type 512 in the Size X box, which is the height of the new file texture in
pixels.
By increasing the file texture size, you will see finer detail and resolution
in a rendered image of your painting. The number 512 is twice the default
size, 256. You could use a higher resolution, but sizes larger than 512
slow the interactive speed as you paint. Notice that Size Y automatically
changes to 512. This is because Keep Aspect Ratio is turned on, ensuring
that the proportions of the texture are maintained.

6 Click Assign/Edit Textures in the Assign/Edit File Textures window.
Maya creates a file texture and assigns it to the Color attribute of the
DinoSkin material. At the end of the lesson you will learn about the name
and location of the file texture that is created.
You are now ready to paint.


Painting with an Artisan brush
In the following steps, you paint various colors on the texture you just
assigned. You also change the size of the brush strokes.
There are two types of brushes you can use. The default is the Artisan brush,
which you’ll use in the next steps. (Artisan refers to a group of painting tools
in Maya that share common tool settings.) The other brush is based on the
Paint Effects brushes; you’ll use it later in the lesson.

To paint using an Artisan brush

1 If you have a tablet and pen, you can experiment with pressure sensitivity
as you paint. Open the Stylus Pressure section and turn on Stylus Pressure.
(You do not need to have a tablet and pen to complete the lesson.)
By default, when you paint with Artisan brushes, the pressure you apply
to the pen affects the Opacity setting of the 3D Paint Tool. The harder
you press, the more opaque the stroke.

2 In the Color section of the Tool Settings, click the box next to Color and
select a color in the Color Chooser. Leave the Color Chooser open. You’ll
use it in the next few steps.

3 Paint a stroke by dragging on the model.

4 Select another color from the Color Chooser and paint over your first
stroke.
The new color paints over the first color by default. Note that you can
blend the colors by choosing a different Blend Mode setting, under the
Paint Operations heading. You won’t blend the colors in this lesson.

5 Move the brush onto Dino, hold down the b key and drag to the left to
make the brush smaller. Drag until the number at the brush icon changes
to about 0.5. You don’t need to be precise.
Use this hotkey when you need to change the brush width. To make the
brush wider, drag to the right. You can also change the width by changing
the Radius (U) setting.

Painting with an Artisan brush | 611

6 Experiment with different colors and brush sizes on Dino.
To undo a brush stroke, choose Edit > Undo, Redo, Repeat. The number
of strokes you can undo is specified by the Queue Size in the Undo
category of the Preferences window (Window > Settings/Preferences >
Preferences).

7 To remove paint, turn on Erase in the Paint Operations section and stroke
the desired region.

Painting symmetrical strokes
You can reflect painted strokes along an invisible axis so that when you paint,
the stroke is mirrored on the opposite side of the axis. Reflection is useful for
creating symmetrical effects.

To paint using the reflection option

1 In the 3D Paint Tool settings panel, open the Stroke section and turn on
Reflection and set the Reflection Axis to X.
Notice that there are now two brush outlines that run along an axis. The
reflection axis is positioned around a point at the center of the object.

2 Paint on one side of Dino, such as one of the legs.


As you paint, the strokes are reflected along the axis and appear on the
other side of Dino. Tumble to see the reflected stroke on Dino’s other
side.

Using Flood All to apply a single color
You can apply a single color to the entire texture without painting individual
strokes.

To use Flood All to apply a single color

1 In the Flood settings of the 3D Paint Tool settings, click the Color box
and select a pale green color from the Color Chooser.

2 Set the Flood setting to All and then click on the Flood Paint button.
The Flood Color overwrites all other painting you’ve done. You can also
use Flood to erase painting.

3 In the Flood settings, click the Flood Erase button.
Maya eliminates all brush strokes, leaving you with the last saved version
of the texture. (To save the texture, click the Save Textures button in the
File Textures section.)

Brush shapes
You can paint with different brush shapes to produce paint strokes with hard
edges, soft edges, or completely different patterns. You can choose from four
standard Artisan brush shapes, plus 40 preset brush shapes.

To modify the shape of the brush

1 At the top of the 3D Paint Tool settings, click Reset Tool.
Reset Tool cancels the Reflection X and other settings from the previous
steps. While painting, it’s useful to reset the tool settings from time to
time so previous settings do not interfere with your next strokes.
If you are using a tablet and pen, you’ll need to turn on Stylus Pressure
again to see the effect of your pressure as you paint.

2 Change the Color setting to dark red or another color that contrasts with
the current green color.

Using Flood All to apply a single color | 613

3 In the Brush settings, click the following icon and paint a stroke:

By changing to the square brush shape, your brush stroke has a straight
edge. Along with the shapes available from the icons, you can choose
from many other unusual brush shapes that are based on image files.
You’ll do this in the next step. Before you do the next step, undo the
brush stroke you just made so it doesn’t distract from the next paint
strokes.

4 In the 3D Paint Tool Brush settings, click the Browse button.
A browse window opens with a list of various image files. Each file
represents a different brush shape.

5 Select dapple.jpg and click Open.

6 Click on Dino’s hump and barely move the brush to create a single spot
of paint.

Instead of a solid color, a pattern appears on Dino. The pattern is a result
of using the dapple.jpg file for the brush shape. Undo the stroke.

7 Now drag the mouse over Dino to paint a single, continuous stroke.


The brush shape pattern overlaps itself as you paint, resulting in a striped
pattern. Undo the stroke.

8 To avoid the overlapping pattern of the prior step, increase the Stamp
Spacing (in the Stroke section) to 50. Paint on Dino with a continuous
stroke and you’ll see the brush pattern without it overlapping.

The Stamp Spacing setting defines how paint is applied when you stroke
the surface. If you set Stamp Spacing to 1, the edges of the brush shape
pattern just touch each other. If you set the spacing to be greater than 1,
there will be spaces between the brush shape pattern. If you set the spacing
to be less than 1, the brush shape pattern will overlap.

Painting with a Paint Effects brush
You can use the 3D Paint Tool with the preset brushes available with Paint
Effects. Paint Effects brushes include not only patterns but also images such
as flowers, feathers, hair, and fire.
In the following steps you paint on Dino with a Paint Effects brush. Before
you begin, consider first becoming familiar with the Paint Effects brushes, as
taught in Lesson 1: Painting in 2D using Paint Effects on page 563.

To paint with a Paint Effects brush

1 In the Brush section of the 3D Paint Tool settings, click the following
icon (Get Brush) to select from the preset Paint Effects brushes:

Painting with a Paint Effects brush | 615

The Visor window opens. The Visor organizes the hundreds of Paint
Effects brushes into category folders.

2 Scroll to the watercolor folder and click it.
To the right, swatch pictures of the Paint Effects brushes appear for this
category.

3 Select the spatterLight.mel brush. (To see the names of the swatches, drag
the pointer over them.)
Leave the Visor window open, but move it so you can see Dino again.
If you are using a tablet and stylus, you need to turn on Stylus Pressure
again to see the effect of your pressure as you paint. Stylus Pressure is off
because you changed from the Artisan brush to a Paint Effects brush.
For Paint Effects brushes, the pressure you apply to the pen affects three
different settings. If you change the settings, it affects only the selected
brush. The settings for each brush are separate from each other.

4 Paint on Dino.

5 In the Brush section of the 3D Paint Tool settings, click the following
icon (Edit Template Brush) to modify other brush settings:

The Paint Effects Brush Settings window opens. Any changes you make
to the settings in this window affect the display of your next stroke. As
an example, you’ll increase the brush’s incandescence.


6 Open the Shading section in the Paint Effects Brush Settings window.
For the Incandescence1 setting, move the slider to the right and stop
midway.

7 Close the Paint Effects Brush Settings window and paint on Dino. Now
the paint has an incandescent glow.

Smearing and blurring
In the next steps you’ll smear and blur the paint on Dino. Smearing with a
Paint Effects brush blends adjacent colors together along the stroke path.
Blurring softens the edges of adjacent colors by averaging their color values.

To smear and blur with Paint Effects brushes

1 Move the Visor window back into view.

2 Click the wetInWet folder and then click the cleanWaterDrip.mel brush.
Close the Visor window.
In the 3D Paint Tool settings, under Paint Operations settings, observe
that the Paint Operation is now set to Paint Effects Smear. The brush you
selected, cleanWaterDrip, has settings that turn on the Smear setting
automatically for you.

3 Paint across the side of Dino. The paint smears and produces an effect
similar to dripping wet paint.

Smearing and blurring | 617

4 In the Paint Operations section of the 3D Paint Tool settings, select Paint
Effects Blur.
This selects the default Paint Effects Blur brush.

5 Paint across the side of Dino to see the effect of Blur.

Painting a bump map texture
Next, you’ll paint a bump pattern on Dino. In Maya, a bump texture creates
the illusion of surface relief. It does this by perturbing the surface normals to
make the surface appear bumpy. This is useful for making Dino’s skin appear
more “reptile-like”.

To paint a bump map texture

1 In the 3D Paint Tool window, click Reset Tool to return to the default
settings.

2 In the File Textures section, set the Attribute to Paint setting to Bump
Map.

3 Click Assign/Edit Textures.
The Assign/Edit Textures window appears.


Earlier in the lesson, your painting affected only the Color attribute. To
paint bumps, it’s necessary to select a BumpMap as the new attribute you
want to paint, and then assign a new texture for the bumps you’ll create.

4 In the Assign/Edit Textures window, set both Size X and Size Y to 512
and then click Assign/Edit Textures.
Maya creates a file texture and applies it to the Bump Map attribute of
the DinoSkin material.
In the scene view, Dino’s color changes to white. Bump map textures are
based on grayscale colors. By default, when you create a rendered image,
bumps will appear in the areas of the surface where there is significant
grayscale color contrast. For instance, if a region has black and white
stripes, you’ll see grooves there. Regions with little or no contrast display
no bump.
The bumps will not show in the scene view; you must create a rendered
image in order to see them. The same is true when you paint certain other
attributes, such as Transparency and Incandescence.
Before you paint bumps on Dino, you must set up the Maya panels so
you can interactively see the results of your strokes in a rendered image.

5 Select Panels > Layouts > Two Panes Stacked.

6 In the bottom panel, select Panels > Panel > Render View.
Maya now displays the perspective view, the Render View, and the 3D
Paint Tool settings. With this arrangement, you’ll be able to see your
strokes render as you paint.

7 In the perspective view, move the camera to a close-up view of Dino’s
side.

8 In the Render View, select IPR > IPR Render > persp. This renders an image
of Dino in the Render View.

9 In the Render View, drag a selection box around Dino’s midsection and
hump.

Painting a bump map texture | 619

This region will update when you paint.
For the IPR renderer to render bumps as you paint, you must update the
bump map texture after each stroke. You can set this to occur
automatically.

10 In the File Textures section of the 3D Paint Tool settings, turn on Update
on Stroke.
For a grooved bump effect, you need to change the brush shape.

11 In the Brush section of the 3D Paint Tool settings, click the Browse button.

12 Select the hatch.jpg brush and click Open.

13 Paint on Dino’s side.
Notice the Render View updates with each stroke.

The bumps appear as grooves in Dino’s surface because you painted
contrasting black stripes on the white texture. In general, gray or black
over a white background results in bumps that appear indented.
If you wanted bumps that appear raised on the surface, you could start
with a black background and paint gray or white over it. For example,
you could flood the texture with a black Flood Color, then paint white
or gray strokes rather than the default black.
Greater contrast between the background color and the color you paint
results in deeper-looking bumps. Less contrast results in more subtle
bumps. In the previous step, you painted using a black color, resulting
in prominent bumps. If you change the Color setting to a light gray and
paint on the white background, only subtle bumps will appear.
This concludes the lesson.

14 Before doing other lessons, restore the Channel Box in the Maya window.


15 Select Display > UI Elements > Channel Box/Layer Editor.

Beyond the lesson
In this lesson you were introduced to a few basic techniques related to the 3D
Paint Tool. You learned how to:

■ Paint textures directly onto surfaces using the 3D Paint Tool.

■ Paint symmetrically onto surfaces.

■ Paint grey scale attributes to create bump texture effects.

There are several other capabilities in the Paint Operations section, such as
the Clone option for Artisan brushes. With the Clone option, you can duplicate
the color and pattern from an area of the texture and then paint that pattern
elsewhere on the texture. For details on these options and other 3D Paint Tool
techniques, refer to the Maya Help.

Location of 3D Paint Tool file textures
If you need to move or rename a file texture that Maya creates from your
painting, look in the 3dPaintTextures directory under the current project
directory. If you paint an existing file texture that you created previously, for
example, with a paint program, Maya creates a copy and stores it in the
3dPaintTextures directory.

Preparing UVs for painting
In this lesson you worked with a polygonal model that was specially prepared
for painting in this lesson. To paint successfully on a polygonal or subdivision
surface, you must set up the surface UVs beforehand. UVs are points positioned
around the surface like vertices. They control how Maya stretches a texture
around a surface. For polygons and subdivision surfaces, you must arrange
the UVs so that textures—including the ones you paint with the 3D Paint
Tool—look correct when applied to the surface material. (The UVs on NURBS
surfaces are automatically arranged for you, so you do not have to change
them.)
You view and edit UVs using the UV Texture Editor (Window menu). You can
obtain an introduction to UVs and the UV Texture Editor by completing the
UV Texture Mapping lesson in this book. You can also learn more about UVs
in the Maya Help by referring to the sections on Polygonal and Subdivisions
surfaces.


If you already have experience with editing UVs, remember these two
requirements for 3D painting:

■ UVs must not overlap.

■ UVs must fit with the 0 to 1 texture coordinates.

This illustration shows the UV Texture Editor with the UVs for the Dino model
used in this lesson. These UVs meet the above two requirements. Notice that
the UVs form several meshes; they do not need to be one solid mesh.

Painting in Screen Projection mode
When you paint on a model, the brush follows the contours of the surface.
This typically produces the most desirable results. However, this default
behavior leads to uneven paint application in some situations. A common
example is along the line where two surfaces join together. It can also occur
if the UVs are not arranged correctly, as described previously.
The solution to these situations is to turn on Screen Projection in the 3D Paint
Tool settings. Screen Projection applies paint as if you are projecting cinematic
film onto a screen. Paint appears where the projection strikes the surface.
The following figure shows an example of this situation with a Paint Effects
brush.


Expressions
12
Introduction
Expressions are program-like instructions you create to control keyable attributes
over time. Expressions can be comprised of mathematical equations, conditional
statements, or MEL™ commands.
Expressions offer an alternative to difficult keyframing tasks similar to Set Driven
Key. With Set Driven Key, attribute relationships can be set up and are defined
using animation curves. Unlike Set Driven Key, an expression does not use an
animation curve to define the animation of the attribute but calculates the
attribute values over time from the formula defined in the expression.
Although you can create an expression to animate attributes for any purpose,
they’re ideal for attributes that you want to change incrementally, randomly,
or rhythmically over time.
It is possible to create custom attributes for objects and control them in
conjunction with expressions. It is not possible to mix expressions with other
animation techniques for the same attribute on an object (keyframing, path
animation, set driven key).

625

This chapter contains the following lessons:

■ Lesson 1 Creating a simple expression: Introduction on page 627

■ Lesson 2 Conditional expressions: Introduction on page 634

■ Lesson 3 Controlling particle attributes: Introduction on page 643




3 Select Window > Settings/Preferences > Preferences. Click the Settings
category and set the Time option to Film (24 fps) so your animation plays
at the default rate of 24 frames per second. Click the Timeline category
and enter 0 and 300 for the Playback Start/End values. (Press the Enter
(Windows and Linux) or Return (Mac OS X) as necessary.) Set the Playback
Speed to Play every frame. Click the Save button in the Preferences
window.
At this playback speed and frame range, the animation results of the
expressions you’ll create in the lessons will be easier to examine and
understand.

Shade All). It’s easier to see the expression effects on shaded objects than
wireframe objects in the following lessons.

626 | Chapter 12 Expressions

Lesson 1: Creating a simple expression

Introduction
This lesson introduces you to some basic concepts regarding the creation and
editing of expressions. You learn how to:

■ Use the expression editor to create and edit expressions.

■ Control both single and multiple attributes of objects in your scene.

Creating expressions to control a single attribute
In the following steps, you create a default sphere and write an expression to
increase its Scale Y attribute as the animation time increases during playback.

To create an expression


2 Create a NURBS or polygonal sphere with an X scale, Y scale, and Z scale
equal to 1. Rename the sphere Ball. (Upper and lower case text is
important)

3 With Ball selected, choose Window > Animation Editors > Expression
Editor.

4 In the Expression Name box, you can optionally enter an expression
name, for instance, ScaleBallHeight.
If you write several expressions in the same scene, giving each a name
might make it easier to find the desired expression if you decide to alter
it later. If you don’t provide a name, the expression receives a default
name, for instance, expression1.

Lesson 1: Creating a simple expression | 627

Note that the Attributes list displays Ball’s keyable, unlocked
attributes—the attributes you’ll most likely want to animate with an
expression. Use the scroll bar to see the entire list.

5 Enter this expression in the expression text area:

Type all characters exactly as shown above. Entries are case sensitive. The
semicolon (;) signifies the end of the expression statement. End each
statement in an expression with a semicolon.
An error message appears in the Script Editor and Command Line’s
response area if the expression has incorrect syntax or typing mistakes.

6 Click Create to create the expression.
Creating the expression checks it for syntax errors and converts it to a
form Maya can execute when you return to the start time or play the
animation. Clicking this button also executes the expression for the
current frame.
The expression sets Ball’s scaleY attribute to the value of time + 1.
Ball.scaleY is the full name of the attribute. A period separates the name
of the object and attribute. Note that you must spell the object and
attribute with uppercase and lowercase letters as they appear in the
Expression Editor’s Objects and Attributes lists.
The word time is a commonly used predefined variable that updates as
an animation plays. It contains the elapsed number of seconds from the
first frame to the current frame. The value increases with the increasing
frame number.
At the default animation playback rate of 24 frames per second, time has
these values (rounded to four decimal places):

Frame Time (seconds)

0 0

1 0.0417

2 0.0833


Frame Time (seconds)

3 0.125

24 1.0

240 10.0

You can find the time elapsed in the animation at any frame by
calculating this formula with a desktop calculator:
For example, if the frame rate is 24 frames/second and the animation is
at frame 1, the elapsed time is 1 divided by 24, or 0.0417. At frame 6, the
elapsed time is 6 divided by 24, which equals 0.25. Note that if your frame
rate was 30 frames/second the calculated values would be different.

7 Go to the start time and play the animation. Ball’s scaleY attribute
increases as the time increases:
Frame Time (seconds) Ball.scaleY (time + 1)

0 0 1

1 0.0417 1.0417

2 0.0833 1.0833

3 0.125 1.125

24 1.0 2.0

240 10.0 11.0

Maya executes the expression each frame. This causes the object size to
scale along its Y-axis, stretching its height during playback.

Creating expressions to control a single attribute | 629

To see the value of Ball’s scaleY attribute at any particular frame, select
Ball, display the Channel Box, and stop the animation at the desired
frame. The Channel Box updates its values after you stop the animation.
The scaling is smooth because the geometry stretches in synch with the
small time increments of the animation playback.

8 Close the Expression Editor window.

Editing expressions
To edit an expression after you’ve created it and closed the window, you must
know how to find the expression in the Expression Editor. The next steps
show how to find and edit the expression. Specifically, you’ll change the
expression to alter how quickly the scaleY value changes.

To edit the expression

1 To display the Expression Editor again, select Window > Animation Editors
> Expression Editor.

2 To find the expression, make sure the Ball is selected. In the Attributes
list of the Expression Editor, select scaleY, the attribute controlled by the
expression.
If you don’t see the scaleY attribute, scroll through the Attributes list as
necessary. You can also use the Select Filter menu option to customize
how you search for your expressions within the Expression Editor.
The expression you created previously appears in the expression text
field:
Ball.scaleY = time + 1;

3 Change the expression to this:
Ball.scaleY = time/5 + 1;
By dividing time by 5, you’ll make the Y scaling increase one-fifth as fast
as with the previous version of the expression.
Note that you can use the keyboard commands Ctrl-c (Windows and
Linux) or Control-c (Mac OS X), Ctrl-x or Control-x, and Ctrl-v or
Control-v to copy, cut, and paste text in the Expression Editor and
elsewhere in Maya.

4 Click Edit to update the modified expression.


Clicking the Edit button does the same action as clicking the Create
button. The Create button exists only for new expressions. The Edit button
replaces the Create button when you display an existing expression.

5 Play the animation to see the results of the new expression.
The sphere scales at a slower rate than before.

6 Stop the animation and go to the start time.

7 At this point and in subsequent steps, save the scene if you think you’ll
want to examine it at a later date.

Using expressions to control multiple attributes
You can change the expression to control two or more attributes of Ball as in
this example:
Ball.scaleX = time/2 +1;
Ball.scaleY = time/3 +1;
Ball.scaleZ = time/5 +1;

Maya scales the Ball at different rates for the X, Y, and Z dimensions.

Linking multiple attributes on the same object
You can change the expression to link the value of one attribute to another
as in this example:
Ball.scaleX = time + 1;
Ball.scaleY = Ball.scaleX;
Ball.scaleZ = Ball.scaleX;

The second statement sets Ball.scaleY to the value of Ball.scaleX. Because
you’ve set Ball.scaleX to the value of time + 1, Ball.scaleY also has the value
of time + 1. You’re linking one attribute’s value to another. The third statement
also sets Ball.scaleZ to the value of the attribute Ball.scaleX.
The advantage of this expression is that if you assign a different value to
Ball.scaleX in the first statement, the second and third statements automatically
receive the new value.

Using expressions to control multiple attributes | 631

Controlling attributes in two objects
You can add an object to the scene and use the expression to control any of
its attributes also. For example, suppose you added a default NURBS or
polygonal cylinder named Drum to the scene. You could control the attributes
of Ball and Drum with the same expression as in this example:
Ball.scaleY = time/2 + 1;
Drum.scaleX = time + 1;
Drum.scaleY = time + 1;

You can link attributes in different objects—so a change in one attribute alters
the behavior of the other. For example, you could cause Drum’s scaleY value
to always equal two times Ball’s scaleY value as in this example:
Drum.scaleY = Ball.scaleY * 2;

If you decide to control attributes in two (or more) objects, you can select
either object to write the expression. In fact, any object or node in a scene
can be selected when you write an expression to control an object other than
a particle object.
Alternatively, you can write two (or more) expressions, for instance, one that
controls Ball.scaleY and one that controls Drum.scaleX and Drum.scaleY.
The advantage of creating separate expressions is that you’ll have two
expression names, each presumably named after the object and attribute you’re
controlling. Having two expression names makes it easier to find the expression
that controls the desired attribute.
The advantage of using a single expression to control the attributes is that all
statements are in a single expression. You don’t need to edit two expressions.

Beyond the lesson

■ Create and edit simple expressions using the Expression Editor.

■ Use variables, for example time, to control the specific attributes within
expressions.
When you write expressions, it is common to assign the built-in time
variable to an attribute so the attribute value predictably increases as the
animation plays. It’s also useful to link an attribute’s value to the value of


another attribute, such as setting the ball’s scale Y and Z attributes to equal
the scale X value.

■ Control multiple attributes with a single expression.
Your expressions can control multiple attributes of the same object or of
multiple objects. Alternatively, you can write a single expression for each
attribute or object.
For more information on the various mathematical operators that are
possible with expressions, refer to the Maya Help.

Behind the lesson
Although not shown in the lessons, you can decrease an attribute value during
playback by subtracting time from some number. Example:
Ball.scaleY = 3 - time;

This decreases the value of Ball’s scaleY attribute for the first three seconds of
playback.
When you use the predefined time variable, note the animation start frame
value. The lessons in this chapter use a start time of 0. In your work, you might
create an animation with a start time of 1. With Maya’s default frame rate of
24 frames per second, time is 0.0417 at frame 1.
Because of this small time offset from 0, the prior lesson would have required
more steps and instructions to work with frame 1 as the start time. For instance,
suppose you use following expression with the start time at 1.

If you go to the start time, the expression sets the initial value of Ball’s scaleY
attribute to time + 1, which equals 0.0417 + 1, or 1.0417. Because Ball’s scaleY
attribute was 1 when you created it, going to the start time sets scaleY to a
value 0.0417 larger than its initial value.
This discrepancy means the Ball scaleY is larger than its scaleX and scaleZ
attributes in the first frame of the animation. Although the difference is minor
in this example, other cases might be more significant.
To start your animation at frame 1 and get the same result as the example,
you can subtract 0.0417 from the attribute:
Ball.scaleY = (time - 0.0417) + 1;

When you go to the start time, the expression sets Ball’s scaleY value to (0.0417
- 0.0417) + 1. This equals 1, its original scaleY value.


Lesson 2: Conditional expressions

Introduction
Conditional statements set one attribute or variable for an expression based
on the condition of another attribute or variable. This means that when a
particular defined condition exists for one attribute then another attribute is
changed based on how the expression defines it to do so.

■ Use conditional statements to control an expression.

■ Refine the conditional statements using if and else statements.

Creating a conditional expression
In the following steps, you create a default sphere and write an expression to
increase its Scale Y attribute based on the animation playback time. In the
first two seconds of the animation time, Scale Y increases with the value of
the time. At two seconds and thereafter, Scale Y no longer increases.

To create an expression using conditional statements


2 Create a NURBS or polygonal sphere at the origin with an X scale, Y scale,
and Z scale of 1.

3 Name the sphere Balloon.

4 Go to the start time.

5 With Balloon selected, choose Window > Animation Editors > Expression
Editor.

6 Enter this expression:
if (time < 2)
Balloon.scaleY = time;
This expression is an if statement. The if keyword causes the expression
to make a decision based on a comparison of two or more items. In this
case, the expression compares the value of time to the value 2.


The expression checks whether the value of time is less than two seconds.
If so, it does the assignment Balloon.scaleY = time. If time is not less than
two seconds, the assignment doesn’t occur.

NOTE When you compare the value of time to a number in an expression,
Maya interprets time as seconds rather than milliseconds, minutes, or any
other unit of time. In the example, Maya interprets 2 as two seconds.

Notice how the assignment Balloon.scaleY = time has been formatted so it
appears indented under if (time < 2). Maya ignores all indentation, extra
spaces, and blank lines between statements. We used the indentation to
make the expression easier to read. You could have also written the
expression as follows:
if (time < 2) Balloon.scaleY = time;
This isn’t as easy to read. Consistent, organized spacing is a good habit
to develop. This lesson attempts to show examples of good spacing style
whenever possible.

7 Click Create to compile the expression.
The ball flattens.

The expression executes when you click the Create button. Because the
animation is at frame 0, animation time is 0. Because time is less than 2,
Maya sets Balloon.scaleY equal to the value of time, which equals 0.
A scaleY value of 0 flattens the object in the Y dimension.

8 Playback the animation.
The flattened Balloon’s scale increases along its Y-axis. It inflates as the
animation plays.

At 2 seconds and thereafter, Balloon no longer inflates.

Creating a conditional expression | 635

When time equals 2 or more, the if condition is no longer true. The
statement that follows it, Balloon.scaleY = time, no longer executes. The
value of the scaleY attribute stays at the last value it had before time
became 2, specifically, 1.9583.
Recall that this example uses a frame rate of 24 frames per second. The
time and Balloon.scaleY have these values at various frames:

Frame Time (seconds) Balloon.scaleY (time)

0 0 0

1 0.0417 0.0417

2 0.0833 0.0833

3 0.125 0.125

24 1.0 1.0

47 1.96 1.9583

48 2.0 1.9583

49 2.04 1.9583

The if statement’s condition, (time < 2), is a comparison. The condition
must be surrounded by parentheses to isolate it from assignment that
follows it.
The < in the condition is a relational operator. A relational operator tests
how one value relates to another. In the example, the < tested whether
time is less than 2.
Besides the < operator shown in this example, there are several other
relational operators such as >, >=, ==, and so on. See the Maya Help for
more details.

9 Stop the animation and go to the start time. Balloon flattens again because
the scaleY attribute becomes 0 when you go to the start time. Time is 0,
so scaleY is 0.


Other conditional statement options
You can make Balloon rise after it inflates by adding another if statement to
the expression.

To add an if statement to the expression

if (time < 2)
if (time >= 2)
Balloon.translateY = time;

2 Click Edit to compile the expression.

Balloon inflates for two seconds. After two seconds, Balloon stops inflating
and its position skips from a Y-axis position of 0 to 2. You’ll eliminate
the motion skip in a later step.
The new if statement increases the translateY position of Balloon after
the animation time rises above two seconds. The >= symbols mean greater
than or equal to. Whenever time is greater than or equal to 2, the
expression assigns Balloon’s translateY the value of time. The translateY
value therefore increases for the rest of your animation’s playback range.
Notice that a semicolon ends each statement for a particular condition.
Forgetting a semicolon after each statement causes a syntax error, and
the changes you’ve made to the expression won’t take effect.

NOTE Always examine the Script Editor for error messages after you edit an
expression and click the Create button. If you alter a previously successful
expression and a syntax error occurs, Maya executes the previous successful
expression when you play the animation. This might make you believe your
changes took effect. Error messages are preceded by the text // Error:.

4 Stop the animation and go to the start time. Balloon flattens but doesn’t
return to the origin. (If Balloon has risen out of view, adjust your camera
to see it.)
Balloon doesn’t return to the origin because the expression doesn’t assign
Balloon a starting point for the beginning of the animation.

Other conditional statement options | 637

5 To make Balloon return to the origin, change the expression to this:
if (time < 2)
Balloon.translateY = 0;
if (time < 2)
if (time >= 2)
Balloon.translateY = time;
The new first statement sets Balloon.translateY to 0 whenever time is less
than 2.
Note that you can put the three statements in any order in this example.
When Maya plays each frame, it executes each statement in the expression
in the order listed. In this example, the statements work independently,
so their order doesn’t matter.
We put the statements in the order of time execution because it’s easier
to see the logic of the expression. If you ever need to change the
expression, you’ll be able to grasp the expression’s actions more quickly.

6 Click Edit.


The flattened Balloon returns to its correct position at the origin.

Balloon inflates for two seconds, then rises. As it rises, it jumps slightly
higher at approximately frame 48.


Fixing a problem in an expression
As mentioned before, Balloon skips from Y-axis position 0 to 2 after two
seconds of animation play. You can eliminate the skipping and make Balloon
rise smoothly from the origin.

To fix the skipping in the animation


2 Change the expression as follows. (Changes are displayed in bold print.)
if (time < 2)
if (time < 2)
if (time >= 2)
Balloon.translateY = time - 2;

3 Click Edit.
Playback the animation. Balloon inflates for 2 seconds, then rises slowly
and smoothly with time, from its position at the origin.

When time is greater than or equal to 2, the translateY position of Balloon
becomes 2 minus 2, which is 0. As time increases beyond 2 seconds, the
translateY position increases in the same increments that time increases.


Using else statements
The expression achieved the desired result, but with unnecessary complexity.
You can use an if-else statement to make the statement more compact and
easier to read.

if (time < 2)

Fixing a problem in an expression | 639

if (time < 2)
else

2 Click Edit.

The animation plays back exactly as before.
This additional variation on the if conditional statement includes the
else statement. It is used as an option when the if statement condition is
not true. The else keyword sets Balloon.translateY to time - 2 when (time
< 2) is false. In English terms, the combination of the if and else
statements means: If time is less than two seconds, set Balloon.scaleY to
the value of time. Otherwise (when time is greater than or equal to two
seconds), set Balloon.translateY to time minus two.
At any instant in the animation’s playback, either Balloon.scaleY = time
executes or Balloon.translateY = time - 2 executes. Under no circumstances
can they both execute. The else statement executes only when the if
condition that precedes it is false.
The first if statement executes whenever time equals 0. It is unrelated to
the if-else statements.
Using else statements instead of multiple if statements makes an
expression simpler to read. If you use an if-else construction instead of a
lengthy list of if statements, you’ll also improve the execution speed of
the expression. This improves your animation’s playback and rendering
speed.
Either expression is valid. If using the if-else construction seems confusing,
stick with multiple if statements.
You can accomplish most expression animation tasks with several if
statements strung after one another.


Simplifying expressions
You can simplify the expression to make it easier to read.



if (time < 2)
{
}
else
We removed the second if statement:
if (time < 2)
In its place, we enclosed the remaining statements with braces { and }.
Maya evaluates both the statements between the braces if the condition
(time < 2) is true. Setting Ball.translateY to 0 here instead of in a separate
if statement makes the expression easier to read and comprehend.
Reducing the statement in this way also makes it more efficient for Maya
to process and easier to troubleshoot if you encounter a problem.
Note that you can put multiple statements between braces for an else
statement, just as you do for an if statement.

2 Click Edit.

The animation plays exactly as before with the new expression.


Editing expressions to refine an animation
You can further refine the animation by expanding Balloon more slowly.

To edit the expression to scale the balloon more slowly

if (time < 2)
{
Balloon.scaleY = time * 0.6;
}
else
(The asterisk (*) multiplies time by 0.6.)

2 Click Edit.

Editing expressions to refine an animation | 641


The scaleY attribute increases at 60% of the value of time, so Balloon
expands slower during playback. (The number 0.6 equals 60%.) By the
time Balloon starts to rise, it has expanded to the size of a typical balloon.
To know whether to multiply time by 0.6 or some other number, you
need to experiment.
For example, you might multiply by various percentages such as 0.2, 0.5,
0.75, and finally 0.6. The 0.6 creates a life-like balloon shape at two
seconds.


You can further refine Balloon’s appearance by eliminating the flattened
Balloon that appears at the origin when you go to the start time. You can also
scale Balloon at different rates along each of its three axes.

To edit the expression to change the balloon’s initial scale

if (time < 2)
{
Balloon.scaleY = time * 0.6;
Balloon.scaleX = time * 0.5;
Balloon.scaleZ = time * 0.5;
}
else

2 Click Edit.
At frame 0, Balloon disappears from view because its scale attributes are
0.
The scaleX, scaleY, and scaleZ attributes are 0 at frame 0 because time is
0. Any number multiplied by 0 is 0.



As time increases, the value of Balloon’s scale attributes increase.

Because the expression sets scaleX and scaleZ to 50% of the value of time,
these dimensions scale slower than scaleY, which is set to 60% of the
value of time. Balloon scales faster in height than in width or depth. This
is true for many real balloons.


5 Save the scene if you plan to examine it later.

Beyond the lesson

■ Use conditional statements to control an expression.
You can accomplish many expression tasks with several if statements strung
after one another. However, using else statements instead of multiple if
statements makes an expression simpler to read.
If statements and else statements are two of the most common programming
features available in expressions. If you’re familiar with programming, you
can write expressions with an extensive syntax similar to the C language.

For further information and related techniques, refer to the Maya Help.

Lesson 3: Controlling particle attributes

Introduction
You can use an expression to control attributes of particle objects. Particle
expressions can be more complex than other types of expressions. For example,


you can write an expression to control all particles in an object the same way,
or you can control each particle differently.

■ create a particle object

■ create a creation expression to set the initial color of the particles

■ create a runtime expression to control the color during playback

■ use a random function to randomize how the color changes

■ control the timing of an expression

Creating particle objects
In the following steps, you’ll create a particle object made of 100 randomly
positioned particles displayed as tiny spheres. You’ll also dynamically add an
attribute to the particles. To color particles with an expression, Maya requires
you to dynamically add the appropriate attribute.

To create a particle object


2 From the Dynamics menu set, select Particles > Particle Tool > .

3 In the Tool Settings window, click Reset Tool, and set the following
options:
■ Particle Name: Bubbles

■ Number of Particles: 100

■ Maximum Radius: 5

■ Click in the scene view (roughly in the center) to create the
100-particle object.

4 From the Toolbox, select the Selection Tool so that particles become
selected.

5 With Bubbles selected, display the Attribute Editor.


6 In the Attribute Editor, select the BubblesShape tab, and then open the
Render Attributes section and set the following:
■ Particle Render Type: Spheres

■ Add Attributes For: Click the Current Render Type button.

■ Radius: 0.5

7 In the Add Dynamic Attributes section of the Attribute Editor, click the
Color button. A window appears that prompts you to choose whether to
add the attribute per object, per particle, or connected to a shader.

8 Turn on Add Per Particle Attribute, then click the Add Attribute button.
This adds an rgbPP attribute to the particle shape node for Bubbles.
Because you’re adding this attribute as a per particle attribute, you can
give each particle a different color.

Using creation expressions to set a constant color
To set an attribute that doesn’t change during the animation (the particle
color), you’ll use a creation expression. A creation expression executes when
you go to the start time. It doesn’t execute while the animation plays. (For
emitted particles, a creation expression executes for a particular particle when
it is emitted.)

To create a creation expression

1 In the Per Particle (Array) Attributes section of the Attribute Editor,
right-click the rgbPP box and select Creation Expression from the pop-up
menu. Note that the shape node of Bubbles (BubblesShape) is displayed
in the Expression Editor.
When you use an expression to control particle attributes, make sure the
selected object in the Expression Editor is a particle shape node, not the

Using creation expressions to set a constant color | 645

transform node of the particle object. If a particle object’s transform node
is selected, move the mouse pointer to the scene view and press the down
arrow key to select the particle shape node.

2 Enter this expression and then click the Create button:
BubblesShape.rgbPP = <<1,0,0>>;
When you click the Create button in the Expression Editor, Maya checks
the syntax of the expression. Assuming you made no typing errors, the
expression executes once for each of the 100 particles.
The expression colors all particles in the object red. The double angle
brackets << and >> enclose a vector that sets the red, green, and blue
components of the rgbPP attribute to 1, 0, and 0. In the RGB color scheme,
this gives the object a red color.
If the particles are uncolored, check that you’ve turned on Shading >
Smooth Shade All. This shading mode is necessary for particles to show
the color assigned in an expression.

3 Play the animation. The particles remain red.

Using runtime expressions
There is one other type of expression you can create for a particle object (shape
node)—a runtime expression. By default, a runtime expression executes each
frame during playback. A runtime expression does not execute when you go
to the start time (or at the time in which a particle is emitted).
You’ll often create both types of expressions for a particle object—a creation
expression that initializes an attribute value in the first frame, and a runtime
expression that controls the attribute value in subsequent frames.
The following steps show how to create a runtime expression to change particle
color during playback.


To create a runtime expression

1 In the Per Particle (Array) Attributes section of the Attribute Editor,
right-click the rgbPP box and select Runtime Before Dynamics Expression
from the pop-up menu.

2 Enter this runtime expression:
BubblesShape.rgbPP = sphrand(1);

3 Click the Create button to compile the expression.

The particles flicker in random colors as the animation plays back. The
runtime expression controls the rgbPP attribute during playback. Because
rgbPP is a per particle attribute, the runtime expression executes for each
particle in the object for each frame. For each particle, the expression
assigns the rgbPP attribute the output from the execution of the sphrand
function with an argument of 1. The sphrand function is one of Maya’s
many built-in mathematical functions that are useful in expressions.
The sphrand function with an argument of 1 assigns each particle’s rgbPP
color a random vector. The vector represents a random point in a spherical
region of radius 1. The left, middle, and right rgbPP color components
get a value no less than -1 and no greater than 1. (R, G, and B values less
than 0 are treated as 0—a black color).

The sphrand function returns a different random vector each execution,
so each particle receives a different random rgbPP value, and therefore,
a different color. The color changes each frame.

5 Rewind and play the animation again.
The particles become red when you go to the start time, and random
colors during playback.

Using runtime expressions | 647

NOTE You can use only one creation and one runtime expression per particle
object (shape node) in your scene. To control multiple attributes of a single
particle object, you must do so within one creation expression and one
runtime expression. You can’t create a separate expression for each attribute
as you can for other types of objects. You therefore don’t need to select an
attribute from the Expression Editor’s Attributes list.

Modifying runtime expressions
You might have trouble seeing the color of a particle in any instant because
the color changes so quickly. You can slow the change of colors to create a
flashing Christmas light effect. The following steps make the particles change
colors every second of animation.

To adjust the timing of the change of color

1 Change the runtime expression to this:
if ((frame % 24) == 0)
This expression uses the modulus operator (%) to control when the rgbPP
attribute of the particles receives a random color. The modulus operator
returns the remainder after division. For example, 24 divided by 24 returns
0, but 25 divided by 24 returns 1. (Dividing 25 by 24 equals 1 with a
remainder of 1.)
If the value of frame divided by 24 is equal to any number with a
remainder of 0, the assignment to BubblesShape.rgbPP occurs. In other
words, the assignment occurs when frame equals 24, 48, 72, and so on.
At an animation rate of 24 frames/second, the assignment happens once
each second.
The == symbols mean is equal to. In conditional statements, be careful
to type == rather than =. The = symbol means assign the value to.

2 Rewind and play the animation again.
When you go to the start time, the particles turn red because the creation
expression executes. When the animation plays, the particles receive a
random color once each second.


Note that you can change the beginning red color to random colors by
changing the creation expression to this:
This is the same expression as the runtime expression.

3 Save the scene if you plan to examine it later. This concludes the lesson.

Beyond the lesson

■ Control particles using creation and runtime expressions.

■ Apply a random function to your expression.

For a particle object, you typically create two expressions—a creation expression
that initializes an attribute value in the first frame, and a runtime expression
that controls the attribute value in subsequent frames. (Creation and runtime
expressions exist only for particle objects, not for other types of objects.)
This lesson described how to color stationary particles as a simple way to
describe creation and runtime expressions. However, it’s more typical to use
particle expressions to:

■ Create sophisticated particle motion and life span; for example, the
movement and fading of exploding fireworks.

■ Create complex colors for emitted particles, for example, rocket exhaust
flames.

■ Create complex colors and movement of particles following collision with
geometry, for example, sparks resulting from fired bullets.
Creating such effects requires experience and experimentation. Expression
writing can be as complex as computer programming. A detailed


understanding of expression execution and syntax is essential. You also
need to become familiar with the built-in mathematical functions such as
the sphrand function introduced in this lesson.
For further information and related techniques, refer to the Maya Help.


Scripting in Maya
13
Introduction
Scripting languages in Maya allow you to:

■ Automate repetitive or frequently performed tasks.
You can write scripts to execute operations that would normally be selected
from the user interface or performed using tools and user manipulation.

■ Change Maya’s user interface.
You can create windows and controls that affect objects in the scene.

■ Establish development standards.
You can enforce naming conventions, workflows and model scales.

■ Create new tools and functions.
You can extend Maya’s functionality in ways that help you do your work.

In this chapter, you learn some common scripting techniques and features that
highlight the capabilities of scripting in Maya:

■ Some basic concepts on page 652

■ Lesson 1 Commands in MEL: Introduction on page 656

■ Lesson 2 Saving scripts to the Shelf: Introduction on page 666

■ Lesson 3 Using Variables with MEL: Introduction on page 674

■ Lesson 4 Procedures and user interface creation: Introduction on page 683

■ Lesson 5 Using Python in Maya: Introduction on page 703

651

Some basic concepts
The following section introduces some basic concepts that help you understand
what’s going on when you use scripting in Maya.

The command architecture
Maya has a command-based architecture for handling all of its operations.
The commands for all of Maya’s functionality are accessed through scripting
language commands tied to the Maya user interface—menus, tools, dialog
boxes; in fact, just about anything you interact with in Maya. As well, you
can explicitly enter Maya commands in the scripting languages that Maya
supports.
Every Maya command has multiple arguments that set the way in which the
command executes. Arguments and their implicit or explicit values are required
for a command to execute.
To set argument values, the scripting languages in Maya use flags. Flags tell
the scripting language which argument of the Maya command is set with
what value. The value that is assigned to the argument follows the flag.
Flags have short and long names in MEL and Python. Commands execute
identically whether or not you use the short or long name of the flag. Long
names are often descriptive and useful for new users; short names abbreviate
flag names for power users.

Scripting languages in Maya
Maya supports two scripting languages:

■ MEL (Maya Embedded Language) is a proprietary scripting language
modeled after Unix shell script.

■ Python is a recent addition to Maya that provides the same access to Maya’s
commands as MEL. Python is a widely-used modern programming
language.

Maya’s user interface is built using scripts that execute (call) Maya commands.
As Python is a recent addition to Maya, the majority of the scripts accessed
through the user interface are written in MEL.
For example, when you click the sphere icon on the Shelf or select an item
from a menu, Maya calls MEL commands to create a sphere or execute the
command associated with the menu item.

652 | Chapter 13 Scripting in Maya

Entering commands in Maya
There are several ways to explicitly enter scripting commands in Maya.

■ To enter single line MEL and Python commands, use the Command Line.
To show the Command Line if it is hidden, select Display > UI Elements.
The Command Line is located near the bottom edge of the Maya interface.

■ To enter multi-line MEL and Python commands, use the Script Editor. The
Script Editor displays a history of executed commands, as well as the results
and outputs of commands. To open the Script Editor, select Window >
General Editors > Script Editor.

■ As well, the Expression Editor uses a subset of MEL commands to create
animation in the scene. MEL commands in the Expression Editor are
evaluated for every frame in the animation. The Expression Editor does
not support Python commands. To open the Expression Editor, select
Window > Animation Editors > Expression Editor.

You can also load external MEL and Python files and run them using the Script
Editor. For more information, see Loading a script file on page 691.

What MEL looks like
Invoking commands in MEL has the basic structure of a command followed
by a combination of flags and arguments. Flags are prefaced by the hyphen
character in MEL.

All MEL commands are case-sensitive; SPHERE is not the same as sphere (and
returns an error message).
If no flags are provided, the command executes with default arguments. The
command fails if it requires arguments that it did not get.

Some basic concepts | 653

NOTE MEL also has an alternate syntax, which implements commands and flags
in a method similar to the C programming language. For more information, see
MEL for programmers in the MEL and Expressions guide.

Getting help on MEL
You can get help with MEL in three ways:

■ To access help on a particular MEL command, open the MEL Command
Reference by selecting Help > MEL Command Reference.

■ Help can also be accessed from within the Script Editor by using the Maya
Command help. For example, entering help sphere shows a list of flags
that can be used with the sphere command.

