Design Realization lecture 4 John Canny 9/4/03

Update  At long last, the Maya Personal Learning CD is in. Good for learning Maya, annoying for displaying models (watermarking).  Two readings:  Chapter on 3D shapes from Hearn and Baker  Chapter on 3D shapes from Wucius Wong  First assignment

Last Time  Basic curve creation/editing.  Basic surface creation/editing.  Two ways to duplicate: copy and instance.  Concepts: Scene graph, transformations, history.

Alignment  A basic operation on curves or surfaces to align endpoints or bounding curves.  Edit Curves → Align Curves (in modeling mode)  Edit NURBS → Align Surfaces (“”)  Use this to “join” curve segments or surfaces so that they stay joined.  Be careful to control which NURB moves, and how. Use the options in the align menu.

Scene graph and hierarchy  The scene graph consists of shape nodes and transform nodes.  Objects can be grouped and arranged in a hierarchy – use hypergraph to edit  Window → Hypergraph  middle mouse button drags to connect.  Changes propagate down the chain, but not up – and transforms are relative.  Very important for character animation.

Constraints  Constraints are relations between objects in the scene, in terms of their attributes.  Alignment creates such constraints. Or they can be added directly with the expression editor.  Window → Animation Editors → Expression Editor

Shape control  For design exploration, we want to quickly control shape (and sometimes appearance) parameters to create a gallery of models.  Maya has a tool for this called Blendshapes. Its based on keyframe animation but works well for design variation.  (Animation) Deform → Blend Shapes

Todo  Please submit critical summaries of todays readings by next Tuesday.  Install and experiment with Maya following the assignment.  Please return the CDs soon.  Blog for Maya help?