Thursday, November 4

Using Surface Mathematics for Character Animation

8:30 AM-9:15 AM
Room: Rio Grande Ballroom
Chair: Tony DeRose, Pixar Animation Studios

Creating characters for animation has always presented some fun and challenging problems for the mathematics of surfaces. Early on we realized that four sided patches were not a natural choice for organic surfaces, but we also found that triangular patches generated visible artifacts. In general, modelers today have to be aware of the underlying mathematical representation, i.e. they know that they are using NURBS. We are so used to this that it almost seems natural. However, an object such as a face is not a NURBS surface and the requirement that the modeler see the control points is an unnatural intrusion into the process. By contrast, artists who model in clay do not think about surface patches - and they are much faster at creating organic shapes than people who use computer tools.

We have reached the stage where the representation of a static surface is not the big problem. Rather we have fascinating problems of the articulation of surfaces that change over time and simulations that need to be directable and predictable. Indeed, we have a whole host of interesting and difficult problems.

Edwin E. Catmull
Pixar Animation Studios


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Created TJF, 5/5/99; Last Updated MMD 6/15/99