■ More information on all aspects of using MEL commands is also available
in the MEL and Expressions guide, part of the Maya Help. Open the Maya
Help and select Using Maya > General > MEL and Expressions.

Basics of Python
Python and MEL are scripting languages with equal prominence and
capabilities in Maya. Python can access all the Maya commands that MEL
does.
Python accesses Maya commands through the Python module maya.cmds.
Modules in Python are sets of commands that add functionality to Python,
and must be imported before using any of the commands from a module.
Flags in Python are implemented through Python’s named arguments. You
specify which argument to modify and use the assignment operator (=) to
assign a new value to the argument.
In order to run this or any example command, you must have imported the
Python module first. Enter import maya.cmds before starting to enter Python
commands.


All Python commands are case-sensitive; maya.cmds.SPHERE is not the same
as maya.cmds.sphere (and returns an error message).

Getting help on Python
You can get help with Python in several different ways:

■ To access help on a particular Maya (Python) command, open the Python
Command Reference by selecting Help > Python Command Reference.

■ You can also access help on Maya Python commands from within the
Script Editor by using the Maya Command help(). For example: typing
maya.cmds.help("sphere") outputs a list of possible flags that can be used
with the sphere command.

■ Help for native Python commands is accessed from within the Script Editor
by typing help("command") where command is the Python command you
want to access help for.

■ More information on using Python commands is also available in the
Python guide, part of the Maya Help. Open the Maya Help and select Using
Maya > General > Python.

■ There are existing reference materials and documentation for Python on
the web, as well as many downloadable modules to add extra functionality
to Python.
■ Getting Started tutorials: http://www.python.org/about/gettingstarted

■ Python documentation: http://docs.python.org

■ Python modules: http://cheeseshop.python.org





3 Make sure the Construction History icon (below the menu bar) is on. (If
it is turned off, it has a large X across it.)

4 Ensure that the interactive creation option for primitives is turned off by
selecting Create > Polygon Primitives > Interactive Creation. The option
menu.

5 Ensure that the interactive creation option for surfaces is turned off by
selecting Create > NURBS Primitives > Interactive Creation. The option
menu.

Lesson 1: Commands in MEL

Introduction

This lesson provides a brief introduction to using MEL scripting commands.

■ Use the Script Editor to view MEL command history


■ Enter MEL commands in the Script Editor

■ Create geometry with MEL commands

■ Modify attributes of objects with MEL commands

■ Interpret Script Editor history

Entering MEL commands
You can enter MEL commands in the Command Line or the Script Editor. The
Command Line can only accept single line MEL commands, while the Script
Editor provides a method to input multiple MEL commands and view the
results.

To use the Command Line to input MEL commands

1 Select Display > UI Elements.
Ensure that Command Line is checked.

2 Click in the Command Line text field to position the text cursor in the
field
By default the Command Line is in MEL script entry mode. You can
change the mode by clicking on the text in the lower left hand corner.
For this lesson, ensure the Command Line is in MEL script entry mode.

3 Type the following in the Command Line.
sphere;
All MEL and Python entries are case sensitive.

4 To execute the command, press Enter on the numeric part of your
keyboard, or press Ctrl+Enter.

5 A NURBS sphere is created at the origin.

Entering MEL commands | 657

In the Script Editor, the Enter (Windows and Linux) or Return (Mac OS X)
key above the Shift key does not execute a command. It starts a new line so
you can type several commands before executing them.

Observing script history
The Script Editor displays a running history of executed commands and the
results of commands that Maya executes. You can copy most commands from
the history section of the Script Editor and paste them in the input section to
execute them.

To set up the Script Editor

➤ Select Window > General Editors > Script Editor.
The Script Editor window opens.

The lower half of the Script Editor is the input section where you enter scripting
commands.
By default, Maya displays basic feedback from executed commands. However,
when Echo All Commands is on, Maya shows all the history from a command,
including when a script calls another script or modifies elements of the user
interface. While learning MEL, the extra lines of output produced when Echo
All Commands is on can be confusing because there is so much output. As
you become more experienced in MEL, the extra lines of history can be useful
for debugging a MEL script.


➤ In the Script Editor window, ensure that there is not a check mark beside
History > Echo All Commands.

To observe script history

1 In the Script Editor, click the Clear History button.

You can more easily isolate the command history created by the
commands you perform when there is no other history in the Script
Editor.

2 From the Shelf, select the Surfaces tab in order to view the tools located
on that shelf.

3 Click the NURBS Sphere button on the Surfaces Shelf.

Command history is displayed in the history section of the Script Editor:
CreateNURBSSphere;
sphere -p 0 0 0 -ax 0 1 0 -ssw 0 -esw 360 -r 1 -d 3 -ut 0 -tol
0.01 -s 8 -nsp 4 -ch 1;objectMoveCommand;
Several MEL commands are executed when the Shelf button is pressed.
The following happens when the button is pressed:
■ The NURBS Sphere button on the surfaces Shelf executes a script called
CreateNURBSSphere;.

■ The CreateNURBSSphere script calls the sphere MEL command using
flags to set the arguments of the command to the values currently
specified in the NURBS Sphere menu option window. The sphere MEL
command is using flags in short form.

■ The objectMoveCommand is executed every time a primitive is created.
It moves the created object to the origin.

Commands in MEL must be separated with semicolons. Additional spaces
and additional carriage returns do not affect the execution of the scripts.
Blank spaces and returns make scripts easier to read. Flags cannot be
separated from the hyphen character by extra spaces or returns.

Observing script history | 659

TIP For more details on these flags, see sphere in the MEL Command Reference.
The MEL Command Reference gives a complete listing of the functionality of all
MEL commands and flags.

NOTE You can copy commands from the Script Editor history section and paste
them in the input section to execute them.

➤ Delete the NURBS sphere by pressing the delete key on your keyboard.

To type a MEL command in the Script Editor

1 Select a MEL tab in the Script Editor.

Script Editor tabs allow you to quickly switch between MEL and Python
script entry modes. You can create additional Script Editor tabs to serve
as a temporary holding area for scripts.

2 Type the following command in the input section of the Script Editor.
polyCube;

TIP When asked to type a command, you can copy it from these tutorials
and paste it into the Script Editor input section.

3 Execute the command by pressing Enter on the numeric part of your
keyboard.
You must always type Enter on the numeric keypad or Ctrl+Enter (the
regular Enter on your keyboard) to execute commands. Typing regular
Enter just creates a new line in the Script Editor input.

A polygonal cube is created at the origin.


The command is removed from the input section of the Script Editor
after execution. The command and the result of the command is output
to the history section of the Script Editor:
polyCube;
// Result: pCube1 polyCube1 //

NOTE In future lessons, when a series of MEL or Python commands creates
output, only the output created by the commands will be referred to as
output to the Script Editor.

Comments in MEL begin with // and anything which follows these characters
on a line is ignored by MEL. The same convention is used for displaying results
of commands and output in the Script Editor history section. Similarly, results,
comments and messages output by Python are prefaced with the Python
commenting character ( # ).

NOTE In the rest of this lesson and the remaining MEL lessons, when asked to
type a command, execute the command after typing it with the Enter on the
numeric keypad on your keyboard. You can also execute commands with Ctrl+Enter
(Windows) or Ctrl+Return (Mac OS X).

TIP If you do not want the command to be removed from the input section of
the Script Editor after execution, highlight the command before execution by
selecting it with the mouse.

Modifying object attributes
When you perform an action on an object in the Maya user interface, you are
using Maya commands to change the attributes of selected objects. You can
use the same Maya commands explicitly to edit the attributes of objects in
the scene.

To use the move command

1 With the polygonal cube selected, type the following in the Script Editor:
move 3 2 1;

Modifying object attributes | 661

The polygonal cube is moved to the XYZ co-ordinates 3,2,1.
The move command has set the translate attributes to the specified
arguments of the command. These arguments are called command
arguments as they are not used with flags.
When a command is typed into the Script Editor, it acts on the current
selection, unless an object name is provided as an argument to the
command.

2 With the polygonal cube selected, type the following in the Script Editor:
move -1 -2 -3 -relative;

The polygonal cube moved relative to its current position by -1,-2,-3 in
XYZ.
The move command is used with the relative flag to change the method
in which the command executes. The relative flag does not have any
arguments; the values -1,-2,-3 are command arguments used with the
move command. The values are prefaced by a negative sign, but are not
recognized as flags as they do not contain any of the flag keywords.

This is equivalent to using the Move tool in the Maya interface.

To specify attributes of geometry with flags

➤ Create a polygonal sphere with a radius of two and four subdivisions in
X by typing the following in the Script Editor:
polySphere -radius 2 -subdivisionsX 4;


The radius flag allows you to specify a value for the radius of the sphere.
The value 2 is associated with the radius flag, and is not a command
argument.

This is equivalent to specifying values within the Polygon Sphere Options
dialog in the Maya interface.

NOTE Flags have short and long names. Commands execute the same way whether
or not you use long or short flag names. The above command could have been
typed as:
polySphere -r 2 -sX 4;

Some flags have the same short names, but they are used in different contexts so
it does not affect the execution of the script. For example: -r is the short name
of the -relative flag, used with the move command, -r is also the short name
of the -radius flag, used with the sphere command.

➤ The sphere has a default name of pSphere#. Rename the selected sphere
by typing the following in the Script Editor:
rename test_Sphere;

The rename command changes the name of the currently selected object.
If multiple objects are selected, the rename command renames the selected
objects to the specified name with a numerical index appended, as every
object must have a unique name.

Modifying object attributes | 663

This is equivalent to renaming an object with the Attribute Editor or the
Channel Box in the Maya interface.

Editing Objects
Some MEL commands can take an edit flag that allows you to make changes
to the attributes of an object. The edit flag is used in conjunction with other
flags specifying which attributes to change.

To edit objects with Maya commands

1 Select the polygonal cube

2 Edit the height of the cube by typing the following in the Script Editor:
polyCube -edit -height 3;

This is equivalent to changing attribute values within the Attribute Editor
in the Maya interface.

3 Edit the radius of the sphere named test_Sphere by typing the following
in the Script Editor:
polySphere -edit -radius 1 test_Sphere;


Commands can operate on objects other than what is currently selected
by specifying an object name as an argument. The name must be the last
argument in the command.

4 Select the cube and the sphere simultaneously by holding down shift
and clicking the sphere.

5 Delete the objects by typing the following in the Script Editor
delete;

NOTE A list of all flags available for a specific command can be displayed in
the Script Editor by typing help command;. For example, help sphere;
provides a list of flags for the sphere command.
For a full list of MEL or Python commands and flags, select one of the following
from the menu bar:

■ Help > MEL Command Reference

■ Help > Python Command Reference

Beyond the lesson
In this lesson, you learned how basic MEL scripting commands work in Maya.
You can:

■ Write basic MEL creation commands to bypass the Maya user interface.

■ Use flags at object creation time to specify the attributes for the objects.

■ Edit the attributes of objects using a command in conjuction with the edit
flag.

■ Observe the history created in the Script Editor and then copy and paste
it into the Script Editor to create your own scripts.


presented in this lesson so you are familiar with the concepts and skills. Some
suggested tasks you can try on your own include:

■ Practice using creation commands through the user interface and observing
the resulting Script Editor history.

■ Look through the MEL Command Reference to see more common
commands.

■ Practice copying and pasting commands from the Script Editor history
section to the Script Editor input section.

Lesson 2: Saving scripts to the Shelf

Introduction

In this lesson, you set up a three-point lighting system using MEL and save
those MEL commands as a button on the Shelf. This lets you quickly set up a
three-point lighting system in future scenes. You learn how to:

■ Enter MEL commands in place of selecting menu items

■ Create a shelf button to run a series of commands

Three-point lighting uses three different kinds of lights:

■ A main light to light the subject, cast shadows and produce highlights

■ A fill light to decrease the contrast caused by the main light

■ A rim light so the object stands out against the background


Three-point lighting is used extensively in film, photography and computer
graphics.

Setting up the scene
Here, you create some primitive objects to display lighting and shading .


2 Select Window > General Editors > Script Editor to open the Script Editor.

3 Create a ground plane by typing the following:
polyPlane -height 40 -width 40;
A plane appears at the origin.
The height and width flags specify the dimensions of the plane.

4 Create a NURBS torus by typing the following
torus -axis 0 1 0 -heightRatio 0.5;
A torus appears at the origin.
The axis of the torus specifies the orientation of the major axis of the
torus. The height ratio flag specifies the ratio of the major radius of the
torus to the height of the torus.

5 Reposition the torus so it is not intersecting the plane by typing the
following with the torus selected.
move 0 0.5 0;
The move command takes the argument (x, y, z), specifying how much
and in what direction to move the selected or named object. This above
command moves the torus 0.5 units up on the Y-axis.

6 Bring focus to the selected torus in the scene view by pressing f.

7 Render the scene by clicking the render button on the Status Line.
The Render View opens with a rendered image of the scene.

Setting up the scene | 667

8 Save the rendered image by clicking the Keep image button . This
lets you compare your rendered image with future rendered images.
A scroll bar at the bottom of the Render View lets you scroll through your
saved rendered images.

In the next steps, you type commands to create three-point lighting in the
scene and record them as script history for later use.

Recording the script history
In order to make a shelf button, you need to create Script Editor history to
copy to the shelf. In this procedure, you create a three-point lighting system
for the current geometry using MEL, copy the script history, and apply the
created three-point lighting to an existing scene.

To create the main lighting

1 Clear Script Editor history by clicking the Clear History button .

2 Create a directional light for the main lighting by typing the following:
directionalLight -intensity 1;


Certain commands require that you to refer to the light by name.

3 Rename the selected light to “main_light” by typing the following:
rename main_light;

4 Enable the main light to cast shadows by typing the following:
setAttr "main_lightShape.useDepthMapShadows" 1;
The setAttr command allows you to set attributes of a node. In the above
command, you are enabling depth map shadows on the main light.

5 Adjust the resolution of the shadow maps so that the shadows appear
sharper by typing the following:
setAttr "main_lightShape.dmapResolution" 2048;
In the above command, you are increasing the resolution of the depth
map shadows to 2048.

6 Position and aim the main light by typing the following:
move 0 3 0;
rotate -30 0 0;

Next, you create a rim light for the scene to help differentiate the torus from
its background.

To create the rim light

1 Create a point light by typing the following:
pointLight -intensity 2 -rgb 0.9 0.9 1;
The intensity flag has been used to set the brightness of the light. The
-rgb flag sets the color and takes three values: red, green and blue. The
red and green values are less than the blue value, so the light has a blue
tint.

2 Rename the light by typing the following:
rename back_light;

3 Reposition the light behind the torus by typing the following:
move -relative -1.5 1 -1.5;

Next, you create a fill light for the scene to soften the main lighting, fill the
shadowed part of the torus and decrease the overall contrast of the lighting
in the scene.

Recording the script history | 669

To create the fill lighting

1 Create a point light with an intensity of 0.5 by typing the following:
pointLight -intensity 0.5;

2 Rename the light by typing the following:
rename fill_light;

3 Reposition the light above the torus in a way so that the light rays from
the fill light are approximately 90 degrees to those of the main light by
typing the following:
move -relative 4 6 2;

Compare the rendered images
Rendering the image

1 Render the scene in the perspective view by selecting the render scene

button on the Status Line.

2 Save the rendered image by clicking the Keep Image button in the
Render View.

3 Compare the two images using the scroll bar at the bottom of the window.

The newly rendered image has a shadow. If there was no fill light, detail would
be lost in the shadowed area, as the shadow would be black. The rim highlights
emphasize the curvature of the torus and help to differentiate the torus from
the background.


When creating three-point lighting in a scene with multiple objects, typically
there is a main light that provides the main lighting for the scene, and each
object in the scene has a linked fill and rim light.
Your three-point lighting script only works for objects of medium scale located
at the origin, but once the lights are created, you can tweak them to better
suit your scene.

Saving the history as a button
You can save Script Editor history as a Shelf button.

To create the shelf button

1 Highlight all the text in the history window by clicking at the beginning
of the history in the upper section of the Script Editor and dragging the
selection to the end of the Script Editor history section.

2 Release the mouse button. The selected text should read:
directionalLight -intensity 1; rename main_light; setAttr
"main_lightShape.useDepthMapShadows" 1; setAttr "main_light
Shape.dmapResolution" 1024; move 0 3 0; rotate -30 0 0; point
Light -intensity 2 -rgb .9 .9 1; rename back_light; move -r -1.5
1 -1.5; pointLight -intensity .5; rename fill_light; move -r 4
6 2;

3 Middle-drag the selected text to the shelf.
A pop-up window asks you which type of shelf button you are saving.

Saving the history as a button | 671

4 Click the MEL button on the pop-up window.
A Shelf button is created that executes the scripting commands you
dragged to the shelf setting up three-point lighting for a scene.

To test the Shelf button

1 Open the scene named Mel_cone.mb.
your Maya project:
GettingStarted/MEL

2 Render the scene in the perspective view by selecting the render scene


3 Save the rendered image by clicking the Keep Image button in the
Render View.

4 Click your newly created MEL Shelf button.
Three point lighting is applied to the scene.

5 Render the scene again by selecting the render scene button on the
Status Line.

6 Compare the two images using the scroll bar at the bottom of the window.


To delete the Shelf button

➤ Middle-drag the Shelf button you want deleted to the trash can icon on
the far right of the Shelf.

NOTE The pointer icon changes to a icon when you are dragging a Shelf
button.

Beyond the Lesson
In this lesson, you learned how to copy history from the Script Editor history
section to create Shelf buttons so that you can quickly execute a series of
commands. You can:

■ Save multiple MEL script commands as a Shelf button.

■ Type basic MEL creation commands to bypass the Maya user interface.

■ Use additional MEL script commands and MEL script command flags.

Here are some other things you can do with Shelf buttons.

■ You can save the custom settings for a menu option box command as a
shelf button by setting the parameters in the option box, and then selecting
the item from the menu while holding down Shift+Ctrl (Windows) or
Shift+Control+Option (Mac OS X).

■ You can add custom images to a shelf button, change the name of a shelf
button, or change the commands associated with a shelf button by selecting
Window > Settings/Preferences > Shelf Editor. For more information, see


■ You can also create custom icons for your Shelf buttons in your favorite
image editing program. Icons must be 32X32 pixels and in bitmap format.

Lesson 3: Using Variables in MEL

Introduction

In this lesson, you learn how to store data in MEL variables. Variables are a
method of storing data in programming, including scripting languages. In
this lesson you use the saved value of a variable to create a pyramid of barrels
using MEL scripting commands. You also learn how to:

■ Use MEL to create copies of existing geometry

■ Use variables to store and recall data

■ Use the built in MEL math functions to modify the value of variables

■ Apply dynamics to scene objects using MEL

Setting up the scene
To import and position the barrel

1 Open the scene named Mel_barrel.mb


This file can be found in the GettingStartedMEL directory that you set
as your Maya project.

2 Open the Script Editor by selecting Window > General Editors > Script
Editor.

3 Select the barrel with the select tool.

4 In the Script Editor, type the following:
Type exactly as below:
rotate -r 0 0 90;
The barrel is rotated 90 degrees about the Z axis.

Storing scene information
You will store the value of the measurement annotation as a variable. A variable
is a name used for convenience to refer to a certain location in memory. This
location in memory can store data.
Variables have four main characteristics; name, type, value and scope. Name,
type and scope are defined at creation time. Defining the name and type of
a variable is referred to as declaring a variable. In MEL the name of the variable
is always prefixed by the “$” symbol, indicating to the scripting language that
the following characters name a variable.
The scope of the variable determines where the variable can be accessed from.
If a variable is declared within a block of code, it cannot be accessed from
outside the block of code.

Storing scene information | 675

Name and type cannot change after creation. The value of a variable can
change, but the value must be of the earlier defined type.

NOTE Variables in MEL should always have their type explicitly defined. If not
explicitly stated, the scripting language attempts to imply a data type for the
variable from the context of the first appearance of the variable. It is good practice
to explicitly declare variables as implicitly defining variables can lead to scripting
errors and slows down the execution of the script.

To store scene information as a variable

1 In the Script Editor, type the following and press enter:
float $diameter_barrel;
This command declares a variable of data type float, with the name
diameter_barrel. A floating point value is a number containing a decimal.

2 To assign a value to the variable, type the following.
$diameter_barrel = 4.2;
The diameter of the barrel is 4.2 units. This value from the scene is
assigned to the variable. A value is assigned to a variable with the
assignment operator (=).

Storing other types of data
MEL also supports other data types that are common to most other
programming languages.

To declare a string variable

➤ Type the following in the Script Editor
string $testString = "this is a test";
print $testString;
The following is output to the Script Editor:
this is a test
The string data type is used to store multiple characters. The print
command outputs the value of a variable to the Script Editor.

NOTE Variables can be declared and assigned a value in the same statement.


To declare an int variable

➤ Type the following in the Script Editor
int $testInt = 5;
print ($testInt/2);
2
The int data type is used to store integer values. Integers are positive and
negative whole numbers. In programming, when an integer is divided
by another integer, the result is an integer, which is why the output here
is not 2.5 (2.5 is not an integer).
The print command’s argument is enclosed in brackets. The print
command can only take one argument, so brackets are used to tell Maya
to evaluate the contents of the brackets before executing the command.
Brackets can also be nested in a method similar to mathematical
statements to determine the order of evaluation of statements.

In the steps that follow, you create a row of barrels by spacing the barrels
evenly. This creates barrels that are just touching, which ensures that there
are no intersections during the rigid body simulation
In the next section, we’ll use the move command to position the duplicate
barrels, using the saved value of the diameter as an argument for the Z value
of the command.

Create a row of barrels
Here, we’ll use the stored value of the diameter to space the duplicates of the
barrel. Variable values can be recalled at any time. Variables can be used as
values for arguments.

To duplicate the barrels

1 Select the barrel.

2 Duplicate the barrel by typing the following:
duplicate;
You have a duplicate of the first barrel, and it is the currently selected
object.

3 Align the duplicate barrel with the original by moving the duplicate in
Z by a value equal to its diameter by typing the following:

Create a row of barrels | 677

move -r 0 0 $diameter_barrel;
A duplicate of the original barrel is created and aligned to the first barrel.

4 Make another copy of the barrel by typing the following:
duplicate;
The current selection switches to the newly created geometry.

5 Duplicate the currently selected barrel and align the duplicate with the
previously created barrel.
duplicate;
When duplicating objects, the selection always switches to the duplicate.
Each barrel is spaced the same relative to its neighbors.

The first row of barrels is complete.

Stacking the row of barrels
Stack the barrels in a triangular arrangement by duplicating the existing row
and offsetting the row in both X and Y.


Using basic trigonometry, you can calculate the unknown height offset. MEL
has a library of built-in functions that include trigonometry functions, to
handle these calculations.

NOTE Trigonometry functions are ratios that relate two sides of a right angled
triangle dependant on one of the angles of the triangle. Trigonometry functions
are often used for animation, as trigonometric functions are periodic. Periodic
functions cycle their output values after a certain period. These functions can easily
create cyclical or repeating animation.

Using MEL built-in functions to calculate the Y offset
Sine is the ratio obtained by dividing the side opposite the angle by the
hypotenuse. Since the center points of the barrels are spaced along the points
of an equilateral triangle, all angles of the triangle are equal to 60°. If you
multiply the sine of 60° by the length of one of the sides of the triangle, the
result is the height of the triangle.

It is important to know which units of measurement the built-in functions
of a programming language use. Many programming languages, including
MEL and Python, perform trigonometric operations in radians. You must
convert from degrees to radians when using the sine function to calculate the
Y offset.

NOTE Radians are a method of measuring sections of a circle. There are 360
degrees in a circle, which is equivalent to 2pi radians.

To calculate the offset in Y

1 Declare a new variable to store the value of the Y offset by typing the
following:

Using MEL built-in functions to calculate the Y offset | 679

float $Y_offset;

2 Calculate the value of the Y-offset using the sine ratio. You must convert
the value of the angle to degrees with the degree to radian conversion
function.
$Y_offset = $diameter_barrel * (sin(deg_to_rad(60)));
The assignment operator evaluates the right hand side of the expression
and assigns it to the left hand side. The degree to radian conversion
function is the first to be evaluated, as it is within the most interior set
of brackets. The sine function calculates the sine of the angle given in
radians. The sine value is multiplied by the diameter to calculate the Y
offset. The variable is assigned the calculated value.

NOTE The variable $diameter_barrel does not change in value. Only the
variable on the left side of an assignment operator changes in value.

To stack the rows of barrels

1 Select and duplicate all the objects in the scene, by typing the following:
select -allDagObjects;
duplicate;
Using the select command with the -allDagObjects flag selects all DAG
(Directed Acyclic Graph) objects, which are a set of objects that exist in
the scene such as geometry, IK chains and measure tools. Textures and
animation information do not belong to the Directed Acyclic Graph.

2 Offset the barrels by the radius of a barrel in X and the calculated
$Y_offset in Y, divide the diameter by 2 to get the value of the radius.
When duplicating the rows, you have created too many barrels.
move -r 0 $Y_offset ($diameter_barrel/2.0);
duplicate;
duplicate;

3 Using the Lasso tool, select the extra barrels.

4 Delete the extra barrels to obtain a pyramid shape.


Creating dynamics with MEL commands
Maya lets you easily add dynamic properties to the objects in your scenes. All
attributes that can be modified by selecting menu items, can be accessed by
setting the arguments of a Maya command.
In this section you create a dynamic simulation using MEL so that the stack
of barrels reacts to gravity and moves in a realistic manner. Apply a rigidBody
node to all of the barrels, add a gravity field and a passive rigid body plane
for the barrels to collide with.
For more information about rigid bodies and fields within dynamics in Maya,
see Lesson 2: Rigid bodies and constraints on page 554 and the Dynamics guide
in the Maya Help.

To add rigid body nodes to the barrels using MEL

1 Select all the barrels by typing the following:

Creating dynamics with MEL commands | 681

2 Move the stack of barrels upwards along Y (by half the height of a barrel)
so they are not intersecting the ground plane.
move -r 0 (0.5*$diameter_barrel) 0;

3 Add a gravity field to the selected geometry by entering the following in
the Script Editor.
performDynamics 1 Gravity 0;
When a gravity field is added to the geometry, rigid body nodes are
automatically added to the geometry.

To create a plane for the barrels to simulate against

1 Make a plane for the barrels to simulate against by typing the following:
polyPlane -height 100 -width 100;

2 With the plane selected, add a rigid body node to the plane by typing
the following:
rigidBody -passive;

To view the simulation

➤ Click the play button on the time slider to view the dynamics simulation.


Beyond the lesson
In this lesson, you were introduced to how to use variables in MEL with Maya.
You can:

■ Declare, set and use variables.

■ Perform mathematical operations to modify the value of a variable.

■ Implement dynamics using MEL commands.

associated with them. Some suggested tasks you can try on your own include:

■ Practice creating, modifying and performing operations with variables. In
the next lesson, you use variables extensively to create a user interface.

Lesson 4: User interface creation and procedures

Introduction
In this lesson, you create a user interface for an existing Maya procedure using
MEL scripting commands. You learn how to:

■ Create a simple window


■ Use conditional statements to check the existence of a window

■ Use a built-in Maya procedure

■ Link a procedure to a user interface

Creating a window
The first step in creating custom user interfaces is to create a window. This
window contains the elements of the user interface such as text, buttons and
other controls.

To create a window

1 Type the following commands into a MEL tab of the Script Editor.
window -resizeToFitChildren 1; showWindow;
A window appears.

The -resizeToFitChildren flag on the window command specifies that
the window automatically resizes to fit all of the elements within the
window. This flag must have a value: a value of 1 turns on the flag, a
value of 0 turns it off.
When you create a window, it is not visible until you use the showWindow
command. The showWindow command without any arguments makes the
last window created visible.

2 Close the window clicking the X in the upper right hand corner.

Referencing controls
When creating windows with MEL scripting, you must ensure that every
window and user interface control is given a unique name. If you do not
explicitly give a window a name, it gets a default name. (In the previous
procedure, the name of the window was window1, even though you didn’t


use it.) You cannot reference or modify windows or controls that you don’t
know the name of.

To refer to a user interface element by name

1 Create a window with text and a button that closes it by typing the
following in a MEL tab of the Script Editor:
window -resizeToFitChildren 1 testwindow; columnLayout; text
-label "This is a test window you can close by clicking the
button below."; button -label "Close" -command "deleteUI
testwindow"; showWindow;

2 Press the Close button in the window.
The window closes.

Discussion: creating a simple window
In your window, you created elements for your user interface, called controls.
All user interface controls must be created within a layout. Layouts instruct
Maya how to arrange the user interface elements in the window.
There are many different types of layouts—for example, formLayout and
rowLayout—but the simplest and easiest to use is the columnLayout. The
columnLayout lays out your controls in a column, one underneath the other.
For more information on layouts, see Layouts of the MEL and Expressions
guide.
Within the layout you created a text control, with the text command. The
label flag’s argument is the text displayed in the window.

The button is created by the button command. The argument of the command
flag is a MEL command that is executed when the button is pressed. In this
case, pressing the button executes the deleteUI command, which deletes the
window you just created.

Scripts spanning multiple lines
In this script, individual commands span multiple lines. Commands can span
multiple lines as long as the end line character is at the end of the command.
One convention in MEL is to have the command keyword on one line, and
pair the modifier flags and values on separate lines underneath the command,
as in this example.

Creating a window | 685

Strings can’t be split up over multiple lines without the use of a special
character. To split a string over multiple lines, use the back slash () character.
For example:
print "With the character, you can split a string over
multiple lines.";

To have a backslash appear in a string, you must use a double backslash. The
backslash character is an escape character. Escape characters tell the script
interpreter that the character that follows is literal. Certain special symbols
can be created using the escape character in combination with other characters.
For example, to display quotes within a string:
print "Jim said "Hello!" to the Maya user";

Window naming
As user interface scripts get more complex, it is possible that you may make
a syntax error. If a user interface script partially executes and halts on an error,
the window still exists, but the window is not visible. If you fix the problem
and would like to execute the script again, you must either give the window
a new name, or delete the hidden window.

Resolving naming conflicts
In the next section, you use conditional statements to resolve window naming
conflicts. Conditional statements allow a section of code to execute depending
on the value of a variable or the state of an object in the scene.

To resolve conflicting window names

1 Create a window with a scripting error inserted before the showWindow
command by typing the following in a MEL tab of the Script Editor:
window testwindow; fake_command; showWindow;
An error is output to the Script Editor.
// Error: line 2: Cannot find procedure "fake_command;". //
The window is not displayed, but still exists.

2 Create another window with the same name by typing the following in
a MEL tab of the Script Editor:
window testwindow; showWindow;


// Error: line 1: Object's name is not unique: testwindow //
All objects in Maya and user interface elements must have unique names.

To query a window’s existence

1 Type the following command in the Script Editor input section, to delete
the hidden window:
deleteUI testwindow;

2 Check if the window exists by typing the following command:
window -exists testwindow;
The following result is output to the Script Editor.
// Result: 0 //
The exists flag of the window command changes the command so that
it either returns a one or zero depending on whether or not the window
exists.

3 Type the following in the Script Editor:
deleteUI non_existing_window; sphere;
// Error: line 1: Object not found: non_existing_window
The sphere command does not execute as the script has halted on the
scripting error.

To be able to delete the existing user interface only if it exists, conditional
statements can be used.

To delete a window on condition

1 Type the following in a MEL tab of the Script Editor:
window testwindow; fake_command; showWindow;
The window is invisible as there is a scripting error, and the showWindow
command did not execute.

if (`window -exists testwindow`==1) { deleteUI testwindow; }
window -resizeToFitChildren 1 testwindow; columnLayout; text
-label "This window deleted the other one"; showWindow;

Window naming | 687

Two concepts are being introduced here:

■ The if statement allows a certain part of code to execute depending on a
condition. The section of code within the curly braces only executes if the
statement inside the parentheses evaluates to true.

■ The paired back-ticks within the parentheses (` `) indicate that the
commands within them are evaluated first. This is a useful part of writing
MEL code: you can make certain commands (here, the conditional
statement) dependent on other commands (here, the evaluation of whether
the window exists), which execute and evaluate first.
Together, the if statement and the evaluation mean that only if the result
of the window existence query is “1” (the window exists) is the window
deleted. Otherwise, the section of code within the curly braces is skipped.

Storing control names
If you refer to a control in your user interface, it must have a name. Instead
of manually specifying the name for each user interface element, you can
allow the command to generate unique default names and then you can store
the name as a variable.
All user interface commands return their full name and path upon creation.
You can store the return value as a variable to refer to the control at a later
point in the script.

To store a control name as a variable

window -resizeToFitChildren 1 pick_me_window; columnLayout;
$button_one=`button -label "Click Me!" -command "deleteUI
$button_two"`; $button_two=`button -label "NO!, Click Me!!"
-command "deleteUI $button_one"`; $button_close=`button -label
"Close" -command "deleteUI pick_me_window"`; showWindow;


We’re using backticks for evaluation again here, though in this case, we’re
creating three variables ($button_one, $button_two, and $button_close)
that hold the results of calling the button command each time.

2 Press one of the “Click Me!” buttons in the window to test the script.
Clicking one of the “Click Me!” buttons deletes the other button by
calling the deleteUI command with the variable that stores the name of
the button control as an argument (button_one or button_two).
(If you click the button a second time, you’ll get an error as the button
you’re trying to delete has already been deleted.)

3 Close the window by pressing the Close button in the window.
When you created your user interface window, you assigned it a unique
name manually. This is a good practice to ensure that you cannot open
multiple copies of a user interface. With more complicated user interfaces,
multiple copies of the same user interface could interfere with each other
or slow down Maya.

NOTE You can view the full name and path of a user interface elements by
using the print command to output the variable.
print $button_one;

pick_me_window|columnLayout2|button1

This is the full path of the user interface control. You are using variables to
store the name and path of controls and therefore you do not have to type
the whole name and path to refer to user interface elements.

In this section, you learned how to create, delete, and check for the existence
of named windows. In the next section, you’ll hook up a more complex
window to a procedure.

Introduction to procedures
A procedure is a series of instructions that are separate from the main flow of
the script. Procedures allow you to reuse certain portions of a script for new
applications.

Introduction to procedures | 689

In this section, you use a procedure that is included with Maya (makeroll,
which simulates an object rolling on a plane). Later in the lesson, you link
this procedure to a user interface to provide an easier way to use the procedure.

To execute the makeRoll procedure

1 Create a cube and a ground plane by typing the following in a MEL tab
of the Script Editor:
polyCube -name roll_Cube; polyPlane -height 10 -width 10;

2 Execute the makeRoll procedure by typing the following in a MEL tab of
the Script Editor:
makeRoll roll_Cube 0 1 1.0;
The makeRoll procedure requires the following arguments: the name of
the object to act on, the height of the ground plane, the type of
simulation, and the diameter of the object. The type of simulation is
either box or sphere simulation. Rolling simulation is determined using
a bounding sphere when simulation type is set to 0, or a bounding box
when simulation type is set to 1.

3 Set the current frame to two by selecting the current frame box and typing
a two.

The expressions set up by the makeRoll procedure only take effect when
the frame is greater than one.

4 Select the cube with the Move tool.

5 Move the cube along the plane in X and Z using the Move tool.

The cube rolls on the ground plane.


You have successfully loaded and used the makeRoll procedure. Now, you’ll
link the procedure to a user interface.

Loading a script file
You can read and edit script files other people have created in the Script Editor.
In this section, you open a script that contains a completed user interface for
the makeRoll procedure. However, the user interface is only a layout, and does
not contain any functionality.

To prepare to open the script

1 In the Script Editor, ensure that Command > Show Line Numbers is
checked.

When Show Line Numbers is on, line numbers appear beside the
commands in the Script Editor. The lesson occasionally refers to line
numbers to tell you where to make a modification to the script. When
line numbers are referred to in the lesson, they are always the line
numbers of the original script.

2 Create a new tab in the Script Editor by selecting Command > New Tab.
A pop-up window asks you in which language should the commands
entered in this tab execute in.

3 Click the MEL button on the pop-up window.
You created a second MEL tab in the Script Editor.

4 Select Command > Rename Tab.

5 Enter MEL2.
The tab is renamed.

Loading a script file | 691

In the next steps, you load a user interface script into both MEL tabs. The MEL
tab will contain the original script, and the MEL2 tab will contain the user
interface script with your modifications. This way, line numbers can be
referenced from the original script to inform you where to make a modification.

To open a script file in the Script Editor

1 Select the MEL tab.

2 In the Script Editor, select File > Load Script.

3 Select the MEL script named Mel_UI_Start.mel.
your Maya project, within the mel sub-directory.
The contents of the MEL file are displayed in the Script Editor.

4 Load the same MEL script into the MEL2 tab by repeating the above
procedure.

5 In the MEL tab, highlight the script by selecting Edit > Select All from
the Script Editor menu bar.

6 Execute the script by pressing Ctrl+Enter.

A user interface is created for the makeRoll procedure. There is a control
in the user interface for each argument of the makeRoll procedure.
(You can leave this window open as we’ll be doing some testing with it,
though it doesn’t do anything yet.)

Discussion: what the script does
➤ The controls in the user interface are created by various commands.
Below,

the script has been broken up into sections to describe the various user interface
controls and their flags. The user interface controls and commands that you
used earlier in the lesson are described only briefly below.


Conditional statement
if(`window -exists makeRoll_Window`==1) { deleteUI makeRoll_Win
dow; }

The conditional statement checks if a window with the specified name exists.
If the window exists, it deletes it.

Window command
window -resizeToFitChildren 1 makeRoll_Window;

The window command creates a user interface window to contain the controls.
For more information, see Creating a window on page 684.

Column layout
columnLayout;

The columnLayout command creates a layout that arranges the controls within
it in a column. For more information, see Referencing controls on page 684.

Text field commands
$obj_name_text = `textField -editable 0 -width 400 -text
name_Of_Object`;

The command textField creates an editable text field. The text field command
has multiple flags. The name and path of the text field are stored as a variable.
See Storing control names on page 688.

■ The editable flag enables or disables editing of the text field.

■ The width flag sets the width of the control.

■ The text flag sets the contents of the text field.

Slider commands
$ground_int= `intSliderGrp -minValue -20 -maxValue 20 -value 0
-fieldMinValue -20 -fieldMaxValue 20 -field 1 -label "Ground
Plane"`; $diameter_float= `floatSliderGrp -value 1.0 -minValue
1.0 -fieldMinValue 1.0 -field 1 -label "Diameter"`;

The commands intSliderGrp and floatSliderGrp create sliders. Commands
ending in Grp create a group of linked controls. The slider commands create
controls for a label, a value box and a slider. The slider command has multiple

Loading a script file | 693

flags. The name and path of the slider are stored as a variable. See Storing
control names on page 688.

■ The editable flag can be used to enable or disable editing of the text field.

■ The minValue and maxValue flags set the minimum and maximum values
for the slider.

■ The field flag enables the visibility of an editable value field beside the
slider. By default, the field is not visible.

■ The fieldMaxValue and fieldMinValue flags set the minimum and
maximum values for the field beside the slider.

■ The label flag sets the text that appears to the left of the slider.

Separator commands
separator -height 20 -width 120;

The command separator creates a horizontal line. It is used to space the
controls vertically in the window. The separator command has multiple flags.

■ The width flag sets the visible width of the separator.

■ The height flag sets the amount of vertical spacing created by the separator.

Check box commands
$box_sim_checkbox = `checkBox -value 1 -label "Box Simulation"`;
$sphere_sim_checkbox = `checkBox -value 0 -label "Sphere Simu
lation"`; separator -height 20 -width 120; $execution_button=
`button -label "Execute!" -command "print ("something");"`;

The command checkBox creates a check box. The check box command has
multiple flags. The name and path of the check box are stored as a variable.
See Storing control names on page 688.

■ The value flag sets the initial value of the check box.

ShowWindow command
showWindow;

This command enables the last created window’s visibility. For more
information, see Creating a window on page 684.


NOTE In the script above, you do not explicitly declare your variables. This is
because the return type of user interface creation commands is known to be a
string, and cannot be any other data type. Later in the lesson, you will allow a
data type to be implied, as you do not know what data type the return will be.

Linking the user interface
Currently the user interface in the window doesn’t do anything: moving the
sliders and clicking the check boxes has no effect. In this section you learn
how to link the user interface to the makeRoll procedure you used earlier:

■ The textField in the user interface will display the currently selected
object.

■ The check boxes in the window will be linked so that only one check box
can be selected at once.

■ The button will execute the makeRoll procedure with the arguments
specified in the window.

In the following steps you modify the user interface script.
A completed version of the user interface script named Mel_UI_Final.mel is
available in the GettingStarted project directory, within the mel sub-directory.

Displaying the currently selected object
The makeRoll procedure does not act upon the currently selected object. You
will modify the script so that the textField control will display the name of
the currently selected object.
To return the name of the currently selected object, use the ls command (list)
with the selection. Since you can select multiple objects in Maya, the return
from the ls command is not a string, it is a string array, even if only one
object is selected. An array is an ordered list of values used to store multiple
items of the same data type within one variable. The makeRoll procedure
cannot accept a string array as an argument, so you must modify the data
returned by ls -selection.

NOTE For more information on the ls command, see ls in the MEL Command
Reference.
For more information on arrays, see Arrays in the MEL and Expressions guide.

Linking the user interface | 695

In this next section, we’ll also create a new tempMEL tab so you’ll have a place
to test commands as you learn them.

To store the names of the currently selected objects as a variable

1 Create a new MEL tab (Command > New Tab in the Script Editor).

2 Rename it tempMEL (Command > Rename Tab in the Script Editor)

3 Type the following in the tempMEL tab:
This command selects all scene objects.

$all_selected_objects =`ls -selection`;
This command lists currently-selected objects and outputs their names
to a variable.

print $all_selected_objects;
This command outputs the list of stored objects to the Script Editor.

6 Execute the commands in the tempMEL tab.
roll_Cube pPlane1

The variable $all_selected_objects is an array of strings. That is, it stores
multiple strings within the variable. Values in an array are called elements.

NOTE Arrays are used frequently in programming to manage large sets of data.
If arrays were not used to store large sets of data, you would need to create a
variable for each element of data, making scripts hard to maintain and taking up
lots of memory. For more information on arrays, see Arrays in the MEL and
Expressions guide.

Reduce your selection by extracting a single value from an array using an array
index.

To reduce the selection to one object

1 In the tempMEL tab, type the following:
$first_selected_object=$all_selected_objects[0];
select $first_selected_object;


The first element of the array, the roll_Cube, is selected.
Elements of an array are accessed using square brackets containing the
index number of the element you want to extract from the array. The
index number of arrays start counting from zero.

2 Add the following commands to the top of your user interface script in
the MEL2 tab:
$all_selected_objects=`ls -selection`;
$first_selected_object=$all_selected_objects[0];
select $first_selected_object;
These commands change your selection to the object you selected first.

3 In the MEL2 tab, change the argument of the text flag located on line
14 of the original script (you can use the MEL tab for reference) from
name_of_object to the following:
$first_selected_object
The command now reads:
$obj_name_text = `textField -editable 0 -width 400 -text
$first_selected_object`;
The text field now displays the currently selected object.
If you attempt to execute the modified user interface creation script
without an object selected, an error occurs, as no elements exist in the
string array $all_selected_objects.

TIP Don’t execute the script from the MEL2 tab yet, as it will clear the tab
and we want to continue modifying the script. If you do want to execute the
script at any interim time, create a new MEL tab, copy the script into it, and
execute that.

Linking the check boxes
Check boxes can also use command flags, similar to a button. A check box
has more functionality than a button, so the command flags are different.
Check boxes have three possible command flags; changeCommand, onCommand,
and offCommand:

■ The changeCommand flag triggers whenever the state of the check box
changes.

■ The onCommand flag triggers when the check box is checked.


■ The offCommand flag triggers when the check box is unchecked.

You can use the checkBox command with an edit flag to change the state of
a check box in the user interface.

To change the values of elements in the user interface

1 In the tempMEL tab, change the state of the make roll window’s check
box by executing the following:
checkBox -edit -value 0 $box_sim_checkbox;

The Box Simulation check box, which was turned on, is now turned off.
You can repeat this command with a value of 1 to turn the check box
back on.
This shows the use of the edit flag with a command as an argument to
a command flag, which allows you to change values.
We’ll now use the onCommand and offCommand flags to keep the two check
boxes in sync, so that when one check box has its state changed, the
other check box is set to the opposite state.

2 Replace the existing check box commands ($box_sim_checkbox and
$sphere_sim_checkbox) in the MEL2 tab. This will be approximately lines
38-46 depending on whether you added lines at the beginning of the file.
Replace these two commands with the following:
$box_sim_checkbox = `checkBox -value 1 -label "Box Simulation"
-onCommand "checkBox -edit -value 0 $sphere_sim_checkbox;" -
offCommand "checkBox -edit -value 1 $sphere_sim_checkbox;"`;
$sphere_sim_checkbox = `checkBox -value 0 -label "Sphere Simu
lation" -onCommand "checkBox -edit -value 0 $box_sim_checkbox;"
-offCommand "checkBox -edit -value 1 $box_sim_checkbox;"`;
The commands you are replacing are located on lines 35-43 of the original
script file.


Executing the procedure
The makeRoll procedure requires arguments to execute. To link it to the
window, you must get the values for the arguments from the controls in the
user interface, and execute the makeRoll procedure with these arguments.
To get the values of the controls, you must use the query flag. The query flag
allows commands to return values of attributes in the scene.

To query a value in the user interface

1 Change the value of the diameter slider to 10.01 by dragging the slider
to the right, or by typing a value in the diameter slider’s text field.

2 Print the value of the diameter slider by typing the following in the
tempMEL tab:
print ("The diameter is: " + `floatSliderGrp -query -value
$diameter_float`);
The following is output to the Script Editor
The diameter is: 10.01
The query flag allows you to output a value to the Script Editor.

Change the command flag of the button so that it calls makeRoll command
with arguments values that are the same as the specified values in the user
interface.

