Animation Techniques
- 2. Computer Animation&Techniques2MahithSeminar by Mahith Mohan
- 3. Animation is the rapid display of a sequence of images of 2-D or 3-D artwork or model positions in order to create an illusion of motion or life.
- 4. Name derived from “Anime” means life.It’s just an optical illusion of motion due to persistence of vision 3Mahith
- 5. Simple ExampleA ball bouncing from just 6 frames4Mahith
- 6. For better smooth transition we must have higher frame rate.Frame Rate: No. of frames in unit secondFilm 24 fps
- 7. NTSC TV 30 fps (interlaced)
- 8. PAL TV 25 fps (interlaced)
- 9. HDTV 60 fps
- 11. Classification of animation techniques 6Mahith
- 12. Traditional Animation Also called Hand drawn animation Or Cel animation
- 13. Pictures are drawn for each frames.
- 14. The animators' drawings are traced or photocopied onto transparent acetate sheets called cels( celluloid transparency)
- 15. The completed character cels are photographed one-by-one onto motion picture film against a painted background by a rostrum camera.7Mahith
- 16. Example8Mahith
- 17. Walt Disney Walt Disney, an American cartoonist and film producer, started an entertainment empire with his creation of animated movies and world-renowned amusement parks. Disney appears here at his drawing board in 1950 with a drawing of Mickey Mouse, his most famous cartoon character. Disney won an honorary Oscar (Academy Award) in 1932 for his creation of Mickey..9Mahith
- 18. Stop Motion AnimationStop-motion animation is used to describe animation created by physically manipulating real-world objects and photographing them one frame of film at a time to create the illusion of movement.10Mahith
- 19. Example11Mahith
- 20. Computer animation Computer animation contains a variety of techniques, the unifying factor being that the animation is created digitally on a computer
- 21. Mainly 2 types-
- 22. 2D animation
- 24. Animation SequencesStep 1:Storyboard layout Outline of action
- 25. Consist set of rough sketches13Mahith
- 26. AnimationSequencesStep 2:Object definitionObjects are defined in terms of basic shapes.
- 27. Associated movement of each object are specified with the shape.14Mahith
- 28. Animation SequencesStep 3: Key frame SpecificationKey frame is a detailed drawing of the scenes at a certain time.15Mahith
- 29. Animation SequencesStep 4: Generation of in-between frames.Frames between the key frames.
- 30. Determined by the media to be used to display. 16Mahith
- 31. 1’12’2Key frame kKey frame k+1In-between frame17Mahith
- 32. Raster AnimationRaster animation is the most basic type of computer animation.
- 33. It involves creating an image, and then using a computer to put that image in motion
- 34. Raster based animation frames are made up of individual pixels. These pixels each contain information about the colour and brightness of that particular spot on the image18Mahith
- 35. Ship is redrawn in background colorStep 2 (move)Step 1 (erase)Step 3 (draw)(x,y)(x+Dx, , y+Dy)(x’,y’)(x,y)x’ = x + Dxy’ = y + DyMove shipExample:19Mahith
- 36. 20Mahith
- 37. Color-tabletransformationSimple 2D animations can be easily implemented using colour lookup table.
- 38. Here we set the successive blocks of pixel value to colour table. Object as “on” rest as background color.
