Design Realization lecture 5 John Canny 9/9/03

Preamble  Reactions to Maya?  Please return the CDs soon (new material needs to be installed on them).  Blog for Maya help is under construction.

Last Time  Alignment – join elements without merging.  Scene graph and hierarchy.  Constraints: using expressions.  Shape control – blendshapes (finish today).

Next Time  We’ll have an in class “critique” of your designs-in-progress.  Please make a first pass at a chair model in Maya by Thursday.  Bring a laptop with your model or send it to a partner who has a laptop, so you can show your model in class.

Shape control  Maya has a tool for controlling parametric shape called Blendshapes.  (Animation) Deform → Blend Shapes  Trick: by default Blendshapes ignores the transform hierarchy.  it only responds to control point deformation.  Changing that default makes it behave obviously.

Materials and texture  Maya includes rich material models (aka shaders) for common materials.  Some will be on the next CD update.  A material includes attributes like  Type: Phong, Blinn – models of reflection (shine).  Color: obvious – usually a texture.  Transparency: can be fixed or a texture.  Bump map: adjustment of surface normals.  Displacement map: adjustment of surface depth.

Texture coordinates  A texture can be any 2D image.  Can be grabbed from clipart, from photographs or scanners, or can be a synthetic image.  2D images have X, Y coordinates. NURB surfaces have U, V coordinates which are used to “map” the texture.  Isoparm curves on surfaces show the U, V directions.  Checkerboard or brick textures are a good way to learn mapping techniques.

From shape to movement…  Motion is one of the most expressive forms available to a designer.  Animation literally means “to give life”.

Qualities of movement  List some…

Qualities of movement  Hint: What are “good” movements?

Keyframing  Keyframing is the traditional digital method for animation.  The scene is posed at all significant transitions and sample poses. Then the animation code interpolates between them.  Motion curves (trajectories) can be edited much like NURB curves.

Movement composition  In character animation, movements are not atomic. They break down as:  Anticipation  Action  Reaction  Example: Jumping block.

Morphing and moving  A general shape deformer like Blendshapes can be used to pose a complex model.  Its relatively easy to use Blendshapes plus keyframing to animate a face.  Create a new copy of the face and set it to each facial expression, then blend with Blendshape to create an expression control.

Todo  Work on your chair designs for Thursday.  Find a partner if needed for in-class demo.  Please return the CDs soon.