To link the button to the makeRoll procedure

➤ Replace the command flag of the execution button block in the MEL2
tab (approximately line 57) with the following:
-command "makeRoll `textField -query -text $obj_name_text`
`intSliderGrp -query -value $ground_int` `checkBox -query -
value $box_sim_checkbox` `floatSliderGrp -query -value $diamet
er_float`;"`;


Every argument of the user interface is defined by querying the user
interface elements. The backslash at the end of a line allows the command
flag argument to span multiple lines.

Your user interface is now fully functional!
A completed version of the user interface script named Mel_UI_Final.mel is
available in the GettingStarted project directory (GettingStarted/mel).

Saving the script
To use your script in other scenes, you must save it. To execute the MEL
commands in a script file without having to open it every time you want to
use it, you must use global procedures.
Once you’ve saved a MEL script file that contains a global procedure in the
default script folder of Maya, you can access it whenever you type MEL
commands. Other procedures in the script file can only be called by the global
procedure(s) defined in the script file or other local procedures.
Maya automatically sources procedures in its default scripts folders at start
up. A script in the default Maya script folder has the same name as a global
procedure defined in the script file, when you type the name of the script file,
the global procedure within the script file will be executed. This allows you
to create scripts that operate similar to built-in Maya commands.

1 Type the following at the top of MEL2:
global proc makeRoll_create_UI() {

2 At the bottom of MEL2, type the following:
}
Your entire user interface script should be between the curly braces.

3 Highlight the entire script by selecting Edit > Select All from the Script
Editor menu bar.

4 With the script highlighted, save the script by selecting File > Save Script
from the Script Editor.
The Script Editor only saves the highlighted commands when saving a
script.

5 Save the script as makeRoll_create_UI.mel in the GettingStarted/mel
folder.


NOTE When saving a script, you must have the .mel extension appended
to the script file name in the Save Script dialogue box.

Using the saved script file
You can apply the makeRoll procedure to any geometry quickly by selecting
the object to apply makeRoll to, and executing the makeRoll_create_UI global
procedure. Before using a script in your scene, you must source it. Sourcing
executes all the commands within a script file.
You can only access global procedures declared in the script file from the Script
Editor. Any local procedures cannot be accessed from the Script Editor, and
must be called from global procedure within the script file.

NOTE Global procedures only have access to local procedures declared before
them in a script file.

To source and use a script file

1 Select File > Source Script

2 In the Source Script dialogue box that opens, select
makeRoll_create_UI.mel

3 Create geometry to test the makeRoll procedure on by creating a new
scene and typing the following:
polyPyramid;

4 Execute the makeRoll_create_UI global procedure to create the user
interface by typing the following in the Script Editor:
makeRoll_create_UI;

The user interface you created opens.

Using the saved script file | 701

5 Set the frame to greater than one to view the effects of the makeRoll
procedure.

6 Set the following values in the makeRoll user interface:
■ Ground Plane = 0

■ Diameter = 1.0

■ Box Simulation = checked

■ Sphere Simulation = unchecked

7 Click the “Execute” button to setup the makeRoll expressions.

8 Move the pyramid in X and Z to view the results of the makeRoll
procedure.

Explore different results that occur when you apply the makeRoll procedure
with different user interface control values. Since you cannot undo the
makeRoll procedure, you will have to create new geometry every time to apply
the makeRoll procedure.
When you open a new Maya session, the makeRoll user interface procedure
is no longer defined and must be sourced to use it.

Beyond the lesson
In this lesson, you learned how to create a user interface from an existing MEL
procedure. You can:

■ Create a window

■ Create user interface controls in a window

■ Use conditional statements to check the existence of a window

■ Use a built-in Maya procedure

■ Modify a user interface to add functionality

■ Access elements of an array

■ Query and edit user interface values

■ Save and source a script


You can create fully customized user interfaces with MEL scripting. There are
additional user interface elements not covered in this lesson.
For a full list of user interface elements, look in the MEL Command Reference.
You can open the MEL command reference by selecting Help > MEL Command
Reference from the menu bar. User interface commands are in the Windows
category of the MEL Command Reference.

Lesson 5: Using Python in Maya

Introduction
Python scripting in Maya is very similar to MEL scripting. Python scripting
has the same access MEL does to Maya functionality with very few limitations
(see Current limitations of the Python guide). Python requires a different
syntax than MEL, so commands in Python can look very different from their
MEL equivalents.
This tutorial is for migrating your MEL scripting experience to a Python
scripting environment in Maya. This lesson does not teach Python, only how
to use Python scripting in Maya. Maya uses Python 2.5 on all supported
platforms.
Python is a highly readable, easy to maintain, high level programming
language. Python is widely used in industry due to its simplicity and standard
libraries.
To learn Python, try a Getting Started tutorial in Python:
http://www.python.org/about/gettingstarted/

■ Enter Python commands in Maya

■ Create geometry with Python scripting commands

■ Return values from Python commands

■ Use flags in Python with the move, scale and rotate commands

■ Set the edit and query flags in Python

■ Refer to named objects in Python

■ Transfer values between Python and MEL

Lesson 5: Using Python in Maya | 703

■ Call MEL scripts from Python

Entering Python commands
Just like MEL, you can enter Python commands in the Command Line or the
Script Editor. The Command Line can only accept single line Python
commands, while the Script Editor provides a method to input multiple Python
commands and view the results.
The Script Editor displays a running history of executed commands and the
results of commands that Maya executes. You can copy most commands from
the history section of the Script Editor and paste them in the input section to
execute them. However, the results of Python commands are not echoed to
the Script Editor exactly like MEL.
For more information, see To set up the Script Editor on page 658.

To type a Python command in the Script Editor

1 Select Window > General Editors > Script Editor.

2 Select a Python tab in the Script Editor.

3 Type the following command in the input section of the Script Editor
and execute it by pressing Enter on the numeric part of your keyboard,
or pressing Ctrl+Enter.
import maya.cmds as cmds
You now have access to Maya commands through the maya.cmds module.

NOTE This is how you load modules in Python. For more information about
other Python modules, see the online Python documentation.

By convention throughout the documentation and the Python command
reference, the maya.cmds module is renamed cmds, but you can rename
the module anything you like.


In the Script Editor, the Enter (Windows) or Return (Mac OS X) key above
the Shift key does not execute a command. It starts a new line so you can
type several commands before executing them.

TIP You can import maya.cmds automatically at startup by creating a file
called userSetup.py in your Maya scripts directory. The userSetup.py file
can contain any Python commands you want to execute at startup.
For more information, see Initializing the Maya Environment in and for Python.

4 Create a polygonal cube by typing the following:
cmds.polyCube()

A polygonal cube is created at the origin. This is equivalent to using the
polyCube command in MEL.
The command is removed from the input section of the Script Editor
after execution. The command and the result of the command is output
to the upper section of the Script Editor. The results of Python commands
are displayed in the Script Editor between a set of Python commenting
characters (#).

You can also enter commands in the Command Line.
Show the Command Line by selecting Display > UI Elements. By default the
Command Line is in MEL script entry mode. You can change the mode by
clicking on the text in the lower left hand corner. To enter Python commands,
the command line must be in Python mode.

Entering Python commands | 705

To use a Maya command with positional arguments

1 Move the polygonal cube that you created with the following Python
command:
cmds.move(1,2,3)

The polygonal cube moves to the XYZ co-ordinates 1,2,3.
The move command accepts XYZ co-ordinates as its commands
arguments.

2 Scale the polygonal cube with the following command:
cmds.scale(2,2,2)

3 Re-scale the polygonal cube with the following command:
cmds.scale(3)


When a command is not provided with enough command arguments,
the command uses the default arguments. The polygonal cube X scale is
set to three, but the Y and Z scale values are set to their default argument
one.

4 Delete the selected polygonal cube.
cmds.delete()

Using flags in Python
Flags are used with commands to modify their execution. Python implements
flags as named arguments. Some flags in MEL do not require values. As all
named arguments in Python require a value, these flags are given the value
True to enable the flag, or False to ignore the flag. When setting multiple
named arguments, argument-value pairs are separated by commas within the
brackets. Command arguments must appear before named arguments in a
command.

To use flags in Python

1 Create a polygonal cube with the width defined at creation time by typing
the following:
cmds.polyCube(width=5)

The width flag allows you to set the width of a cube at creation time.

Using flags in Python | 707

2 Create a polygonal sphere with the radius and subdivisions in X and
name defined at creation time.
cmds.polySphere(radius=1, subdivisionsX=4, name="testSphere")

You can use multiple flags to modify the execution of a command by
separating the flag-value pairs with a comma. The radius flag sets the
radius of the created sphere. The subdivisionsX flag sets the number of
subdivisions in X for the sphere.

NOTE A list of flags available for a command can be output to the Script
editor by typing cmds.help("command"). For example: cmds.help("sphere")

To use flags with command arguments in Python

1 Move the polygonal sphere by typing the following in the Script Editor:
cmds.move(2,2,2)

2 Select the polygonal cube.

3 Move the polygonal cube by typing the following:
cmds.move(1,2,3)


4 Move the polygonal cube relative to its current position by typing the
following:
cmds.move(-1,0,-2,relative=True)

The polygonal cube moves relative to its current position. The relative
flag must be placed after the command arguments, as in Python, when
passing arguments, named arguments must appear after positional
arguments. The command arguments must always be the first arguments
of the command.

5 Move the polygonal sphere without selecting it by typing the following:
cmds.move(3,2,1,"testSphere",relative=True)

The name of the object must be passed as a string after the command
arguments, but before the flags.

Using flags in Python | 709

To use flags with multiple arguments in Python

1 Create a yellow tinted point light by typing the following:
cmds.pointLight(rgb=(1,1,0.5))
The point light command creates a point light at the origin. The rgb flag
specifies the color of the light. The rgb flag require three values; red,
green and blue.
When flags require multiple values, the values must be packed within
Python’s tuple or list data types. Tuples are a method of storing multiple
items of homogenous data within a single variable, similar to an array
in MEL. The list is similar to the tuple, but supports multiple data types
within a single variable. The above command packs the RGB values into
a tuple. You could also use a list to achieve a similar effect.

2 Move the currently selected light by typing the following:
cmds.move(12,15,12)

3 Create a blue tinted light by typing the following:
cmds.pointLight(rgb=[0.2,0.2,1])
Square brackets [ ] indicate lists, and parentheses ( ) indicate tuples.
The values for the rgb flag can be packed into either a list or a tuple and
perform the identical operation.

4 Move the currently selected light by typing the following:
cmds.move(12,15,-5)

5 Select the polygonal cube and polygonal sphere by clicking the polygonal
cube, then shift clicking the sphere.

6 Frame the selected objects by pressing the f hotkey on your keyboard.

7 Render the scene by pressing the render current frame button on
the Status line.
The Render View opens and displays the following image.


8 Select all objects in the scene and delete them by typing the following
cmds.select(allDagObjects=True)
cmds.delete()
Using the Maya command select with the allDagObjects flag selects
objects that exist physically in the scene such as geometry, IK chains and
measure tools. These appear on an internal Maya representation called
the DAG. For more information, see DAG.

Using the edit flag in Python
When you perform an action on an object in the Maya user interface, you’re
using Maya commands to change the attributes of selected objects. You can
use the same Maya commands explicitly to edit the attributes of objects in
the scene.
Some Maya commands take an edit flag that allows you to make changes to
the attributes of an object. The edit flag is used in conjuction with other flags
to specify which attributes to change.

To edit the attributes of an existing object

1 Create a NURBS torus by typing the following:
testVarName=cmds.torus(r=1, axis=(0,1,0) )

Using the edit flag in Python | 711

The axis flag specifies the initial orientation of the torus. Geometry
creation commands return the name of the created object, so you can
easily refer to the object by storing the name of the object as a variable.

NOTE Most creation commands return the name of the created object as a
return value. This value can be stored as a variable to refer to the object at a
later time. This is especially useful when referring to controls within a user
interface.

2 Deselect the torus using a Python command.
cmds.select(deselect=True)

3 Edit the height ratio of the named torus by typing the following:
cmds.torus(testVarName,edit=True, hr=0.4)

When the edit flag is set to True, the command is put in edit mode. When
in edit mode, all flags within the brackets of the command now change
the attributes of the specified object.

NOTE The edit flag does not need to be the first flag in a command. It is a
named argument and can be positioned anywhere within the command after
the positional arguments.


Communicating between Python and MEL
MEL and Python in Maya each have built in commands to communicate with
each other. MEL and Python communicate by calling commands in the other
language and evaluating the results of the last executed command.
Python communicates with MEL using the eval() command. Unlike the other
Python commands in this lesson, the eval() function does not belong to the
Maya commands module (maya.cmds). The eval() function belongs to the
maya.mel module. The eval() function can call MEL scripts or execute MEL
commands by sending the commands as a string. Multiple MEL commands
can be called in the string by separating the commands with semi-colons. The
Python eval() function returns the results of the last executed MEL script or
command within the eval brackets.
MEL communicates with Python using the python command. The python
command accepts a string as its only argument. The string is sent to Python
to be evaluated, and the result is returned to MEL. As Python has a more
descriptive type system, some results from Python commands returned to
MEL have their data type modified. For more information on type conversion,
see MEL/Python communication of the Python guide.

To call MEL commands from Python

1 Select a Python tab in the Script Editor

2 Import the MEL module
import maya.mel
The maya.mel module is a module for evaluating MEL expressions in
Python.

3 Call a MEL command by typing the following:
maya.mel.eval("sphere -radius 3;")
A sphere of radius three is created at the origin, just as if you had used
the Python command.

4 Select a MEL Tab in the Script Editor

5 Declare a variable in the MEL tab by typing the following:
global float $MyMELVariable=22.7;
Only global MEL procedures, variables and scripts are accessible from
within Python.

6 Select a Python tab.

Communicating between Python and MEL | 713

7 Transfer the MEL variable’s value to Python by typing the following:
TransferMELvar = maya.mel.eval("$temp=$MyMELVariable")
When transferring variables between MEL and Python, the functions
return the value of the statement. MEL syntax does not allow you to
return the value of a variable by using the variable as a command string.
In MEL, when a variable is assigned a value, the value is returned to the
Script Editor. Within the eval() statement, you assign the value of the
global MEL variable to a temporary variable.

8 Output the value of the transferred MEL variable using Python commands:
print TransferMELvar;

To call Python commands from MEL


Commands typed in the MEL tab are executed in MEL.

2 Call a Python command by typing the following:
python "cmds.sphere()";
A sphere is created at the origin, just as if you had typed the command
in the Python tab.

3 Select a Python Tab in the Script Editor

4 Declare a variable in the Python tab by typing the following:
MyPythonVariable=22.7


6 Transfer the Python variable’s value to MEL by typing the following:
float $TransferVarPy = `python "MyPythonVariable"`;
Evaluation back quotes are used in MEL to use the return value of a
command in assignment, when the return value is normally returned to
the Script Editor history window.

7 Output the value of the transferred variable in MEL:
print $TransferVarPy;


TIP Transferring values between Python and Maya can also be accomplished
by using invisible user interface elements. You can edit and query the contents
of user interface elements with both scripting languages.

Beyond the lesson
In this lesson, you learned how to access Maya’s functionality through Python
scripting commands. You can:

■ Type basic Python commands in the Script Editor to access Maya
Commands.

■ Use named arguments as flags at object creation time to specify the
attributes for the objects.

■ Use commands that require multiple arguments by packing the arguments
in a tuple or list.

■ Edit the attributes of objects using a command with the edit flag.

■ Execute Python commands from the MEL interpreter and execute MEL
commands from the Python interpreter.

■ Transfer values between Python and MEL.

The MEL tutorials introduce some other uses for scripting in Maya. You can
follow through with the MEL tutorials by using the Python Command
Reference to translate MEL commands to their Python equivalents.
Python can also be used to write scripted plug-ins. For more information, see
Introduction to Maya Python API in the API guide.


Assets
14
Introduction

In Maya, a container is a special type of node that can be used to encapsulate
sets of related nodes. A template is an external file that specifies a common
interface that can be applied to multiple containers (for example, a container
of a car, a truck, and an ambulance all have similar components and can thus
can have a common interface) and accessed from the Maya UI. A container with
an applied template is called an asset.
In complex scenes with many nodes and attributes, assets become a key
organizational tool by allowing you to package nodes together and expose only
the attributes you need. This allows you to keep all the Maya editors clean and
clutter-free.
Assets also allows you to customize which attributes are shown to which users
while simultaneously locking them out of other attributes. This allows you to
ensure the integrity of your scene even when others work on it.



2 If you have not already done so, copy the GettingStarted folder from its
installation location to your projects directory. Then, set the

717


3 As you work through these lessons, remember to save your work
frequently and increment the name of the file every so often (filename1,
filename2, and so on).
In this way you’ll have earlier versions of your work to return to should
the need arise.

4 (Optional) Set the current project folder to the Assets tutorial folder by
selecting File > Project > Set. Then navigate to the GettingStarted
folder, select the Assets folder and click OK.

Lesson 1: Setting up an asset

Introduction
In this lesson, you create a container representing the provided fire truck
model. You then publish attributes from each part and create a template to
define future emergency vehicles.
In this lesson you’ll be introduced to some of the asset options Maya provides
by learning how to:

■ Place a polygon object into a container.

■ Publish attributes to the container.

■ Publish the root node transform to the container.

■ Set container-centric selection.

■ Create a template for the container.

Lesson setup
To ensure the lesson works as described, do the following steps before
beginning:

1 Make sure you’ve done the steps in Preparing for the Lesson.

2 Open the scene file named FireTruck.mb.

718 | Chapter 14 Assets

your Maya project:
Getting Started/Assets/Firetruck.mb
The scene contains a model of a fire truck split into various pieces such
as the body, axles, and doors.

Creating a container
A container is the first building block of an asset and is used to contain related
nodes in your scene. A container is not visible in the main viewport, but you
can select it from the Outliner, Hypergraph Connections editor, and Asset
Editor.
In this case, all the fire truck components (including lights) are grouped
together. This is important because you want the fire truck components to
move together when animated. Thus, the fire truck group node is the central
node to the container, and thus will become the container’s root node.

To create a container for the fire truck

1 Select Fire_truck_GRP in the Outliner.

2 Select Assets > Create Container > .
The Create Container options window appears.

Creating a container | 719

3 In the Create Container options window, select Edit > Reset Settings.

4 Under Create Container Effect, set the Name to Fire_truck_CNT.

5 Under the Include Options, turn on Include Shaders and Include
Hierarchy, and set the hierarchy to Below (including shapes).
Setting these options ensures that everything the firetruck needs to
maintain its current appearance is packaged into the container.

6 In the Publish Options, turn on Root Transform and Root Attributes.
Setting these two options automatically publishes Fire_truck_GRP as the
container’s root node (thus allowing it to be a parent or child in a scene)
and publishes its attributes to the container so that they can be tweaked
from the container’s interface.

Maya encapsulates the fire truck in a container.

Publishing attributes

Now that the fire truck is encapsulated, you can publish attributes from the
individual pieces to make them available at the container level.
A published attribute on a container is bound to an attribute of the object
inside. When a user changes the published attribute’s value, the value of the
corresponding internal attribute is changed as well. You can choose to publish


all or only a subset of the available internal attributes, allowing you to limit
how much access a user has to the object contained inside.
The published attributes of a container are often referred to as the container’s
interface, and is useful because it allows you access to every important control
for your asset in a single place.

To organize objects under their containers

➤ In the Outliner, select Display > Container Contents > Under Container.
Now Fire_truck_GRP and its children appear under the Fire_truck_CNT
object.

To publish the right cab door

1 In the Outliner, expand Fire_truck_CNT by clicking next to its name.
Fire_truck_GRP appears under Fire_truck_CNT.

2 Expand Fire_truck_GRP, then Doors_GRP.

3 Select Cab_door_f_r_GRP and open the Channel Box by clicking .

4 In the Channel Box, under the Cab_door_f_r_GRP heading, Ctrl +
right-click the label Door Open and select Publish to Container >
from the marking-menu.
The Publish Attribute Options window appears.

5 In the Publish Attribute Options window, select Edit > Reset Settings.

6 In the Attribute name section, select Custom name and then type
Front_Right_Door in the Custom name field.
The name Front Right Door represents the published name for this
attribute and represents the door’s rotation in the fire truck container’s
interface.

7 Click Apply.
The Front Right Door attribute now appears in the Fire_truck_CNT section
of the Channel Box.
Now, in the Attribute Editor or Channel Box you can input values into
the Front Right Door field to open and close the door. Notice that as you
change the value, the value of door_open under Doors_GRP changes to
match. This is because your published name (Front_Right_door) is bound

Publishing attributes | 721

to the Rotate Y attribute of Cab_door_f_r_GRP. When one changes, both
are updated.

8 Repeat steps 3 - 7 to publish the following:
Node Name Published name

Cab_door_f_l_GRP Front_Left_Door

Cab_door_r_r_GRP Rear_Right_Door

Cab_door_r_l_GRP Rear_Left_Door


10 Click Close.

NOTE The Door Open attribute for each door is a custom attribute that controls
the Y rotation of each door. Although you could publish the rotate Y attribute of
each door directly, these custom attributes are provided so that each door opens
as the value increases from 0 to 1. Without these attributes, some doors would
open as their rotation increases and others would open as their rotation decreases.

You will learn how to create a custom attribute in the next section.

Publishing multiple attributes to a single published name


Unlike the doors, a fire truck’s wheels are expected to move together. For
example, the wheels on the front and back axles should spin together, and
the front wheels should turn together. To do this, you need to create a custom
attribute to control both components at once. Then you can publish your
custom attribute to the container.

To turn the front wheels together

1 In the Outliner, expand Axles_GRP, then select Wheels_GRP.

2 Open the Attribute Editor by clicking .

3 Make sure the Wheels_GRP tab is currently active, then in the Attribute
Editor, select Attributes > Add Attributes.
The Add Attribute window appears.

4 Under Numeric Attribute Properties, set Long Name to Front_wheel_turn.

5 Set Minimum to -30 and Maximum to 30.

6 Click Add.
Maya adds the new attribute to Wheels_GRP in the Extra Attributes section
of the Attribute Editor. The Add Attribute window stays open.

7 Repeat steps 4 to 6 setting Long Name to Wheel_spin. Do not set a
Minimum/Maximum value for this attribute.

8 Click Close.

Your custom attributes can be found in the Extra Attributes section of the
Attribute Editor. However, if you modify their values, nothing happens. This
is because you have not connected them to anything yet.

To make the front wheels turn together

1 Open the Connection Editor by selecting Windows > General Editors >
Connection Editor.

2 In the Connection Editor, Wheels_GRP should already be displayed in
the Output section. If it is not, select Wheels_GRP in the Outliner and
click Reload Left in the Connections Editor.

NOTE If Outputs does not appear over the left column in the Connections
Editor, click the to <- from button to reset its position.

Publishing multiple attributes to a single published name | 723

3 Scroll to the bottom of the left column and select Front_wheel_turn.

4 In the Outliner, expand Wheels_GRP and select Wheel_f_l_GRP.

5 In the Connection Editor, click Reload Right.
The right column is filled with the left wheel’s attributes.

6 In the right column, expand rotate and select rotateY.
rotateY turns to italics to signify that it has been connected.

7 In the Outliner, select Wheel_f_r_GRP and repeat steps 5 and 6.

If you adjust the value of Front_wheel_turn, both front wheels turn together.

Next you need to make the front and rear wheels spin in unison.

To make the front and back wheels spin together

1 In the Connection Editor, select Wheel_Spin in the left column and
rotateX in the right column.

2 In the Outliner, select Wheel_f_l_GRP.

3 In the Connection Editor, click Reload Right.

4 In the right column, expand rotate and select rotateX.


5 Repeat steps 2-4 for the other 3 wheels.

Now if you adjust the value of the wheel_spin attribute in the Attribute Editor
or Channel Box, all four wheels spin in unison. Although, in some cases, it’s
useful for the front and back wheels to be able to spin at different rates, the
current setup is fine for this tutorial.
Now you can publish your custom attribute to the container. You can do this
directly from the Attribute Editor.

To publish the wheel turn and wheel spin

1 In the Attribute Editor, right-click Front Wheel Turn and select Publish
to ‘Fire_truck_CNT’ from the marking menu.

2 Right-click Wheel Spinand select Publish to ‘Fire_truck_CNT’ from the
marking menu.

Both attributes are published to the fire truck container with the same
published names as their corresponding custom attributes.

beginning:

➤ Open the scene file named FireTruck_published.mb.
your Maya project:
Getting Started/Assets/Firetruck_published.mb
The scene contains the same fire truck model but with a complete set of
published attributes.

Creating a template
Once you’ve published all your attributes, you can create a template from
your asset. A template defines which published attributes an asset needs to be
considered complete. You can then re-purpose this template for use with
future fire truck models, or in our case, any emergency vehicle.
To create a template, you first need to open the Asset Editor.


To open the Asset Editor

1 In the Outliner, select Fire_truck_CNT.

2 Select Assets > Asset Editor.
The Asset Editor appears.

The Asset Editor allows you to manage all the containers and templates in
your scene from a single interface. From the Asset Editor you can publish and
unpublish attributes, change published names, bind and unbind attributes to
published names, and create templates and views.
The Asset Editor is divided into two columns. The left column shows you all
the containers in your scene in a format similar to the Outliner. The right
column shows you all the published names associated with a container. In
order to see the published names for a container, you have to pin a container
first.

To pin the fire truck container

1 Select Fire_truck_CNT in the left column.

2 Click the pin icon ( ).
The fire truck’s published names appear in the right column.

Now that you’ve pinned the fire truck container, you are ready to create a
template.

To create a template

1 In the Asset Editor, select Template > Save As.

2 Navigate to the assets folder.

3 Set the File name to emergency_vehicle.

4 Click Save.
Maya creates a template file.

Notice that once you create a template file, the small arrows next to the
published names in the right column change from red to green. This signifies
that these published names come from the template and are currently bound.


Creating Views
One advantage to creating a template for your asset is that you can create
multiple Views for it. You can use Views to customize which attributes certain
users can see in the Maya editors. For example, you can create a View that
limits an animator to only the door controls and wheel spin controls and
another View to limit a shader to only the truck’s body materials and textures.
Not only do Views cut down the amount of editor clutter for each artist, but
it also adds a layer of protection so that users don’t accidentally change an
attribute they shouldn’t have control over.

To create a View for an animator

1 In the Asset Editor, select View > Add > .
The Add View Options window appears.


3 Set the Name to Animator.

4 Set Layout Mode to Flat.

Maya creates a new View for the asset.

Notice that even though you created a new View, all the attributes are still
visible in the right column. Since we only want the animation controls visible,
we need to customize this View.

To customize a View

1 Open the Script Editor by clicking .

NOTE If you prefer, you can also use any external text editing tool to perform
the following steps.

2 In the Script Editor, select File > Load Script.

3 Set Files of type to All types.

4 Navigate to the Assets folder and select emergency_vehicle.template.

Creating Views | 727

5 Click Open.
The template is now displayed in the Script Editor. The template is an
XML file and thus is arranged with a series of tags.

6 Scroll to the bottom of the Script Editor until you find the tag
<view name='Animator' template='emergency_vehicle'>
Underneath this tag, delete the following:
■ <property name='headlight_intensity'/>

■ <property name='siren_intensity'/>

■ <property name='interior_light_intensity'/>

■ <property name=’transMinusRotatePivot’/>

7 Highlight the text of the XML file or press Ctrl + A.

8 Select File > Save Script.

9 Set Files of type to All types.

10 Navigate to the Assets folder and select emegency_vehicle.template.

11 Click Save.

12 Close the Script Editor.

You’ve now customized the View by leaving only the attributes an animator
would be interested in. However, this is still not reflected in the Asset Editor.
To see your changes, you need to refresh to the Asset Editor.

To update the Asset Editor

➤ Select Template > Reload.
The right panel updates to show you your customized View.

Now repeat the procedure to create a Shader view, but with the following
changes:

■ Set the template Name to Lighter.

■ When viewing the template in the Script Editor, scroll down to
<view name='Lighter' template='emergency_vehicle'>


And remove the following:
■ <property name='translate'/>

■ <property name='rotate'/>

■ <property name='scale'/>

■ <property name='visibility'/>

■ <property name =’Front_R_Door_Open’/>

■ <property name='Front_L_Door_Open'/>

■ <property name='Rear_R_Door_Open'/>

■ <property name='Rear_L_Door_Open'/>

■ <property name='front_wheel_turn'/>

■ <property name='wheel_spin'/>

■ <property name=’transMinusRotatePivot’/>

■ <property name='toggle_headlights'/>

■ <property name='toggle_front_flashers'/>

■ <property name='toggle_rear_flashers'/>

■ <property name='toggle_sirens'/>

■ <property name='toggle_interior_light'/>

Now you have two different Views that are useful for two different artists. You
can switch between Views in the Asset Editor by selecting View > Name, and
then selecting the name of the View you want to set.

Creating Views | 729

Notice that in both views, the Trans Minus Rotate Pivot attribute is hidden.
This is another great use for views, they allow you to hide attributes that
cannot or should not ever be modified manually, but still need to be published
(for reasons that are evident in Lesson 2).
You can now close the Asset Editor and save your file.

Assigning a custom icon
Currently, Fire_truck_CNT is displayed in the Outliner and Hypergraph with
the standard container icon. You can customize this icon to make the container
more obvious when you place the fire truck in a scene with more than one
container.

To customize the container icon

1 Select Fire_truck_CNT in the Outliner.

2 In the Attribute Editor, under the Fire_truck_CNT tab, open the Container
Attributes section.
This section displays all of the container’s own attributes.

3 Click the file icon button next to Icon Name.



4 Navigate to Getting Started/Assets/sourceimages/xpm and select
fire_truck_icon.xpm.

5 Click Open.

The image changes to a small fire truck icon.

Setting Black Box mode
Although Views encourage certain users to only modify certain attributes, it
is still possible for a user to inadvertently access and change attributes that
they shouldn’t. To greatly increase the integrity of your asset, you can set it
to Black Box mode.
When Black Box mode is turned on, users can only see the container itself
and all of its published attributes and published nodes. A user cannot open a
container in the Outliner, Hypergraph, or other editors, to view the
unpublished attributes and unpublished nodes inside. An additional benefit
of this is that it greatly decreases the complexity of scenes in editors since it
reduces entire trees of objects to a single object.

To turn on Black Box mode

1 In the Outliner, select Fire_truck_CNT.

2 In the Attribute Editor, in the Container Attributes section, turn on Black
Box.

Now if you look at the Outliner, the expand icon next to Fire_truck_CNT has
disappeared. If you try clicking it, Maya does not allow you to expand it to
see its children.

Setting Black Box mode | 731

Beyond the lesson
In this lesson you learned how to encapsulate objects into an asset.

■ You can create a container that encapsulates existing objects in the scene.

■ You can publish attributes to a container.

■ You can create custom attributes, connect them to objects in the scene,
and then publish those custom attributes.

■ You can use the Asset Editor to create a template for an existing asset.

■ You can create and customize Views of an asset.

■ You can assign a custom icon to an asset.

■ You can set an asset to Black Box mode to hide its unpublished contents.

Lesson 2: Using assets in a scene

Introduction
In this lesson you first learn how to import existing assets into a scene. You
then apply the emergency vehicle template you created in Lesson 1: Setting
up an asset to a police car in the scene and then use the matching published


attributes to replace it with your fire truck. You then reference a fire into the
scene and finish dressing the scene with a number of external assets.

■ Apply an existing template to a container.

■ Bind container attributes to a template’s published names.

■ Reference an asset in another file with File Referencing.

■ Transfer values from one asset to another.

■ Use container proxies to dress a scene.

Lesson setup
beginning:

1 Make sure you’ve done the steps in Preparing for the Lesson.

2 Open the scene file named EmergencyCity.mb.
your Maya project:
Getting Started/Assets/EmergencyCity.mb
The scene contains a model of a city block and a police car. If you play
back the animation, the police car drives along the road, stops outside
one of the apartment buildings, and opens its front doors.

Lesson setup | 733

Importing assets to dress a scene
If you open the Outliner, you can see that this scene has already been organized
into assets (the buildings and the animated police car). Now you can add some
lightposts to make the city more believable.

To add lightposts to the scene

A File Browser appears.

2 Navigate to the Assets directory and select lightpost.mb.

3 Click Import.
The lightpost is imported into the scene.

4 Select the lightpost and open the Channel Box.

5 In the lightpost_CNT section, set the translate values to -637, 0.85, -72.
You can now duplicate this lightpost container to set up more lightposts
in regular intervals across your scene.


To clean up the Outliner, you can select all the lightpost containers and place
them all in a single container as well.

To create an container for all the lightposts

1 Select all the lightpost containers in the Outliner.

2 Select Assets > Create Container > .
The Create Container options window appears.

3 In the Create Container options window, select Edit > Reset Settings.

4 Under Create Container Effect, set the Name to All_lightposts_CNT.

5 Under the Include Options, turn on Include Shaders and Include
Hierarchy, and set the hierarchy to Below (including shapes).

Maya encapsulates all the lightpost containers into a single container.

Assigning an existing template to a container
You can use assets to replace the existing police car in the scene with the fire
truck model you created in Lesson 1, without losing the existing animation.
First you need to make sure that the published attributes of the police car and
fire truck match precisely. To do this, you can reuse the template you created
in Lesson 1 from the fire truck to define the police car.

Assigning an existing template to a container | 735

NOTE If you did not start at Lesson 1, both the fire truck model and template can
be found in the Getting Started/Assets/assets folder.

To assign a template to a container

1 Select Assets > Asset Editor.
The Asset Editor appears.

2 In the left column of the Asset Editor, select police_car_CNT.

3 Click the pin icon ( ).

4 Select Template > Assign > Assign New Template.

5 Navigate to the emergency_vehicle.template file you created in Lesson 1
and select it.
If you didn’t start at Lesson 1, navigate to Getting
Started/Assets/assets/templates and select the file
emergency_vehicle.template.


6 Click Select.
A number of the attribute icons turn green, while others turn yellow. To
better organize this, you can apply the template’s views.

7 View > Mode > Use Template.
The right panel is split into a number of sections.
The majority of the attribute icons in the police_car_CNT section are
green. This signifies that they have been bound to identical published
names that were found in the template.

However, there are a set of published names without icons next to them. These
represent published names that the template is expecting, but couldn’t find.
In some cases this may mean you need to bind and publish additional
attributes to fulfill them.

NOTE The icons in the Published Nodes section appear yellow because templates
do not recognize published nodes.

Assigning an existing template to a container | 737

Binding attributes
In order for your asset to be considered valid, every published name in the
police_car_CNT section must be bound to an attribute of the police car.
Currently, the transMinusRotatePivot attributes are not bound, so the template
is invalid. To fulfill this template, you must bind them manually.

To bind the doors

1 In the left panel of the Asset Editor, click the square expand icon ( ).
The contents of the container appears.

2 Click the circular expand icon ( ) next to police_car_GRP.
A list of the node’s attributes appears.

NOTE If you do not see the circular expand icons ( ), make sure that
Display > Attributes (Channels) is turned on in the Asset Editor.

3 Scroll down and click the circular expand icon ( ) next to the Trans
Minus Rotate Pivot attribute.


4 Do one of the following:
■ In the left panel, select Trans Minus Rotate Pivot X, and then in the

right panel, click the bind icon ( ) next to
transMinusRotatePivotX. Do the same for Trans Minus Rotate Pivot
Y and Trans Minus Rotate Pivot Z.

■ In the left panel, select Trans Minus Rotate Pivot and then in the right

panel, click the bind icon ( ) next to transMinusRotatePivot. This
is the parent attribute and binding it automatically binds the X, Y, Z
children.

A small green icon appears next to the published name indicating that
it is now bound and the bind icon changes to an unbind icon. The name
of the attribute it is bound to appears on the right side of the bind icon.

NOTE Binding an attribute automatically publishes it to your container.

When you are finished all the icons in the police_car_CNT section should be
green. Your template is now valid.

Binding attributes | 739

NOTE You could also fulfill the template by selecting the container and then
selecting Assets > Publish Connections. This publishes all incoming and outgoing
connections to and from your container and binds them to appropriate published
names. However, this option also publishes extra attributes which you do not
necessarily need published in this case. In most cases it is up to you to decide
which method works better for your given situation.

Swapping assets
Assets with partial or fully identical sets of published names can be swapped
while maintaining the values of the matching published attributes. This allows
you to quickly re-purpose scenes or swap different assets in and out of your
current scene.

To swap the police car for a fire truck


2 Navigate to the Fire truck file that you saved in Lesson 1.


If you didn’t start at Lesson 1, navigate to Getting
Started/Assets/assets and select the file firetruck_templated.mb.
Maya imports the fire truck into your scene.

3 In the Outliner, select police_car_CNT and Ctrl + select fire_truck_CNT.

4 Select Edit > Transfer Attribute Values > .
The Transfer Attribute Values Options window appears.

5 In the Transfer Attribute Values Options window, select Edit > Reset
Settings.

6 Turn on Values.

7 Turn on In connections and set it to Transfer from source.

8 Turn on Out connections.


The fire truck jumps to the police car’s position so that they overlap. If you
play the animation now, the fire truck follows the police car’s previous path
and then stops outside the apartment building and opens its doors. The police
car remains stationary.

Swapping assets | 741

You can now delete the police car asset from the scene by selecting it in the
scene and pressing Delete. Remember to delete the container from the Outliner
afterward.

Referencing assets in a scene
In the previous section you imported a fire truck asset directly into the scene.
However, you can also reference assets from other files. File referencing allows
you to represent an object from another file in your scene without actually
importing that file.
References do not use as much memory as full imports, and have the added
benefit of allowing you to tweak referenced material in their source files, and
have the referenced material automatically update in your main file. This
allows multiple people to work on different pieces of a single scene
simultaneously.

To reference an asset

1 Select File > Reference Editor.
The Reference Editor window appears.

2 In the Reference Editor, select File > Create Reference > .


4 Click Reference.



5 Navigate to Getting Started/Assets/assets and select police_car.mb.

6 Click Reference.

An entry appears in the Reference Editor. This represents the police car. You
can turn the reference on and off by clicking the check box next to the
reference name.
Now you can move the police car asset to the appropriate spot in your scene.
Up until now, you’ve been using the Outliner to select your containers.
However, you can change the selection method so that you can select them
in your scene.

To turn on container centric selection

The Preferences window appears.

2 In the select the Selection section under Settings.

3 Turn on Container centric selection.

4 Click Save.

Now if you click on any part of the police car in the main scene, Maya selects
the object’s container.
Now select the Move Tool and move the police car to the edge of one of the
streets in the scene. Using the same procedure outlined above, reference the
same police car file 3 more times and arrange the police cars around the scene,
but not in the path of the fire truck.

Referencing assets in a scene | 743

Now you need a reason for all the emergency vehicles crowding around.

To reference a fire asset

1 In the Reference Editor, select File > Create Reference > .

2 Click Reference.

3 Navigate to Getting Started/Assets/assets and select flames.mb.

4 Click Reference.

5 Use the Move Tool to position the explosion a window on the building
that the fire truck stops at. You can also use the Rotate Tool to angle the
fire out towards the street.

Now if you play the scene, the apartment burns before the fire truck arrives.


Creating a proxy container
With so many new additions to the scene, you may notice the interactive
performance slowing down. You can speed up your scene by using proxy
containers.
A proxy is an object that stands in a scene for another, more complex object.
Proxy objects allow you to quickly switch between complex and simple
representations of an object in your scene. They are useful for temporarily
reducing the complexity of the scene as you work with it.

To export a proxy container

1 In the scene view, select the fire’s fluid container.
Since container-centric selection is on, this selects the fire’s container.

2 Select File > Export Proxy Container.

3 Navigate to Getting Started/Assets and type the name flame_proxy.mb.

4 Click Export.
Maya creates a proxy file.

Now you can load the proxy to represent the container.

Creating a proxy container | 745

To load a proxy

1 In the Reference Editor, select the referenced flame file that appears next

to the proxy container icon ( ).

2 Select Proxy > Reload Proxy as > proxyContainer (flame_proxy.mb).
The police car disappears and a locator appears in its place.

The container for your fire still appears in the Outliner, however if you expand
it, only a single locator node appears (instead of the fire’s group node).

Likewise, the fire in your scene has been replaced with a locator node. Your
interaction with this container has not changed, you can still assign values
to the published attributes and move the locator around the scene. When you
reload the proxy container again, the fire reflects those changes. However, if
you play the scene when the proxy container is active, the scene playback is
much faster.


Modifying a proxy container
Although the locator in the scene gives you the position of your referenced
asset, it doesn’t accurately convey the size or shape of the object it represents.
You can modify the proxy file to give the proxy container a more useful shape.

To modify the proxy container

1 Save your current scene file.

2 Select File > Open Scene.

3 Navigate to Getting Started/Assets and select flame_proxy.mb.

4 Click Open.
Maya opens the proxy file.
The proxy file consists of a single locator at the center of the scene. You
can add geometry to this file to customize the representation of the fire.


NOTE Make sure Interactive Creation is turned off in the Create > Polygon
Primitives menu.

The Create Polygon Cube window appears.

Modifying a proxy container | 747


7 Set the following attributes:
■ Width: 10.5

■ Height: 16.5

■ Length: 6.5

8 Click Create.
A polygon cube appears in the scene.

9 Select the cube and open the Channel Box.

10 Set Translate to 400.581, 84.139, -90.849.

11 Set Rotate Y to 15.

12 Open the Outliner (Window > Outliner).

13 Expand flame_CNT.

14 Select pCube1 and middle-mouse drag it onto the locator node inside
flame_CNT.
Performing this step allows you to move the cube and locator together.

You can add vertices and model the cube to shape it look more like fire if you
choose. You can find polygon modeling tips in Polygonal Modeling on page
71.
Now save this file and return to your original scene file. The proxy that was
once a single locator has now changed to a cube that is roughly the size of
the referenced fire effect.


You can switch back to the the fluid effect by right-clicking the proxy and
selecting Reload Proxy As > original from the marking menu.

Dressing the rest of the scene with assets
To finish dressing the scene you can import (or reference) a number of other
assets located in the Assets directory. For example, you could:

■ Import barricade.mb to block roads and give the fire truck a clear path.

■ Import trafficlight.mb and place a copy over each intersection.

■ Import park.mb to add a public park.

■ Import trashbag.mb and trashcan_A.mb to make the city dirtier.

■ Import a few more police cars to create a police barricade.

■ Import additional instances of flames.mb to make all the windows in the
building burn.

Notice that assets can range from very simple objects (trashbags, trashcans),
to collections of objects (the park), to complex objects with moving parts (the
police car), yet all of them are treated as single black box container nodes in
the scene each with a single interface. You could take this further by placing

Dressing the rest of the scene with assets | 749

all similar objects (all trash bags and trash cans for example) into a single
container.

You can now batch render the scene to see your finished product.

To batch render the scene

1 If you haven’t done so already, set all proxies to their original
representations by right-clicking them and selecting Reload Proxy As >
original from the marking menu.

2 Position the camera in a spot where you can see the majority of the action.

3 Click the Render Settings button ( ).

4 Set the following:
■ Image format: Maya IFF (iff)

■ Frame/Animation ext: name.#.ext

■ Start frame: 0

■ End frame: 170

5 Click Close.

6 In the Rendering menu set, select Render > Batch Render.


Maya batch renders the scene. This may take a few minutes. You can
monitor the progress in the Status Line.

When the batch render is complete, you can view the sequence by selecting
File > View Sequence, and then opening the first file of the sequence (it has
an extension of .001). Maya then plays back the sequence of rendered images
showing you the final animation.

Beyond the lesson
In this lesson you learned how to incorporate assets into a scene.

■ You can use an existing template to define an asset.

■ You can swap one asset for another.

■ You can reference assets into a scene and instance them multiple times.

■ You can create proxy containers to stand in for referenced assets.

■ Imported additional assets to dress the scene.


Hair
15
Introduction

With Maya® HairTM, you can create a dynamic hair system to model realistic
hairstyles and hair behavior.
Since Hair is a generic dynamic curve simulation, you can also use these curves
to create non-hair effects, including ropes, chains, a suspension bridge, sea
creatures, or lofted surface from a curve.
With Hair you can simulate:

■ natural movement and collisions of long hair

■ hair blowing in the wind or being blow dried

753

■ hair when swimming underwater

■ various hairstyles, including ponytails, braids, and updos

■ other dynamic curve effects such as ropes, chains, cables, wires, etc.

A hair system is a collection of hair follicles.
A hair follicle in human hair typically hosts one hair, whereas in Maya each
hair follicle hosts a hair curve. The hair follicle controls the attributes and curves
associated with a particular hair clump, and how the hairs attach to a NURBS
or polygonal surface. The input to each follicle is a Start Position NURBS curve,
a surface and a UV position to attach to.
When creating hair, the hair system output can be in the form of NURBS curves,
Maya® Paint EffectsTM strokes, or both. If the specified output when creating
hair is NURBS Curves, each follicle will contain one NURBS curve that
represents the position of the hair in that follicle. If the specified output is
Paint Effects, each follicle has a hair clump, made up of Paint Effects strokes.
There are various attributes on a hair system for modifying the look and
behavior of the hair as a whole. There are also follicle level attributes that will
override the hair system attributes; the visible result will be affected by both
the follicle and hair system attributes.
You can have more than one hair system on the same surface.
With the Paint Hair Tool you can create new hair systems, add and remove
follicles, as well as paint hair attributes, including Clump Width Scale, Stiffness,
and Braid.
Paint Effects hair can be rendered using the Maya Software renderer. You can
also convert Paint Effects hair to polygons and render in another renderer,
such as mental ray® for Maya®. Or you can output just the dynamic NURBS
curves to an external renderer, such as Renderman.
Consider outputting to Paint Effects if you want to:

■ render with the Maya Software renderer

■ convert the Paint Effects hair to polygons and render in any renderer

Consider outputting to NURBS curves if you want to:

■ use the curves as path or control curves for any standard Paint Effects
brush, such as feathers or vines. These brushes behave differently than the
default built in Paint Effects as the curves are not the hairs, but controls

754 | Chapter 15 Hair

that interpolate and affect Paint Effects. This scenario is slower to update
and takes a bit of time to set up.