- 39. Later successively positions along the path is changed to “on” and older position to background color.21Mahith
- 40. Computer Animation languagesKey frame Systems:Designed simply to generate the in-betweens from the user specified key frames
- 41. Each object is formed with set of rigid bodies connected by several joints with limited degree of freedom.22Mahith
- 42. Computer Animation languagesParameterized system :Object-motion characteristics are specified as a part of the object definition likeDegree of freedom
- 44. Allowable shape changes …. 23Mahith
- 45. Computer Animation languagesScripting System:Object specifications & animation sequences are defined with a user-input script24Mahith
- 46. Morphing Transformation of object shape from one form to another is called Morphing ( Metamorphosis) 25Mahith
- 47. Key frameKey frameIn-between frameThree frames form a morph from George W. Bush to Arnold Schwarzenegger showing the mid-point between the two extremes26Mahith
- 48. 1’14’4added point2’2Key frame kKey frame k+1Halfway frameLinear interpolation for transforming triangle into a quadrilateral33’27Mahith
- 49. General preprocessing rules for Equalizing key frames Using edge count:Let Lk & L k+1 no of line segment in 2 consecutive key frame.Then Lmax =max(Lk ,Lk+1 ) , Lmin =min(Lk , Lk+1 )And Ne = Lmax mod Lmin Ns = int(Lmax / Lmin )Then the preprocessing is accomplished byDividing Ne edges of keyframemin into Ns +1 sectionsDividing the remaining lines of keyframemin into Ns sections.28Mahith
- 50. Key frame k+11’Key frame k14’2’2General preprocessing rules for Equalizing key frames Example for by using edge count:33’L k =3L k+1 =4L max =4 , L min =3, N e = 1 , Ns =1Divide 1 (N e ) edges of keyframe k (keyframe min ) to 2 (N s+1 ) section Since Ns =1 leave the remaining sections.29Mahith
- 51. General preprocessing rules for Equalizing key frames Using vertex count:Let Vk& Vk+1 no of vertex in 2 consecutive key frame.Then Vmax =max(Vk,Vk+1 ) , Vmin =min(Vk, Vk+1 )And Nis = (Vmax -1) mod( Vmin -1) Np = int((Vmax-1) / (Vmin -1)Then the preprocessing is accomplished byadding Np points to Nis line section of key framemin.Adding Np -1 points to the remaining edges of key framemin30Mahith
- 52. Key frame k+11’Key frame k14’2’2General preprocessing rules for Equalizing key frames Example for by using vertex count:33’V k =3V k+1 =4V max =4 , V min =3, N is = 1 , Np =1Add 1 (N p ) point to 1 (N is ) line of keyframe k (keyframe min ) Since Np -1 =0 leave the remaining edges31Mahith
- 53. Simulating AccelerationsIt perform non linear spline interpolation Here the speed is not constant
- 54. Non linear path is taken at the in-between frames.
- 55. To stimulate acceleration we adjust the time spacing for the in-betweens32Mahith
- 56. For constant speed we use equal interval of time spacing.Let consider key frames at times t1 and t2 and having n in-between frames between these. thendt= (t2 – t1)/ n+1And time for any in-between as:tBj = t1 +j* dtFor accelerating we can use functions like 1-cosq, 0<q<p/2Then time for any in-between is:tBj = t1 +dt ( 1-cos(jp/2(n+1) )33Mahith
- 57. Motion SpecificationsDirect Motion Specification: Explicitly give the rotation angles and translation vector.
- 58. Then transformation matrices are applied to transform coordinate positions .
- 59. Or we can use approximate equation to specify some motion.34Mahith
- 60. Path of a bouncing ball35Mahith
- 61. y(x) = A sin(wx+ q0 ) e-kxwhere A =initial amplitudew = angular frequency q0 = phase angle k= damping constantThis show the path of a bouncing ball acquired from damped sine function36Mahith
- 62. Goal-Directed SystemsReferred as goal directed because they determine the specific motion parameters given as the goals of the animation.
- 63. At the opposite extremes we specify the motions in general terms which describes the action.
- 64. Later input directives will interpret in terms of component motion.37Mahith
- 65. Kinematics SpecificationDetermines parameters needed for a jointed, flexible object to achieve a pose.
- 66. Also factors in maintaining balance, joint angle limitations, and collisions between the body and limbs.
- 67. And all this will be mentioned in kinematic description of the respective points.
- 68. It’s alternate approach is inverse kinematics.38Mahith
- 69. Inverse KinematicsHere we will mention the parameters at the initial & final positions of object only.
- 70. Rest motion parameters are computed by the system.Disadvantage: There is no general analytical solution.Must be solved through non-linear programming techniques.39Mahith
- 71. Dynamic SpecificationHere force acting on the body will also mention with the motion parameters.
- 72. Referred as Physically based system.
- 73. Motion is obtained from the force equations like Newton’s Law etc.
- 74. It give realistic effects in motion.
- 75. So it is used in case of complex rigid body system and some non rigid bodies like cloth etc40Mahith
- 76. Motion CaptureA person wears sensors near each joint
- 77. Computer software records positions, angles, velocities, accelerations, and impulses for all sensors
- 78. Typically captures sub-millimeter positions41Mahith
- 79. Advantages:
- 80. Faster than manually creating animations
- 81. Can have much more natural looking motions and catch all movements of the object.
- 82. Disadvantages:
- 83. Can’t do anatomically impossible motions
- 84. Motion is restricted to the laws of physics.
- 85. Sensors attached to the skin can shift out of position during human movement causing real performance to differ from data recorded.42Mahith
- 86. Applications of computer animationSpecial Effects (Movies, TV)
- 87. Video Games
- 88. Virtual Reality
- 90. Medical
- 91. Robotics
- 92. Visualization