VISUAL REALITY [Chapter 3 - transforming shapes]
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The document discusses how VRML files use coordinate systems and transformations to position 3D objects in a virtual world. It explains that a Transform node creates a new local coordinate system that can be translated, rotated, and scaled relative to the parent coordinate system. Any shapes built within this new local system will be positioned, oriented, and scaled along with the transformations applied to that coordinate system. The order that translation, rotation, and scaling are applied is important, with the transformations always occurring from bottom to top.
![The Transform group node creates a group with its own coordinate system translation - position rotation - orientation scale - size children - shapes to build Transform { translation . . . rotation . . . scale . . . children [ . . . ] } Prepared By : NURAINI MOHD GHANI](https://image.slidesharecdn.com/chapter3transformingshapes-120116191643-phpapp02/85/VISUAL-REALITY-Chapter-3-transforming-shapes-5-320.jpg)
![The children field includes a list of one or more nodes Transform { . . . children [ Shape { . . . } Shape { . . . } Transform { . . . } . . . ] } Prepared By : NURAINI MOHD GHANI](https://image.slidesharecdn.com/chapter3transformingshapes-120116191643-phpapp02/85/VISUAL-REALITY-Chapter-3-transforming-shapes-6-320.jpg)
![Translation positions a coordinate system in X, Y, and Z Transform { # X Y Z translation 2.0 0.0 0.0 children [ . . . ] } Prepared By : NURAINI MOHD GHANI](https://image.slidesharecdn.com/chapter3transformingshapes-120116191643-phpapp02/85/VISUAL-REALITY-Chapter-3-transforming-shapes-7-320.jpg)
![Rotation orients a coordinate system about a rotation axis by a rotation angle Angles are measured in radians radians = degrees / 180.0 * 3.141 Transform { # X Y Z Angle rotation 0.0 0.0 1.0 0.52 children [ . . . ] } Prepared By : NURAINI MOHD GHANI](https://image.slidesharecdn.com/chapter3transformingshapes-120116191643-phpapp02/85/VISUAL-REALITY-Chapter-3-transforming-shapes-10-320.jpg)
![Scale grows or shrinks a coordinate system by a scaling factor in X, Y, and Z Transform { # X Y Z scale 0.5 0.5 0.5 children [ . . . ] } Prepared By : NURAINI MOHD GHANI](https://image.slidesharecdn.com/chapter3transformingshapes-120116191643-phpapp02/85/VISUAL-REALITY-Chapter-3-transforming-shapes-17-320.jpg)
![Scale , Rotate , and Translate a coordinate system, one after the other Transform { translation 2.0 0.0 0.0 rotation 0.0 0.0 1.0 0.52 scale 0.5 0.5 0.5 children [ . . . ] } Read operations bottom-up : The children are scaled, rotated, then translated Order is fixed, independent of field order Prepared By : NURAINI MOHD GHANI](https://image.slidesharecdn.com/chapter3transformingshapes-120116191643-phpapp02/85/VISUAL-REALITY-Chapter-3-transforming-shapes-20-320.jpg)
![Transform { translation -2.0 -1.0 0.0 children [ Shape { appearance Appearance { material Material { } } geometry Cylinder { radius 0.3 height 6.0 top FALSE } } ] } . . . Prepared By : NURAINI MOHD GHANI](https://image.slidesharecdn.com/chapter3transformingshapes-120116191643-phpapp02/85/VISUAL-REALITY-Chapter-3-transforming-shapes-22-320.jpg)
VISUAL REALITY [Chapter 3 - transforming shapes]
- 1. Prepared By : NURAINI MOHD GHANI
- 2. Using coordinate systems A VRML file builds components for a world A file's world components are built in the file's world coordinate system By default, all shapes are built at the origin of the world coordinate system Prepared By : NURAINI MOHD GHANI
- 3. Prepared By : NURAINI MOHD GHANI XYZ axes and a simple shape XYZ axes and a complex shape
- 4. A transform creates a coordinate system that is Positioned Rotated Scaled relative to a parent coordinate system Shapes built in the new coordinate system are positioned, rotated, and scaled along with it Prepared By : NURAINI MOHD GHANI
- 5. The Transform group node creates a group with its own coordinate system translation - position rotation - orientation scale - size children - shapes to build Transform { translation . . . rotation . . . scale . . . children [ . . . ] } Prepared By : NURAINI MOHD GHANI
- 6. The children field includes a list of one or more nodes Transform { . . . children [ Shape { . . . } Shape { . . . } Transform { . . . } . . . ] } Prepared By : NURAINI MOHD GHANI
- 7. Translation positions a coordinate system in X, Y, and Z Transform { # X Y Z translation 2.0 0.0 0.0 children [ . . . ] } Prepared By : NURAINI MOHD GHANI
- 8. Prepared By : NURAINI MOHD GHANI World coordinate system New coordinate system, translated 2.0 units in X
- 9. Prepared By : NURAINI MOHD GHANI Shape built in new coordinate system
- 10. Rotation orients a coordinate system about a rotation axis by a rotation angle Angles are measured in radians radians = degrees / 180.0 * 3.141 Transform { # X Y Z Angle rotation 0.0 0.0 1.0 0.52 children [ . . . ] } Prepared By : NURAINI MOHD GHANI
- 11. A rotation axis defines a pole to rotate around Like the Earth's North-South pole Typical rotations are about the X, Y, or Z axes: Prepared By : NURAINI MOHD GHANI
- 12. Prepared By : NURAINI MOHD GHANI World coordinate system New coordinate system, rotated 30.0 degrees around Z
- 13. Prepared By : NURAINI MOHD GHANI Shape built in new coordinate system
- 14. Positive rotations are counter-clockwise To help remember positive and negative rotation directions: Open your hand Stick out your thumb Aim your thumb in an axis positive direction Curl your fingers around the axis The curl direction is a positive rotation Prepared By : NURAINI MOHD GHANI
- 15. Prepared By : NURAINI MOHD GHANI X-axis rotation Y-axis rotation
- 16. Prepared By : NURAINI MOHD GHANI Z-axis rotation
- 17. Scale grows or shrinks a coordinate system by a scaling factor in X, Y, and Z Transform { # X Y Z scale 0.5 0.5 0.5 children [ . . . ] } Prepared By : NURAINI MOHD GHANI
- 18. Prepared By : NURAINI MOHD GHANI World coordinate system New coordinate system, scaled by half
- 19. Prepared By : NURAINI MOHD GHANI Shape built in new coordinate system
- 20. Scale , Rotate , and Translate a coordinate system, one after the other Transform { translation 2.0 0.0 0.0 rotation 0.0 0.0 1.0 0.52 scale 0.5 0.5 0.5 children [ . . . ] } Read operations bottom-up : The children are scaled, rotated, then translated Order is fixed, independent of field order Prepared By : NURAINI MOHD GHANI
- 21. Prepared By : NURAINI MOHD GHANI World coordinate system New coordinate system, scaled by half, rotated 30.0 degrees around Z, and translated 2.0 units in X
- 22. Transform { translation -2.0 -1.0 0.0 children [ Shape { appearance Appearance { material Material { } } geometry Cylinder { radius 0.3 height 6.0 top FALSE } } ] } . . . Prepared By : NURAINI MOHD GHANI
- 23. All shapes are built in a coordinate system The Transform node creates a new coordinate system relative to its parent Transform node fields do translation rotation scale Prepared By : NURAINI MOHD GHANI