■ select a few Current Position curves and loft a surface through them with
construction history.

■ extrude a circle down the curve to create a tube.

■ use the curves for output to another renderer that directly supports curve
rendering.

Consider outputting to both NURBS curves and Paint Effects if you want to:

■ use both the curves (for example, as particle emitters to simulate spray
flying off wet hair) and render using the integrated Paint Effects either
directly or by converting to polygons.

About hair simulation
This is the general workflow to create and animate hair:

■ create hair on models

■ style hair curves

■ modify hair attributes

■ set up hair shading/shadowing

■ render the scene

This chapter includes these lessons:

■ Lesson 1 Creating a basic hairstyle: Introduction on page 756

■ Lesson 2 Creating a dynamic non-hair simulation: Introduction on page
777


1 Make sure you understand the basic concepts of modeling NURBS curves,
animation, and dynamics. For more information, see Maya Help.

About hair simulation | 755

2 Select the Dynamics menu set.
Unless otherwise noted, the procedures in these lessons assume the
Dynamics menu set is selected.

3 Select File > New Scene to create a new scene before you start each lesson.
For those scenes that require you to open a file, the Hair scene files are
located in GettingStarted/scenes directory. The GettingStarted
directory is installed in the same location as your Maya software
application.

4 Select Window > Settings/Preferences > Preferences. Click Timeline under
Categories and make sure the Playback Speed is set to Play every frame.
Dynamic animation plays more accurately with this setting.
Also set the playback and animation end times to 10000. This ensures
you have lots of time to interact with the playback of the hair simulation.

see Copying and setting the Maya project on page 25 in the Getting
Started with Maya guide.

6 We also provide a completed scene for each of the lessons in this chapter.
If you want to see the expected results of the lessons, you can open the
scenes located in the GettingStarted/Hair directory. The scene filenames
end with Finish.mb, for example, hairFinish1.mb.

Lesson 1: Creating a basic hairstyle

Introduction
You can create hair on NURBS and polygonal surfaces. For polygons, UVs
should be non-overlapping and fit between 0 and 1. Automatic mapping is a
quick way to achieve this. (See Automatic UV mapping in the Mapping UVs
Guide in the Maya Help.) In this lesson you are creating hair on a head model.
There are three sets of curves for the hair system.

Start Curves/Posi- This is the position of the hair at the start frame of the simulation.
tion When first created, the Start curves stick straight out from the
surface.


Rest Curves/Posi- This is the position of the hair when no forces (such as gravity)
tion are acting upon it. You can use these curves to influence the shape
of the hair.
Working with Rest curves is like styling hair with hairspray. The
Rest curves are styled into curls and flips, etc. When the simulation
is played back, the hair adheres to the Rest curves position as
much as possible depending on dynamic forces and attribute
settings in the hair system and follicles. For example, if your hair
is not very stiff and you’re simulating a windy day, the hairspray
(Rest curves position) is less likely to hold the hair in position.

Current Position This is how the hair behaves when you play the simulation, which
includes dynamics. Do not edit the Current Position; just view it.
The Stiffness and Iterations attributes in the Hair system’s Dynam-
ics section are what control the tolerance of the Current Position
achieving the Rest Position.

In this lesson you are introduced to some of the basic concepts of hair by
creating a simple long hairstyle. In this lesson, you learn how to:

■ Create hair on a surface.

■ Play a hair simulation and interact with it during playback.

■ Manipulate hair curves to create a hairstyle.

■ Use collision constraints to make hair collide with a model’s head, neck
and shoulders.

■ Modify hair attributes.

■ Set up hair self shadows.

■ Render hair.

Lesson setup
In this lesson, you'll work with a scene we created for your use.

1 Before beginning the lesson, do the steps in Preparing for the lessons on
page 755.

2 Open the scene named hairStart.mb that is located within the
GettingStarted/Hair directory of your Maya project.

Lesson setup | 757

This scene provides a NURBS head model, named Marion, and the scalp
surface for creating the hair. Part of the model has been templated to
make picking the scalp easier.

Creating hair on a surface
When you first create hair it appears sticking out normal to the surface. For
a more natural look, play the hair simulation to see the hair react to gravity
and then you can set a more realistic Start position for the hair. In these steps
you create hair on a NURBS model and set a Start position after playing the
simulation. You use Interactive Playback to play the simulation while adjusting
dynamic hair system attributes and see how your changes affect the simulation.

NOTE Before continuing with the procedures below, make sure the End Time and
Playback End Time in the Range Slider are both set to 10000.

To create hair on a model

1 Select Marion’s scalp, as shown in the image below.

2 Select Hair > Create Hair > and in the Create Hair Options window,
specify the following:
■ Set Output to Paint Effects.


■ Set the U count to 26 and the V count to 22. These determine how
many hair curves within each UV range.

■ Set the Passive fill to 0. No passive curves will be used in this lesson.
The behavior of passive curves is interpolated between neighboring
active curves. For more information, see Passive hair curves in the
Hair guide.

■ Set the Randomization to 0.5. A value of 1 represents total
randomization of placement of hair curves on the surface, whereas a
value of 0 represents no randomization.

■ Set the Points per hair to 10. This sets the number of segments per
hair. More segments are needed to make long hair look natural or to
create complex short hairstyles. As you increase the number of
segments, you decrease the performance (speed) of the simulation.

■ Set the Length to 10. This value is relative to the world space units.

■ Both the Create Rest Curves and Edge Bounded options should be
turned off.

■ Turn the Equalize option on. This ensures the hair curves are evenly
distributed over the surface.

■ Click Create Hairs.

The hair is attached to the scalp and sticks out perpendicular to the
surface. You are looking at the Current Position of the hair, which is also
referred to as the “dynamic” position. Do not edit the hair curves in this
view; edit only in Start Position or Rest Position.

Creating hair on a surface | 759

To play the hair simulation

1 Click the Play button to play the simulation.
The hair falls due to default dynamic forces, such as gravity, which are
found in the hair system attributes. However the hair takes a while to
fall, which is as a result of a high Display Quality setting.

2 Click the Stop button to stop the simulation when the hair is relaxed
as it is in the following image.


Notice the hairs are quite stiff and stick out from the scalp instead of
naturally falling closer to the scalp. To make the hair appear less stiff you
can either increase the number of Points Per Hair (segments), which
increases the simulation and render time, or you can reduce the Stiffness
value in the hair system’s Dynamic attributes.
In the next part of the lesson you adjust dynamic settings of the hair
system, including Stiffness and Gravity, to achieve more naturally
behaving hair.

To improve playback performance and modify dynamic settings

1 In the Attribute Editor (Ctrl + a) select the hairSystemShape1 tab and
change Display Quality to 2. This affects how many hairs display in the
scene view, but has no effect on how much hair appears in the software
render. By reducing the Display Quality, this speeds up the playback of
the hair simulation.

2 In the Dynamics section the default value for Stiffness is 0.10. Since the
hair is quite stiff, reduce the Stiffness value to 0.07.

3 Select Solvers > Interactive Playback to play the simulation. Watch the
hair begin to relax more.

4 With the simulation still playing go to the Dynamics section of the
hairSystemShape1 tab and change the Gravity value to 2.5. Watch the
hair relax even more and rest closer to the scalp, as hair does naturally.

Creating hair on a surface | 761

5 Click the Stop button when the hair has relaxed as in the following
image.

To set the position of the hair for the start frame

1 When you are playing the hair simulation, by default you are viewing
the Current position curves. To select all the Current position curves,
click any hair curve and then select Hair > Convert Selection > to Current
Positions.

2 To set the start frame of the hair simulation to how the hair appears now,
select Hair > Set Start Position > From Current.

3 Select Hair > Display> Start Position to view the Start curves and see that
they took on the Current Position.

4 Click the button to rewind to the start frame.
The position of the hair at the start frame is now relaxed.

Styling the hair
To style the hair you manipulate either the Start or Rest curves to achieve the
look you want. In these next steps you first edit the Start curves to create the
basic hair shape. Then you set an initial Rest position for the hair and style
the hair by editing the Rest curves.


To edit the Start curves to create the basic hair shape

1 Display the Start curves. (Hair > Display> Start Position.

2 Tumble the camera so you’re looking at the side of Marion’s head.

3 To select the Start curves on the front half of Marion’s face, do the
following:

■ On the Status Line, click the Object Selection Mask button and
choose All Objects Off from the drop-down menu that appears.

■ On the Status Line, click to highlight the icon to restrict the
selection to curves.

■ Drag around the front half of Marion’s head to select the Start curves
as shown in the following image.

4 Now tumble the camera so Marion is again facing you.

5 To trim the Start curves in the front, do the following:
■ Select Hair > Modify Curves > Lock Length. This allows you to
manipulate the curve while maintaining the curve’s hull length.

■ Click the in the Status Line to display the curves’ CVs.

■ Using the Lasso Tool , select CVs in an inverted U-shape around
the front of Marion’s face, as shown in the following image.

Styling the hair | 763

■ Press Delete to remove the selected CVs.

6 To curl under the ends of all the Start curves, do the following:

■ Click the button to display the curves and then drag around
Marion’s head to select all the Start curves.

■ Click the button to display CVs and then, using the Select Tool,
select the CVs in the bottom half of all the curves.

■ Select Hair > Modify Curves > Bend .

■ In the Bend Curves Options window, set Bend Amount to 0.5 and
Twist to 1.0 and then click Bend Curves.


The selected CVs are bent under towards Marion’s neck. To fix any unruly
hairs, you could select them and then select Hair > Modify Curves>
Smooth.

7 Click the button to display the curves.

8 Change the display to include the Start curves and the Current Position.
(Hair > Display> Current and Start)

9 Click the Play button to play the hair simulation.
Even though you styled the Start curves, notice how they fall straight
and lose the bend at the end. Start curves only define the position of the
hair at the Start frame of the simulation; once the simulation is started
the Start curves are affected by the dynamic forces applied to the hair
system. To “hairspray” a hairstyle, you need to style Rest curves and adjust
dynamic hair system settings. In the next steps you create Rest curves
from the Start curves.

10 Click the Stop button to stop the simulation.

To create and modify the Rest curves to achieve a hairstyle

1 To create Rest curves from the shaped Start curves, do the following:
■ Select Hair > Display > Start Position

Styling the hair | 765

■ Using the Select Tool , drag to select all the Start curves and
then select Hair > Set Rest Position> From Start.

2 To see the new Rest curves, select Hair > Display> Current and Rest.

3 Select all the hair curves and then click the Play button to play the
simulation. Watch how the Current position hairs flop down because
the Gravity value is quite high (2.5).

4 To see what the hair would look like without any gravity, go to the
Dynamics section in the hairSystemShape1 tab and change the Gravity
value to 0.
Watch the hair try to achieve the Rest position.

5 After the hair reaches the Rest position, change the Gravity value back
to 1.0.

6 As the hair starts to fall due to gravity, increase the Stiffness value to 0.2.
If some Rest curves won’t relax and stabilize, increase Length Flex and
Iterations in the hairSystemShape1 tab.

7 Once the hair stabilizes, click the Stop button to stop the simulation.

8 You can further “hairspray” the curled ends of the Rest curves using the
Stiffness Scale attribute. The curve in the Stiffness Scale graph illustrates
the amount of stiffness applied along the hair curve from root (left side
of the graph) to tip (right side of the graph). Go to the Dynamics section
in the hairSystemShape1 tab and change the Stiffness Scale attribute as
shown in the following image. These changes add more stiffness to the
end of the hair, which will hold the bend more firmly.

9 Play the simulation to see the effect of the changes to Stiffness Scale.


10 Stop the simulation once the hair relaxes as in the following image.

11 To reset the Start curves from the simulation, select Hair > Set Start
Position> From Current.

12 Click the button to rewind to the beginning of the simulation.

Setting up hair collisions
Before trimming Marion’s hair you may have noticed that some hairs
intersected her face. As well hairs currently intersect the lower part of her
neck. To fix this you set up hair collisions. You can set hair to collide with
itself, other objects or the ground (grid). In the next steps you use collision
constraints to prevent the hair from intersecting with Marion’s head and neck.

Setting up hair collisions | 767

To make Marion’s hair collide with her head and neck

1 In the panel, select Show > Locators so you can see collision constraints,
which are locators, when you create them.

2 To create the collision constraint for Marion’s head, do the following:
■ Select Hair > Display > Start Position.

■ Using the Select Tool, drag around all the hair curves and select Hair
> Convert Selection > To Start Curves.

■ Select Hair > Create Constraint > Collide Sphere.

■ Using the Scale Tool, resize the sphere so it expands beyond Marion’s
head and you can see it.

■ Using the Move Tool, move the sphere up the Y-axis so the top of the
sphere is aligned with the top of Marion’s head.

■ Using the Scale Tool again, resize the sphere so it matches the basic
shape of Marion’s head. First try scaling in the X direction to adjust
the width of the sphere from ear to ear. Then tumble the camera to
see the side of Marion’s head and scale in the Z direction to adjust
the sphere width from the back of Marion’s head to her nose. You
may also need to move the sphere to tweak its size and position, as
shown in the images below.


3 To create the collision constraint for Marion’s upper torso, do the
following:
■ Using the Select Tool, drag around the hair curves and select Hair >
Convert Selection > To Start Curves.

■ Select Hair > Create Constraint > Collide Sphere.

■ Using the Scale Tool, resize the sphere so it extends beyond Marion’s
neck and you can see it.

■ Using the Move Tool, move the sphere down the Y-axis so the top of
the sphere is aligned with the top of Marion’s torso.

■ Using the Scale Tool again, resize the sphere so it matches the basic
dimensions of Marion’s upper torso. First try scaling in the X direction
to adjust the width of the sphere from shoulder to shoulder. Then
tumble the camera to see the side of Marion’s head and scale in the
Z direction to adjust the sphere width from the back of Marion’s torso
to the front of it. You may also need to move the sphere to tweak its
size and position, as shown in the images below.

Setting up hair collisions | 769

4 Select Hair > Display> Current Position.

5 Click the button to rewind to the start frame and play the
simulation.
Watch how the hair collides with the collision constraints you created.
The hair at the front now rests on the torso and the hair at the back curls
under the torso, instead of intersecting it like it did before the collisions
were set.

6 Stop the simulation when the hair is relaxed. Should the hair be unruly
and not relax, you may need to increase the Stiffness or the Iterations in
the Dynamics section of the hairSystemShape1 tab of the Attribute Editor.

7 Select the hair, then select Hair > Set Start Position > From Current so
the hair respects the collisions at the start frame of the simulation.


8 Select Show > Locators to turn them off, which hides the collision
constraints.

Rendering the hair
When you modify hair attributes, many of these changes are not visible in
the scene view; the Paint Effects hair must be rendered in the Maya Software
renderer. In the next steps you render Marion’s hair as it is now, which allows
you to see what aspects of the hair need work to make it look more realistic.
Before rendering, be sure to set the appropriate Render Settings.

To render Paint Effects hair using the Maya Software renderer

1 Modify the Render Settings for Paint Effects.

■ Click the Render Settings button on the Status Line. The Render
Settings window appears.

■ Select Maya Software from the Render using drop-down list.

■ In the Maya Software tab, go to the Paint Effects Rendering Options
section and turn on Oversample and Oversample post filter. These
help achieve a better look for the Paint Effects rendering. The option
Enable stroke rendering is already on by default.

■ Click Close to close the Render Settings window.

2 Before rendering be sure to display the hair system’s Current Position
(Hair > Display > Current Position).

3 Click the Render Current Frame button on the Status Line.
The hair model is rendered and should look something like the image
below.

Rendering the hair | 771

Modifying hair attributes
You can modify the hair as a whole by modifying the hair system attributes.
You can modify the look of individual hairs or clumps of hair by editing their
follicle attributes. In the next steps, you modify various hair system attributes
to make Marion’s hair look fuller and more realistic. Then you add curl to
Marion’s hair.

To modify the thickness of the hair all over

1 To select the hair system, drag around the hair curves and select Hair >
Convert Selection > to Hair Systems.

2 Go to the Clump and Hair Shape section in the hairSystemShape1 tab of
the Attribute Editor and adjust the following:
■ Hairs Per Clump to 30, which controls the number of hairs per curve
(hair clump). Increasing the number of Hairs Per Clump increases the
rendering time.

■ Sub Segments to 2, which adds this many points between
segments/points and helps to smooth the hair curves.

■ Thinning to 0.5, which controls how much the hair thins out from
root to tip.

■ Clump Width to 0.3, which controls the width of the hair clump from
root to tip. To further modify the hair clump width, you could adjust
the Clump Width Scale attribute, which allows you to vary the width
along the hair from root to tip.


■ Hair Width to 0.02, which controls the width of each hair.

3 Click the Render Current Frame button to render the hair to see
the changes you’ve made to the hair.

To make hair curly

1 With the hair system still selected, go to the Displacements section in
the hairSystemShape1 tab of the Attribute Editor and set the following:
■ Curl to 1, which is the amount of curl displacement applied to each
hair. The amount of displacement is relative to the hair width.

■ Curl Frequency to 15, which is the rate of curl. The higher the value
is, the more curls there are.

2 Click the Render Current Frame button to render the hair to see
the changes you’ve made to the hair.

Modifying hair attributes | 773

Setting up shadowing on hair
Hair, by default, is translucent so you need to set up self shadowing, otherwise
hair appears glowing, like nylon. The darker the hair color is, the more
important the specular color and highlights become.
There are three directional lights in this scene. In the software render you did
in the previous steps, Marion’s hair appears blond and glowing, even though
the default hair color is dark brown, as in the scene view. This apparent hair
color discrepancy occurs because:

■ hair is by default translucent (like a glass tube)

■ the hair is being lit by all three lights, therefore the intensity of the light
is tripled

■ there are no shadows, so all the hairs are illuminated

In these next steps you set up shadows on all three lights.

To set up shadows and self shadows on hair

1 Select Window > Outliner.

2 In the Outliner menu, select Show > Objects > Lights.

3 Select one of the three directional lights.

4 In the light’s Attribute Editor, go to the Shadows section and in the Depth
Map Shadow Attributes subsection, turn on Use Depth Map Shadows.


Normally you would increase the Filter Size to blur the light in the hair
for realism, and increase the Bias, which sets how far the light filters
through the hair. These attributes were set for you in the scene.

5 Repeat steps 3 and 4 for the other two directional lights.

6 Render the hair to see the changes.
The shadows on the hair are hard and there is very little specularity. You
fix this in the next steps.

To create specular highlights on hair

Convert Selection > to Hair Systems.

2 Go to the Shading section in the hairSystemShape1 tab of the Attribute
Editor and set the following:
■ Click the Specular Color box and set the values as shown in the image
below.

■ Increase Specular Power to 15.

3 Render the hair to see the changes. The hair looks much more natural
now.

Setting up shadowing on hair | 775

Beyond the lesson

■ Create dynamic hair on a surface.
You can add hair to a NURBS or polygonal surface by creating or painting
the hair. For polygons, UVs should be non-overlapping and fit between 0
and 1. Automatic mapping is a quick way to achieve this (seeAutomatic
UV mapping in the Mapping UVs guide). For more information, see
Creating hair in the Hair guide.
Before creating hair, you should determine which renderer you’ll be using
as this will affect what type of hair output you select: NURBS curves or
Paint Effects, or both.

■ Interact with the dynamic playback.
While using interactive playback you can modify the hair and see the hair
react to dynamic forces. For more information, see Play a hair simulation
in the Hair guide.

■ Model hair curves.
Style hair by transforming hair curves and using Lock Length to maintain
the length between CVs on a curve. You can also use Fields to style hair
and then add constraints to hold hair in position. For more information,
see Styling hair and modifying the hair look and behavior in the Hair
guide.

■ Modify hair system and follicle attributes.
You can change the look (color, curl, etc.) of the overall hair by modifying
attributes in the hairSystemShape node. But individual follicle attributes
can be modified in the follicleShape node, which override or blend with
the hair system attributes. For more information, see the following topics
in the online help: Hair system attributes (hairSystemShape in the Hair
guide), Follicle attributes (follicleShape in the Hair guide) and Set up hair
shading in the Hair guide.

■ Render the hair.
Paint Effects hair can be rendered using the Maya Software renderer. You
can also convert Paint Effects hair to polygons and render in another
renderer, such as mental ray. Or you can output just the dynamic curves
to an external renderer, such as Renderman. For more information, see
Rendering scenes with hair in the Hair guide.


You can also create non-hair models and effects with Hair. Any NURBS curve
can be made into a dynamic hair curve. In addition to creating long hair and
hairstyles you can use hair curves to create:

■ ropes and chains (dynamic curves)

■ a fish (wire deformer)

■ a fishing line (single hair with expressions)

■ an octopus (select hair curves and create a lofted surface)

■ a paint brush painting on canvas, bristles colliding with the surface (hair
simulates paint brush bristles, Fluid emitters on the canvas controlled by
expressions)

In addition you can assign a Paint Effects brush to a hair system as shown in
the image below.

Lesson 2: Creating a dynamic non-hair simulation

Introduction
Using Maya Hair, you can create dynamic non-hair models and effects. You
can make NURBS curves dynamic, or you can use a hair system to create a

Lesson 2: Creating a dynamic non-hair simulation | 777

non-hair simulation, such as chains or ropes. In this lesson, you create a hair
system to simulate a beaded curtain. To make the hairs look like beads, you
assign a Paint Effects brush to the hair. Then you modify the hair attributes
and set constraints so the hair behaves like a beaded curtain hanging from a
curtain rod.

■ Make hair collide with an object

■ Assign a Paint Effects brush to hair

■ Set up hair constraints

Lesson setup
In this lesson, you work with a new empty scene and change the playback
range.


2 In the Time Slider change both the End Time value and Playback End
Time value to 300.

Setting up the curtain scene
In these steps you model a 2D curtain rod from a plane and attach hair to it.
Then you add and keyframe a sphere in the scene to later be used as a collision
object.


To create the curtain using Hair

1 To create a NURBS plane, select Create > NURBS Primitives > Plane, then
click-drag in the scene to create a plane.
(If you have previously shut off the interactive primitive creation option,
simply click once in the scene to create the primitive at the origin.)

2 Using the Scale Tool , resize the plane in the X direction as shown
in the image below.

3 With the plane selected, select Hair > Create Hair > , set the following
options and then click Create Hairs:
■ Output to NURBS Curves

■ U Count to 20, V count to 1

■ Passive fill to 0

■ Randomization to 0

■ Points per hair to 12

■ Length to 10

■ Turn off the options Create Rest Curves, Edge Bounded and Equalize

Hair is created and attached to the plane.

Setting up the curtain scene | 779

4 Select the plane and, using the Rotate Tool , rotate the plane so
the hair appears to be on the underside of the plane. Then, using the

Move Tool , move the plane up the Y axis so the bottom of the
hair just touches the ground plane, as shown in the following image.
(Ensure you do not select the hair when selecting the plane.)

5 Create a directional light (Create > Lights > Directional Light) and do the
following:
■ Move the light above and to the left of the curtain.

■ Rotate the light so it aims at the curtain.

■ In the light’s Attribute Editor (ctrl + a) go to the Directional Light
Attributes section and change the Intensity value to 1.5.

6 Create a NURBS sphere (Create > NURBS Primitives > Sphere) and move
it along the Z-axis so it’s in front of the curtain.


7 To set the start keyframe for the sphere, do the following:
■ Go to frame 1 on the Time Slider.

■ In the Channel Box, drag to select the Translate X, Y, and Z channels.

■ Right-click the channels and select Key Selected.

8 To set the keyframe for the sphere and move it through the curtain, as
in the image below, do the following:
■ Go to frame 100 in the Time Slider.

■ Move the sphere in the Z direction as shown in the image below.

■ In the Channel Box, select the Translate Z channel.

■ Right-click the channel and select Key Selected.

9 Rewind the Time Slider to 0 and play the animation.
The sphere passes through the curtain as though the curtain weren’t
there. In the next steps you set the sphere as a collision object with the
hair.

Setting up the curtain scene | 781

Making the hair collide with another object
To have hair interact with a surface, you must set the hair to collide with the
surface. A collision object can be a NURBS or polygonal surface. In the next
part of the lesson you set the curtain to collide with the sphere and then play
the simulation.

To enhance the curtain for collisions

1 To select the hair system, drag around the hair curves and then select
Hair > Convert Selection > To Hair Systems.

2 In the hairSystemShape1 tab of the Attribute Editor, set the hair system
attributes as follows:
■ In the Clump and Hair Shape section, set Clump Width to 0.

■ In the Dynamics section, set Stiffness to 0.

To make the hair collide with the sphere

1 Select the hair system and the sphere (drag around the hair curves and
sphere).

2 Select Hair > Make Collide.

3 Play the simulation.
Now the sphere collides with the curtain, pushing the strands of hair
aside as it passes through.

Assigning a Paint Effects brush to the hair
You can assign a Paint Effects brush to a hair system to achieve a variety of
effects. In these next steps you apply the red beads brush to the hair system
to create the beaded curtain. Then you modify the brush and hair system
settings to achieve the desired look.

To turn the hair curtain into a beaded curtain

Convert Selection > To Hair Systems.

2 Open the Visor (Window > General Editors > Visor).

3 Go to the glass folder and select the beadsRed.mel brush.


4 Select Hair > Assign Paint Effects Brush to Hair.
You don’t see the beads in the scene view, but you will when you render
it later using the Maya Software renderer. The brush needs some
adjustments to make it look like a beaded curtain when it is rendered.

5 In the hairSystemShape1 tab of the Attribute Editor, set the following:
■ Hairs Per Clump to 1 so there is one strand of beads

■ Hair Width to 0.03

■ in the Hair Color Scale section, Hair Color to white so the brush’s
bead color appears

■ in the Shading section, Specular Color to red

■ in the Displacements section, Noise to 0.5 to create some variety in
the appearance and behavior of the beads

6 In the beadsRed tab of the Attribute Editor, go to the Texturing section
and change the RepeatU to 10 so the beads appear as a more realistic
bead size. (If the beadsRed tab does not appear in the Attribute Editor,
re-select the hair curves. The beadsRed tab should now appear.)

7 Dolly in close to the curtain (Alt + the right mouse button) and click the

button to render the current frame.

Assigning a Paint Effects brush to the hair | 783

Setting up constraints
In these next steps you tie up the middle section of the beaded curtain by first
modeling the Start curves into a bound position and then creating a constraint
to hold the curves in that position during playback. With a Hair to Hair
constraint the hair curves stick together at the constraint locator, but also
dynamically move from root to tip when forces or collisions occur.

To model the curtain into a tied-back position

1 Dolly and tumble in the scene until you are facing the curtain directly.

2 Drag to select all the hair curves and then select Hair > Convert Selection
> To Start Curves.

3 Select a block of Start curves in the middle of the curtain.

4 Select Hair > Modify Curves > Lock Length. This ensures the entire curve
is modified when you transform CVs in the next steps.

5 Click the button on the Status Line to display the CVs on the curves.

6 Select the middle three rows of CVs on the selected hair curves and then,
using the Scale Tool, scale the CVs inwards so the hairs are pulled together.


To constrain the curtain in the tied-back position

1 Click the button on the Status Line to display the Start curves (not
the CVs).

2 With the bound hair curves still selected, select Hair > Create Constraint
> Hair to Hair.
A constraint locator is created and connected to the selected curves.

3 In the hairConstraintShape tab in the Attribute Editor, set the constraint
attributes as follows:
■ Stiffness to 0.5 (default)

■ Glue Strength to 1.0 (default)

■ Point Method to Nearest (default) (Since the constraint locator is
created in the middle of the bound hair, the locator is “nearest” the
bound area to be constrained.)

4 Change the hair display to the Current Position (Hair > Display > Current
Position).

5 Rewind to the start frame and play the simulation.
When the sphere passes through the bound curtain it collides with all
the bound hairs.
The bound part of the curtain relaxes within the first several frames, but
in the next steps you reset the position of those Start curves so they look
more natural at the beginning of the simulation.

Setting up constraints | 785

To reset the Start position

1 Display the Start curves and the Current Position (Hair > Display > Current
and Start).

2 Rewind to the start frame and play the simulation.

3 Stop the simulation as soon as the curves relax below the constraint, but
before the collision occurs.

4 Select the bound Start curves (these are the bound curves that are not
blue) and then select Hair > Set Start Position > From Current.
You may have to repeat steps 2 to 4 a few times until you are happy with
the look of the bound curtains at the beginning of the simulation.

Rendering the curtain scene
In these next steps you render the curtain, which is Paint Effects hair, in the
Maya Software renderer.

To render the Paint Effects hair using the Maya Software renderer

1 To modify the Render Settings for Paint Effects do the following:

■ Click the Render Settings button on the Status Line. The Render
Settings window appears.


■ Select Maya Software from the Render Using drop-down list.

■ In the Maya Software tab, go to the Paint Effects Rendering Options
section and turn on Oversample and Oversample Post Filter. These
help achieve a better look for the Paint Effects rendering.

■ Click Close to close the Render Settings window.

2 Before rendering be sure to display the hair system’s Current Position
(Hair > Display > Current Position).

3 Play the simulation and stop at the frame you want to render.

4 Click the Render Current Frame button on the Status Line.
The curtain scene is rendered and should look something like the image
below.
If you have trouble seeing the beads, try moving the light closer to the
curtains or increasing the light intensity in the Channel box.

Beyond the lesson

■ Set up objects to collide with hair.
You can set up hair to collide with itself, the ground plane or other objects.
You can even use the Collision Sphere and Collision Cube constraints to
establish implicit collisions. For more information, see Make hair collide
in the Hair guide.


■ Assign a Paint Effects brush to a hair system.
This is useful for creating a variety of effects, such as vines or ivy for hair.
The hair output can be Paint Effects or NURBS curves. For more
information, see Assign a Paint Effects brush to Hair in the Hair guide.

■ Create constraints on hair curves.
Use hair constraints to hold hair in position for a hairstyle, such as a
ponytail or a clasp. You can even use hair constraints for more realistic
hair behavior, such as using the Transform constraint to hold the hair to
the head. For more information, see Set up hair constraints in the Hair
guide.


Fluid Effects
16
Introduction

Fluids are substances that change shape continuously or flow in response to
forces.
Using Maya Fluid EffectsTM, you can realistically simulate 2D and 3D
atmospheric effects (such as clouds and mist), combustion effects (such as smoke,
explosions, and burning flames), and viscous fluid effects (such as molten lava).
You can also use the Fluid Effects ocean shader to simulate open water.
In Maya, there are three basic types of fluid effects:

■ Dynamic fluid effects – Behave according to the natural laws of fluid
dynamics and simulate the effects by solving fluid dynamics equations for
each time step.

■ Non-dynamic fluid effects – Use textures and animation to simulate fluid
and fluid motion. These types of effects do not use fluid dynamics equations.
Dynamic and Non-Dynamic effects render as 3D volumes, so they interact
appropriately with objects that move through them.

789

■ Open water fluid effects – Use shaders to create realistic wave motion on
large bodies of water.

This chapter includes the following lessons, which introduce you to some
basic Fluid Effects concepts:

■ Lesson 1 Creating a dynamic 2D fluid effect: Introduction on page 791

■ Lesson 2 Creating a non-dynamic 3D fluid effect: Introduction on page
801

■ Lesson 3 Creating a dynamic 3D effect: Introduction on page 810

■ Lesson 4 Creating an ocean effect: Introduction on page 819




3 Select the Dynamics menu set.
selections assume you’ve already selected the Dynamics menu set.

4 Switch to shaded display mode for a hardware render view of the fluid
simulations (Shading > Smooth Shade All on the view menu bar).

5 In the Time and Range slider, set the start frame to 1 and end frame to
200.

6 Before you perform the lessons in this chapter, ensure that the Interactive
Primitives > Interactive Creation and Create > NURBS Primitives >
Interactive Creation. That is, ensure that a check mark does not appear
beside either of these menu items.

790 | Chapter 16 Fluid Effects

7 Make sure you understand the basic usage of the animation playback
controls. See the chapter entitled “Animation” in Getting Started with
Maya or refer to the Maya Help.

Lesson 1: Creating a dynamic 2D fluid effect

Introduction

Fluid dynamics is a branch of physics that uses mathematical equations to
describe how things flow.
In Fluid Effects, dynamic fluid effects simulate fluid motion by solving fluid
dynamics equations at each time step. You can texture dynamic fluids, have
them collide with and move geometry, affect soft body geometry, and interact
with particles.
Non-dynamic fluid effects do not use fluid dynamics equations to simulate
fluid behavior. You create the look of a non-dynamic fluid using textures, and
you create fluid motion by animating (keyframing) texture attributes. Because
Maya doesn’t solve the equations, rendering this type of fluid is much quicker
than rendering a dynamic fluid.
In this lesson, you create a simple two-dimensional dynamic fluid. You learn
how to:

■ Create a fluid using fluid emitters

■ Modify the dynamic behavior of the fluid by applying forces to it and
changing the effect the boundary has on the fluid

■ Change the color of the fluid

■ Collide the fluid into an object

In the next lesson, you’ll create a non-dynamic fluid effect.

Lesson 1: Creating a dynamic 2D fluid effect | 791

Creating a two-dimensional fluid container
You begin the lesson by creating a two-dimensional fluid container. The fluid
container is the basis for dynamic and non-dynamic fluid effects. As its name
implies, it contains the fluid effect. Fluids cannot exist outside a fluid container.

To create a two-dimensional fluid container

➤ Select Fluid Effects > Create 2D Container.
Maya creates an empty 2-dimensional fluid container centered at the
origin in the XY plane.

Next, you add fluid to the container. To do this, you add values to the
container for specific properties of the fluid: Density, Color, Velocity,
Fuel, and Temperature. You can add any or all of these properties to create
a fluid effect. One way to put properties into a container is to create them
with a fluid emitter.

Adding a fluid emitter to a container
Fluid emitters create fluid property values and emit them into containers as
the simulation plays. The emitter controls the position, rate of emission, and
turbulence forces applied to the fluid properties when they are created. After
fluid property values are created, the attributes of the fluid container control
their appearance and behavior.
You can add multiple fluid emitters to containers. You move fluid emitters
the same way you move any geometry (for example, by setting keys).

To add a fluid emitter to the container

1 With the container selected, choose Fluid Effects > Add/Edit Contents >
Emitter.
Maya creates a fluid emitter called fluidEmitter1 and places it at the center
of the fluid container.


TIP You can create a fluid container with a fluid emitter in one step using
Fluid Effects > Create 2D Container with Emitter.

2 Play the simulation using the playback controls at the bottom of the
Maya window.
The fluid emitter creates Density values and emits them into the
container.

The white in the container represents Density. Density is the substance
of the fluid and the visible fluid property. Where the Density values are
highest, the Density appears more opaque.
Notice that the Density rises to the top of the container and moves along
the boundary of the container, eventually flowing down the sides. Forces
built into the container are acting on the Density values, causing them
to change. The fluid collides with the boundaries rather than penetrating
them.

Adding a fluid emitter to a container | 793

3 Stop the playback and go to the start of the playback range.

Changing the behavior of a fluid
By modifying the attributes of the fluid container you affect the appearance
and behavior of the fluid. Note that no matter what changes you make to the
attributes, the fluid can never leave the container.
In the next steps you’ll look at some of the attributes of the fluid container
to gain some understanding into dynamic fluid effects.

To modify attributes for the fluid

1 Select the fluid container.

2 Show the Attribute Editor in the right panel of the Maya window, and
click the fluidShape tab.

3 Look in the Contents Method section. The Contents Method defines how
a fluid property is defined in the container, if at all.
Notice that Density and Velocity are set to Dynamic Grid.
The Dynamic Grid setting divides the container into virtual rectangular
units called voxels (volume pixels). You place the values in this virtual
grid by emitting them, painting them, or adding a predefined initial state.
At each step of the simulation, Maya recalculates the values in each voxel
using the fluid dynamics solver. This is what creates the dynamic motion
of the fluid.


TIP You can display Density values for the virtual grid by changing Numeric
Display to Density in the Display section of the fluid Attribute Editor. Set the
shading mode to Wireframe.

For dynamic fluid simulations, Density must be set to Dynamic Grid.
Also, Velocity cannot be turned Off because velocity moves the property
values around inside the grid.
You look at defining properties as Gradient and Static Grid in the next
lessons.

4 Make the density fall instead of rise by opening the Dynamic Simulation
section of the Attribute Editor and setting the following:
■ Change the Gravity value to -9.8. (Acceleration due to gravity is -9.8
m/s2 in the physical world.)

Negative values move the Density down.

Maya window.

6 To add turbulence to the container and give the Density a whirling
circular motion.
■ Ensure the fluid container is selected if it is not already.

Changing the behavior of a fluid | 795

■ In the Attribute Editor, open the Contents Details section, and then
open the Turbulence section.

■ Change the Strength value to 1.0.

Maya window.


9 Change the effect of the container boundaries on the fluid:
■ In the Container Properties section at the top of the Attribute Editor,
set the following options:

■ Boundary X: None

■ Boundary Y: None

Maya window.

Notice that the fluid no longer collides with the sides of the container—it
appears to pass through the sides. The fluid behaves as though the
container boundaries don’t exist. Note that even though the fluid appears
to pass through the container boundaries, it does not exist outside the
boundary. Fluids can only exist inside containers.

11 Change Boundary X and Boundary Y back to Both Sides to restore the
boundaries at all sides of the container.



Combining colors in a fluid
In the next steps, you’ll add another emitter to the container and make each
emitter create different colored Density. You’ll see how different colored
Density interacts in the container.

To combine colored fluids in the container

1 Select the fluid container and choose Fluid Effects > Add/Edit Contents
> Emitter.
Maya creates a second fluid emitter called fluidEmitter2 and places it at
the center of the fluid container, in the same position as the first emitter.

2 With fluidEmitter2 still selected, select the Move Tool (Hotkey: w) and
drag the emitter to the right of the container, so the emitters no longer
overlap.
Make sure you keep the emitter inside the container and on the plane
by dragging only the X and Y manipulators. If you move the emitter
outside the container, it will not emit.

3 Open the Attribute Editor in the right panel of the Maya window, and
click the fluidEmitter2 tab.

4 In the Fluid Attributes section, turn on Emit Fluid Color.
A message appears prompting you to set the fluid’s Color Method to
Dynamic Grid.
By setting the Color Method to Dynamic Grid, the color values you place
in the container grid are recalculated by the fluid dynamics solver and
changed during simulation. This means colors can interact during the
simulation.

Combining colors in a fluid | 797

5 Click Set to Dynamic.

6 Click the Fluid Color color box in the Attribute Editor.
The Color Chooser opens.

7 Select blue from the Color Chooser and click Accept.

8 In the scene view, select fluidEmitter1, the emitter in the center of the
container.

9 In the Attribute Editor, turn on Emit Fluid Color for fluidEmitter1.
You are not prompted to set the contents method to Dynamic Grid,
because you already set the container to Dynamic grid when you modified
fluidEmitter2.

10 Click the Fluid Color color box.
The Color Chooser opens.

11 Select green from the Color Chooser and click Accept.

Maya window.


Colliding a fluid with an object
The 2D fluid you created is dynamic, so it can interact with objects. In the
next steps, you’ll create a plane inside the fluid container and make the fluid
collide with it, rather than pass through it.


To make the fluid collide with a plane

1 Create a polygon plane:

■ Select Create > Polygon Primitives > Plane > . The Polygon Plane
Options window opens.

■ In the window, select Edit > Reset Settings to reset the plane settings
to the default ones, and then click Create.

2 In the Attribute Editor, click the pPlane1 tab and scale, translate, and
modify the plane as follows:
■ Translate: -2 2 0

■ Rotate Axis: 0 0 40

■ Scale: 10 1 1

3 Select both the plane and the fluid container.

4 Select Fluid Effects > Make Collide. This makes the plane a collision object.

Maya window.

The fluid collides with the plane as it moves through the container. It
does not pass through the plane.

Colliding a fluid with an object | 799

Beyond the lesson
This lesson introduced you to some basic concepts of dynamic fluids. You
learned how to:

■ Create an empty fluid container.

■ Emit fluid properties into the container to create a dynamic fluid effect.

■ Modify forces acting on the fluid container to change the behavior of the
contents of the container (Gravity and Turbulence).

■ Add color to a fluid by emitting color into the container.

■ Make a fluid collide with an object.

The hardware render of the simulation provided you with a fast, realistic
representation of the fluid. The final step would be to do a software render.
Although we looked at a 2D fluid, the same concepts apply to 3D fluids. In
the lessons that follow, you’ll work with 3D fluids and explore methods other
than fluid emitters for adding contents to a fluid container. You’ll look at the
texturing capabilities that are part of the built-in shader. You’ll also learn
about the Temperature and Fuel fluid properties and how you can use them
in your effects.
Beyond this, you can also:

■ Emit fluid from the surface of an object.

■ Give the fluid a hard surface (surface render) for a globby or lava-like effect,
rather than the soft, cloud-like surface you saw in this lesson.

■ Cache the fluid simulation for faster playback.

■ Deform an object with the force of a fluid.

For details on these topics, see the Fluid Effects information in the Maya Help.


Lesson 2: Creating a non-dynamic 3D fluid effect

Introduction

In the first lesson, you created a simple 2D dynamic fluid. 3D fluids intrinsically
require extra data to define them, which can make them very complex. This
extra data can slow a dynamic simulation exponentially because more
calculations (solving) must be performed at every step of the simulation. For
a less memory intensive effect, you could use a 2D fluid (with less data), or
you could create a 3D non-dynamic effect.
In non-dynamic fluid effects, the fluid property values are predefined within
Maya and stay constant over time, which means they don’t have to be
recalculated. You create the appearance of the fluid by texturing a special fluid
shader that is assigned to the fluid. This shader is built into the fluid for better
performance. If you want the fluid effect to have motion, you can animate
(keyframe) the texture attributes. Because Maya doesn’t solve the fluid
dynamics equations, rendering this type of fluid is much quicker than
rendering a dynamic fluid.
In this lesson, you learn the fundamentals of creating non-dynamic fluids by
creating a cloud bank using a 3D non-dynamic fluid. You learn how to:

■ Create a 3D fluid using predefined gradient contents.

■ Texture the contents of the fluid using the built-in fluid shader.

Before beginning the lesson, do the steps in Preparing for the lessons on page
790.

Creating a 3D fluid container
Creating a fluid container is the first step in creating a non-dynamic fluid
effect.

Lesson 2: Creating a non-dynamic 3D fluid effect | 801

Fluid containers do not need to be uniform in X, Y, and Z. In fact, because
larger fluids take longer to render, you should make containers only as large
in each direction as necessary for the effect. A cloud bank sits above the ground
like a blanket, so the container can be rectangular rather than cubic.

To create a 3D fluid container

1 Select Fluid Effects > Create 3D Container > .
The Create 3D Container Options window opens.

2 Set the container options as follows, then click Apply and Close:
■ X Resolution: 50

■ Y Resolution: 5

■ Z Resolution: 60

■ X Size: 50.0

■ Y Size: 5.0

■ Z Size: 60.0

The resolution is defined in voxels. Higher resolutions produce finer
detail, but increase rendering time. The size of the container is defined
in the working units set for Maya. The size of the fluid determines the
size of each voxel.

TIP It’s good practice to make the container’s Resolution and Size proportional
to ensure that the voxels are square making the quality the same along each
axis.

origin.

Next, you add fluid to the container.


Adding fluid to a container
To make this a non-dynamic fluid, you add fluid property values to the
container that will stay constant over time. There are two ways to do this: add
these values to a static grid, or select a set of values from a list of predefined
gradients that come with Maya. For this lesson, you’ll use the latter method.
For a cloud bank, Density is the only property you need to define—the other
properties are typically used in dynamic solving.

To add fluid to the container

1 Dolly the scene view to see the entire container.

2 With the fluid container selected, show the Attribute Editor in the right
panel of Maya, and click on the fluidShape1 tab.

3 In the Contents Method section of the Attribute Editor, set:
■ Density: Gradient

■ Density Gradient: Constant

Set Velocity, Temperature, and Fuel properties to Off. (They’re not used
in this effect.)

By setting the Density Gradient to Constant, you made all the Density
values in the container the same—a value of 1. You can scale these values,
but otherwise, they cannot change.

Defining shader attributes for a fluid
The fluidShape has a built-in shader that you can use to modify color, texture,
and other attributes to give the fluid a particular look. In the next steps, you’ll
make the shader apply specifically to the Density values inside the container.

Adding fluid to a container | 803

To define shader attributes for the fluid

1 Open the Shading section in the Attribute Editor.

2 In the Color subsection, change Color Input to Density.
The Density values in the container will now take on the colors defined
on the color bar. Leave the color white to make the clouds appear white.

3 In the Opacity subsection, check that the Opacity Input is set to Density.
The opacity represents how much the Density will block light. You’ll
look more at Opacity later in this lesson.

Texturing the contents of a fluid container
So far the container is filled with solid white Density. To create the cloud
effect, you texture the Density so that some areas are transparent and some
areas are opaque.

To texture the density of a fluid

1 Turn on hardware texturing display so you can see the effect of the
textures on the fluid without rendering by selecting Shading > Hardware
Texturing from the scene view menu.

2 Open the Textures section in the Attribute Editor.

3 Turn on Texture Opacity to apply the current texture to Opacity values.
The current texture is Perlin Noise, defined by Texture Type.

Notice that the Density now has a slightly blotchy look to it, with areas
that are more opaque and areas that are more transparent. This texture
provides the standard 3D noise used in the 3D Solid Fractal texture
included with Maya.

4 Change Texture Type to Billow for a fluffy, cloud-like effect.
The Billow texture is computationally intensive and therefore slower than
the other texture types.


5 Change the look of the texture by setting the following texture attributes:
■ Amplitude: 0.5

■ Depth Max: 4

Decreasing the Amplitude makes the areas with low Density more
transparent and the areas with high Density more opaque.
Increasing Depth Max adds detail. Increasing it will also increase render
time.

6 Stretch the texture in the X direction by changing the X, Y, and Z
components of the Texture Scale to 2, 1, 1.

7 Change the following Billow texture attributes to make the “billows” less
dense, more spotty, and with randomly different sizes.
■ Billow Density: 0.6

■ Spottyness: 2.0

■ Size Rand: 0.40

Texturing the contents of a fluid container | 805

8 Modify the Opacity so that areas in the container that are very dense
appear less opaque, areas that have very little Density become totally
transparent, and the transition between areas that are totally transparent
and areas that are more opaque is less gradual.
In the Attribute Editor, go to the Shading section. Look at the Opacity
graph in the Opacity subsection. This graph represents the relationship
between Opacity values and Density values (the Opacity Input).

Opacity values range from 0 on the bottom (totally transparent, no
opacity) to 1 on the top (totally opaque).
Density values range from 0 on the left side (no Density) to 1 on the right
side (high Density).
So for the linear graph shown above, where Density values are 0, Opacity
values are 0, making the Density totally transparent, where Density values
are 0.5, Opacity values are 0.5, making the Density partially opaque, and
where Density values are 1, Opacity values are 1, making the Density
totally opaque.

■ Click the first dot on the Opacity graph to select the position marker.
Position markers mark the location on the graph from left to right (the
Opacity Input value). The outline of the dot is white when a position is
selected.


■ Change Selected Position to 0.10 to change the position of the marker.

The position marker moves to the right. Now, for Density values between
0 and 0.10, the Opacity values will be 0. This means that Density that was
previously partially transparent will be completely transparent.

The more transparent areas of cloud disappeared, but now the solid areas
of cloud are less opaque.

■ Click on the graph to create a new position marker.

■ Change the marker position and value as follows:
■ Selected Position: 0.15

■ Selected Value: 0.30

Texturing the contents of a fluid container | 807

Density values that are greater than 0.15 are now more opaque, and the
transition between areas of total transparency (Opacity 0), and areas where
the Density becomes more visible (Density 0.15) is less gradual.

Adding self shadowing to texture density
Give the clouds some depth by adding self shadowing. Self shadowing causes
the fluid to cast shadows on itself using a single internal directional light at
-1, -1, -1.

To add self shadowing to the texture density

1 In the Attribute Editor, under the fluidShape1 tab, open the Lighting
section.

2 Turn on Self Shadow.

The clouds now have some darker areas on them, giving them some
depth.

3 In the Display section, change Boundary Draw to None to hide the
container. This gives you a better idea of how the fluid will look before
you render it.


Beyond the lesson
This lesson showed you a basic technique for creating non-dynamic fluids.
While creating the effect, you learned how to:

■ Create a 3D fluid container of a specific resolution and size.

■ Add predefined gradient contents to the container to create a non-dynamic
fluid.

■ Texture the contents of the fluid using the built-in fluid texturing
capabilities of the fluidShape. (You can also texture dynamic fluids using
the same techniques.)

To make the texture move, you would keyframe the Texture Time attribute
in the Textures section of the Attribute Editor. For details on keyframing
attributes, see the Maya Help.
You modified several texture attributes in this lesson, but there are many more
attributes for customizing textures. Also, note that the non-dynamic effects
you can create using texturing are not limited to clouds. Here are some
examples:

To learn more about how to use texturing and other fluid attributes, study
the Fluid Effects examples that are included with Maya (Fluid Effects > Get
Fluid Example) and look at the Notes section at the bottom of the Attribute
Editor for example fluids. It includes information about the selected effect,
pointing out the key aspects of its construction.
For further information on Fluid Effects, see the Maya Help.


Lesson 3: Creating a dynamic 3D effect

Introduction

In the real world, gasoline reacts chemically with oxygen at a certain
temperature, creating flames (light, heat) and the gaseous products of
combustion. Over time, the gasoline burns until it’s totally consumed. You
can simulate this situation in Fluid Effects using Fuel, Density, and Temperature
properties.
In this lesson, you create a dynamic explosion effect by filling the bottom of
a container with Fuel and Density, then “igniting” it with Temperature. You
learn how to:

■ Add property values to a container by painting them.

■ Paint in a 3D container.

■ Use Fuel, Density, and Temperature to create an explosion effect.

790.

Creating a 3D container
1 Select Fluid Effects > Create 3D Container > .
The Create 3D Container Options window opens.

2 In the window, select Edit > Reset Settings to restore the Resolution and
Size settings to the defaults 10 10 10 and 10 10 10, respectively.
The default container size and resolution are adequate to illustrate the
concepts in this lesson.



origin.

Next, add fluid to the container. In the first lesson, you added fluid to
the container by emitting it into a Dynamic Grid. In the second lesson,
you added fluid to the container by selecting a predefined gradient. In
this lesson, you will add fluid to the container by painting property values
inside it.

Painting Fuel and Density into a container
In Fluid Effects, Fuel defines the state of a reaction (unreacted, completely
reacted, and states in between). Density represents the substance that is
reacting, while Temperature causes the reaction. Combining Density with
Fuel defines a situation in which you can see a reaction. You add Temperature
to this situation to start the reaction. As the reaction takes place, Density
values become smaller and the Fuel values get smaller to represent how much
of the reaction has yet to take place. The reaction also creates more
Temperature, and it creates light.
In the following steps you’ll paint Fuel and Density values in the container.
To paint in a 3D container you actually paint in two dimensions on “slices”
of the container. A slice is a plane in X, Y, or Z that represents where you
paint. (You could think of a slice as a 2D canvas.) You paint each slice
individually, but the accumulative effect of adjacent slices is a 3D fluid.

To paint Fuel and Density into a container

➤ With the container still selected, choose Fluid Effects > Add/Edit Contents
> Paint Fluids Tool > .

The Tool Settings window opens and a slice displays at the origin of the fluid
container. The slice is represented by a plane with dotted edges and fluid

Painting Fuel and Density into a container | 811

subvolume manipulators at one corner. When you move the pointer over the
slice the pointer changes to a brush indicating that you can paint.

1 At the top of the Tool Settings window, click Reset Tool to set the Paint
Fluids Tool settings to the default values.

2 Select the fluid properties you want to paint. In the Paint Attributes
section of the Tool Settings window, beside Paintable Attributes, select
Density and Fuel. You will paint both these properties at the same time.
You could paint each property separately, but for this example, the values
you paint will be the same for both. It is more efficient to paint them
both at the same time.
A message appears prompting you to set the fluid’s Fuel method to
Dynamic Grid. By setting the Fuel method to Dynamic Grid, the fuel
values you place in the container grid (in this case, by painting them)
are recalculated by the fluid dynamics solver and changed during
simulation. The Density method is defined as Dynamic Grid by default.

3 Click Set to Dynamic.

4 Tumble the scene and look at the slice and manipulators.

The orientation of the slice changes relative to your view. The slice is
perpendicular to the axis with the manipulators. The color of the


manipulators corresponds with the color of the axis in the View or Origin
axes.
Painting properties relative to different axes is good practice to ensure
there are no gaps between slices when the fluid is viewed from different
angles.

5 Tumble so that the slice is perpendicular to the Y axis and then click the
open lock icon to lock the slice axis.

The lock closes. Now when you tumble, the slice remains perpendicular
to Y. It does not switch to the other axes. This allows you to change the
view in any way and still be able to paint on the same slice.

6 Drag the top move arrow down along the axis to the first slice at the
bottom of the container. The number of slices along each axis corresponds
with the resolution of the fluid container. The numbering starts at 0 at
the intersection of the axes. For this container the resolution is 10 10 10,
so the slices are numbered from 0 to 9.
The help line displays the location of the selected slice.
Fluid Slice Location: 0.000


7 In the Paint Attributes section of the Tool Settings window, ensure that
Value is set to 1. A Fuel value of 1 represents a totally unreacted state
while a Fuel value of 0 represents a completely reacted state. A Density
value of 1 is totally opaque while a Density value of 0 is completely
transparent.

8 Drag the brush on the slice to paint values. Paint until the entire slice is
filled with values.

The values display as yellow because you are painting two properties at
the same time. Density values are represented by the opacity of the shaded
values, while Fuel values are represented by color. The range of Fuel values
corresponds with a ramp of colors from blue (values of 0) to yellow (values
of 1).
To make the fluid deeper, you could move the slice to Fluid Slice Position
1, paint, move the slice to Fluid Slice Position 2, paint, and so on. But a
quicker way is to resize the slice to make it thicker and then flood the
entire slice with values.

9 Resize the paint slice, making it thicker:
■ Click the target icon once to switch to the subvolume scaling mode.


The slice becomes thicker and the manipulator changes to include scaling
boxes at the ends of the move arrows.
■ Click the top scaling box and read the help line to determine that the
Fluid Slice Thickness is 3.00. You could drag the scaling boxes to
change the thickness of the slice, but the slice is thick enough for the
lesson.

10 In the Tool Settings window, click the Flood button.

Flooding filled each voxel in the subvolume with Fuel and Density values
of 1.
Notice that the values display as shaded planes rather than as a solid
mass. This is an interactive display feature for shaded display mode.
Displaying more shaded planes (slices) produces more detail but reduces
the speed of the screen draw. You can change this display feature (Slices
Per Voxel) and others in the Display section of the Attribute Editor.

Now that the container has Density and Fuel in it, you are ready to start
a reaction by adding Temperature. You could think of this as putting a
lit match into a container of gasoline.


Painting Temperature values into a container
By default, the Fuel and Density will react when there is no Temperature in
the container, but adding higher temperature values will make the reaction
more immediate.

To paint Temperature values into a container

1 In the Tool Settings window, beside Paintable Attributes, select
Temperature. A message appears prompting you to set the fluid’s
Temperature method to Dynamic Grid or Static Grid.
By setting the Temperature method to Dynamic Grid, the temperature
values you place in the container grid are recalculated by the fluid
dynamics solver and changed during simulation.
By setting the Temperature method to Static Grid, the temperature values
you place in the container grid are used by the fluid dynamics solver
during the simulation, but they cannot change during the simulation.
Static Grid is useful when you want to define specific values in specific
areas of the container, but you do not want these values to change over
time.

2 Click Set to Dynamic. The Density and Fuel values disappear. The values
are still there, but only Temperature values now display. Currently there
are no temperature values in the container.

3 Change the brush so you can paint through the entire thickness of the
slice with a single stroke. In the Stroke section of the Tool Settings
window, change Stamp Depth (3D) to 2. The brush changes, showing
how deep the brush stroke will paint.

If you make the brush depth thicker than the depth of the slice, only the
space within the slice will be painted.

4 Paint a small amount of Temperature in the center of the slice.


The stroke adds Temperature values through the entire thickness of the
slice.
The next steps are to view all the property values together, and color the
properties to differentiate them.

Adding color to Density and Temperature
Use the built-in shader to modify the color of Density and Temperature in
the container.

To add color to the Density and Temperature

1 Choose the Select Tool (Hotkey: q) to leave the Paint Fluids Tool. The
manipulators disappear and now you see the fluid as it will render

2 With the fluid container selected, open the Attribute Editor.

3 Change the color of the fluid as follows:
■ In the Shading section of the Attribute Editor, expand the Color
section, and change Color Input to Density.

■ The Density values in the container will now take on the colors defined
on the color bar.

Adding color to Density and Temperature | 817

■ Click the Selected Color box. The Color Chooser opens.

■ Select black in the Color Chooser and click Accept.

The Density turns black.
Look closely at the center of the fluid. The area where you painted
Temperature has a reddish orange color. In the Incandescence section of
the Attribute Editor, notice that Incandescence Input is set to Temperature.
Temperature gives off light and Incandescence controls the amount of
light emitted from regions of Density due to self illumination. The ramp
defines the color of this light.

Maya window.

By frame 160, most of the Density values have reacted completely.


Beyond the lesson
This lesson introduced you to the Fuel and Temperature fluid properties. You
learned how to:

■ Combine Fuel, Density, and Temperature to create a dynamic explosion
effect.

■ Add property values to a container by painting them.

■ Paint in a 3D container.

You can control how quickly the reaction takes place during the simulation,
the temperature required to start the reaction, how much heat and light the
reaction releases over time, and other aspects of the reaction using the
attributes in the Fuel section under Contents Details in the fluidShape Attribute
Editor.
For a more realistic look, you can also texture the fluid using the built-in
texturing attributes in the Textures section.
For more information on Fuel and texturing attributes, see Fluid Effects in the
Maya Help.

Lesson 4: Creating an ocean effect

Introduction

An ocean effect is defined by a plane with an ocean shader assigned to it.
Ocean effects are not created with fluid containers like the dynamic and
non-dynamic fluid effects you created in the first three lessons.


A shader is a collection of attributes that define color and other surface
characteristics of the plane it is assigned to. For an ocean shader, these
attributes define realistic waves on large bodies of water.
In this lesson, you create an ocean, put a cube in it, and see how the cube
floats in the ocean. You learn how to:

■ Create an ocean plane and shader.

■ Create a preview plane to see the effects of the shader, including
displacement, without rendering.

■ Modify the ocean shader attributes to make the waves bigger.

■ Make an object a boat in the scene.

■ Modify the attributes for an expression that controls the buoyancy of the
boat in the ocean.

790.

Creating an ocean plane and shader
Fluid Effects simplifies the process of creating an ocean by providing a single
command that creates a plane that is optimized for best results, and an ocean
shader with appropriate connections to the plane.

To create an ocean plane with ocean shader

1 Select Fluid Effects > Ocean > Create Ocean. Maya creates an ocean plane
and assigns an ocean shader to it.

2 Dolly out to see the plane.


The plane is a NURBS plane with more patches concentrated in the center.
This is so you can see more detail in the center and less detail as the ocean
extends to the horizon.
Because interactive shading would slow down playback, the shading is turned
off for the surface.

Adding a preview plane to an ocean
Because shading is turned off for the ocean plane, you need a preview plane
to see displacement and shading in the hardware render. Displacement changes
the surface of the ocean plane so you can see the different wave heights.

To add a preview plane to the ocean

1 Dolly back in to the center of the plane.

2 Select Fluid Effects > Ocean > Add Preview Plane.
Maya creates a preview plane that interactively shows the displacement
of the ocean on a shaded patch of ocean. You can scale and translate it
to preview different parts of the ocean. This plane does not appear in
renders.

3 With the preview plane still selected, choose the Scale Tool (Hotkey: r)
and make the patch bigger by dragging the center scale box to the right.
Make it approximately 25 times bigger. (Look at the scaling numbers in
the help line.)

Maya window.

Adding a preview plane to an ocean | 821

The preview plane ripples slightly showing the small wave displacement.

5 Light the scene to prepare it for rendering later in the lesson:
■ Select Create > Lights > Directional Light. Maya creates a directional
light called directionalLight1 at the center of the grid.

■ Open the Attribute Editor and in the Directional Light Attributes
section of the directionalLightShape1 tab, change Intensity to 2 to
make the light brighter.

■ Click the directionalLight1 tab and rotate the light as follows to direct
the light rays onto the ocean. Rotate: -100 42 20

Modifying ocean attributes
In the next steps, you will modify ocean shader settings to make the waves
bigger.

To modify attributes for the ocean shader

1 Render the current frame to see what the ocean looks like before you
modify the ocean shader attributes. On the Status line, click the render
current frame icon.


2 Select the preview plane or the ocean plane (it doesn’t matter which one),
and in the Attribute Editor, click the oceanShader1 tab.

3 Open the Ocean Attributes section and change the following values:
■ Num Frequencies: 12

■ Wave Length Max: 40

Num Frequencies controls the number of frequencies between minimum
and maximum wave lengths. Increasing this value results in a more
textured look on the water surface.
Wave Length Max controls the maximum length of waves in meters.
Longer wave lengths make bigger waves.

4 Play the simulation to see the effect of your changes on the displacement
of the ocean waves.


6 Render the current frame.

7 Make the tops of the waves form crests by adjusting the Wave Peaking
graph in the Attribute Editor.
Wave Peaking controls the amount of crest formation for waves across
the range of wave frequencies. It simulates a side-to-side sloshing of waves,
as opposed to an up-down motion. Wave Peaking is only applied to
turbulent waves (where Wave Turbulence is not zero).

Modifying ocean attributes | 823

Click on the graph to create the position markers shown in the next
illustration.

Where the wave frequency is lower, the waves peak more.


The tops of the waves now crest slightly.
Notice the white highlights on the ocean. These are specular highlights
caused by the light hitting the water.

9 Make the highlights dimmer so they don’t pop out as much, and bigger.
Open the Specular Shading section and change the following settings:
■ Specularity: 0.45

■ Eccentricity: 0.1

Specularity controls the brightness of the specular highlights. Higher
values create brighter highlights.
Eccentricity controls the size of the specular highlights. Higher values
create bigger highlights.



Floating objects
You can make geometry (for example, a boat) float in the ocean, moving
appropriately with the motion of waves. The following steps show you how
using a simple polygon cube.

To float a cube in the ocean

1 Create a polygon cube (Select Create > Polygon Primitives > Cube).

2 In the Attribute Editor, click the pCube1 tab and scale the cube as follows:
■ Scale: 10 10 10

3 Select both the cube and the ocean plane (not the preview plane) at the
same time and select Fluid Effects > Ocean > Make Boats.
Maya creates a boat locator at the center of the cube to mark the cube’s
position in space. The locator is connected to a predefined expression
that simulates buoyancy effects. The expression is connected to the wave
heights (displacement) of the ocean.
To learn more about expressions, look at the Expressions lessons in
Getting Started with Maya.

Floating objects | 825

Maya window.

The cube bobs, pitches and rolls in the ocean.

5 In the Attribute Editor, click the locatorShape tab and in the Extra
Attributes section, modify the following options. These serve as inputs
to the expression.
■ Buoyancy: 0.75

■ Roll: 0.1

■ Pitch: 0.2

Increasing Buoyancy makes the box float more and sink into the ocean
less. Decreasing the Roll and Pitch values causes the cube to roll less from
side to side, and pitch less forwards and backwards as a result of the wave
motion.

Beyond the lesson
In this lesson, you learned that ocean effects are different from the dynamic
and non-dynamic volume fluid effects. An ocean effect is created with a plane
and shader rather than a container and fluid properties. With ocean effects
you learned how to:

■ Create an ocean plane and shader.

■ Create a preview plane to see the displacement of the shader without
rendering.

■ Modify ocean shader attributes to customize the look of the ocean.

■ Make geometry bob and move in the ocean.

To learn more about ocean shader attributes, look at the ocean shader examples
that are included with Maya (in the Fluid Effects menu). Some of these


examples use a 3D non-dynamic volume fluid to create the atmosphere above
the ocean.

Motor Boats
You can create a game-style boat simulation using the Fluid Effects > Ocean
> Make Motor Boats command. Once you set up hotkeys for the rudder and
throttle of the boat, you can “drive” the boat in the ocean. The boat will roll,
pitch, and jump over waves appropriately.

Boat Wakes
You can create boat wakes using the Fluid Effects > Ocean > Create Wake
command. Wake fluids do not use the Navier Stokes solver like regular fluids,
but use the Spring Mesh Solver. A fluid emitter is used to drive the motion of
the fluid.

Ponds
If a smaller body of water is what you had in mind, you can create a pond
using Fluid Effects > Pond > Create Pond. Ponds are 2D fluids that use a spring
mesh solver and a height field. You can generate bubbles, ripples, and waves
using the Create Wake options for the pond.
For details on these topics and others, see Fluid Effects in the Maya Help.


Fur
17
Introduction

With the Maya® FurTM feature, you can create fur and short hair on all surface
types in Maya. A fur description in Maya defines all the attributes for the fur (for
example, fur color, width, length, baldness, opacity, curl, density, and so on).
When applying fur, you can use one of the predefined fur descriptions included
with Maya, or you can create your own custom fur description by setting all
the fur attributes yourself.
You can animate fur with keyframe effects like growing fur or changing color.
For a more natural appearance, you can also add movement to fur with dynamics
(for example, wind and gravity).

■ Lesson 1 Assigning a fur description: Introduction on page 830

829

■ Lesson 2 Rendering fur: Introduction on page 855


GettingStarted/Fur directory as your Maya project. For more
information, see Copying and setting the Maya project on page 25 in the
Getting Started with Maya guide.

the Rendering menu set

3 If you don’t see a Fur menu, perform these additional steps:
■ Select Window > Settings/Preferences > Plug-in Manager.

■ In the Plug-in Manager, locate the Fur plug-in (Fur.mll) and turn on
the loaded checkbox. Wait for the check mark to appear in the
checkbox, then close the Plug-in Manager. You can set the Fur plug-in
to auto load so that it automatically loads each time the Maya
application is launched. The Fur menu will appear to the right of the
Paint Effects menu.

Lesson 1: Assigning a fur description

Introduction
Maya provides many predefined fur descriptions. These fur descriptions, also
referred to as presets, can be used as a starting point in creating fur for a model.
Fur description presets can also be customized.

■ Duplicate parts of a model across its axis of symmetry.

■ Rename surfaces.

■ Assign surfaces to display layers.

830 | Chapter 17 Fur

■ Apply a fur description preset to the surfaces of a model.

■ Reverse surface normals on surfaces to ensure the fur description is oriented
correctly.

■ Change the direction of the fur description on some of the surfaces.

■ Paint a fur attribute map to modify the fur length in an area of a surface.

■ Modify the fur color attributes of a fur description.

■ Create a new fur description for a surface and modify its attributes.

Lesson setup

➤ Open the scene named furStart.mb that is located in the
GettingStarted/Fur/scenes directory of your Maya project.
This scene includes a model that has been created for you.

Duplicating objects across an axis of symmetry
3D artists often construct one half of a symmetrical model in order to simplify
the data requirements. The scene provided for this lesson reflects this situation.
The teddy bear has only one half of its body. In the next steps, you’ll duplicate
the surfaces that make up the arms, legs, and body across the center axis to
complete the model.

Lesson setup | 831

To duplicate surfaces

1 In the scene view, select the five surfaces to be duplicated: the arm, arm
paw, leg, leg paw, and body. Click one surface, then shift-click the other
surfaces until all of the five surfaces are highlighted.

2 Select Edit > Duplicate Special > . In the Duplicate Special Options
window that appears, select Edit > Reset Settings, then do the following:
■ Change the X Scale value to -1.

■ Click the Duplicate Special button.

Setting the X Scale value to -1 duplicates the surfaces in corresponding
positions across the negative side of the X-axis.


Renaming surfaces on a model
After duplicating the surfaces you need to rename the duplicated surfaces so
you can easily identify and select them by name when required.
The surfaces you duplicated were originally named using the naming
convention leftArm, leftArmpaw, leftLeg, and leftLegpaw. When you duplicate
objects, Maya assigns names to the new objects automatically. Change the
names of the duplicated surfaces to match the naming convention used for
the model.

To rename objects

➤ For each of the surfaces listed in the following table, do the following:
■ Click the object in the scene view.

■ In the Channel Box, click the object name to select it. You can display
the Channel Box by clicking Show/Hide Channel Box/Layer Editor

■ Type the corresponding new name from the table and press Enter.
Old name New name

leftArm1 rightArm

leftArmpaw1 rightArmpaw

Renaming surfaces on a model | 833

Old name New name

leftLeg1 rightLeg

leftLegpaw1 rightLegpaw

leftBody1 rightBody

Assigning objects to a reference layer
In this section you will assign any objects that will not have fur assigned to
a referenced display layer so they become temporarily unselectable when
adding or changing a fur description.
Layers are overlapping views of your scene that can have objects assigned to
them. You can assign any objects within a scene to layers. One useful
characteristic of layers is that they let you simplify your scene so you can work
on specific objects without disturbing other objects. You can choose which
objects of the scene you want to assign to a layer and then selectively make
them visible or invisible. You can also template or reference all objects
associated with a given layer.

To assign objects to a display layer

1 If the Channel Box isn’t already displayed, click the Show/Hide Channel
Box/Layer Editor button in the Status Line to display the Layer Editor

.

2 Ensure the Layer Editor is set to Display Layers by clicking the Display
radio button.


3 Click the Create Layer button .

4 Double-click the new layer’s name in the Layer Editor.
The Edit Layer window appears.

5 In the Edit Layer window, set the following and click Save:
■ Name: ExtraParts

■ Display type: Reference

In the Layer Editor, the name of the layer updates and its status is now
set to Reference. The Reference display state indicates that the objects in
that layer can still viewed in the scene but cannot be selected.

6 In the scene view, select the following surfaces:
■ nose

■ mouth

■ leftEye

■ rightEye

■ leftLid

■ rightLid

■ leftInEar

■ rightInEar

■ leftArmpaw

■ rightArmpaw

Assigning objects to a reference layer | 835

■ leftLegpaw

■ rightLegpaw

■ groundPlane

7 Right-click the ExtraParts layer in the Layer Editor and choose Add
Selected Objects from the drop-down list that appears.
The selected objects are assigned to the ExtraParts display layer which is
currently set to Reference. You can still view these objects but they cannot
be selected again until you set the display setting for this layer to Normal.
Using reference layers in this fashion aids your workflow by ensuring you
don’t accidentally select unwanted surfaces when applying Fur.

Assigning a fur description preset to a model
A fur description defines all of the attributes for the fur, for example, fur color,
width, length, baldness, opacity, curl, density, and so on. Maya includes a set
of fur description presets you can use as is, or as a starting point in creating
your own custom fur descriptions.
Any surfaces that should not have fur applied have already been assigned to
a referenced display layer. This makes the application of a fur description
easier.


To assign a fur description preset to the model

1 In the scene view, drag a selection marquee around the entire model.
All of the surfaces on the bear model are selected except for the ones you
assigned to the referenced ExtraParts display layer.

2 In the Shelf, click the Fur tab.

3 With the surfaces still selected, click the Duckling fur preset in the Fur
shelf.

The Duckling fur preset is assigned to the selected surfaces of the model.

Assigning a fur description preset to a model | 837

4 In the Channel Box, rename the Duckling fur description to TeddyBear.
Observe the yellow spikes that have appeared on the model. This is the
fur feedback - a rough approximation of how the fur will appear when
rendered.
Fur feedback shows various fur attributes such as color, density, length,
direction, and scraggle. By looking at the fur feedback you can
immediately see how the changes you make to the fur attributes affect
the appearance of the fur, without having to render the scene.
The fur feedback on the legs, arms, and top of the head of the model
appears different in comparison to how it appears on the body and snout
surfaces. It should appear consistently on all of the assigned surfaces,
which indicates that the surface normals may not be oriented consistently
for all of the assigned surfaces.

Reversing surface normals
When you apply a fur description to a surface, each hair making up the fur
description points in a direction normal (perpendicular) to the surface by
default. This direction is called the surface normal. When the fur does not
display consistently on a model it may indicate that the surface normals are
oriented inconsistently.

➤ Dolly the camera so you can view inside the arm.


The fur feedback is pointing towards the inside of the arm.
In this model, the fur was applied to the inside of the leg, arm, and head
surfaces because the surface normals on these surfaces are pointing in
the wrong direction. There are several reasons why this can occur,
including when a surface is duplicated with a negative scale value.
To correct this, you’ll need to reverse the surface normals on the legs,
arms, and head surfaces of the model.

NOTE Reversing the surface normals (Polygons menu set: Normals > Reverse)
is useful when you want to change the surface direction (that is, whether the
surface is oriented inwards or outwards in relation to the model). For example,
duplicating a surface across its axis of symmetry can reverse the surface
normals on the duplicated surface. Using the Reverse Normals feature corrects
this.
When a character has existing animation rigging or texturing and you need
to assign fur, the desired technique for reversing the orientation of the fur
feedback is by reversing the fur normals (Fur > Reverse Fur Normals). Reversing
the fur normals leaves the surface direction unchanged.

Reversing surface normals | 839

To reverse the surface normals

1 With only the legs, arms, and top head surfaces selected, switch to the
Polygons menu set and then select Normals > Reverse > .

2 Set the Reverse normals on setting to Selected faces and then click Reverse
Normals.
The normals of the selected polygon surfaces are reversed so that the fur
description points in the correct direction.

Before proceeding to the next section, return to the Rendering menu set.

Modifying the fur direction
Real fur usually doesn’t stick straight out of a surface but appears angled in a
particular direction. The teddy bear’s fur appears to point in different directions
depending on the particular surface.
In this section, you modify the direction of the fur so it points in a consistent
fashion on the model. You’ll also modify the direction of the fur to simulate
a seam along the center of the bear’s forehead like a real stuffed toy might
have.


There are three methods for modifying the direction of fur. Each method has
specific conditions for use. You can modify the direction of fur by:

■ Modifying the Inclination, Polar, and Roll attributes for the fur description
globally.

■ Setting a Fur Direction Offset to change the fur feedback direction locally
on a selected surface.

■ Combing the fur feedback locally on a surface using Maya’s Paint Fur
Attributes tool.

Modifying the Inclination, Polar, and Roll attributes for the assigned fur
description changes the direction attributes on the fur description globally.
You can set these attributes using either the Channel Box or the Attribute
Editor. Inclination sets the angle or slope at which the fur description will
lean in relation to the surface. Polar sets the direction the fur description will
point in relation to the surface normal, much like the hands on a clock face.
Roll sets the angle about which the fur description will be rotated about its
follicle and is used mostly when the fur has curl attributes applied. That is,
you can control whether the curls point up, down, or lay flat on their side.
Modifying these attributes is a good starting point for creating a realistic fur
description. For the original Duckling fur description preset the Inclination,
Polar, and Roll attributes are set to 0.6, 0.5, and 0.5 respectively. You won’t
need to change these for this lesson.
However, when a model is comprised of many surfaces, the fur may have a
tendency to point in a different direction on each separate surface depending
on how the surfaces were originally constructed.
To correct this you can change the direction of the fur using the Fur Direction
Offset. The Fur Direction Offset lets you change the orientation of a fur
description locally on a per-surface basis by applying a relative rotation value
to the fur description as it is applied to the selected surface.

To modify the fur direction using the Fur Direction Offset

1 Dolly the camera closer to the bear’s head so you can more closely view
the direction of the fur description on the bear’s snout.
The fur appears to point in a clockwise direction about the bear’s snout.
You can change the direction the fur points by changing the Fur Direction
Offset value for the bear’s snout.

2 Select the snout surface.

Modifying the fur direction | 841

3 Select Fur > Offset Fur Direction and click on the double lines at the top
of the menu that appears so you can tear off the Offset Fur Direction
menu.

The Offset Fur Direction menu lets you rotate a fur description on a
selected surface using direction presets.

4 Click on the 0, 90, 180, and 270 degree presets one at a time until the
fur feedback on the snout points toward the bear’s face.

5 Repeat this process for the remaining surfaces that have fur assigned by
selecting each surface one at a time and orienting the direction of the fur
feedback as follows:
■ The fur feedback on the arms and legs should point in a direction
towards the paws.

■ The fur feedback on the body surfaces should point downwards.

■ The fur feedback on the head surfaces should point away from the
center line so it simulates a sewn seam.

■ The fur feedback on the outer ear surfaces should point away from
the bears head.

TIP Dolly and tumble the camera as you work to ensure you have the fur
feedback oriented correctly. Try each offset direction so you know its
effect on the fur feedback on each surface. You can easily set the direction
offset back to its previous setting if it appears incorrect.

6 Close the Offset Fur Direction menu when you are finished orienting the
fur feedback for all of the surfaces that have fur assigned.


Painting fur attributes
The fur feedback on the bear’s snout appears too long in the region of the
bear’s mouth and nose. The fur will poke through the nose and hide the mouth
in the final rendered image unless you shorten the fur in that region on the
snout. You can reduce the length of fur in a localized area of a surface using
the Paint Fur Attributes Tool.

Using the Paint Fur Attributes Tool you can paint virtually any fur attribute.
In this lesson you use the Paint Fur Attributes Tool to:

■ reduce the fur length in a localized area on a surface. This is useful when
you want regions with shorter or longer fur on a surface.

■ create bald regions on a surface. This is useful for creating localized fur
effects such as a moustache or goatee on a character, or whiskers on an
animal.

The Paint Fur Attributes Tool does all of the above via attribute maps that you
create by painting directly on the surface. The attribute map modifies the
associated fur attributes you have selected for modification based on the
regions of black, white, or gray that you paint in the map.
Before you begin painting an attribute map you’ll want to hide the nose and
mouth surfaces. Earlier in the lesson you assigned the nose and mouth surfaces
to the ExtraParts reference layer to prevent them from being accidentally
selected in the scene view. To hide these objects you can set the referenced
display layer to invisible.

Painting fur attributes | 843

To hide the referenced display layer

➤ In the Display Layer Editor, make the ExtraParts layer invisible by clicking
the V that indicates that the layer is visible.

To shorten the fur using the Paint Fur Attributes Tool

1 In the scene view, select the snout surface.

2 Select Fur > Paint Fur Attributes Tool > .
The cursor updates to display as a paint brush indicating that the Paint
Fur Attribute Tool is active. The Paint Fur Attributes Tool Settings window
and the Paint Tool Settings editor appears. These windows let you set and
control which attributes get painted for an attribute map.

3 In the Paint Fur Attributes Tools Settings window, ensure the following
options are set:
■ Fur Attribute: Length

■ Fur Description: TeddyBear


4 In the Paint Tool Settings editor, set the following:
■ Brush - Radius (U): 0.2

■ Brush - Radius (L): 0.2

■ Brush - Profile: Soft

■ Paint Attributes - Paint Operation: Replace

■ Paint Attributes - Value: 0.2

These settings set the brush to paint a relatively small, soft edged region,
with each stroke of the tool as you replace the existing fur with shorter
fur.

5 Position the brush cursor over the centre of the bear’s snout and begin
stroking in a small circular motion about the center of the snout.
Wherever you paint, the fur feedback updates and becomes shorter in
length.


6 In the Display section of the Paint Tool Settings editor turn on the Color
Feedback option.

The snout surface updates to display the fur length attribute map you are
currently painting. The black region at the end of the snout indicates the
area you have just painted. This region of the attribute map indicates
where the fur will be shorter in length when it is rendered. The lighter
gray region indicates where you have not yet painted and where the fur
length will remain unaffected.

You also want the fur to be short in the region of the bear’s mouth as
well.

7 Paint a few overlapping strokes on the region of the snout below the nose
where the mouth surface is located, as shown below.


Notice that the attribute map has a gradual color falloff. This ensures that
the fur transition between the original attribute values and the map does
not appear abrupt. You can smooth the attribute map even further by
applying a smooth operation.

8 In the Paint Tool Settings editor, set the Paint Operation to Smooth, and
then click Flood to apply a smooth to the entire fur length attribute map.
You can click Flood more than once to apply multiple smooth operations.

TIP If you accidentally paint an area that is too large you can click Ctrl + z
repeatedly to undo your paint strokes.
If you want to begin painting the attribute map again, you can set the Value
to 1 and then click Flood to fill the surface with a white color.

To create whiskers using the Paint Fur Attributes Tool

1 Ensure that the snout surface is still active and click the Porcupine fur
preset from the Fur shelf.

A second fur description is assigned to the bear’s snout. The snout appears
cluttered at this point but you’ll rectify it in the following steps.

2 Ensure that the snout surface is still active and select Fur > Paint Fur
Attributes Tool > .

3 In the Paint Fur Attributes Tools Settings window, set the following
options:
■ Fur Attribute: Baldness

■ Fur Description: Porcupine

4 In the Paint Tool Settings editor, set the Paint Attributes - Paint Operation
to Replace, Value to zero, and then click Flood.
This creates a baldness attribute map for the Porcupine fur description
that is black in color making the Porcupine fur feedback disappear
temporarily.


5 In the Paint Tool Settings editor, set the following:
■ Brush - Radius (U): 0.2

■ Brush - Radius (L): 0.2

■ Brush - Profile: Soft

■ Paint Attributes - Paint Operation: Replace

■ Paint Attributes - Value: 0.2

■ Stroke - Reflection: On

These settings set the brush to paint a relatively small, soft edged stroke,
that is gray in color on the baldness map so that some of the porcupine
fur (that is, whiskers) appear. When reflection is turned on, the stroke
you make on one half of the surface is mirrored on the opposite half.
This lets you create identical whiskers on either half of the snout.

6 Position the brush cursor over the left side of the bear’s snout and make
one short stroke from about the halfway point to the back of the snout,
as shown below.


The fur feedback updates immediately after your stroke to show the
whiskers on both sides of the snout. Tumble the scene view if they are
not immediately apparent.
The whiskers are not pointing outwards at the correct angle. To rectify
this you need to modify the Polar attribute on the Porcupine fur
description.

To edit the fur description

➤ Select Fur > Edit Fur Description > Porcupine.
The Attribute Editor appears and displays the attributes for the Porcupine
fur description.

To rename the fur description

➤ In the Attribute Editor rename the fur description to Whiskers.

To modify the whiskers

1 In the Attribute Editor, set the following attributes to modify the whiskers
on the snout surface:
■ Length: 1.5

■ Polar: 1.0

The whiskers update to point outwards on either side of the snout and
appear shorter as a result.

2 Display the Channel Box/Display Layer Editor, and click the visibility
box to display the ExtraParts layer again.


Modifying the color of a fur description
Next you’ll change the color of the fur description so it resembles a real teddy
bear. To do this you’ll edit the fur description and set the Base and Tip Color
attributes using the Attribute Editor.

To modify the fur description

1 Select Fur > Edit Fur Description > TeddyBear.
The Attribute Editor appears and displays the attributes for the assigned
TeddyBear fur description.

2 In the Attribute Editor, modify the Base and Tip Color attributes for the
TeddyBear fur description by clicking the color swatches for each attribute,
setting the RGB range to 0 to 255, and entering the following RGB values:
■ Base Color R: 62

■ Base Color G: 30

■ Base Color B: 8

■ Tip Color R: 106

■ Tip Color G: 52

■ Tip Color B: 14

These values change the color of the base of the fur to a dark brown, and
the tips of the fur a lighter brown. The fur feedback is updated on the
bear model.


Creating a new fur description
To make the bear appear more interesting you’ll assign a new fur description
to the inside of the ears and then modify fur attributes such as density, scraggle,
and inclination.
Before you can assign a fur description to the inner ear surfaces you’ll need
to select them by first turning off the referenced display layer.

To turn off the referenced display layer

1 Display the Channel Box/Display Layer Editor.

2 In the Display Layer Editor, click the box that displays the letter R until
the box is empty.
To change the display state of a display layer, click repeatedly in the
middle box next to the layer name to cycle the display state from
Reference (R), Template (T), or Normal (empty). When the box is empty
the display layer is no longer referenced and its possible to select all of
the surfaces on the model.

To create a new fur description

1 In the scene view, select the following surfaces of the model:
■ leftInnerEar

Creating a new fur description | 851

■ rightInnerEar

2 Select Fur > Attach Fur Description > New.
A new default fur description is assigned to the selected surfaces.

To rename the fur description

1 Select Fur > Edit Fur Description > Fur Description1.
The Attribute Editor appears and displays the attributes for the new fur
description.

2 In the Attribute Editor rename the fur description to InnerEar.

To modify the color of the fur description

1 In the Attribute Editor, modify the Base and Tip Color attributes for the
InnerEar fur description by clicking the color swatches for each attribute,
setting the RGB range to 0 to 255, and entering the following RGB values:
■ Base Color R: 106

■ Base Color G: 52

■ Base Color B: 14

■ Tip Color R: 164

■ Tip Color G: 119

■ Tip Color B: 91


2 Modify these additional InnerEar attributes by entering the following
values:
■ Density: 50,000

■ Length: 0.25

■ Inclination: 0.8

■ Base Width: 0.2

■ Tip Width: 0

■ Scraggle: 0.1

Density specifies the number of hairs on a surface. The higher the value,
the thicker the fur. Notice that changing the Density value does not affect
the fur feedback in the scene view; changes to fur density only appear in
the rendered image.
Length sets the fur’s length, in grid units.
Inclination sets how the fur slopes or leans. A value of 0 is fully erect
(normal to the surface), while a value of 1 is flat (tangent to the surface
at the root).
Base and Tip Width specifies width of the hairs at their base and tip.
Scraggle sets the crookedness of the fur. A value of 0 creates no
crookedness, while a value of 1 creates maximum crookedness.
The fur description for the Inner Ear surfaces is updated.

NOTE Some attributes of a fur description are only visible when you render
an image of the fur. You’ll render an image of the teddy bear fur in the next
lesson.

Beyond the lesson
The Teddy Bear now has brown fur and whiskers. The fur in the bear’s ears is
a lighter brown color.

■ Duplicate surfaces across the axis of symmetry—you duplicated the arm
and body surfaces and created a mirror-copy of them.


■ Rename surfaces—Naming objects as you create them ensures you can
easily identify and select them later on.

■ Assign parts of a model to display layers—any surfaces that you did not
want fur applied were assigned to a referenced display layer so they would
not get selected accidentally.

■ Assign an existing fur description preset to a model—Fur presets are a useful
starting point for creating various fur types. All of the fur presets included
with Maya can be customized. You also created a new fur description for
the inner ear surfaces and customized its attributes.
You can assign more than one fur description to a surface. In this lesson,
you added a second fur description to the bear’s snout in order to create
whiskers.

■ Reverse surface normals so the fur was oriented to point in the correct
direction—Two methods are possible for correcting the normals; reversing
the surface normals, and reversing the fur normals.

■ Modify the direction of the fur description on individual surfaces using
the Fur Description Offset—when a model is comprised of multiple surfaces
the fur description may point in different directions. You can modify the
fur direction using a variety of techniques depending on the situation.

■ You modified the length of the fur description on the bear’s snout and
created whiskers using the Paint Fur Attributes Tool. This tool lets you
paint an attribute map to modify specific fur attributes on an area of a
surface.
You can use the Paint Fur Attributes tool to paint the direction of the fur.
This technique is also referred to as combing the fur because it resembles
the stroking action you perform when combing real hair. Combing the
fur feedback is useful when you need to hide a visible seam between two
surfaces.

■ Modify fur attributes—You learned how to modify the attributes of a fur
description using the Attribute Editor.
Though not covered in this lesson, you can keyframe changes you make
to fur attributes to animate effects such as growing fur or changing fur
color. You can add movement to fur with attractors and dynamics. Using
attractors, you manually keyframe fur movement. Using dynamics, you
can make the fur react to forces, for example, wind and gravity. You can
also use dynamics to cause fur to react to movement of the attached surface,
for example, when a dog shakes itself.

■ UV texture coordinates—When applying fur to a surface the UVs must be
laid out so they are non-overlapping and reside between 0 and 1 in the


UV texture space. The UVs were prepared for the model in this lesson but
you should remember this when you assign Fur to your own models.

For more information and related techniques about Fur, refer to the Maya
Help.

Lesson 2: Rendering fur

Introduction

In order to see how all of the fur attributes of a fur description appear on a
model you must render an image.

■ Set up lights in a scene.

■ Assign fur shadow and shading attributes to the lights.

■ Render an image of the bear.

■ Make changes to the fur description and render the scene again.

Lesson setup
To ensure the lesson works as described, complete the steps in lesson 1, or do
the following before beginning:

Lesson 2: Rendering fur | 855

➤ Open the scene named FurRender.mb that is located in the
GettingStarted/Fur/scenes directory of your Maya project.
This scene includes a model that has been created for you. The model
has three fur descriptions assigned. You will add lights to the scene, render
an image, make some final adjustments, and render again.

Creating lights in a scene
You must add lights to your scene to illuminate the model before you render
it. You will create and position three spotlights to highlight the fur properties
on the bear model (see the plan view below). Spotlights are used in this lesson
because they can cast shadows.
The first spotlight will be positioned to the right of the model. The second
spotlight will be positioned to the left of the model. The third spotlight will
be positioned so it shines down onto the model from above.

To add lights to the scene

1 Click Create > Lights > Spot Light > .
The Create Spot Light Options window appears.

2 Click Edit > Reset Settings, set the following attributes, and then click
Create:
■ Intensity: 1.5

A new spotlight is created at the origin, named spotLight1. By default, it
is selected in the scene view. Check the Channel Box or the Attribute
Editor to make sure the spotlight is selected.


3 In the Channel Box, enter the following values to reposition the spotlight:
■ Translate X: -39

■ Translate Y: 12

■ Translate Z: 34

■ Rotate X: -5

■ Rotate Y: -49

4 Click Create > Lights > Spot Light to create another spotlight at the origin.
This new spotlight will be named spotLight2 and have the same intensity
setting as the first spotlight.

5 In the Channel Box, enter the following values to reposition the second
spotlight:
■ Translate X: 25

■ Translate Y: 15

■ Translate Z: 35

■ Rotate X: -10

■ Rotate Y: 35

6 Click Create > Lights > Spot Light > , set the following attribute, and
then click Create:
■ Intensity: 0.5

A third spotlight is created at the origin, called spotLight3.

7 In the Channel Box, enter the following values to reposition the third
spotlight:
■ Translate Y: 85

■ Translate Z: 7

■ Rotate X: -88

These three light sources will evenly illuminate the model: one will create a
shadow once you have set fur shadowing attributes for the spotlights.

Creating lights in a scene | 857

Adding fur shadowing attributes to lights
If the scene were rendered at this point, the fur would not appear realistic
because it would not contain shadows. To correct this you must turn on fur
shadowing attributes for the spotlights.

NOTE In this lesson, we will render with the Maya software renderer. However,
the following instructions for fur shadowing can also be applied to lights set up
to render Fur with the mental ray for Maya renderer.

To add fur shadowing attributes to spotlights

1 Select all three spotlights in the scene by selecting Edit > Select All by
Type > Lights.
All three spotlights in the scene are selected.

TIP When more than one item is selected in the scene view, the Channel
Box displays the name of the last item in the selection list with three dots
after its name to indicate that more than one item is selected.

2 Click Fur > Fur Shadowing Attributes > Add to Selected Light.
This adds adjustable fur shadowing attributes to all three spotlights in
the scene that were not included with the default spotlights. These extra
attributes let you refine how the lights affect the fur on the model when
rendering.

3 Select Window > Outliner to display the Outliner.


As your scene gets increasingly complex the Outliner becomes useful for
selecting specific objects in the scene, especially when you want to select
objects that are hidden by other objects, or are outside the camera’s field
of view. Selecting items in the Outliner is much easier when you have
named the objects and lights in your scene.

4 In the Outliner, click spotLight1 to select it in the scene.

5 Open the Attribute Editor by clicking the Show/Hide Attribute Editor
icon on the Status Line.

6 Select the spotLightShape tab, and under Fur Shadowing/Shadowing, set
the Fur Shading Type to Shadow Maps.

7 In the Attribute Editor, under Shadows > Depth Map Shadow Attributes,
set the following options:
■ Use Depth Map Shadows: On

■ Use Auto Focus: Off

■ Focus: 40

Depth Map Shadows are one technique for producing shadows in a scene
by determining which objects in the scene are in the path of a shadow
casting light.
Fur Shadows can be incorrectly placed when Auto Focus is turned on. To
avoid this, turn off Auto Focus for all spotlights that have Fur Shadow
Maps turned on and instead set the Focus value to Cone Angle +
(Penumbra * 2).

Adding fur shadowing attributes to lights | 859

8 Shift-select spotlight2 and spotlight3 using the Outliner.

9 In the Attribute Editor, under Fur Shadowing/Shadowing, set the Fur
Shading Type to Auto Shading.
The Autoshade attribute provides a quick simulation of shading that
occurs at the root and back of the fur strands without the added
complexity of a shadow map.

Rendering the scene
To see the fur in full detail, you need to render an image of the scene.

To render the scene

1 Select Window > Rendering Editors > Render Settings to show the Render
Settings window.

2 Ensure that Render Using is set to Maya Software in the drop-down list.

3 From the Render Settings window menu, select Presets > Load Preset >
Default Settings.
This sets the renderer to render an image that is 640 by 480 pixels in size;
large enough to see the fine detail on the fur.


5 To render the fur, do one of the following:
■ Select Render > Render Current Frame.

■ Click the Render Current Frame button in the Status Line.

The Render View window appears and an image of the scene is rendered.


At this point, you can modify any of the light attributes, or fur attributes as
required and render the scene again.

Beyond the lesson

■ Add spotlights to the scene—A three light setup is a good starting point
for many renderings.

■ Add spotlight fur shadowing attributes to lights—The fur shadowing
attributes must be turned on for the lights to produce shadows on fur.

■ Render the scene to produce an image with fur—You will usually need to
produce multiple iterations of an image in order to produce the final image
or frames of animation that you require.

For more information and related techniques about Fur, Lighting, or Rendering,
refer to the Maya Help.


nCloth
18
Introduction

With the Maya® nCloth™ feature, you can create dynamic cloth effects in Maya.
nCloth is a fast and stable dynamic cloth solution that uses a system of linked
particles to simulate a wide variety of dynamic polygon surfaces, such as fabric
clothing, inflating balloons, shattering surfaces, and deformable objects. nCloth
is generated from modeled polygon meshes. You can model any type of polygon
mesh and make it an nCloth object, which is ideal for achieving specific poses
and maintaining directorial control.

nCloth is built on a dynamic simulation framework called Maya® Nucleus™. A
Maya Nucleus system is composed of a series of nCloth objects, passive collision
objects, dynamic constraints, and a Maya Nucleus solver. As part of the Maya
Nucleus system, the Maya Nucleus solver calculates nCloth simulation, collisions,
and constraints in an iterative manner, improving the simulation after each
iteration, to produce accurate cloth behavior.

863

Maya provides many predefined nCloths. These sample nCloth objects, also
referred to as presets, can be used as a starting point in creating your own
custom cloth effects.

■ Lesson 1: Creating nCloth collisions on page 865

■ Lesson 2: Creating nCloth constraints on page 880

■ Lesson 3: Creating nCloth Clothing on page 895


1 Make sure you understand the basic concepts of polygon modeling,
animation, and dynamics.


3 Select the nDynamics menu set. Unless otherwise noted, the directions
the nDynamics menu set.

864 | Chapter 18 nCloth

Lesson 1: Creating nCloth collisions

Introduction

For nCloth objects to have realistic cloth behavior, they need to interact or
collide with their environment. This is accomplished by converting the meshes
you want to act like cloth into nCloth objects, and turning all the objects in
their environment that it will come into contact with into passive collision
objects.

■ Convert a polygon object to nCloth.

■ Create passive collision objects for your nCloth.

■ Improve the quality of your nCloth collisions.

Lesson setup

➤ Open the scene file named TableCloth.ma.
your Maya project:

Lesson 1: Creating nCloth collisions | 865

GettingStarted/nCloth/TableCloth.ma
This scene includes textured models that have been created for you. The
table cloth, table, table base, floor, and wall models provided are all
polygon meshes.

Creating an nCloth object

The first step in the nCloth creation process is to convert the polygon object
you want to behave like cloth to an nCloth object.

To make a polygon mesh nCloth

1 Select the checkered table cloth.

2 Select nMesh > Create nCloth > .
The Create Cloth Options window appears.

3 Select nucleus1 from the Solver drop-down list.


Selecting a solver determines which Maya Nucleus system the nCloth
belongs to.

4 Turn on Local Space Output.
Defining a space output determines whether the table cloth’s input and
output nCloth meshes are both (Local Space Output) attached to the
selected Maya Nucleus solver, or just the output nCloth mesh (World
Space).

5 Click Create Cloth.
The static quad polygon table cloth is automatically tessellated and
converted to a dynamic nCloth object, and an nCloth handle appears
on your table cloth in the scene view. The nCloth handle resembles a
small wireframe sphere, and it is located at the center of table cloth. You
can use the table cloth’s nCloth handle to quickly select its nClothShape
node in the Hypergraph or its tab in the Attribute Editor.

6 Select Window > Hypergraph: Connections to view the new node
connections for the table cloth in the Dependency Graph (DG).
The Hypergraph appears with a new Maya Nucleus network of nodes.
Note that the table cloth is now a member of the nucleus1 Maya Nucleus
system.

Creating an nCloth object | 867

nClothShape1 is the nCloth properties node, which carries all the nCloth
attributes for the table cloth.
nucleus1 is the Maya Nucleus solver node, which carries all the attributes
affecting the nucleus1 solver system, including internal forces.
TableClothShape is the input mesh and start object for the table cloth.
outputCloth1 is the output mesh or current mesh, and the resulting nCloth
table cloth that you see in the scene view.
polyPlane2 is the history node for the table cloth.

7 Close the Hypergraph and play back your table cloth’s simulation.
The table cloth passes right through the table, its base, and the floor. This
is because the nCloth does not recognize any of the other objects in your
scene. For the nCloth table cloth to be able to interact with the table, its
base, and the floor, they need to be members of the same Maya Nucleus
solver system as the table cloth.

8 Go to the beginning of the playback range.

Making an nCloth collide with its environment
The second step in creating realistic cloth effects is to make your nCloth object
interact with its environment, and have the objects and surfaces in its scene
deform the nCloth and drive its movements. You can do this by making each
surface the nCloth comes into contact with during its simulation passive collision
objects.


To create passive collision objects for your nCloth

1 Select the table.

2 Select nMesh > Create Passive Collider > .
The Make Collide Options window appears.

3 Select nucleus1 from the Solver drop-down list and click Make Collide.
The table polygon mesh is converted to a passive collision object, and
an nRigid handle appears at the center of its mesh in the scene view. You
can use the table’s nRigid handle to quickly select its nRigidShape node
in the Hypergraph or its tab in the Attribute Editor.

The table is also now a member of the nucleus1 Maya Nucleus system.

4 Select Window > Hypergraph: Connections to view the new node
connections for the table in the Dependency Graph (DG).

nRigidShape1 is the passive object properties node which carries all the
passive object attributes for the table.

5 Close the Hypergraph and play back your table cloth’s simulation.
The table cloth now collides with the table. The table cloth now interacts
with the table because the table is a member of the table cloth’s nucleus1
solver system.

Making an nCloth collide with its environment | 869

NOTE You may need to increase the total number of frames on your time
line for the table cloth to collide with the table.

Adjusting the accuracy of nCloth collisions
The third step in creating believable cloth effects is to make your nCloth
object’s collisions as accurate as possible. In reality, a falling piece of cloth
comes into close contact with the object it lands on and it deforms, reflecting
the shape of the object it has come into contact with. Currently, the table
cloth does not exhibit this behavior.

To set the thickness of your nCloth and passive objects

1 Select the table cloth.

2 Open the Attribute Editor and select the nClothShape1 tab.

3 In the Collisions section, select Collision Thickness from the Solver
Display drop-down list.


The table cloth’s collision thickness appears in the scene view.

An nCloth’s Thickness attribute determines the radius or depth of the
table cloth’s collision volume. The collision volume is a non-renderable
surface offset from the table cloth’s surface that the nucleus1 solver uses
when calculating the table cloth’s passive object collisions. Collisions
occur at the table cloth’s collision volume, not at the surface of the table
cloth itself.

Adjusting the accuracy of nCloth collisions | 871


5 In the Collisions section, change the table cloth’s Thickness attribute
value to 0.066.

The table cloth’s collision volume is noticeably reduced, so that it will
now behave like a thin piece of fabric rather than a thick surface. This
new Thickness will contribute to improving the accuracy of the table
cloth’s collisions when it falls onto the table.

6 Select Off from the Solver Display drop-down list.


The table cloth’s Collision Thickness is no longer displayed in the scene
view.

7 Play back the table cloth’s simulation.

Even though you adjusted the table cloth’s Thickness, the table cloth still
does not appear to be making contact with the table’s surface. This is
because passive collision objects, like the table, also possess collision
volumes.


To further improve the accuracy of the table cloth’s collisions, you need
to adjust the table’s Thickness.


9 In the scene view select the table, and in the Attribute Editor select its
nRigidShape1 tab.


The table’s collision thickness appears in the scene view.

11 Set the table’s Thickness attribute value to 0.066.


The table’s collision volume is noticeably reduced, so that the table cloth
will now conform closely to the actual shape of the table when you play
back its simulation.

12 In the Collisions section, select Off from the Solver Display drop-down
list.
The table’s Collision Thickness is no longer displayed in the scene view.



Adjusting the Thickness of the table cloth nCloth and the table passive
object dramatically improved the accuracy of the table cloth’s collisions.


The way Collision Thickness appears in the scene view is determined by your
nCloth’s current Collision Flag selection. The Collision Flag drop-down list lets
you specify which of the table cloth’s components participate in its collisions
and which type of collision volume is used by the table cloth. You can adjust
the speed of your nCloth collisions with the Collision Flag at the cost of
collision accuracy.


To set which nCloth components participate in collisions

1 Select the table cloth.

2 In the Attribute Editor, select the nClothShape1 tab.


4 By default, the Collision Flag is set to Face.

Face provides the best and most accurate collisions, but it is the slowest
to calculate the collisions for.

5 Change the Collision Flag selection to Vertex. Vertex produces the least
accurate collisions, but it is the fastest to calculate the collisions for.

The table cloth’s collision volume changes from a surface to multiple
collision spheres.



The table cloth passes through the table and floor collision objects, as if
they were not passive objects. This is because when you select Vertex as
your component type, only the small collision spheres surrounding the
table cloth’s vertices participate in the table cloth’s collisions, rather than
the entire surface as with Face.

Vertex and face are useful when you want to speed up your simulation
by reducing the number of collision calculations, or your cloth simulation
does not require the maximum level of collision accuracy (for example,
for a distance shot of colliding nCloth objects).

7 Reset the Collision Flag to the default Face selection, and select Off from
the Solver Display drop-down list.


The table cloth once again easily and accurately collides with the table.


Beyond the lesson
The table cloth now is a dynamic nCloth object that behaves like real cloth
as it collides with the table, floor, and wall in its scene.

■ Turn a regular polygon mesh into a dynamic nCloth object.

■ Run an nCloth simulation.

■ Turn objects in an nCloth’s scene into passive collision objects.

■ Refine nCloth collisions by adjusting the Thickness and Collision Flag of
the nCloth and passive objects in a scene.

For more information and related techniques about nCloth, refer to the Maya
Help.


Lesson 2: Creating nCloth constraints

Introduction

Often times, to create certain cloth effects, you need to attach nCloth to other
nCloths or passive collision objects and have those other Maya Nucleus objects
restrict or drive your nCloth’s movements. For example, you can use nCloth
constraints to create buttons on nCloth garments, replace collisions, bind
topologically different nCloth objects together, and exclude and limit nCloth
and passive object collisions.

■ Constrain an nCloth object.

■ Manage an nCloth constraint’s membership.

■ Adjust nCloth constraint behavior.

■ Make an nCloth flag flap in the wind.

Lesson setup

➤ Open the scene file named Flag.ma.


your Maya project:
GettingStarted/nCloth/Flag.ma
This scene includes dynamic meshes that have been created for you. The
pirate flag and the flag pole provided are an nCloth object and a passive
collision object respectively.

Constraining an nCloth to a passive object
You can constrain nCloth by creating dynamic links between its vertices and
the components of other nCloths or passive collision objects. The stretchiness
and compressibility of these collision links depends of the type of constraint
they belong to.

To constrain an nCloth

1 Play back the flag’s simulation.

The flag falls downward through the air. For the flag to retain its position
beside the flag pole in XYZ space, it needs to be constrained to the static
flag pole passive object.

NOTE You may need to increase the total number of frames in the timeline.


Constraining an nCloth to a passive object | 881

3 Select the flag.

4 Right-click the flag and select Vertex from the context-sensitive menu
that appears.
The flag switches to vertex display mode.

5 Dolly in the camera so that you can view the vertices along the left side
border of the flag closely.

6 Select the left border’s vertices.

7 Shift-select the flag pole passive object to include it in your selection.


8 Select nConstraint > Point to Surface.


A Point to Surface constraint is created, and constraint links appear
between the vertices you selected on the nCloth flag, and the surface of
the flag pole passive object.


The flag gently falls and ripples, but does not continue to fall out of view.
This is because the point to Surface nCloth constraint attaching the flag
vertices to the flag pole now restricts the position of the whole flag in
XYZ space.



Changing which nCloth points are constrained
After you create a dynamic nCloth constraint, you often times need to edit
which nCloth and passive object components participate in the constraint.
When Maya Nucleus system components are constrained, they are members
of their respective constraints. You can change an nCloth constraint’s
membership by adding or removing nCloth and passive object components
from the constraint.

To edit nCloth constraint membership

1 Dolly in the camera so that you can view closely the Point to Surface
constraint links that are visible between the flag and its flag pole.

2 Select the Point to Surface constraint by clicking its links.


3 Select nConstraint > Select Members.

The flag points and the flag pole surface that are members of the selected
Point to Surface constraint highlight in the scene view.

Changing which nCloth points are constrained | 887

4 Right-click the flag and select Vertex from the context-sensitive menu
that appears.
The flag switches to vertex display mode.


5 Select all the flag points, except the top most and bottom most points.


6 Select nConstraint > Remove Members.

The selected constrained flag points are removed from the constraint and
their constraint links disappear from the scene view.


7 Play back the pirate flag’s simulation.
The flag gently falls and ripples, but does not continue to fall out of view
because it is attached to the flag pole by the two remaining Point to
Surface constraint links.



Making nCloth flap in dynamic wind
After creating the nCloth flag, you can dynamically animate it to flap in the
wind by altering certain Dynamic Properties and Maya Nucleus solver Gravity
and Wind properties.

To make nCloth appear to wave and flap in the wind

1 Select the flag.

2 Open the Attribute Editor and select the nClothShape tab.

3 In the Dynamic Properties section, decrease Mass and increase Tangential
Drag.


Mass specifies the density of the flag and Tangential Drag biases the
amount of drag applied to the flag relative to the surface tangent, which
is necessary otherwise the flat plane will not have any wind resistance.
■ Change the Mass attribute’s value to 0.5.

■ Change the Tangential Drag attribute’s value to 0.05.

Making nCloth flap in dynamic wind | 893

The flag appears lighter, however it still falls.


6 Select the nucleus tab.

7 In the Gravity and Wind section, increase the Wind Speed.
You can increase the speed at which the flag flaps, as well as the amount
of ripples moving across the flag’s surface, by increasing the Maya Nucleus
solver’s Wind Speed.

8 Change the Wind Speed attribute’s value to 10.

9 Play back the pirate flag’s simulation.


The flag rises quickly into the air, appearing to be tugged by the increased
dynamic air flow. The flag now waves and flaps forcefully, and ripples
appear on its surface.

Beyond the lesson

■ Constrain nCloth.

■ Edit nCloth constraint membership.

■ Make nCloth appear to blow in the wind.

Lesson 3: Creating nCloth Clothing

Introduction

A common use for cloth effects is to simulate dynamic clothing on a character.
When you attach nCloth clothing to a character, you want to ensure that it
correctly simulates the proper material when the scene is animated. For
example, you can use nCloth to simulate heavy leather or soft silk. While
creating these effects you also want to make use of Maya’s nCloth caching
abilities to improve playback.

■ Adjust and paint properties of nCloth to make it behave like real life fabric.


■ Utilize the nCloth cache.

■ Constrain an nCloth dress to an animated character.

Lesson setup

➤ Open the scene file named dressStatic.mb.
your Maya project:
GettingStarted/nCloth/dressStatic.mb
This scene includes static meshes that have been created for you. Both
the character and the dress are polygon objects.

Making the dress into an nCloth object

The dress in this scene is initially just a mesh and not an nCloth object. Your
first step will be to convert the dress into an nCloth object.

To convert the dress into an nCloth object

1 Select the dress.

2 Select nMesh > Create nCloth > .
The Create nCloth Options window appears.



4 Click Create Cloth.
The dress is automatically tessellated and converted to a dynamic nCloth
object. Maya also creates a new solver named nucleus1 and adds the dress
to it.

Making the character wear the dress
If you playback the animation, the dress will fall through the body of the
character. To make the character wear the dress, you need to make her a passive
object.

To make the character wear the dress

1 Select the model of the character.



4 Click Make Collide.

5 Playback the nCloth simulation.
The dress now stays on character’s body.

Making the character wear the dress | 897

Caching nCloth to speed up playback
Notice that the playback of the nCloth simulation is quite slow. This is due
to the additional calculations required for nCloth and its associated collisions.
However, you can use Maya’s nCache feature to view the scene at full speed.

To view the scene at full speed

1 Select the nCloth dress.

2 Select nCache > Create New Cache > .
The Create nCloth Cache Options window appears.

3 Set the Cache directory to the folder to which you want your caches
saved.

4 Set the Cache name to DressCache.

5 Click Create.
Maya will begin to play the scene automatically and store the frames in
the directory you specified. When it is finished, click the Play button in


the animation controls. You will notice that the scene now plays back at
full speed. However, if you change any of the dress’ settings you will need
to create a new cache to view your changes. This will be addressed later
in this lesson.

Adjusting the fit of the dress
You will notice during playback that the dress (especially the straps) do not
actually touch the body. This is because the collision volumes of both the
character and the dress are too thick. This means that Maya believes the two
are in contact when they are not. You can fix this by adjusting the collision
thickness of both objects.

To adjust the collision thickness of the dress

1 Select the dress.

2 Open the Attribute Editor select the nClothShape1 tab.

3 In the Collisions section set Collision Flag to Face, Self Collision Flag to
Vertex Face, set Thickness to 0.066 and Self Collide Width Scale to 1.885.

4 Select the character model.

5 From the Attribute Editor select the nRigidShape1 tab.

6 In the Collisions section set Thickness to 0.083.


Adjusting the fit of the dress | 899

Notice that the simulation appears exactly the same as before. This is
because you are actually playing your cached simulation. In order to view
your changes, you will need to make a new cache.

To make a new cache for your nCloth simulation

1 Select the dress.

2 Select nCache > Create New Cache.
Maya automatically plays back the nCloth simulation and saves it to disk
as a cache.

3 Playback the scene.
The dress now appears to rest on the character’s skin.

Defining the behavior of nCloth clothing
Although your dress now fits properly over the character, the dress itself seems
to be made of a very heavy material in a very low gravity environment. Ideally,
you want the dress to behave like a light weight material such as silk in a
gravitational environment similar to our own.


To improve the behavior of the dress

1 Select the dress.

2 Open the Attribute Editor and select the nucleus1 tab.

3 In the Scale Attributes section, set the Space Scale to 0.016.
By reducing the Space Scale attribute, Maya evaluates the large nCloth
model as if it were a much smaller object. This will result in a visibly
increased gravitational affect on the dress. For more information on Space
Scale see Space Scale

4 Select the nClothShape1 tab and in the Dynamic Properties section set
Mass to 0.7.

5 In the Dynamic Properties section set Stretch Resistance to 140 and
Compression Resistance to 120.
By lowering the mass of the cloth, Maya will simulate it as a lighter fabric
such as silk.
Increasing the Stretch Resistance and Compression Resistance ensures
that the cloth will not become stretched or compressed too greatly as a
result of the increased affect of gravity from step 3.

as a cache.

The dress now behaves more like a light weight material. However, this
causes a problem around the breasts where the dress now slips and hangs
loose around them rather than over them.

Defining the behavior of nCloth clothing | 901

Painting nCloth properties
In a real dress, the area around the breasts (the bodice) is often made of a
stiffer material to ensure the cloth does not hang loose. In order to simulate
a bodice on your nCloth dress you will use the Paint Vertex Tool to paint
Input Attract values on specific areas of the dress.

To paint Input Attract

1 Go to the first frame of the scene.

2 Select the dress and open the Attribute Editor.

3 Select the nClothShape1 tab and in the Dynamic Properties section set
Input Mesh Attract to 1.0.

as a cache.

The dress now maintains its shape. This is because the Input Mesh Attract
value you set in step 3 makes the nCloth mimic the shape of its input
mesh. The input mesh is the original polygon mesh from which the
nCloth dress was created.

6 Select nMesh > Paint Vertex Properties > Input Attract > .
In the Tool Settings Editor, the Paint nCloth Attributes Tool becomes the
current tool.


7 Click the Reset Tool button and then set the following settings:
■ Radius(U): 3.0

■ Radius(L): 3.0


■ Value: 0

Move the cursor to the dress and you will notice that the cursor becomes
an artisan brush.

8 Paint over a portion of the dress.
Notice that the portion you paint over turns black. Black regions of the
dress indicate an input attract value of 0 meaning that those areas will
be fully dynamic when the simulation is played back. Conversely, white
regions indicate an input attract value of 1 meaning those areas will
remain identical to the input mesh throughout the simulation.

as a cache.

The dress now maintains its shape everywhere except those places which
you painted with the cursor. This is because the areas that you painted
now have an input attract value of 0, making them fully dynamic.

11 Click the Flood button.
The entire dress turns black indicating that a value of 0 has been applied
to the Input Mesh Attract attribute for the entire dress.

Painting nCloth properties | 903

12 Set Value to 1.

13 Using the Tool brush, paint around the top of the bodice.
Make sure to dolly and tumble the camera to ensure you have painted
the entire top of the bodice.

14 Set Value to 0.5.

15 Using the Tool brush, paint the rest of the bodice. Be careful not to paint
over your previous values.

16 Dolly and tumble to ensure that you have painted the entire bodice.

as a cache.

The dress now appears to be made of a light silk, except around the bodice
where it maintains its shape. If your dress does not appear as the example
below, you may need to increase the values painted on your bodice.


This completes the first half of the nCloth clothing lesson. In the second half
of the lesson you will work with an animated character.


➤ Open the scene file named DressAnimated.mb.
This file can be found in the GettingStarted directory that was installed
with your Maya software:
GettingStarted/nClothDressAnimated.mb

This scene includes an nCloth dress worn by an animated character model.
A walk and pose animation is already applied to the character.

Setting the initial state
When you load the file you will notice that in the first frame of the animation
the dress is suspended such that it does not touch the character’s body. This
is because this was the input mesh’s original position. However, for this
character you want the dress to be in a relaxed position before the animation
begins. To do this, you need to edit the nCloth’s initial and rest states.

To edit the initial state of the dress.



The character takes a number of steps from her starting point and then
poses. You will notice however that the dress begins in a suspended
position and falls onto the character as she walks.


3 Select the dress.

4 Select nSolver > Initial State > Relax Initial State > .
The Relax Initial State Options window appears.


6 Set Steps to 300 and then click Relax Initial State.

By setting the Steps option to 300 you are setting the nCloth dress’ initial
position to mimic that of its position at frame 300 of the animation
(when the dress has fallen onto the body and relaxes).


7 Select nMesh > Rest Shape > Set Rest to Start Shape.
The rest shape specifies the shape that the dress attempts to achieve
through its stretch, compression and bend resistance values. Thus, by
setting it to the Start Shape, you ensure that the dress attempts to return
to its initial configuration throughout the simulation.

Maya automatically plays back the nCloth simulation and saves it to disk.

The dress now fits tightly on the character from the beginning of the
animation to the end.

Constraining nCloth clothing

Constraining nCloth clothing | 907

Notice when you playback the scene the straps fall off the character’s shoulders
as she walks. You can fix this by constraining the straps to her body.

To constrain the dress straps

1 Go to beginning of the playback range.

2 Right-click the model and select Vertex.

3 Select only the vertices of the dress straps.

4 Shift-select the character.

5 Select nConstraint > Point to Surface.
An nConstraint creates a dynamic link between an nCloth’s vertices and
the components of other nCloth or collision objects. A Point to Surface
constraint attaches nCloth components such as vertices, edges, or faces
to a target surface. In this case we are attaching the vertices of the dress
straps to the character’s body.


6 With the newly created constraint still selected, select Display > Hide >
Hide Selection.
The constraint markers disappear to give you a better view of the dress
straps.

NOTE If you de-selected the constraint and have trouble re-selecting it, you
can select Window > Outliner to open the Maya Outliner. You can then select
the constraint by left-clicking dynamicConstraint1 in the Outliner.

7 Select the dress.


The dress straps now stay with the character’s body throughout the
animation.

Improving the quality of the nCloth simulation
Although the dress behaves roughly the way a real dress would, you will notice
that some of the collisions (the places in which the dress intersects with itself
or with the character) do not appear correct. Specifically, in some areas, the
character’s mesh shows through the dress or the dress bunches up and becomes
trapped in that state.

Improving the quality of the nCloth simulation | 909

To improve the quality of the nCloth collisions


2 Select the dress.

3 Open the Attribute Editor and select the nClothShape1 tab.

4 In the Quality Settings section, set Max Self Collide Iterations to 20 and
turn on Self Trapped Check.

The Max Self Collision Iterations value specifies the maximum number
of self-collision related nCloth calculations performed per substep.
Increasing this value allows Maya to recognize more self-collisions and
thus simulate more realistic cloth, but at the cost of slower speed.


Activating Self Trapped Check allows Maya to monitor collision crossovers.
When points crossover one another, Maya will attempt to push them
apart. This stops the dress from bunching up and becoming stuck.

5 Select the nucleus1 tab.

6 Under Solver Attributes, set Substeps to 10 and Max Collision Iterations
to 50.

Increasing the substeps increases the number of times Maya calculates
the nCloth’s position per frame. By increasing this value, Maya updates
the position of the cloth more often; resulting in a more accurate
simulation at a slower speed.
The Max Collision Iterations value specifies the maximum number of
collision-related nCloth calculations performed per substep. Increasing
this value allows Maya to recognize more collisions and thus simulate
more realistic cloth, but at the cost of slower speed.


The collisions now looks more accurate, the character’s body no longer
shows through the dress, and the dress no longer bunches or becomes
trapped.

You may increase the values in the above steps to further improve the
simulation. However, keep in mind that caching the animation becomes
progressively slower as these values increase.

Improving the quality of the nCloth simulation | 911

Smoothing nCloth clothing
To improve the quality and overall look of the dress you can perform a polygon
smooth. Polygon smoothing will increase the number of polygons in your
nCloth mesh to give it a smoother overall appearance.

To smooth the dress

1 Select the dress and in the Polygons menu set select Mesh > Smooth.

2 Return to the nDynamics menu set.


The dress in the final animation is smoothed giving it a much silkier
appearance.


Beyond the lesson

■ Create and playback nCloth caches.

■ Adjust the properties of an nCloth object.

■ Paint nCloth properties.

■ Modify the initial and rest state of an nCloth object.

■ Improve the quality of nCloth clothing.

For more information and related techniques about nCloth, refer to the Maya
Help.


nParticles
19
Introduction

nParticles is a particle generation system that uses Maya® NucleusTM, the same
dynamic simulation framework that generates nCloth simulations. An nParticle
object natively collides and interacts with other nParticle objects, as well as
with nCloth and passive collision objects. nParticles can also self-collide,
meaning that particles from the same nParticle object can collide with each
other.

915

Nucleus dynamics allows you to create particle effects and dynamic simulations
that cannot be achieved with Maya classic particles. For example, you can use
Liquid Simulation attributes to create particle systems that behave like liquids.
You can also create effects in which particles interact and drive nCloth
animations and deformations.
This chapter includes these tutorials:

■ Lesson 1: Creating nParticles on page 917

■ Lesson 2: Creating a smoke simulation with nParticles on page 930

■ Lesson 3: Creating a liquid simulation with nParticles on page 953

Preparing for the tutorials

1 Make sure you understand the basic concepts of polygon modeling,
animation, and dynamics.


3 Select the nDynamics menu set. Unless otherwise noted, the directions
the nDynamics menu set.

916 | Chapter 19 nParticles

Lesson 1: Creating nParticles

Introduction

In this lesson, you will be introduced to the basic concepts of Nucleus
dynamics, as well as learn how to create an nParticle and emitter object. You
will then adjust nParticle object attributes to create a simple nParticle effect.
In this lesson, you also learn how to:

■ Create passive collision objects for your nParticles to collide with.

■ Set nParticle size.

■ Adjust Nucleus node attributes.

■ Adjust attributes to control the behavior of your nParticles.

Lesson 1: Creating nParticles | 917

Lesson setup
To ensure this lesson works as described, open the scene file named
nParticle_Candy.mb. This file is in the GettingStarted directory that you set
as your Maya project:
GettingStarted/nParticles/nParticle_Candy.mb

This scene includes textured polygon models including a desk, bowl, and
candy package.

Creating an nParticle system
Before creating an nParticle system, you must decide which nParticle style
and creation method suits your nParticle effect. In this lesson, nParticles are
used to simulate candies that are poured from a package into a bowl.
To achieve the appropriate look and behavior, you will use Ball style nParticles.
nParticle styles are like templates that provide preset attribute settings for the
nParticle object's appearance, size, render type, and collision properties. To
create the nParticle system, you will emit nParticles from the surface of a
polygon plane that is located inside the candy package.

To create an nParticle system

1 Select nParticles > Create nParticles > Balls.

2 In the Outliner, select candy_emitter_surface, then select nParticles > Create
nParticles > Emit from Object > .


The Emitter Options (Emit from Object) window appears.

3 In the Emitter Options (Emit from Object) window, select Edit > Reset
Settings.

4 For the Emitter name, type Emitter_Candy.
Naming your emitter object makes it easier to identify in the Outliner
when you want to select it and make attribute adjustments.

5 From the Solver list, select Create New Solver.
Selecting a solver determines which Maya Nucleus system your nParticles
belong to.

6 From the Emitter type list, select Surface.
A Surface emitter will randomly distribute nParticles from positions on
or near the surface of the polygon plane that is inside the candy package.

7 Set Rate (particles/sec) to 50.
This determines the number of particles that are emitted.

8 In the Basic Emission Speed Attributes section, set Speed to 5.0.

9 Click Create.

10 From the perspective window menu, select Shading > Smooth Shade All.

11 Play back your nParticle simulation.

Creating an nParticle system | 919

nParticles are emitted, but they fall through the side of the candy package
and disappear. This is because the nParticles cannot yet collide with any
of the other objects in your scene. For your nParticles to collide with the
candy package and bowl, these meshes need to be passive collision objects
and members of the same Maya Nucleus solver system as the nParticles.

Making nParticles collide with their environment
In the second step of creating an nParticle effect, you convert the meshes you
want the nParticles to collide with to passive collision objects. When nParticles
collide with passive collision objects, their behavior, speed, and direction
change. Passive collision objects are not affected by collisions with other
objects.
In this lesson, you convert the candy package, bowl, and the desk surface
geometry to passive collision objects. The nParticles can then collide with
these objects.

To convert geometry to passive collision objects

1 Rewind the simulation to the start frame.

2 In the scene view, Shift-select the package and bowl meshes as well as
the surface of the desk.




4 From the Solver list, select nucleus1.

The candy package, bowl, and desk surface meshes are converted to
passive collision objects. nRigid handles appear at the center of the meshes
in the scene view. You can use the nRigid handles to quickly select
nRigidShape nodes in the Hypergraph or their tabs in the Attribute Editor.
These objects are now members of the same Nucleus system (nucleus1)
as the nParticles.

6 To rename the nRigid objects, in the Outliner, double-click them and
type nRigid_Package, nRigid_Bowl, and nRigid_Desk respectively. Press Enter
after you type each object name.

7 Play back the simulation.
When you play back the simulation, the nParticles now fall from the end
of the package and are collected in the bowl.

Making nParticles collide with their environment | 921

Notice that the nParticles are not falling from the candy package as
quickly as you might expect. Instead, they fall slowly, as if the simulation
was playing back in slow motion. This is because the Nucleus solver
properties need to be adjusted to suit the simulation.
In the next section of the lesson, you set Nucleus solver properties so
that the particles fall realistically.

nParticle and Nucleus nodes
You have now created all of the objects for your Nucleus dynamics system.
The following section describes each Nucleus system node.
nParticleShape1 is the node that carries all the nParticle object attributes that
define the appearance, size, and overall behavior of each particle in the
nParticle system.
Emitter_Smoker1 is the nParticle emitter node, which carries all the particle
emission attributes such as particle emission rate and emitter type.
nucleus1 is the Maya Nucleus solver node, which carries all the attributes
affecting the solver system including internal forces.
nRigidShape1 is the passive object properties node which carries all the passive
collision object attributes.

Setting Nucleus Space Scale
Adjusting the Nucleus solver properties is an important step of creating an
nParticle effect. The Nucleus solver properties control internal forces that
affect all of the nodes that are members of a solver system. One of the most
significant Nucleus solver attributes is Space Scale.
The Nucleus solver applies Gravity and Wind forces to objects as if the objects
were scaled in meters, regardless of the units in which your scene was created.
To maintain the effect of real world gravity, you need to adjust the Nucleus
Space Scale to suit your simulation.

To set Space Scale

1 In the Outliner, select nParticle1.

2 In the Attribute Editor, click the nucleus1 tab.



When you reduce the Space Scale value, Maya evaluates the objects in
the simulation as if they were much smaller in size. This results in a visibly
increased gravitational affect on the nParticles.

4 Play back your simulation.
When you play back the simulation, notice that the nParticles are now
falling from the candy package at a realistic speed.

Adjusting nParticle size and color
You can adjust nParticleShape node attributes to specify how the particles
look, move, and collide with other Nucleus objects. Adjusting the emitter
attributes also affects the overall characteristics of your nParticle simulation.
To make the nParticles look and behave like candy, you will increase their
size, change their color, and make their surfaces sticky.

To increase nParticle size


2 In the Attribute Editor, click the nParticleShape tab.

3 In the Particle Size section, set Radius to 1.8.

To change the color of the nParticles

1 In the Shading section, go to Color.

2 Click the far left circle marker (at Selected Position 0) of the ramp.

3 Click the color swatch beside Selected Color.

Adjusting nParticle size and color | 923


4 In the Color Chooser, select white, then click Accept.

5 Click the far right square marker of the ramp to delete it.
For this simulation, the color of the nParticles will not change so you
only need one ramp marker.

6 From the Color Input list, select Constant.

The nParticles now look more like candy, but too many nParticles are
being emitted, which is overflowing the bowl.
To solve this problem, you can reduce the number of nParticles by
adjusting the emitter attributes. Like many Maya attributes, you can set
a key to change the emission rate at a specified time in the simulation.

To key nParticle emission rate

1 Go back to the beginning of the playback range.

2 Play the simulation and stop at frame 50.

3 In the Outliner, expand candy_emitter_surface and select Emitter_Candy1.

4 In the Attribute Editor, click the Emitter_Candy tab.

5 In the Basic Emitter Attributes section, right-click Rate (Particles/Second)
and select Set Key from the context menu.


A key is created with the nParticle emission rate set at 50.

6 Play the simulation for five more frames to frame 55.

7 Set Rate (Particles/Second) to 0.

8 Right-click Rate (Particles/Second) and select Set Key from the context
menu.
A key is created with the nParticle emission rate set at 0.

9 Go back to the beginning of the playback range and play the simulation.
nParticles are now emitted until frame 55.

Adjusting nParticle collision attributes
nParticle Collisions attributes determine the behavior of nParticles when they
collide each other and with other Nucleus objects. In this section of the lesson,
you make the nParticles sticky like candy by adjusting the Friction and
Stickiness attributes.

To adjust nParticle Collisions attributes


2 In the Attribute Editor, click the nParticleShape tab.

3 In the Collisions section, set the following:
■ Bounce: 0

■ Friction: 0.2

■ Stickiness: 0.5


5 Notice that the nParticles are now sticking each other and piling up at
the edge of the bowl.
Friction and Stickiness are similar attributes in that Friction is a force
acting in the tangent direction, while Stickiness is an adhesion force in
the normal direction. When Nucleus objects collide, the affect of their
Friction and Stickiness values are additive. For example, if the Stickiness
value of the nParticles and the bowl are 0.5, the overall Stickiness acting
on both objects is equal to 1.0.

Adjusting nParticle collision attributes | 925

6 To set Friction and Stickiness on the bowl, in the Outliner select
nRigid_Bowl.

7 Click the nRigid_BowlShape tab, then in the Collisions section, set Friction
to 0.2 and Stickiness to 0.5.

Notice that the nParticles have greater tendency to stick to the surface
of the bowl. This is because of the additive effect of the Friction and
Stickiness attributes.

For more information see Friction and Stickiness.

9 Set the nParticle Stickiness 0.2.
The particles now stick to one another and to the bowl like candies.

Adjusting nParticle self collisions
When you play back the simulation, the nParticles are piling up as they fill
the bowl. This is because the nParticles are self-colliding with each other. For
some nParticle effects, such as liquid simulations, lava flows, and splatters,
you do not want the nParticles to self-collide. You can turn nParticle
self-collisions on and off by setting the Self Collide attribute.

To turn off nParticle self-collisions

1 In the Collisions section of the nParticle Attribute Editor, turn off Self
Collide.


Notice that the nParticles no longer pile up, but blend and overlap with
each other.
Each nParticle has an outer boundary that determines the distance
between the nParticle and an object at collision. The Collide Width Scale
attribute sets the collision distance between the nParticles and other
Nucleus objects. The Self Collide Width Scale attribute sets the collision
distance between self-colliding nParticles.
By default, Collide Width Scale and Self Collide Width Scale are set to 1
for normal collisions. Turning off Self Collide is like setting the Self Collide
Width Scale to 0.

3 Turn on Self Collide, and set Self Collide Width Scale to 1.5.

Notice that the nParticles appear to collide with each other when they
fill the bowl, but they don't touch one another. The gaps between the
nParticles are due to the increased Self Collide Width Scale.

Adjusting nParticle collision attributes | 927

In the next step, you will display the current Self Collision Width Scale
by turning on the Solver Display.

5 From the Solver Display list, select Self Collision Thickness.
The nParticles now appear with their Self Collision Thickness displayed
in yellow. You can make adjustments to the Self Collide Width Scale and
see how the thickness affects the space between colliding nParticles.

6 Set Self Collide Width Scale back to 1.0, and the Solver Display to Off.



Beyond the lesson
In this lesson you were introduced to the basic concepts of nParticles and the
Nucleus dynamics system. In addition, you learned how to:

■ Create nParticles by emitting them from a polygon object using a Surface
type particle emitter.

■ Set the size of the nParticles using the Radius attribute.

■ Set the color of you nParticles.

■ Set nParticle Collisions attributes to control the behavior of nParticles.

■ Turn off nParticle self-collisions.

■ Set the collision distance between self-colliding nParticles by setting Self
Collide Width Scale.

For more information and related techniques about nParticles, refer to the
Maya Help.


Lesson 2: Creating a smoke simulation with
nParticles

Introduction

For the smoke simulation in this lesson, you create an nParticle system
composed of an nParticle object, an emitter object, and a nucleus node. You
will add a Volume Axis field to your effect to create turbulence and swirling
in the nParticle smoke. This field helps create the realistic behavior of smoke
as it cools, rises and dissipates. To finish your smoke simulation, you will also
add a Nucleus Wind force to make the smoke drift as it disappears.

Lesson setup
Smoke_Simulation_1.mb. This file is in the GettingStarted directory that you
set as your Maya project:
GettingStarted/nParticles/Smoke_Simulation_1.mb


This scene includes textured polygon models including a desk, ashtray, and
cigarette.

Creating an nParticle system
In this part of this lesson, you create an nParticle object and its emitter object.
An emitter controls the position, direction, quantity and initial velocity of
the emitted nParticles when they are born (emitted into the scene).

Creating an nParticle and emitter object

To create an nParticle and emitter objects

1 Select nParticles > Create nParticles > Cloud.

Selecting Cloud presets some nParticleShape attributes that are suitable
for simulations such as smoke, dust, or fog.


2 To create an nParticle emitter object, select nParticles > Create nParticles
> Create Emitter > .
The Emitter Options (Create) window appears.

3 In the Emitter Options (Create) window, select Edit > Reset Settings.

4 In the Emitter name field, type Emitter_Smoke.
Naming your emitter object makes it easier to identify in the Outliner
when you want to select it and make attribute adjustments.

Selecting a solver determines which Maya Nucleus system your nParticles
belong to.

6 In the Basic Emitter Attributes section, set the following:
■ Emitter type: Directional.

■ Rate (particles/sec): 120
This sets the number of particles that are emitted into the scene. The
higher the emission rate the thicker the smoke appears.

7 In the Basic Emission Speed Attributes section, set the following:
■ Speed: 2.5.

■ Speed random: 5.0.


When Speed random is set to a positive value, the emitter generates
random speeds for each nParticle.

8 Click Create.
An Emitter_Smoke1, nParticleShape1, and a nucleus1 node appear in the
Attribute Editor.

9 To rename the nParticle object, in the Outliner, double-click nParticle1
and type nParticle_Smoke then press Enter.
Renaming your nParticle object makes it easier to identify when you have
more than one in your scene.

Moving the nParticle emitter
When you create an nParticle and emitter objects, they are placed at the scene
origin. For this lesson, you need to move the emitter so that the particles are
emitted near the tip of the cigarette.

To move the nParticle emitter object

1 In the Outliner, select the Emitter_Smoke1 object.

2 Display the Channel Box by clicking .

3 In the Channel Box enter the following values:
■ Translate X: 49.3

■ Translate Y: 121

■ Translate Z: -27.3

4 In the scene view, dolly and tumble so that you get a close-up view of
the cigarette.
The nParticle emitter is now positioned near the tip of the cigarette.


nParticles are emitted from the end of the cigarette, however, they moving
along the X axis and away from the cigarette. This is because the force
of the Nucleus Gravity is not yet affecting the nParticles. By default, the
Cloud type nParticles are created with Ignore Solver Gravity on, so you
need to turn this option off.

6 In the Outliner, select nParticle_Smoke.


8 In the Attribute Editor, click the nParticle_SmokeShape tab.

9 In the Dynamic Properties section, turn off Ignore Solver Gravity.

nParticles are emitted from the end of the cigarette, however, they are
falling down and out of the scene. This is because the force of Nucleus
Gravity is negative, so it pulls the nParticles down. You must change the
direction of gravity to force the nParticles up.


12 In the Gravity and Wind section, change the Gravity Direction for Y from
-1.0 to 1.0.

The smoke now rises.


Editing nParticle Lifespan and Radius
When you play back the simulation, notice that the nParticles are not
dissipating into the air like smoke does. This is because the nParticles lifespan
is not yet defined.
In this lesson, you make the nParticles disappear from the scene after they
reach a specified age by using the nParticle Lifespan attributes. You can set
the nParticle object’s size (Radius) according to its lifespan so that nParticles
decrease or increase in size as they age.

To set nParticle Lifespan



3 In the Lifespan section, select Random range from the Lifespan Mode
list.

The nParticles now die (disappear from the scene) shortly after they are
emitted. nParticle Lifespan is measured in seconds, meaning that at a
Lifespan of 1.0, the nParticles die after one second.

Editing nParticle Lifespan and Radius | 935

5 Set Lifespan to 5.

6 To add some randomization to the nParticle’s lifespan, set Lifespan
Random to 5.

7 Rewind the simulation and play it back.
The nParticles die off more randomly, but the nParticle object is still not
dense enough to look like smoke. You can make your nParticle object
denser by increasing the nParticle Radius.


For a realistic smoke simulation, the nParticles must gradually disperse as they
rise in the air. You can use the Radius Scale ramp to increase the radius of
nParticles as they age, which creates the effect of smoke dispersing until it
gradually disappears.

To set nParticle size


2 In the Radius Scale section, select the first marker in the ramp, set Selected
Position to 0.016, and set Selected Value to 0.04.
Creating a new marker allows you to set two Selected Value and Selected
Position values. Each Selected Value specifies a scaling value for the
nParticle object's Radius attribute. By default, ramps define a scaling value
of 1, meaning that only one mark exists on the ramp and that marker

Editing nParticle Lifespan and Radius | 937

represents an attribute scaling factor of 1. Setting a selected position to
0.5 sets per-particle radius to half the Radius value.

3 Click in the ramp to create additional markers and set the Selected
Position and Selected Value for the new markers to the following values:
Marker Selected Posi- Selected
tion Value

2 0.732 0.180

3 0.882 0.480

4 1.0 1.0

For each point in the ramp, leave Interpolation at its default setting of
Linear.

4 To map nParticle Radius to the nParticles’ age, set Radius Scale Input to
Normalized Age.
When Normalized Age is used, per-particle radius is mapped within the
range of the nParticle object’s lifespan.

5 To add randomization to the per-particle radius, set Radius Scale
Randomize to 0.25.

You can continue to adjust the per-particle radius by adding more markers
to the ramp, or optimize the ramp values as the simulation plays back.


Adding a Volume Axis field
You can use Maya Fields to animate the motion of nParticles and create the
effect of nParticles flowing around obstacles, as well as creating pluming
smoke, swirling tornadoes, and rocket exhaust. For a smoke simulation, you
can add a Volume Axis field to the scene to create turbulence and swirling
effects in the smoke as it rises through the air.
Maya Fields are not part of an nParticle object's Nucleus system and therefore
you may need to compensate for the force of Nucleus Gravity and Wind by
increasing or decreasing the field's magnitude. Depending on the effect you
are creating, you can also turn on Ignore Solver Gravity or Ignore Solver Wind
on the nParticleShape node so that your nParticle object is only affected by
Maya Fields. For more information about Maya fields see the Dynamics guide.

To create a Volume Axis field

1 In the Outliner, select nParticle_Smoke, then add a Volume Axis field by
selecting Fields > Volume Axis > .
The Volume Axis Options window appears.

2 In the Volume Axis Options window, select Edit > Reset Settings.

3 In Volume axis field name, type Field_Smoke.

4 Set the following Volume Axis field settings:
■ Magnitude: 90

■ Attenuation: 2.0

■ Volume Shape: Cube

■ Away From Center: 4.546

■ Directional Speed: 1.834

■ Direction: X to 0 and Y to 1.0.

■ Turbulence: 0.661

■ Turbulence Speed: 0.157

5 Click Create.
A Field_Smoke1 node appears in the Attribute Editor and in the Outliner.


The Volume Axis field is placed at the scene origin by default. You must
reposition the field so that the emitted nParticles travel through the
volume.

To position the field in the path of the emitted nParticles

1 In the Outliner, select Field_Smoke1 and open the Channel Box by clicking

.

2 In the Channel Box under Field_Smoke1, set the following:
■ TranslateX: 49.57

■ TranslateY: 133.8

■ TranslateZ: -26.49

■ ScaleX: 10

■ ScaleY: 10

■ ScaleZ: 10


Adding a Volume Axis field | 941

The field creates turbulence in the nParticle smoke as it rises.
However, to create the effect of the smoke curling and dissipating, you
need to adjust the field and nParticle attributes further. For example, the
emitted nParticles have too much velocity for the field to influence their
behavior. You will make these adjustments in the next section.

Adjusting nParticle velocity
When using Maya Fields with emitted nParticles, some particles move too
quickly through the field to produce the desired effect. You can control how
much of an nParticle object's velocity is retained from frame to frame by
adjusting the Conserve attribute. You can further control the velocity of the
particles as they enter the Volume Axis field by increasing the nParticle object’s
Drag. Drag adds friction between the air and nParticles, which slows the
particles down.

To adjust nParticle velocity for the field



3 In the Dynamic Properties section of the nParticle_SmokeShape Attribute
Editor, set Conserve to 0.05 and Drag to 0.149.


The particle smoke is still not rising as expected because now it is not
forced up enough by the Nucleus Gravity. Maya Nucleus solver applies
Gravity to objects as if the objects were scaled in meters, regardless of the
units in which your scene was created. Therefore, to maintain a real world
force of gravity acting on the objects in your simulation, you may need
to adjust the Nucleus node Space Scale. Decreasing Space Scale results in
a visibly increased gravitational affect on the nParticles and makes them
rise properly.


6 In the Scale Attributes section, set Space Scale to 0.05.


The nParticles now rise through the field and behaving more like smoke.
In the next section, you use the nParticle Shading attributes to make the
nParticle object look more like cigarette smoke.

Adjusting nParticle Shading attributes
By adjusting nParticle Opacity, you can mimic the way smoke disappears into
the air as the nParticles age. You can then set the Color ramp to add shades
of white, gray, and blue to the smoke.

Adjusting nParticle Shading attributes | 943

Like the nParticle Radius attribute, Opacity and Color can be set on a per
nParticle object or per-particle basis. Using the nParticle object's Shading
ramps, you can map per-particle Opacity and Color to nParticle properties
such as particle Age, Particle ID, and Radius.

To set nParticle Shading attributes

1 To make it easier to see the changes you make to the nParticle object’s
Shading attributes, you can hide the Volume Axis field shape by selecting
Field_Smoke1 in the Outliner then selecting Display > Hide > Hide
Selection.
The Volume Axis field still affects your nParticles, but you no longer see
the volume shape in the scene view.

2 In the Outliner, select nParticle1_Smoke.

3 In the Attribute Editor, click the nParticle_SmokeShape1 tab.

4 In the Shading section, set Opacity to 0.1.

Notice that the emitted nParticle cloud appears thinner and more like
cigarette smoke than before.
To further improve the appearance of the smoke as it rises and dissipates
in the air, you can use the Opacity Scale ramp to adjust the opacity of
individual nParticles as they age.

6 In the Opacity Scale section, click in the ramp to create additional markers
then set an Opacity ramp by setting the following marker settings:
Marker Selected Posi- Selected Interpolation
tion Value

1 0.299 0.980 Spline

2 0.560 0.915 Spline

3 0.709 0.580 Spline

4 0.984 0.0 Spline

7 Set Opacity Scale Input to Normalized Age.
As each nParticle ages from birth (emission), its opacity changes from
the opacity values specified by the left marker to the one specified by the
right marker.


8 Set Opacity Scale Randomize to 0.116.

9 To set the color of the nParticles when they are first emitted, click the
far left circle marker of the ramp (at Selected Position 0) then click the
color swatch beside Selected Color.


10 In the Numeric Input section, click the HSV tab.

11 In the Color Chooser, select white and add a little grey, or type the
following color values into the HSV (Hue-Saturation-Value) fields:
■ H:210

■ S: 0

■ V: 0.95

12 To set the color of the nParticles as they continue to age, click inside the
ramp to create a marker, set the Selected Position to 0.834, then click the
color swatch beside Selected Color.

13 In the Color Chooser, select a shade of grey that is slightly darker than
the color you selected for the first marker, or type the following color
values into the HSV (Hue-Saturation-Value) fields:
■ H:210

■ S: 0

■ V: 0.85


14 Select the far right marker of the ramp (at Selected Position 1.0) and set
the color to the following color values into the HSV
(Hue-Saturation-Value) fields:
■ H:191.73

■ S: 0.084

■ V: 0.85

15 Set Color Input to Normalized Age.
As each nParticle ages, its color changes from the color specified by the
left marker to the one specified by the right marker.

16 To improve the way the nParticles colors blend as they age, do the
following:
■ Set Interpolation to Smooth for each marker.

■ Set Color Randomize to 0.5.

When you play back the simulation, the nParticles look more like cigarette
smoke.
Adding more volume to the smoke would further improve the simulation.
Instead of reducing the nParticle Opacity values, you can emit more
particles and increase the nParticle Radius to create more smoke volume.


To add volume to the nParticle smoke



3 In the Lifespan section, set Lifespan to 10.


5 In the Attribute Editor, click the Emitter_Smoke1 tab.

6 In the Basic Emitter Attributes section, set Rate (Particles/Sec) to 128.4.

You can continue adjusting the Opacity Scale and Color ramps to create
the exact dissipation effect and color you want for the smoke.


Open the third scene for the lesson

Fine tuning your smoke effect
With nParticles, you can use dynamic wind generated by the Maya Nucleus
solver to affect the motion of your particles. Gravity and Wind forces generated
by the Nucleus system are different from the Maya dynamic forces that you
create with Maya Fields. Nucleus forces are internal, meaning that they only
affect Nucleus objects. Nucleus object that are assigned to the same Nucleus
solver are affected by the same intensity of the solver’s wind and gravity.
In this section of this lesson, you create an Axial Magnitude ramp to control
the field’s magnitude at various points in the field volume. You specify that
the field’s magnitude gradually increases from the bottom of the volume to
its top, so that as the nParticles travel through the field volume, the field’s
influence on the nParticles increases. To finish the smoke simulation, you use
the Nucleus Wind to make the smoke drift as it rises.

NOTE If you had other Nucleus objects (nCloth objects or other nParticle objects)
assigned to the same Nucleus solver, they would also be affected by the force of
the wind.

To create an Axial Magnitude ramp

1 In the Outliner, select Field_Smoke1.

2 In the Attribute Editor, expand the Volume Control Attributes section,
and browse to the Axial Magnitude section.

3 Click in the Axial Magnitude ramp to create two new markers, and create
a ramp by setting the following:
Marker Selected Position Selected Interpolation
Value

1 0.055 0.520 Linear

2 0.315 0.900 Linear

Open the third scene for the lesson | 949

Marker Selected Position Selected Interpolation
Value

3 0.961 1.0 Linear


To add Nucleus Wind in your simulation.



3 In the Gravity and Wind section, set Wind Speed to 0.85.
Wind Speed determines the force and intensity of the wind. A higher
value means a faster wind speed, which has a more pronounced effect
on the smoke.

4 To set Wind Direction, do the following:
■ Set wind direction to 0 in the X-axis.

■ Set wind direction to -1 in the Y-axis.

■ Set wind direction to -1 in the Z-axis.

5 Set Wind Noise to 0.686.
This adds some randomization to the wind direction.



To make the smoke simulation more realistic, you can set up your effect
so that the cigarette smoke is rising in the first frame of the simulation.
You do this by setting the nParticle object’s initial state.

To set the nParticle Object’s initial state

1 Play the simulation and stop the playback at or around frame 300.


3 Select nSolver > Initial State > Set From Current.

4 Rewind the simulation to the start frame and play it back.

Fine tuning your smoke effect | 951

Beyond the lesson
In this lesson you created an nParticle system and used Maya Fields to influence
the behavior of the particles to create a smoke simulation effect. In addition,
you learned how to:

■ Use a volume emitter with an nParticle system.

■ Use a Volume Axis field to create a disturbance in the path of your
nParticles.
You can also add other Maya fields, such as Turbulence, Radial, or Vortex
fields to affect the behavior of nParticles.

■ Adjust nParticle lifespan so that nParticles die off at the appropriate
moment of your simulation.

■ Use the Radius Scale ramp to map per-particle radius to nParticle age.

■ Use the Opacity and Color attributes to define the color and thickness of
the smoke.
You can further optimize the color and thickness of the smoke by
continuing to adjust the Opacity Scale and Color ramps.

■ Create an Axial Magnitude ramp to control how a field’s Magnitude affects
nParticles as they travel through the field's volume.
You can fine tune your smoke simulation by adjusting the markers on the
curve to produce the desired effect of turbulence as the smoke rises.

■ Add Nucleus Wind to your nParticle effect. You can experiment with the
Nucleus solver’s Wind Speed, Wind Density, and Wind Direction attributes
to change the direction of the rising smoke.

For more information and related techniques about nParticles and Maya Fields,
refer to the Maya Help.


Lesson 3: Creating a liquid simulation with
nParticles

Introduction

A common use of particle systems is to simulate liquids such as flowing lava,
water sprays, and mud splatters. Using nParticle Liquid Simulation attributes,
you can add properties to an nParticle object so that it behaves like a liquid.
For example, you can add viscosity and incompressibility properties so that
the nParticles fill a volume uniformly and flow like a continuous substance.
When creating a liquid simulation, it is easiest to start with a small nParticle
system (small particle count) and set the attributes that control the behavior
of the particle flow. You can then increase the density of the particle system
and edit the attributes that give the nParticles the appearance of a liquid.
In this lesson you create a small-scale liquid simulation that involves pouring
Water type nParticles from a pitcher into a glass. You can then use the
techniques described in this tutorial to create larger liquid simulations.

■ Use Fill Object to create a Water style nParticle system.

Lesson 3: Creating a liquid simulation with nParticles | 953

■ Adjust nParticle Liquid Simulation attributes to create particles that look
and behave like water.

■ Cache your nParticle simulation.

■ Convert a liquid simulation to an nParticle output mesh.

■ Assign mia_material_x mental ray shaders to your nParticle output mesh.

■ Render a single frame of your nParticle simulation using mental ray for
Maya renderer.

Lesson setup
Liquid_Simulation_1.mb. This file is in the GettingStarted directory that
you set as your Maya project:
GettingStarted/nParticles/Liquid_Simulation_1.mb

This scene includes textured polygon models including a desk, water pitcher,
and water glass. The water pitcher mesh is animated to lift off the desk, tip to
pour water into the glass, then set back down on the desktop.

Creating a Water style nParticle object
In the first step of creating your liquid simulation, you fill a polygon water
pitcher with Water style nParticles. To do this, you use the Fill Object option.

To create a Water style nParticle object

1 Select nParticles > Create nParticles > Water.
Selecting a Water style nParticle object presets some nParticleShape
attributes including turning on Liquid Simulation attributes, turning off
nParticle Self Collisions, and setting the Particle Render Type to Blobby
Surface.

2 In the Outliner, select geo_pitcher, which is contained in the grp_Pitcher
object.
This is the geometry that you will fill with Water style nParticles.

3 Select nParticles > Create nParticles > Fill Object > .
The Particle Fill Options window appears.


4 In the Particle Fill Options window, select Edit > Reset Settings.


6 Ensure that Resolution is set to 10.
Resolution specifies how many nParticles are evenly placed along the
geometry’s longest axis.

7 Ensure that Close Packing is on.

8 Turn on Double Walled.
Turning on Double Walled ensures that the thickness of the pitcher
geometry is taken into account when it is filled with nParticles. The
particles now only fill the pitcher's empty volume, rather than the space
between the polygon walls.

9 Click Particle Fill.
Maya creates the nParticle object inside the water pitcher geometry.

Creating a Water style nParticle object | 955

10 In the Outliner, double-click nParticle1 and type nParticle_Water to rename
it, then press Enter .
Renaming your nParticle object makes it easier to identify when you have
more than one in your scene.

In this lesson, both the pitcher and the glass mesh will hold nParticles,
so you must convert meshes to passive collision objects and assign them
to the same Nucleus system as the nParticles.

To convert the pitcher and glass meshes to passive collision objects

1 In the scene view, Shift-select the pitcher and glass meshes.

The Make Collide window appears.


3 From the Solver list, select nucleus1.


5 Rename the pitcher and glass nRigid objects in the Outliner. For example,
rename nRigid1 and nRigid2as nRigid_Pitcher and nRigid_Glass respectively.

When you play back the simulation, notice that the nParticles do not
behave as you might expect. Rather than immediately falling to the
bottom of the pitcher like water, they fall slowly, as if the simulation is
playing in slow motion. To make the nParticles behave realistically, you
can set the Nucleus Space Scale for the simulation.
For more information about Space Scale, see Setting Nucleus Space Scale
on page 922.

To set Space Scale



When you reduce the Space Scale value, Maya evaluates the nParticle
system as if the particles are much smaller in size. This results in a visibly
increased gravitational effect on the nParticles.

3 Rewind the simulation to the start frame, then play it back.

Creating a Water style nParticle object | 957

When you play back the simulation, notice that the nParticles are still
contained in the pitcher, but they occupy a small amount of the pitcher’s
volume. Also, the nParticles appear to be pushing down as if they are
under a force of pressure or compression. In the next section, you begin
adjusting the Liquid Simulation attributes that make the nParticles look
and behave more like a liquid.

Adjusting Liquid Simulation attributes
One of the main characteristics of water is its volume uniformly fills the area
inside a holding vessel or container. To give nParticles this volume
characteristic, there needs to be space between individual particles. Be aware
that having too much space can hinder the fluidity of the particles, which is
another important characteristic of a liquid simulation.
Using the Liquid Radius Scale attribute, you can control the amount of space
between nParticles.


Adjusting the liquid volume

To set Liquid Radius Scale and create liquid volume

1 In the Outliner, select nParticle_Water.

2 In the Attribute Editor, click the nParticle_WaterShape tab.

3 In the Liquid Simulation section, ensure that Enable Liquid Simulation
is on.

4 Set Liquid Radius Scale to 2.0.

The nParticles are now stacked on top of each other, creating more volume
in the pitcher.

For this liquid simulation, you want the nParticles to fill one-third of the
pitcher. You can add more volume to the nParticles by adjusting the
Nucleus solver Substeps and Max Collision Iterations.

6 Set Substeps and Max Collision Iterations by doing the following:
■ In the Attribute Editor, click the nucleus1 tab.

Adjusting Liquid Simulation attributes | 959

■ In the Solver Attributes section, set Substeps to 7.

■ Set Max Collision Iterations to 10.

The nParticles now fill the water pitcher, and when the pitcher tilts to
pour, the nParticles have enough volume to exit and fill the glass.

More about Liquid Radius Scale
Be aware that Liquid Radius Scale can be affected by other nParticle attributes
such as Radius and Collide Width Scale. For example, Liquid Radius Scale uses
the nParticle object's Radius to determine how nParticles overlap, and any
change in the nParticle Radius affects how nParticles overlap in the liquid
simulation.
Adjusting the Nucleus solver Substeps and Max Collision Iterations also affects
the volume that is generated by the Liquid Radius Scale value. You can
experiment with these settings by changing Substeps to 10 and Max Collision
Iterations to 15 and observing how your liquid simulation is affected.
In the next section of this lesson, you adjust nParticle Collide Scale Width
and Incompressibility attributes to add fluidity to your simulation.

Adding fluidity to the nParticles
To make it easier to see how the nParticles interact with the pitcher and glass
objects, you can turn on the Solver Display to see the nParticle collision
volume. Collision volumes are a non-renderable surface offset from each
nParticle radius that the nucleus solver uses when calculating collisions
between Nucleus objects.

To edit Collide Width Scale and add fluidity




Display list.

4 Set Collide Width Scale to 0.6.

For liquid simulations, set Collide Width Scale to a value that is one-third
the nParticle object Radius value.

5 Play the simulation, and stop at frame 40.

6 In the scene view, dolly and tumble so that you get a close-up view of
the nParticles at the bottom of the pitcher.
The nParticles occupy the pitcher in two distinct layers one on top of the
other. In the bottom layer, the nParticles are evenly spaced and level,
while in the upper layer, there are gaps between particles. Since the top
layer of nParticles represent the surface of the liquid, the gaps between
particles create a surface that is uneven and unlike the surface of water.

Increasing Incompressibility decreases the tendency of the particles to be
pushed together. This forces the nParticles into a more uniform distribution
throughout the volume, which creates a smoother surface for the liquid.

Adding fluidity to the nParticles | 961

To set Incompressibility



3 In the Liquid Simulation section, set Incompressibility to 20.


More about Liquid Simulation attributes
For this tutorial, you leave the following Liquid Simulation attributes at their
default values:

■ Viscosity: 0.1

■ Rest Density: 2.0

You can experiment with Rest Density by setting it to 0.5 and then to 4.0.
Play back your simulation with each new setting to observe how the values
affect your nParticles. Set Viscosity to 10, play back the simulation, and observe
how long it takes for the nParticles to move from the pitcher to the glass.
Ensure you set Viscosity and Rest Density to their default values before
continuing the tutorial.


For more information about these attributes, see Viscosity and Rest Density
in the nDynamics guide.


Convert nParticles to a polygon mesh
To create a smooth surface for your liquid simulation, you can convert the
nParticles to a polygon mesh. Converting nParticles to a mesh has many
advantages, because you can edit it like any other polygon object.
For example, you can improve the quality and overall look of your liquid
simulation by performing polygon smooth operations on the output mesh.
Polygon smoothing increases the number of polygons in your mesh and gives
it a smoother appearance. For your liquid simulation, this helps create a
smooth, continuous surface, like the surface of water.
Before converting the nParticles to an output mesh, you can set the initial
state of your simulation to an advanced frame. Doing this ensures that the
nParticles have settled down to the bottom of the pitcher before its animation
starts. From frames 1 to 30, Nucleus gravity and the initial collisions between
the nParticles and the inside wall of the pitcher cause the particles to move.


For a realistic effect, you want the water to be motionless at the bottom of the
pitcher at the start of the simulation.

To set the initial state of the nParticles

1 Play the simulation and stop the playback at or around frame 30.


3 Select nSolver > Initial State > Set From Current.

4 Rewind the simulation to the start frame.

To convert your nParticle object to a polygon mesh


2 Select Modify > Convert > nParticle to Polygons.
The PolySurface1 object appears in the Outliner, and a new
polySurfaceShape node appears in the Attribute Editor.

3 Rename the new PolySurface1 polygon object to Water_Mesh in the
Outliner.

4 In the Attribute Editor, select the nParticle_WaterShape tab.


5 In the Output Mesh section, set Blobby Radius Scale to 3.5.

In the scene view, the nParticle output mesh is superimposed over your
nParticle object.

6 In the Output Mesh section, select Quads from the Mesh Method list.
Selecting Quads creates your converted mesh using quad-based polygons,
while Tetrahedra, Cubes, and AcuteTetrahedra create meshes using
triangulated polygons. Output meshes that are quad-based respond better
to polygon smoothing (Mesh > Smooth) than triangle-based output
meshes.

7 Dolly and tumble the scene so that you can closely observe the nParticle
output mesh, and experiment with the following Threshold values:
■ Set Threshold to 0.2.
At this value, the nParticle output mesh extends beyond the nParticle
object’s collision width and penetrates the inner wall of the pitcher
mesh.

Convert nParticles to a polygon mesh | 965

■ Set Threshold to 1.5.
At this value, the nParticle output mesh cuts into the nParticle object,
and no longer surrounds the nParticles.

■ Set Threshold 0.6.

8 Set Mesh Triangle Size to 0.2.


This setting determines the size of the triangles used to create the mesh.
Small values produce higher resolution meshes with smoother surfaces.
Be aware that higher resolution meshes take more time to simulate.

9 To apply smoothing to the corners of the mesh quads, set Mesh
Smoothing Iterations to 2.

The output mesh is noticeably smoother.

Cache your nParticle simulation
When you play back the simulation, notice that it plays back much slower
than before. This is due to the additional calculations required for the nParticle
object’s output mesh. You can use Maya's nCache feature to cache the
simulation and play back the scene at full speed.

To cache your nParticle simulation

1 Before caching the simulation, hide the Water_Mesh object by selecting
it in the Outliner and selecting Display > Hide > Hide Selection.
Hiding the output mesh speeds up the nCaching process.



Cache your nParticle simulation | 967

The Create nCache Options window appears.

4 In the Create nCache Options window, do the following:
■ Set the Cache directory to the folder where you want your caches
saved.

■ Set the Cache name to LiquidSimulationCache.

■ For File distribution, select One file.

■ Click Create.

Maya plays the scene automatically and stores the frames in the directory
you specified.

5 When it is finished, play back the simulation.
Notice that the scene now plays back faster. You can also scrub slowly
through the timeline and view your simulation frame-by-frame. If you
change any of the nParticle attribute settings, create a new cache to see
your changes.

In the next section of this lesson, you use the nParticle cache to help optimize
specific areas of the simulation.

Adding Motion Streak
You can set the Motion Streak attribute to optimize the motion of the nParticles
during the pouring sequence of the animation. Motion Streak is useful for
creating a motion blur type of effect, and for shaping the flow of liquids.


To set Motion Streak

1 Go to frame 119, then dolly and tumble the scene so that you have a
close-up view of the water nParticles pouring into the glass.

2 Show the Water_Mesh object by selecting it in the Outliner and selecting
Display > Show > Show Selection.
At this frame, notice that the droplet mesh pouring into the glass looks
too spherical. It does not resemble the continuous flowing behavior of
water poured into a glass.

To make the mesh a continuous flowing object, you can adjust the Motion
Streak attribute.


4 In the Output Mesh section, set Motion Streak to 0.50.
Maya updates the output mesh with the new setting. To further improve
the quality of the mesh, you can perform a polygon smooth operation.

Adding Motion Streak | 969

5 Select the mesh then, from the Polygons menu set, select Mesh > Smooth.
The mesh is noticeably smoother and looks more like a liquid. In the
next section, you will assign material shaders to the pitcher, glass, and
water meshes. You will then render single frames of the simulation using
mental ray for Maya.

Open the third scene for the lesson


Render your liquid simulation
In this section, you render your nParticle effect using the mental ray for Maya
renderer. Since rendering a particle effect can take several minutes to an hour,
in this lesson, you only render selected frames of the simulation. Rendering
simulated frames is the easiest way to see how some attributes affect your
simulation.
To prepare your scene for rendering, you assign mental ray mia_material_x
shaders to the pitcher, glass, and water meshes. Lights have been created and
placed in the scene so that realistic shadows and reflections appear in the
rendered frame. The scene also includes a camera named renderCam that is
positioned for the rendered view. For more information about rendering, see
the Rendering and Render Setup guide.

Preparing to render
To prepare your scene and workspace for rendering, you will do the following:

■ Cache your simulation so that you can play it or scrub through it to locate
the simulated frame you want to render.

■ Change the view arrangement of your Maya workspace to make it easier
to assign material shaders to meshes and view rendered frames of your
simulation.

■ Show hidden light objects and the camera you use to render a simulated
frame.

To cache your simulation


The Create nCache Options window appears.

3 In the Create nCache Options window, do the following:
■ Set the Cache directory to the folder where you want your caches
saved.

■ Set the Cache name to LiquidSimulationCache.

■ For File distribution, select One File.

■ Click Create.

Render your liquid simulation | 971


To change the view arrangement and display hidden objects

1 Select Windows > Saved Layouts > Hypershade/Render/Persp.
The Hypergraph, Render View, and the current perspective view are
displayed. This view arrangement makes it easier to assign shaders to
your objects and to view rendered frames of your simulation.

2 Open the Outliner in a separate window by selecting Window > Outliner.

3 Hide the nParticle_ Water object by selecting it in Outliner, then selecting
Display > Hide > Hide Selection.

4 Show the Water_Mesh object by selecting it in the Outliner then selecting
Display > Show > Show Selection.

5 In the Outliner, Ctrl-click the main, rim, and fill lights, then select Display
> Show >Show Selection.
The lights used for rendering the simulation appear in the scene.

6 In the perspective view, select Panels > Perspective > renderCam.
You now view the scene through the camera that you will use to render.

Assigning material shaders
To prepare the geometry for rendering, you assign the mental ray
mia_material_x shader to the pitcher, glass, and water meshes. Using the
mia_material_x shader presets for the glass and water provides a quick and
easy way to have proper refraction, reflectivity, and transparency values set
on these materials. For more information about material shaders, see the
mental ray mia_material/mia_material_x shader attributes section in the
Rending and Render Setup guide.

To assign a material to the pitcher and glass objects

1 In the Hypershade, on the Create tab, click Create Maya Nodes and select
Create mental ray Nodes from the drop-down list.
The Hypershade now shows the list of mental ray shader nodes.

2 Click Materials to open the list of mental ray material shaders.

3 Select mia_material_x from the Materials list.


A mia_material_x material swatch appears in the Work Area tab of the
Hypershade, and the material attributes appear in the Attribute Editor.

4 In the Attribute Editor, rename the material to mia_material_pitcher.

5 Click and hold the Presets button, select GlassThin, then Replace
(GlassThin > Replace).

6 In the Refraction section, click the color swatch beside Color.

7 In the Color Chooser, type the following color values into the RGB fields:
■ R: 0.190

■ G: 0.574

■ B: 0.190

8 Click Accept.

9 In the Outliner, select the grp_Pitcher object.

10 To assign the material to the pitcher, in the Work Area tab of the
Hypershade, right-click mia_material_glass then select Assign Material To
Selection from the marking menu.
In the scene view, the pitcher turns black. You can only see the true color
and texture of the material after the frame is rendered using mental ray
for Maya.

Assigning material shaders | 973

11 Assign materials to the glass and water meshes by repeating steps 3 to 10
using the following settings:
For the glass (geo_glass) mesh:
■ Rename the material to mia_material_glass.

■ Select Presets > GlassThin > Replace.

■ In the Refraction section, set Color to R: 0.797, G: 0.875, and B: 0.915.

For the water (Water_Mesh) mesh:
■ Rename the material to mia_material_water.

■ Select Presets > Water > Replace.

■ In the Diffuse section, set Color to R: 0.164, G: 0.512, B: 0.402.

■ In the Refraction section, set Transparency to 1.0.

Rendering a simulated frame
Now that you have assigned mental ray mia_material_x shaders to the objects
in the scene, you can use the mental ray for Maya renderer to render selected
frames of your simulation.

To render a selected frame

1 Go to frame 119.


You will render this frame where the water nParticles pour into the glass.

2 In the Render View, select Options > Render Settings

.

3 From the Render Using list, select mental ray.

4 Click the Common tab and set the following:
■ In the Renderable Cameras section, select renderCam from the
Renderable Camera list.

■ In the Image Size section, select 320×240 from the Presets list.

5 Click the Quality tab, and do the following:
■ From the Quality Presets list, select Production.

■ In the Raytracing section, turn on Raytracing.

■ Set Shadows to 4.

6 Click the Indirect Lighting tab, and in the Caustics section, turn on
Caustics.

7 Click Close to close the Render Settings window.

8 To render the current frame, in the Render View, select Render > Render
> Current (renderCam).
The current frame appears as a rendered image in the Render View.

Rendering a simulated frame | 975

You can continue to make changes to the render settings, change the
renderCam view, or select another simulated frame to render. After you
are satisfied with your render settings, you can render the frame as a
full-size image.

To render a full-size image

1 In the Render View, select Options > Render Settings.

2 Click the Common tab and in the Image Size section, select 640×480
from the Presets list.

3 From the Rendering menu set, select Render > Render Current Frame.

Beyond the lesson

■ Use Fill Object to create an nParticle system.

■ Create passive collision objects to contain your nParticles.

■ Adjust the Nucleus solver’s Space Scale attribute to suit the scale of your
simulation.


■ Adjust Liquid Simulation attributes to set the volume and fluidity
characteristics of your liquid nParticles.
You can continue to adjust the Liquid Simulation attributes, such as Liquid
Radius Scale and Viscosity, to create liquid simulations of thicker substances
such as oil, mud, or lava.

■ Create and play back nParticle caches.

■ Convert your nParticle object to a polygon mesh.

■ Optimize the appearance of your nParticle output mesh using Output Mesh
attributes such as Threshold, Mesh Smooth Iterations, and Motion Streak.

■ Assign mia_material_x mental ray shaders to your nParticle output mesh.

■ Render a single frame of your nParticle simulation using the mental ray
for Maya renderer.


Live
20
Introduction
Maya® LiveTM simplifies the process of matchmoving. Matchmoving is a process
where you match the camera or object movement in a live-action shot with the
camera in Maya. This subsequently lets you place your 3D objects into live-action
footage.
Matchmoving is an iterative process where the camera movement for the Maya
camera is calculated using processes of tracking and solving.
Objects are tracked in the live action scene and a solver then calculates the
camera position for a given image. This chapter includes the following lessons:

■ Lesson 1 Track and solve: Introduction on page 983

■ Lesson 2 Solving with survey data: Introduction on page 1002

About Live
Imagine that you must replace the contents of a live-action shot of a fence with
a fence modeled in Maya. In the live-action shot, the camera sweeps around
the fence. You can use Live to animate a Maya camera that sweeps around your
modeled fence in the same way. When you render the Maya fence from this
camera, it will have the same camera perspective as the live-action fence. You
can therefore composite them together precisely.

979

Live can also match the movement of objects in the live-action shot. Suppose
you want to replace the hat of a moving, live-action person with a cartoon
hat created in Maya. You can use Live to create 3D locators that follow the
movement of certain points on the live-action hat. You then attach a hat
created in Maya to these moving points, so that the rendered Maya hat follows
the movements of the live-action person. The steps for matching object
movement are about the same as matching the camera.
To use Live, you do the following major tasks in order:

Setting up
You begin by loading digital images of the live-action shot. In this lesson,
you’ll use images scanned from film footage.
Images appear on an image plane. This plane is part of the Maya camera. It
displays images as part of a background.

980 | Chapter 20 Live

Track
In this task, you mark a variety of points within the images, such as the center
of a flower or a mark on the fence, and have Maya track how they change
position from frame to frame.

Solve
In this task, you run a solver program that computes an animated camera,
based on the movement of the track points.

Fine Tune
This is an optional task where you can make frame-by-frame adjustments to
the camera position. (This task is rarely used and is not covered by this lesson.)

In the following lessons, you will create a match move for live footage of a
sweeping shot of a backyard and fence. In the second lesson, you will load a
fence created in Maya to evaluate how well the Maya camera movement
matches the live-action camera.

1 Make sure you understand the basic usage of the animation playback
controls. See the chapter entitled “Animation” in Getting Started with Maya
to learn about these controls.


2 Select Window > Settings/Preferences > Preferences. Click the Timeline
category under Settings and make sure the Playback Speed is set to Play
every frame. Animation plays more accurately with this setting.

3 Locate the Live Lesson Data at http://www.autodesk.com/maya-training in
the Tutorials section.
You’ll need about 300 Mb of disk space and a program (such as Winzip)
to extract the .zip file.

4 If Live doesn’t appear in the menu set selection menu, select Window >
Settings/Preferences > Plug-in Manager. In the Plug-in Manager, locate
mayaLive.mll (Windows) and click the loaded checkbox. Wait about 20
seconds for the operation to finish, then close the Plug-in Manager.

5 Select the Live menu set. All instructions in this lesson assume you have
the Live menu set selected.

6 Choose Scene > New MatchMove.
When you create a new matchmove scene, Live places the Setup control
panel at the bottom of the standard Maya window. There are different
control panels for each of the main tasks: Setup, Track, Solve, and
Fine-Tune. The control panel is where you control most of the Live
operations.

Also notice Live creates a camera and an image plane in your scene. This is
the camera Live animates. The image plane serves as the background plate
when you look through the camera. It is where the images for the live shot
will appear once you’ve loaded them.


Lesson setup
You begin the lesson by loading digital images of a live-action sequence. You’ll
work with images we created for your use.

To load and set up the images for the lesson

1 If you haven’t already done so, download and extract the Maya Live
Lesson Data at http://www.autodesk.com/maya-training in the Tutorials
section.

2 In the Setup control panel, click the Browse button next to the Full Res
Image box.

3 Navigate to the MayaLiveLessonData/sourceimages directory that you
extracted and select any image file from the list, such as
shot1BG.rgb.0001.

4 Click the Open button. Live loads the entire image sequence, from
shot1BG.rgb.0001 to shot1BG.rgb.0240.

5 From the Predefined Filmbacks list (on the Setup control panel), choose
35mm Full Aperture.
Filmback is the aspect ratio (width/height) of the exposed film negative
used during filming. Before using Live, you need to find out which
filmback was used during filming. Without it, Live cannot determine the
correct angle of view (camera aperture) and focal length.

NOTE If the images do not appear on the image plane, you may need to
adjust the image cache settings. Click the Cache option on the far left to
display the cache settings. Set Texture Method to Image. If the images still
do not appear, try selecting None.

Lesson 1: Track and solve

Introduction
This lesson guides you through the main tasks in Live: tracking and solving.

■ Review footage to determine the location of tracking points.

Lesson setup | 983

■ Position tracking points for the live-action footage.

■ Track points in the scene

■ Evaluate how closely points are tracked using the Track Summary panel.

■ Modify the location of tracking points for a scene.

■ Import track points into Maya.

■ Solve for the camera movement.

■ Evaluate and modify the solution that the Solver creates.

Tracking provides Live with information about the way objects in the shot
appear to move. Just as objects move in your field of view when you walk by
them, the way objects move in the camera view gives Live information on
how the camera moved during filming.
You’ll track points for various spots, such as a mark on the fence. To track a
point, you mark each spot in the image and have Live run a tracker that
automatically follows the point’s movement from frame to frame. The result
is called a track point.
Later, in the solve task, Live will animate a Maya camera based on the track
point movement.

Tracking preparation
Which spots should you track? To answer this question, do these steps:

To review a shot and plan for the tracking

1 Open the Track control panel by clicking the menu on the far left of the
control panel and choosing Track.

Above the Track control panel, Live displays preset view panels. The view
panels match the needs of tracking. The following illustration labels these
panels, shown the way they might look at the end of the lesson.


2 Play the shot and watch it in the shotCamera view panel. Don’t worry if
the playback seems jerky, because you are only getting a rough look at
how the camera moves. In fact, you can skip through the frames quickly
by dragging in the Time Slider.

NOTE Playing shots can be slow because the images require a lot of memory.
To speed up playback, Live has settings for creating an image cache (Setup
Cache control panel). Image cache is an allocation of system memory
dedicated to storage and retrieval of images so that they play back faster. For
this lesson, the default image cache settings usually suffice. If you later find
that caching the images appears too slow you can change the Pixel Type
from the default RGB setting to Luminance. This will cache black and white
versions of the images thereby reducing the amount of data cached and
increasing the performance of tracking points in Live.

The following figure gives recommendations on which points to track
(you will have a total of 15 in the end). You will track two of the points
and import the other points from a prepared file.

Tracking preparation | 985

Tracking object points in a shot
In the next steps, you track the motion of a flower. Tracking points on the
ground is common practice and the flowers are easy targets to track.

To track objects in the shot

1 Go to frame 1.

2 Click the Create button in the Track control panel. Live places a track
box in the center of the shotCamera view, ready for you to reposition.
If you don’t see a full-color image of the scene in the view, go one frame
forward in the Time Slider and go back to the start time to refresh the
view.

3 Before you reposition the track box, enter flower1 in the Name box in
the Track control panel. We recommend you name track points for future
reference.

4 In the Track control panel, click the track box tool so you can reposition
the track box.


If you switch to another tool, such as rotate, remember to select the track
box tool again if you thereafter need to move track boxes.

5 In the shotCamera1 view, drag the track box down to the fourth clump
of flowers from the right.

This pair of flowers is good to track because it is visible in all frames.
Strive to track points that are visible for a large number of frames.

6 In the pointCenteredCamera view, drag the image until the track box
cross-hair is centered over the flower closest to the fence. Dragging in
this panel has the opposite effect from the shotCamera view, because
you are actually panning the camera, not moving the track box.

Tracking object points in a shot | 987

Notice that the track box resizes if you drag the edges. For this track point,
keep the boxes at the default size. Choose Edit > Undo if you resize it
accidentally. It may require a number of Undo commands to return to
the original configuration of the track box.
The point you are tracking is at the center of the track box cross-hair. To
track this point, Live uses the pattern of pixels defined by the inner box.
The outer box is the range Live searches for the target pattern.

7 Make sure Tracking Direction is set to Forward.
During the course of creating track points, you will change this setting
often. Depending on the situation, you might track Forward, Backward,
or Bidirectional.

8 Click the Start Track button.
First a progress dialog box appears, then a movie of the track point. These
point-centered movies are important tools for evaluating how closely the
track point stays on target (see the following steps).


Evaluating the tracking of a point
Making sure the track point stays on target will help later when you solve.
Don’t worry if the connection between tracking and solving is not clear yet.
For now, simply identify major tracking errors by following these steps:

To evaluate the flower1 track

1 Review the movie file that Live generates at the end of tracking.
Identify any areas where the cross-hair slips noticeably from the original
position on the flower. This takes some judgment. Since the flower
changes shape over time, you must visualize where the original point
would be as the camera perspective changes.
If the cross-hair appears to stay within two pixels of the original target
point, you have tracked the flower successfully. If the cross-hair moves
completely off the flower or the tracking stops before it reaches the last
frame, you must track again. Delete the track point (click Delete in the
Track control panel), return to frame 1, position the track box cross hair
exactly in the center of the flower closest to the fence, and click Start
Track.

2 Close the Movieplayer window.

3 Look at the graph in the Track Summary panel.

Evaluating the tracking of a point | 989

This graph shows how closely Live matched the track box’s pixel pattern
on each frame. Specifically, Live compares each frame and the frame
before it to see how well they match. Green is a good match, yellow is a
warning, and red is a stronger warning.

As illustrated, the green region drops over time, leaving the graph mostly
yellow toward the end. This is a normal occurrence, caused by the
changing pixel pattern of the point you tracked. In this case, you can
ignore the yellow color, because the main evaluation tool—the movie
file—indicates the track is on target.

NOTE The curved blue (or red) line next to the track point is a trace line. It
is an optional tracking feature you will not use in this lesson.

Tracking additional points
Now that you’ve tracked one point successfully, you’ll continue with tracking
a different spot in the image sequence. In general, you keep tracking points
until you have enough to solve. (You will learn how to make this determination
later in the lesson.)
The point you are about to track demonstrates what to do if the spot falls out
of view midway in the shot.

To track the fence corner

1 Go to frame 1.

2 Click Create and drag the track box over the bottom corner of the far
right fence post. If you have trouble dragging the track box, click the
track box tool again:


3 In the PointCenteredCamera view, position the track box to match the
following illustration.

Knowing where to position the track box involves two important factors.
One factor is the pattern framed by the inner target box. This pattern
must have at least some contrast and must be distinct from the
surrounding region that is framed by the outer box. By having a distinct
pattern within the inner target, you will prevent the tracker from jumping
off target and onto a similar pattern.
Another important factor is choosing where you place the cross-hair. You
want it to be over a spot that you can recognize in later frames when the
pattern changes. By aligning the vertical cross-hair line with the post
edge and the horizontal cross-hair line with the bottom of the post, you
can identify this same spot in later frames.

4 Type fenceCorner in the Name setting.

5 Click Start Track.
The tracker stops around frame 60 or 80 because the corner falls out of
view. The track box also moves off target toward the end. You will correct
both of these tracking problems in the next steps.

Tracking additional points | 991

Deleting tracking data
Because the fence corner disappears from view in the middle of the shot, you
need to skip several frames and track from where it reappears. First, you need
to remove the bad tracking data where the track box moves off target.
To delete the bad tracking at the end, you use the Track Summary panel (the
panel below the pointCenteredCamera view).

To delete the bad tracking data

1 To see fenceCorner’s tracking graph better, click the Track Summary panel
and tap the space bar.

2 You need to select and remove the tracking data after frame 52—the last
frame still on track. To identify this frame in the graph, move to frame
52 in the Time Slider. In the Track Summary panel, a black bar shows the
location of frame 52.

3 In the Track Summary panel, draw a selection box from right to left
around the end of fenceCorner’s graph. Do not select beyond the black
bar that indicates frame 52. Also, be careful to select only the frames for
fenceCorner, not flower1.

4 In the Track Summary panel, choose Edit > Delete Region. Live removes
the bad tracking data from fenceCorner.
Deleting regions where the track is off target is crucial to successfully
solving your shots. Whenever you find difficulty tracking a point for a
specific segment of frames, consider deleting the tracking data.

5 Tap the space bar to shrink the Track Summary panel.

To continue tracking data in the shot

1 Move to frame 143, where the fence corner reappears in view. In the
following steps, you will continue to track from this frame to the end of
the shot.
You’ll skip tracking a large amount of frames for the fenceCorner point
(the ones in the middle of the graph), which is common practice when


creating track points. In general, track as many frames as possible for
each point and skip, retrack, or delete any frames where the tracker does
not stay on target.

2 Reposition the track box over the fence corner. In the
pointCenteredCamera view, align the vertical cross-hair line with the
edge of the fence post and the horizontal cross-hair line with the bottom
of the post.

3 Shorten the track box’s inner target box by clicking the inner target box’s
bottom edge and dragging up as shown below. The tracker will not work
if the target area extends beyond the image.

4 In the Track control panel, click Start Track. If the tracker successfully
tracks to the last frame, you’ll see a graph similar to the following

Deleting tracking data | 993

illustration. (The second track area will be mostly green or all green in
the Track Summary.)

If the tracker fails to create a graph similar to the above illustration, three
actions might have occurred:

■ The tracker stays stuck at the same frame and the animation frame doesn’t
advance

■ The tracker stops before the final frame

■ The tracker drifts off target
Whichever of these actions occurred, repeat the previous step, but this
time shorten the track box’s inner target box.

Importing tracking data
To reduce the repetition of tracking many more points in this lesson, you
import additional track points for the scene from a file we created for your
use in this lesson.

To import track data

1 Choose Track > Import Track Points from the Live menu set.

2 Navigate to the MayaLiveLessonData/points directory and open
fence_1.txt.
This imports the track point data for seven more points. (The track data
was created using the Track > Export Track Points operation.) Ordinarily,
you will not need to use the export and import operations; they are
intended for situations where you start over with a new scene but want
to retain track information.

Preparing to solve
Are there enough track points for you to solve the camera movement? Follow
these instructions to see how you make this decision.


To decide if you are ready to solve for the camera movement

1 In the Track Summary panel, choose View > Frame All.

2 For each frame, make sure there are at least four points with graphed
tracked data. Experience has shown that four points is the minimum
average you need to solve a shot.
In the middle frames, such as frame 135, there is less track data. However,
on this frame and all frames in the middle, there are at least four.

3 Look for large areas of red in each track point’s graph.
Small areas of red are okay. A track point’s graph does not have to be
completely green in order to solve. In general, if you do find a large area
of red for a point, either retrack over the region or select it in the Track
Summary graph and choose Edit > Delete Region.

4 As a preventive measure, look for blue tick marks in the graphs for flower1
and fenceCorner—the track points you created.
A blue tick mark indicates you moved the track box for that frame. You
may have moved it accidentally—for example, if you clicked on the track
box to select it. Click on the blue tick mark to go to that frame. Then, in
the pointCenteredCamera view, compare the frames next to this frame.
A shift as small as one pixel can cause problems when you solve.
If you see a sudden shift between the frames, go to that region in the
Track Summary graph, select two or three frames (you can simply
estimate), and choose Edit > Delete Region.

5 Look at the Ready to Solve bar at the bottom of the Track Summary.
It’s mostly green and yellow, with little red. The red area is mostly in the
middle because there is less track data there. However, since you meet
the minimum number of points, it’s worth trying to solve. You can always
add more track points later.

Preparing to solve | 995

Solving the shot
The solver is the part of Live that animates a Maya camera. You rarely obtain
a correct solution the first time you run the solver. Once the solver is run, you
need to evaluate the solution and make improvements to the track data until
the solver can create a correct solution.

To solve the shot

1 Open the Solve control panel by clicking the control panel menu on the
far left and choosing Solve.
The Solve control panel has a different arrangement of view panels than
the ones you used for tracking. You will learn about these other panels
as you continue with the lesson.

2 In the Solve control panel, click the Solve button to begin the solve
process. This process will take several minutes to complete. (You do not
need to go to frame 1 when you solve; Live solves for all frames by
default.)
Notice the column of buttons next to the Solve button, with Start at the
top and Register at the bottom. These buttons run the solver in stages—the
same stages that it performs when you click Solve. Running the solver in
stages is only for advanced use; you can ignore these buttons for now.


When the solver finishes, the solution, called solution_rf, appears in the
solution list on the Solve control panel. Because you will run the solver
several times, Live keeps a list of each solve attempt.
A solution consists of an animated camera and locators, which appear as
crossed lines in the perspective view. Locators are marks in the world
space that you can use as reference points when modeling. Each locator
corresponds to a track point and has the same name, plus the suffix
“_3D,” such as fenceCorner_3D.
The following illustration shows an example solution with these parts
labeled. Note that images do not appear on the image plane in the
perspective view because this view is in wireframe mode.

Evaluating a solved solution
Now you must determine if the solution correctly matches the camera
movement. If correct, the solution locators will be arranged like the points
from the actual film set. For example, the points along the fence should be
aligned along a plane. Also, Maya’s camera will move around the locators in
a way similar to the real camera movement.

To evaluate the solved solution

1 Check the Overall Pixel Slip in the Solve control panel.
The Overall Pixel Slip is a general indicator of the solution’s accuracy.
Overall means it is an average for all points on all frames. Pixel slip
measures how well each 3D locator matches with the track point in the
background—as viewed through the solved camera. For example, if flower1
and flower1_3D appear separated by one pixel on all frames, the pixel
slip is 1.0. The lower the pixel slip, the more accurate the solution.

Evaluating a solved solution | 997

Ideally, Overall Pixel Slip should be less than 2. But this doesn’t mean
the solution will mimic the live footage camera movement satisfactorily.
In the next steps, you’ll find out whether it does.
If Overall Pixel Slip reads “poor” or a number higher than 2, you need
to fix a problem in your track points. Return to the Track control panel
and repeat the instructions Preparing to solve on page 994.
If you still cannot reach a solution below 2, we recommend you continue
the lesson using a scene we have prepared for you. Choose File > Open
Scene, navigate to the MayaLiveLessonData/scenes directory, and
double-click goodPoints.ma. Live loads a scene with the same track points,
carefully created to avoid problems. When you click Solve in the
goodPoints scene, your Overall Pixel Slip will read about 1.0.

2 Play the animation and tumble the perspective view while the animation
plays so you can see how the camera moves.
You need to judge whether the camera moves the way you expect. You
know the camera starts above the set and moves down, so it should start
above the locators and sweep down in the same way. Compare the frames
in the following illustration.

In this case, the camera starts below the locators and moves up instead
of down. It also makes a series of abrupt movements. This solution is
incorrect.

3 Stop playing the animation.

4 For further evaluation, examine the graphs in the panel on the lower left.
This is the Locator Summary.
The Locator Summary graphs the pixel slip of each point over time. You
already looked at the overall pixel slip, but the Locator Summary lets you
find which point has the most pixel slip and on which frames.


If one point had a very red and yellow graph, you could conclude that
the point was the source of the problem solution. In this case, many
points have red and yellow areas, but those areas appear mainly in the
first 100 frames.
Because red and yellow areas all occur within the first 100 frames, you
can conclude that the solver does not have enough information for those
frames. To improve the information, you’ll need to add one or more track
points for those frames.
How many points you’ll need is not important to fixing this problem.
Rather, choosing the right points is what will help the solver. In the
following steps, you’ll load another set of points into your scene. These
points will illustrate which types of points to choose.

NOTE The other panels in the layout are the Graph Editor and the
shotCamera. The Graph Editor is for advanced users. It can be helpful for
examining the camera animation curves so that you can pinpoint problem
areas. The shotCamera panel is useful in later stages, after you have a correct
solution. You can ignore both of these panels for now.

Importing additional tracking data
To help you improve the solution, we have created another set of track points
for you to import.

To import the additional tracking data

1 Choose Track > Import Track Points.

2 Navigate to the MayaLiveLessonData/points directory and double-click
fence_2.txt. Live loads five more track points.

3 Click Solve.

Importing additional tracking data | 999

While the solver runs, examine the following illustration to learn about
the points you just loaded and why they were chosen to improve the
solution.

In general, having a diversity of points, such as points far and near the
camera, is critical to helping the solver.

4 When the solver finishes, solution_rf1 appears in the solution list. Check
the Overall Pixel Slip in the Solve control panel. It reads about 0.322, so
the new points have made an improvement.
If you have a larger Overall Pixel Slip, the problem may be that initial1
was selected when you solved again. Try selecting solution_rf instead and
clicking Solve again. The solution you have selected when you click Solve
can affect the outcome of the solver.

5 Play the animation and watch in the perspective view.
In this case, viewing from below the grid is best because the locators and
camera are below the grid in this solution. You must ignore where Live
has placed the camera and locators relative to the perspective grid.
Only look at the arrangement of the locators and the movement of the
camera. They should resemble the arrangement of points and the camera
motion as seen in the shot. For example, notice the points along the
fence are aligned along a plane, just as they are in the shot.
If you compare frames 80 and 180, you’ll see that the camera now moves
downward relative to the locators. This movement is what you would
expect the camera to do for this shot.


At this point, you can assume that your matchmove is complete and
accurate. However, to be absolutely sure, you need to play the animation
with a model placed in front of the camera. If the model does not appear
to slip relative to the background, then your matchmove is accurate. To
learn about this type of testing, continue with the next lesson.

6 If you plan to continue with the next lesson, we recommend you first
save your scene into the current scenes directory.

Beyond the lesson
In this lesson you learned the fundamentals of the Live workflow.
You learned how to:

■ Position tracking points for the live-action footage.

■ Track points in the scene

■ Evaluate how closely points are tracked using the Track Summary panel.

■ Modify the location of tracking points for a scene.

■ Import track points into Maya.
We made numerous decisions for you regarding which points to track and
how to improve the solution. With more practise, you will learn these
decision-making skills. Additionally, you may want to review the section
on “Shot Strategy” in the Maya Help.

■ Solve for the camera movement.

■ Evaluate and modify the solution that the Solver creates.
In general, you can expect to run the solver several times to find a correct
solution. Before each solve, make improvements by adding track points
in a variety of places and by deleting regions from the track data if they


are not accurate. Even if one track point is off alignment on one frame, it
could result in an incorrect solution.
Your solution has the correct camera movement, but you may wonder
why the camera and locators are placed below the perspective view grid.
If you want to control where the solution is placed within the scene, you
need to give the solver more information, called survey constraints.
Continue with the next lesson to learn more.

Exporting and rendering solutions
With the camera movement solved, you can create your animation using the
solved camera to make sure the animation does not move out of the camera
view. If your animators use Maya Complete or another software product, you
must export the camera solution from Live (Scene > Export Scene As). You
can also export to other 3rd party 3D and compositing applications.
When you render the animation, we recommend you do so without the image
plane background. A better workflow is to render the animation created in
Maya separately and then use a compositing software application to combine
it with the live footage background.
However, if you do want to render the image plane, you must turn off the Use
Cache option on the Setup control panel. The Use Cache option utilizes a Roto
node, which does not render. By turning Use Cache off, Live switches to the
standard Maya image plane, which is renderable.

Lesson 2: Solving with survey data

Introduction
This optional lesson is a continuation of the previous lesson.
The objective in this shot is to replace the filmed fence with a fence modeled
in Maya. Suppose you had taken measurements of the fence from the film set
and used the measurements to model a fence in Maya. The locators created
by Live would not match the same scale that you used for the model. Also,
the locators and camera Live created are not near the perspective view grid,
which is a convenient reference for modeling and animating.
To solve these issues, you can incorporate the measurements you surveyed
from the set into the Live solver. You do this with the survey constraints
feature.


In this lesson, you learn how to change the positioning of the camera and
locators within the Maya scene. You typically need to do this so you can more
easily model and animate objects you want to match up with the live shot.
You will learn how to:

■ Create a variety of survey constraints.

■ Apply survey constraints to the solution.

■ Evaluate the solution with imported geometry.

Even if you do not have survey measurements, you can use estimates to change
the spacing between locators and their orientation within the Maya scene.

Creating a Distance constraint
Live has a variety of survey constraints. As your first example, you will create
a Distance survey constraint. The Distance constraint defines the distance
between two tracked points. Based on that one distance, the solver can establish
the distances between all the locators.

To create a Distance constraint

1 Open the Live scene you created in the previous lesson.

2 In the Solve control panel, click the Survey option to open the survey
constraint settings.

3 Choose Distance from the Constraint Type menu.
Now you’ll need to specify two points that you want to constrain to a
distance.

4 To help select the points, open the Outliner (Window > Outliner).

5 Select the following track points in the Outliner under
clip1TrackedPointVisibilityGroup > clip1TrackedPointGroup:
■ fenceCorner

■ tileInFront

6 In the Solve Survey control panel, click Create.

7 Enter 2 in the Distance setting.
With this constraint, Live will force the locators for fenceCorner and
tileInFront to be 2 units apart. Live does not incorporate the constraint

Creating a Distance constraint | 1003

until you run the solver again and create a new solution. You will do this
later in the lesson.
This constraint is not based on a film set measurement; it is simply an
estimate. Using estimates to control the space between locators is often
useful, but be careful not to use too many estimates. Too many estimates
can prevent the solver from finding a solution.

Creating a Plane constraint
In addition to the space between locators, you may want them to be
repositioned within the scene. For example, you may want the flower locators
in the solution to rest on top of the perspective view grid, just as the flowers
in the shot rest on the ground. In the current solution, the flower locators
rest below the grid.

A convenient way to bring points onto the grid is to use a Plane constraint,
which aligns locators onto a plane.

To create a Plane constraint for the ground

1 Choose Plane from the Constraint Type menu.

■ flower1

■ fenceCorner

■ flower2

■ tileInFront

In the shot, these points correspond to points on the ground.

3 Click Create. Live places the Plane constraint on the perspective view
grid by default.


4 In the Solve Survey control panel, change the Name setting to ground.
Because you will later create another Plane constraint, you should give
this constraint a unique name.

Registering a solution
To incorporate your survey constraints, you could solve from scratch (click
Solve). However, you do not need to. You already have an accurate solution;
you only want to incorporate the survey constraints.
For this reason, Live lets you run the last step of solving: Register. In this step,
the solver applies survey constraints to the solution as a whole without
changing the relative positions of locators and the camera.

To register the solution

1 Click the Solve option to switch back to the Solve settings.

2 Make sure solution_rf1 is selected from the solution list.
This is the most accurate solution so far, so you want Live to apply the
survey constraints to this solution.

3 Click the Register button.
When the solver finishes, registered appears in the solution list. In the
perspective view, you can see the flower, fence corner, and tile locators
aligned with the grid.

Registering a solution | 1005

If you dolly in the view, you’ll also see that the locators for the points
you constrained by distance—fenceCorner and tileInFront—are now
about two grid units apart.

Creating additional Plane constraints
A top view reveals an illogical placement of the fence locators. Instead of being
aligned with the XY plane, they are at an angle. To correct this problem, you
need another Plane constraint that represents the fence.

To create a Plane constraint using the fence locators

1 Click the Survey option to switch to the Survey settings.

2 Make sure the Constraint Type is still set to Plane.


■ fenceCorner

■ fenceX4

■ fenceX1

■ fenceRailSpot

■ fencePostEdge

■ fenceleft1

■ fenceleft2

These are the points that are on the front of the fence.

4 Click Create.

5 Change the Name setting to fence.

6 In the Channel Box, rotate the fence plane by entering 90 in the Rotate
X attribute. Because the real fence is at a 90 degree angle to the backyard
ground, you must rotate the fence constraint the same way in Maya.

In this case, only the plane’s rotation matters, not where you move it.
No matter where you move the fence Plane constraint, the fence points
will remain on the grid because the solver must obey the ground
constraint you created.
The scale of the Plane constraint never matters because the solver treats
it as infinitely large.

7 Switch to the Solve control panel, select registered from the solution list,
and click the Register button. The solver creates registered1 with the fence
points aligned with the XY plane.

Creating additional Plane constraints | 1007

Evaluating the solution with imported geometry
The best evaluation of your solution is to set an object in front of the solved
camera and see if it matches the background as you play the animation. In
this case, we will import a fence modeled in Maya.
Before you load the modeled fence, do the following steps to add one more
survey constraint. You add a Point constraint to orient the solution so
fenceCorner is at the origin. You need fenceCorner at the origin because the
fence model has its corner at the origin and you want the two to match exactly.

To reorient the solution with fenceCorner at the origin

1 Switch to the Survey settings.

2 Choose Points from the Constraint Type menu.

3 Select the following track point in the Outliner under
■ fenceCorner

4 Click Create. Maya creates a Point constraint in your scene, located at
the origin (0,0,0) by default.

5 Switch to the Solve control panel, select registered1 from the solution
list, and click the Register button. The solver creates registered2 with
fenceCorner at the origin.

You will now import a fence that has been modeled to exactly match the fence
that was filmed.


To import a modeled fence

1 Choose File > Import.

2 Navigate to the MayaLiveLessonData/scenes directory in the Import
browse window.

3 Double-click fenceModel.ma to import it.

To evaluate the solution

1 Hide the Plane constraints by selecting them and choosing Display >
Hide, Show > Hide Selection By hiding them, you can see the fence better.

2 Enlarge the shotCamera view panel, which is in the upper right of the
Solve panel layout. This panel shows the view from the solved Maya
camera.

In frame 1, you can see that the modeled fence accurately matches the
fence that was filmed. To quickly see if it matches well in the other frames,
you can scrub through the shot in the Time Slider.

3 To scrub through the shot, drag slowly from left to right in the Time
Slider.
The fence model does not appear to slip in relation to the background,
so this confirms that the solution is accurate. If you rendered a sequence
of the camera moving around the modeled fence, you could composite
the sequence with the original background and they would exactly match.
Although scrubbing tends to skip frames, it gives a preliminary
confirmation that the fence model matches the background in all frames.

4 To evaluate the solution in a more accurate playback, select Window >
Playblast.

Evaluating the solution with imported geometry | 1009

The Playblast movie is an approximation of how the rendered sequence
will appear. In this movie, you can look for subtle mismatches between
the model and the background, such as momentary jitter.

NOTE As an alternative to the Playblast, you could play the animation in
Maya, provided you allocate enough memory in the Setup Cache control
panel. If you have memory allocated for all 240 frames, the playback will be
as fast and accurate as the Playblast movie. When using Playblast, you’ll need
approximately 20 Mbytes of free space in your computer’s temporary
directory.

Beyond the lesson
In this lesson you learned how to apply survey constraints to improve the
overall solution. Survey constraints are useful not only for orienting your
solution, but also for the initial creation of a solution. In these lessons, you
solved using track data alone. In more complex shots, the solver may fail
unless you use survey constraints to broaden the information that the solver
can use.
You cannot tell in advance which survey constraints are needed to solve a
shot so it is a good idea to plan for some of the survey constraints before you
start tracking. A common example is the Plane constraint, because most shots
have coplanar or approximately coplanar points in them.
Do not add too many estimated survey constraints, as they may conflict with
each other. When you create a Plane constraint for points that are only
approximately coplanar, we recommend you turn on Registration Only in the
Solve Survey control panel. This option keeps the solver from forcing the
points to be perfectly coplanar.
Maya Live includes other constraints such as camera constraints and infinite
points to help with solving. Camera constraints help control the focal length,
translation, and rotation of the solved camera. You set them in the Solve
control panel Camera settings.
Infinite points are tracked points that you designate as infinitely far from the
camera, such as a cloud, mountain, or any feature in the distant background.
Knowing a point is infinite, lets the solver use it exclusively for calculating
camera movement. Infinite points are helpful for zoom shots, when the camera
is static.
For further information and related techniques on Maya Live, refer to the
Maya Help.


Index
{ } in expressions 641 Assign Edit Textures button 610
% in expressions 648 Assign New Material 467
Assign Paint Effects Brush to Hair 783
2D fluid container Assign Textures button 618–619
creating 792 assigning a texture map 366
3D fluid container Attribute Editor
creating 801, 810 attribute tabs 65
3D Paint Tool 610 description 65
Fur 849
viewing 65
A Attribute to Paint 610, 618
attributes
Accuracy 531 controlling multiple 631
active rigid body 558 description 37
Add Attribute button 645 displayed in Attributes list 628
Add Attributes 548 linking 631
for Current Render Type 547 shading 68
Add Dynamic Attributes 548, 645 audio clips 275
Add Influence 341 Autodesk
Add Keys Tool 212 technical support 11
Add Per Particle Attribute 548, 645 Web site 11
Add Preview Plane 821 Automatic Mapping 376
Add/Edit Contents 792, 797, 811 applications 376
age, particles 549 triplanar projection 376
Along Axis 540 Away From Axis 540, 543
Alpha Gain 77 Axial Magnitude ramp 949
Amplitude 805 axis indicator 19
animation
curves 206
planning, storyboarding 308 B
Animation Preferences 202
Annotation bald region 843
creating 293 base object
description 293 influence object 342
anti-aliasing 458, 515 base shape
Append to Polygon Tool 105 blend shape 359
arms base width 853
joint chain 324 Bend
Around Axis 540, 543 hair 764
array Bend Amount 764
description 548 Bend Curves Options 764
Artisan Erase 612 Billow 804

1011 | Index

Billow Density 805 camera
birth, particles 549 applications 496
blend modes 611 create 496
blend shape deformer 352 Camera Attribute Editor 452
adding shape to 357 camera constraints 1010
editor 353 camera tools
improving deformations 359 Dolly Tool 44
blending animation types 231 overview 43
Blinn shading material 441, 443 Track Tool 45
description 67 Tumble Tool 45
Blobby Radius Scale, nParticles 965 cameras
Blur, 3D Paint 617 animating 498, 500
boat locator 825 Film Gate 500
boat wakes 827 undoing changes 498
bones 319 Canvas
Boolean operations 129 Clear 568
border edges 84 Set Size 568
Bounce 925–926 Canvas Clear 566
Boundary Draw 808 Caustic Photons 532
Boundary X, Y 796 Caustics
Bounding Box 214 Caustic Photons 527
braces, in statements 641 description 519
brackets, double angle 646 Emit Photons 527
Break Tangents light sources 533
Graph Editor 208 Photon Intensity 527
Bridge 102 photon maps 526
Browse button 614, 620 photons 526
brush profile 615 Channel Box 24
brushes blend attributes 233, 235
3D Paint, Paint Effects 615 description 37
description 577 hiding, showing 24
Kelp 594 locking channels 298
Mesh 598 naming and renaming objects 38
Teapot 599 transforming and rotating
Thin Line 608 objects 38
bump, painting 618 translation, rotation, scaling 24
Buoyancy 826 character set 246
character setup
description 317
C Circle 172
cache clear canvas 566
for Live images 985, 1010 clip cycle
caching description 261
nCloth 898–899 clip library 270
nParticles 967 clip manipulator 258
caching fluids 800

1012 | Index

clips giving object constant color 645
applications 242 giving particles randomly changing
audio 275 color 646
blending 274 particles 548
components 245 ramp 549
creating 244, 247 Color 611
cycling 261 color bleeding 515
description 239, 242 Color Chooser 68, 454
duration 246 Color Feedback
importing 253 Paint Fur Attributes Tool 846
inserting 270 Color Input 804, 817
keyframing 275 Color Method 797
name 246 Combine 102
Outliner 275 components
regular clips 244 description 62
renaming 248 conditional statements
repositioning 250 if 636
reusing 253 Conserve attribute 545
scale 246 constraints 554, 880–892
scaling 257 description 291
source 244, 253 nCloth 881, 886, 908–909
Visor 275 orient 296
cloth texture 446–447 parent 305
Clump Width point 294
hair 772 Point to Surface 881
cluster deformer 346 rigid bodies 554
cluster handle 348 construction history 117, 153, 179
cluster weights 349 container
Collapse 294 boundaries 796
collapse hierarchy 294 creating 792, 801, 810
Collide Sphere 768 resolution 802
Collide Width Scale 926, 928, 960 size 802
Collision Flag 876–878 Contents Method
collision object dynamic fluid 795
fluid 798 Dynamic Grid 794, 797, 812, 816
collisions Gradient 803
nCloth 868–878, 899–900 control object (IK) 290
nParticles 925–926, 960 control vertices (CVs) 152
collisions, rigid bodies 554 description 63
color Convert Selection
Christmas light effect with hair 768
particles 648 converting a UV selection 384
emitting 797 Crease Proxy Edge Tool 127
fluid property 792 creasing
fluid shader 817 subdivision surface 195
fur 850

Index | 1013

Create D
Expression Editor 628
Create 2D Container 792 deforming objects with fluids 800
Create 2D Container with Emitter 793 Delete by Type 118
Create 3D Container 802, 810 Delete Keys 332
Create Blend Shape 352 Delete Region 992
Create Clip Density
options 261–262 description 793
Create Cluster 348 emitting 792
Create Constraint 556 fluid property 792
hair 768, 785 fur setting 853
Create Hair 758, 779 painting 811
Create Ocean 820 Depth Map Shadows 774, 859
Create Polygon Tool 95 Depth Max 805
Create Ramp 549 detail
Create Rest Curves subdivision surface 191
hair 759 Dim Image 377
creating directional light
constraints 881–886, 908–909 create 486
liquid simulations 953, 976 description 486
nCloth 866–868, 895 editing attributes 487
nParticles 918, 920, 931, 933 displacement
passive collision objects 868, 897 ocean 821
creation expressions 645 Displacements
assigning to rgbPP 645 hair 773
cross-hair in track box 988 display
cube primitive 21, 78 creased edges 128
options 46 only selected object 355
Curl Poly Count 129
hair 773 soft and hard edges 124
Curl Frequency template 60
hair 773 Display Image 379, 384
Current Position 759 Display Level 192
curve Display Quality
direction 152 hair 760–761
edit revolved 153 Display Resolution 452
start 152 Display Start Position
curves, dynamic 753 hair 762
curves, hair 756 Display Unfiltered 387
cutting Distance survey constraint 1003
subdivision surface 190 Dmap Focus 859
CV Curve Tool 151 Dolly Tool 44
cycling a clip 261 description 44
double angle brackets 646
Draft rendering setting
description 505

1014 | Index

driven keys Emit Fluid Color 798
description 215 Emit from Object 538
duplicate emitter, nParticles 918, 931
symmetrical 831 emitters 536
Duplicate Tool 174 creating 537
description 39, 55 Omni 538
options 39, 48 emitting
Duration 246 color 797
dynamic attributes Density 792
adding 546, 644 fluid 792
dynamic curves 777 fluid from surface 800
hair 753 End Bounds 582
dynamic fluid End Time 202
behavior, changing 794 equal to (==) operator 648
Contents Method 795 Equalize
creating (3D) 810 hair 759
description 791 errors
Dynamic Grid 794, 797, 812, 816 syntax 637
Dynamic Properties 892, 895 Essential Skills Movies 5
dynamics closing the movie window 6
definition 535 playing 6
exiting Maya 27
Expression Editor 627
E expressions 825
Eccentricity 824 advantage of separate 632
Edge Bounded advantage of single 632
hair 759 creating 628
edge loop 84 description 625
description 84 editing 630
termination 115 execution details 633
edges naming conventions 627
border 84 Extrude 97
creasing 123 extrusion manipulator
hardening 123 subdivision surfaces 189
selecting subdivision surface 193
Edit button F
expressions 631
Edit Deformers > Blend Shape > Add 357 face selection mode 82
Edit Ramp 553 faces
elbow splitting 107
influence object 341 facial animation 344
electronic tablet FCheck 462, 553
sculpting surfaces 164 feedback
else keyword fur 838
expressions 640 fields 536, 553
emission rate 924 file saving 27

Index | 1015

Fill Object, nParticles 954 Fuel
filmback for Live 983 painting 811
fingernails 193 Full Crease Edge/Vertex 195
fingers 185 Full Res Image 983
Flipbooks 553 fur
floating geometry 825 Attribute Editor 849
Flood 815, 847 attributes 838
Sculpt Geometry Tool 161 base width 853
Flood All 613 color modification 850
fluid container Density 853
boundaries 793 description 836
creating 792, 801, 810 direction 840
fluid dynamics 791 Direction Offset 841
fluid properties 792 feedback 838
adding constant values 803 Inclination 853
emitting 792 Length 853
painting 811 Paint Attributes Tool 843
Fluid Slice Location 813 Polar 841
fluids presets 830
attributes, changing 794 reduce length 843
color 797 Roll 841
deforming geometry with 800 Scraggle 853
emitting 792 tip width 853
emitting from surface 800
forces 793
painting properties 811 G
resolution 802 Get Brush icon 615
self-shadowing 808 Get Fluid Example 809
shader attributes 803 Getting Started with Maya
texturing 804 about the lessons 2
follicle before you begin 3
attributes 772 introduction 1
hair 754 lesson conventions 4
forces using lesson files 5
container boundaries 793 using tutorials online 3
Gravity 795 Global Illum Photons 509, 514
Forward Kinematics (FK) 276, 328, 332 Global Illumination
Four Panes 151 Accuracy 513
Frame In 245 color bleeding 515
Frame Out 245 description 501
Frame Selection light sources 517
Graph Editor 206 photon maps 508
frames per second setting 440 photons 508
Freeze Transformations Radius 513
description 292 rendering process 508, 510
Friction 925–926 Glue Strength 785

1016 | Index

Go to Bind Pose 340 Hardware renderer
Graph Editor 205 description 451
path animation 227 Help
Set Driven Key 219 Find Menu 10
tangent modification 228 launching 7
Gravity 557, 584, 795, 892 Help resources 5
hair 761, 766 hide layers 844
Gravity and Wind 949 Hide Selection 179
ground plane 579 hierarchy
group nodes about 278
animating 214 collapse 294, 304
Group Under 345 description 52
grouping objects grouping 52
description 52 skeleton 319
Growth attributes 605 viewing in hypergraph 279
Hinge constraint 556
hole
H creating subdivision surface 190
hair Hotkeys
assigning a Paint Effects brush 782 brush scale 594
colliding with objects 782 description 55
constraining 784 setting 55
creating 758 Hypergraph 53
creating Rest curves 765 character setup 321
improving playback description 53
performance 761 overview 53
modifying 772 viewing 53
Paint Hair Tool 754 viewing hierarchies 53
playing the hair simulation 760 Hypershade
rendering 771, 786 Create Textures 477
setting up collisions 767 description 474
shadowing 774 rename operation 477
styling 762
Hair Color 783 I
hair curves 756
hair system 754 if statements
attributes 772 expressions 634
Hair to Hair constraint 784–785 if-else statements
Hair Width 773 expressions 639–640
hairConstraintShape 785 Ignore Solver Gravity 934
Hairs Per Clump 772 IK handles 328
hairSystemShape 761 control object 290
Harden Edge 125 creating 288
hardware render 551 creating and animating 329
Hardware Render Buffer 551 description 288
parenting 300

Index | 1017

IK Rotate Plane handle 331 Joint Tool 320
IK Solvers joints 319
Enable and Disable 340 influence on skin 335
ikSCsolver 289 moving 324
image cache in Live 985, 1010
image plane
description 75 K
importing 76 Keep Aspect Ratio 610
transparency 77 Keep Hard Edge 126
image plane and rendering 1002 Keep Image 507, 525
image size 505, 515, 524 keyframes (keys)
Import Clip 253 adding 212
Import Tracked Points 994, 999 deleting 211
Incandescence 818 description 200
Incandescence1 617 setting 202
Inclination 841, 853 keying into a clip 275
Incompressibility 961 keys
Influence list delete redundant 212
Paint Skin Weights Tool 337 Key Selected 314
influence object moving 207
smooth skin 340 setting 311
initial orientation
hinge constraint 557
Initial State 905–907 L
Input Mesh Attract 902
Insert Edge Loop Tool 103, 111 Lambert shading material 441–442
Insert Isoparms 168 Layer Editor 834
Inverse Kinematics (IK) layers
description 276, 328 assign objects to 836
limiting motion 298 create 835
translation limits 304 description 834
IPR 619 editor 834
description 451 hide 844
region to be updated 454 reference 835, 851
IPR Render Current Frame 453 settings 851
Isolate Select 355 template 851
isoparms 157 layouts
Iterations changing panel layout 32
hair 766 four view layout 39
shortcuts 32
Leaf Width Scale attributes 604
J Leaves attributes 605
legs
jaw joint chains 319
joint 322 Length
joint chains 319 hair 759
Joint Size 320

1018 | Index

Length Flex Make Collide 799
hair 766 hair 782
level of detail Make Motor Boats 827
subdivision surface 191 Make Paintable 594
lifespan attribute 549 manipulators, subvolume 811
Lifespan, nParticles 935 Map Visualizer 517, 533
lights mapping UVs 375
add to a scene 856 applications 375
applications 485 marking menu 63
attributes 491 masks and modes, selection
directional 586 description 56
dropoff 492 Mass 892
intensity 586 match moving 979
penumbra 492 material
spotlight 488, 506 assigning 467
spotlights 856 Blinn 441
Line Smoothing 552 default shading 67
Line Width 547 description 441, 467
Linear Lambert 441
Graph Editor tangents 208 surface 67
linking attributes 631 Max Displacement 162
Liquid Radius Scale 959 Max Influences 335
Liquid Simulation attributes 958, 963 Max Photon Depth 529
Live Max Self Collide Iterations 910–911
control panels 982 Maya
solver 997 about 1
starting 982 installing 3
Load Driver launching 15
Set Driven Key 217 user interface 15–16
Load Selected Characters 245 using Maya Help 7
loading Maya Hardware renderer
Live 982 description 451
Locator Summary 998 Maya Help
Locators index 7
hair 768, 771 popup help 8
Lock Length Tutorials 3
hair 763, 784 using 7
Loft Tool 172, 176 using Help index 7
Look Through Selected 490 using Help Line 10
using Search 8
Maya nCloth 863
M Maya nParticles 915
Magnitude 540 Maya Nucleus 863, 915
main menu 20 Maya Software renderer
Make Boats 825 description 450

Index | 1019

Maya Vector renderer UVs 384
description 451 Move and Sew UVs 382
mayaLive.mll 982 Move Snap Settings 85
mayalive.so 982 Move Tool 35, 86
mental ray for Maya renderer 438, 523 N (normal) manipulator 94, 194
description 451 X, Y, Z manipulator 35
mental ray shaders mute track 257, 270
assigning to an nParticle output
mesh 972–974
menu sets 20 N
description 20 nCloth 863
Polygons 72 caching 898–899
selection 20 Collision Flag 876, 878
Mesh brushes collision thickness 870, 876
applications 598 collisions 868, 878, 899–900
attributes 603 constraints 880, 892, 908–909
description 598 creating 866, 868, 895
meteors 546 Dynamic Properties 892–895
Mirror Across 322 Initial State 905, 907
Mirror Geometry 119 Input Mesh Attract 902
modeling Mass 892
description 71, 717 Max Self Collide Iterations 910–911
polygons 72 painting properties 902–905
shaded mode 80 Quality Settings 909–911
symmetry 82 Self Trapped Check 910–911
types 71 Tangential Drag 893
Modify Curves neck
hair 763 joints 322
modules 20 New Matchmove 982
modulus operator (%) 648 new scene 30
morphing facial expressions 353 nodes
motion description 37
speeding up with Graph Editor 209 initialShadingGroup 66
motion capture data input 66
creating clips from 260 nParticleShape 922
description 259 Nucleus 922
extending the length of 261 parent 54
redirecting 266 pivot point 57
Motion Path renaming 54
Attach to Motion Path 222 root 54
motion path animation shape 66
description 220 transform 66
Motion Streak, nParticles 968 Noise
move hair 783
key points 207 non-dynamic fluid 791
objects 35 creating 801

1020 | Index

description 791 shading attributes 943–948
non-hair simulation 777 Stickiness 925–926
non-proportional scaling 50 Threshold 965
nonlinear animation tutorial 916
description 239 Nucleus 863, 915
normals Gravity 892
reversing 839 Gravity and Wind 949
surface 160, 838 node 922
Normals Space Scale 901, 922, 957
Harden Edge 125 Wind Speed 892
Soften Edge 124 Num Frequencies 823
nParticle tutorials Number of Sections 157
creating nParticles 917 Circle 172
overview 916 Number of Spans 157
simulating liquids 953 Numeric Display 795
simulating smoke 930 NURBS
nParticles applications 149
Blobby Radius Scale 965 creating NURBS curves 151
Bounce 925–926 editing tools 179
caching 967 Loft Tool 172
Collide Width Scale 926, 928, 960 sculpting NURBS surfaces 156
collisions 925–926, 960 Smoothness 158
Color 923 NURBS curves
converting to polygons 963–967 hair 754
creating 918–920, 931–933
creating liquid simulations 953–976
emission rate 924 O
emitter 918, 920, 931, 933 object selection 34, 120
Fill Object 954 ocean
Friction 925–926 attributes, modifying 822
Ignore Solver Gravity 934 creating 819
Incompressibility 961 plane 820
Lifespan 935 shader 819–820
Liquid Radius Scale 959 offset 294
Liquid Simulation attributes 958– Opacity 611, 806
963 Paint Cluster Weights Tool 350
Motion Streak 968 Sculpt Geometry Tool 163
nParticleShape node 922 Opacity Input 804
Nucleus nodes 922 operators
Nucleus wind 949 assigning values to 648
Output Mesh 965 equal to 648
Radius 923, 935 less than 636
Radius Scale 937–938 order of statements 638
rendering 971–976 orient constraint
Self Collide Width Scale 926–928 creating 297
self-collisions 926–928 description 296

Index | 1021

origin 18 pressure sensitivity 576
orthographic view 43 strokes 577
Outliner 244, 248, 275, 859 Temperature 816
description 153, 178 UV preparation 621
parenting objects 178 pairBlend attribute 236
placing clips from 254 panel 18
Output panel layout 509, 522
hair 754 parent constraint
Output Mesh, nParticles 965 description 305
Output window 457 weighting 308
Overall Pixel Slip 997 parent node 54
Oversample 771 parenting
Oversample Post Filter 771 description 285
particle attributes, per object and per
particle 548
P particle object 538
paint brushes particles
blending 572 applications 535
Paint Effects changing form of 545
3D objects 589, 593 description 536
applications 607 render type 545
Brush Settings window 617 streaks 546
brushes, 3D Paint 615 passive collision object 868, 897, 920,
making surfaces paintable 594 956
panel 587 Passive Fill
Paint Effects hair 754, 771 hair 759
Paint Effects to Polygons 601 path animation
Paint Fluids Tool 811 blending 231
Paint Fur Attributes Tool 843 description 220
Color Feedback 846 position marker 226
Flood 847 Twist attribute 230
Reflection 848 UValue 224
Smooth operation 847 per object attributes 548
Paint Hair Tool 754 Per Particle (Array) Attributes 645
Paint Selection Tool 83, 347 per particle attributes 548
Paint Skin Weights Tool 337 how to distinguish 548
Paint Weight Menu 338 Perlin Noise 804
painting perspective view 43
2D strokes 564 Photon Intensity 509, 512, 530
3D strokes 575 photon maps 526, 533
3D strokes in scene view 579 description 508
bump 618 visualizing 517
Density 811 Photon Refractions 529
fluid properties 811 photons
Fuel 811 Accuracy 531
interactively 618 Caustic Photons 532

1022 | Index

description 508 Ponds 827
Emit Photons 509 creating 827
Global Illum Photons 509 Predefined Filmbacks 983
Max Photon Depth 529 preferences
Photon Intensity 509, 512, 530 modeling 74
photon maps 533 preview plane 821
Photon Refractions 529 primitives
Radius 531 applications 29–30
Pitch 826 creating 21, 77
pivot point interactive creation 75
description 57 modifying 176
Plane constraint 1004 NURBS sphere 49
playback NURBS torus 61
animation 313 plane 590
controls 202 polygonal cube 46, 77
quickening 213 polygonal cylinder 31, 47
speed 202 types 30, 171
Playblast 205, 213 procedural textures 442
description 237 description 445
Playblast for matchmoving 1010 process 437
Plug-in Manager 982 projection mapping UVs 375
Fur 830 PSD file format 368
point constraint
description 294
Point constraint 1008 Q
Point Method 785 quads 78
Points Per Hair 759 Quality Settings 909, 911
Polar 841 Quaternion rotation 236
pole
surface 162
Pole Vector Constraint 331 R
Pole Vector XY Z 331
polygon count 129 Radius 531, 611, 923
Polygon Proxy Mode 185 Circle 172
polygonal cylinder Sphere 157
creating 31 Radius Scale 937–938
options 31 Radius, nParticles 935
polygons Radius(L) 164
component types 72 Radius(U) 160
display settings 74 Paint Cluster Weights Tool 350
extruding 97 Paint Skin Weights Tool 339
four-sided quads 78 rain 546
selection settings 74 ramps 549, 553
smoothing 79, 121 Randomization
Polygons to Subdiv 184 hair 759
Range Slider 202
raytracing 503

Index | 1023

Redirect Tool 266 Replace
creating redirect control 266 Paint Cluster Weights Tool 350
keyframing control 268 resolution, fluid 802
positioning control 267 Rest Position 759
reduce fur length 843 Retain component spacing 85
reference layer 835, 851 return to start time 202
Refine Selected Components 194, 196 reusing clips 253
reflect reverse normals 839
Paint Fur Attributes Tool 848 Revolve Tool 150
Reflection creating surfaces 153
Sculpt Geometry Tool 165 editing surfaces 153
Reflection X 612 rewind 202
refractions rgbPP attribute 548
Max Trace Depth 529 use in expressions 645
photon refraction 529 ribs
refraction levels 529 joints 324–325
Register step 1005 ridges
renaming clips 248 subdivision surface 195
renaming surfaces 833 rigid bodies 554
render a scene 860 active 558
Render Current Frame 585 applications 535
render image plane 1002 collisions 554
Render Sequence 552 constraints 554
Render Settings 458, 504, 860 passive 558
render types, setting for particles 545 rigid skinning 343
Render View 451, 523, 619 Roll 826, 841
Keep Image 507, 525 root
rendering skeleton 327
anti-aliasing 515 root node 54
batch rendering 459, 464 Rotate Tool
compositing layers 464 description 36
description 437 X, Y, Z manipulator 36
hardware 438, 464 X, Y, Z, manipulator 90
image size 505, 515 Rotate UVs 385
methods 438 rotating objects
overview 439 options 50
panel layout 509, 522 rotInterpolation 236
raytracing 503 runtime expressions 646
render settings 504 assigning rgbPP in 647
sampling 516
shading surfaces 466
shadows 506 S
software 438, 450 sampling 516
view region to be rendered 452 Save As 609
rendering nParticles 971, 976 Save Scene 27
rendering particles 553 saving files 27, 40, 59

1024 | Index

scale Set to Dynamic 798, 812, 816
non-proportional 50 Setup Cache control panel 985, 1010
Scale sewing UVs 381
Paint Skin Weights Tool 339 shaded mode 51, 80, 601
scale, multiplying by percentage 642 shader
scaling clips 257 fluid 803
scene painting view 587 Shading
scene view vs Render View 451 hair 775
Scraggle shading attributes 943, 948
fur setting 853 shading material
scrub 203 assigning 67
Sculpt Geometry Tool 156, 159 Blinn 67
basic techniques 159 shading networks
preparing surfaces 157 description 445
sculpting terrain 592 shading surfaces 466
Section Radius 543 shadowing
Selected Position 807 attribute for spotlights 858
selection Depth Map 859
border edges 89 Dmap Focus 859
Convert Selection 97 shadows 506, 523
faces 82 description 494
hierarchy 57 Shelf 22
hierarchy, object, component 56 preset brushes 578
masks and modes 22, 56 saving preset brushes 571
mode 22 shotCamera view panel 985
objects 24, 34, 120 Show/Hide Attribute Editor icon 859
Paint Selection Tool 83 Show/Hide Editor 22
polygon components 86 Size Rand 805
Select Border Edge Tool 90 Size X, Size Y 610, 619
UVs 379–380 size, container 802
vertices 87 skeletons 318
Self Collide Width Scale 926, 928 creating 282
Self Shadow 808 hierarchy 281
Self Trapped Check 910–911 moving group node 331
self-collisions, nParticles 926, 928 parenting models 285
self-shadowing posing and animating 328
fluid 808 root 327
semicolon terminator skin 333
expressions 628 skin weights 335–336
Set Driven Key 216 modify 338
Graph Editor 219 slice 811
Set Initial Position 557 Slices Per Voxel 815
Set Key 203 Smear 617
Set Preferred Angle 328 Smear, 3D Paint 617
Set Rest Position 766 Smooth
Set Start Position 762, 767 hair 765

Index | 1025

Paint Fur Attributes Tool 847 Standard Mode 191
Paint Skin Weights Tool 339 Start Position 759
Smooth Bind 335 setting 762
Smooth Shade All 80, 441 Start Track button 988
smooth skin 335 starting Maya 15
influence object 340 statements
unnatural deformation 336 expression order 638
smoothing polygons 79, 121 static channels
Snap Mode 22 remove 212
Snap to Grid 85 Static Grid 816
Snap to Points 173 Status Line 20–21
Soft Modification Tool 130 expanding and collapsing items 22
Soften Edge 124 Stickiness 925–926
Software renderer Stiffness
description 450 hair 761, 766
software rendering 450 Stiffness Scale
solo track 256 hair 766
Solve control panel 996 Streak render type 546
solver for Live 997 stroke
source clip 244 attributes 581
Source In 246 attributes, Global Scale 583
Source Out 246 attributes, Gravity 584
Space Scale 901, 922, 957 attributes,Turbulence 595
spans, displaying 158 description 577
Specular Stroke Refresh 588
hair 775 strokes
Specular Power deleting 596
hair 775 polygon conversion 601
Specularity 824 rendering 584, 597, 600
sphere primitive 49 tubes 580
options 63 Stylus Pressure 164, 576, 611
sphrand function, use with random Sub Segments
color 647 hair 772
spinal column Subdiv Proxy
joint chain 322 Crease Proxy Edge Tool 127
spine description 121
parenting arms and legs 327 toggle display 123
Split Polygon Tool 107 using 122
spotlight subdivision surfaces
aiming 489 converting polygons 183
Cone Angle 492 cutting 190
description 488 Extrude Face 187
spotlights 856 extrusion manipulator 189
Spottyness 805 selecting faces 187
Stamp Depth (3D) 816 selecting vertices 189
Stamp Spacing 615 Split Polygon Tool 185

1026 | Index

subvolume manipulators 811 Texture Type 804
summary track textures
description 255 cloth 446–447
surface interactive 3D placement 480
material 67 procedural 445
normals 160 texturing, fluid 804
pole 162 The Art of Maya 3
surface render 800 Thickness 870–876
surfaces normals 838 Thinning
survey constraints 1002, 1010 hair 772
Survey option 1003 Threshold, nParticles 965
symmetry 82 ticks
syntax, errors 637 red key 203
time
expressions 635
T predefined variable 628
Tail Fade 547 value at different frames 628
Tail Size 547 Time option 440
Tangent Time Slider 202
Graph Editor 214 time warps 275
handles in Graph Editor 208 tip width 853
Tangential Drag 893 Toggle Texture Borders 383
target applications 383
blend shape 352 Tool Settings 609
Temperature Toolbox 32
fluid property 792 transformation tools 34, 85
painting 816 torus
template brush options 61
description 566, 578 track 245
modifying settings 566 description 245
resizing 566 muting 257
template display 60, 319 soloing 256
applications 60 view area 246
description 60 track box tool 986
untemplating objects 65 Track control panel 984
template layer 851 track point 984
Test Render 551 Track Summary panel 989
texture map Track Tool 45
applications 361 description 45
assigning 366 Tracking Direction 988
description 361 transform nodes
procedural 442 not used for particle expressions 645
UVs 363 transparency, skin 335
Texture Opacity 804 Trax Editor
Texture Scale 805 character sets 246
Texture Time 809 clip library 270

Index | 1027

clip manipulator 258 UV Texture Editor
cycling a clip 264 applications 371
Graph Anim Curves 252 converting a selection 384
Load Selected Characters 245 description 371
motion capture data 259 Dim Image 377
mute track 257 Display Image 379, 384
Offset attribute 265 Display Unfiltered 387
panel layout 241 Move and Sew UVs 382
repositioning clips 250 Rotate UVs 385
scaling clips 257 Toggle Texture Borders 383
solo track 256 viewing UVs 373
summary track 255 UVs
time warps 275 Automatic Mapping 376
Toolbar 247 description 363
track 245 image range 373–374
triplanar projection 376 mapping 375
tubes modifying 379
attributes 604 moving 384
Creation 599 preparing for painting 621
editing attributes 570 projection mapping 375
Flower 599 selecting 379–380
Leaves 599 sewing 381
Tumble Tool shells 382
description 45 viewing 371, 373
turbulence 795
Turbulence
options 595 V
Twist 331 V Count
hair 764 hair 759
Twist attribute 230 Value
Two Panes Stacked 619 Paint Cluster Weights Tool 350
Vector renderer
U description 451
velocity
U Count controlling in particles 545
hair 759 Velocity, fluid property 792
UI Elements 609 vertices
undo 37, 592 subdivision surface 189–190
Update on Stroke 620 viewing rendered frames 462
Use Cache option 1002 viewing shaded objects 51
Use Depth Map Shadows 491, 495 views
user interface 15–16 orthographic 43
user preferences perspective 43
restoring 12 shaded 51
saving 11 wireframe 54

1028 | Index

Visor 244, 275 Wave Peaking 823
description 254 Wind Speed 892
placing clips from 254 Wireframe on Shaded mode 80
preset brushes 577, 593 workspace 17
volume axis field 539 world space coordinates 93
Volume Axis field 940–942
volume pixels 794
Volume Shape 539 X
voxels 794, 802 X-Ray 81, 335
X, Y, Z
W axes 19
axis indicator 19
Wakes origin 18
creation 827 X, Y, Z Resolution 802
water X, Y, Z Size 802
open 819 X, Z ground plane 579
Wave Length Max 823

Index | 1029

Maya 2010 Getting Started

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Maya 2010 Getting Started