Broad Area Colloquium For AI-Geometry-Graphics-Robotics-Vision

Physical simulation in "Monsters, Inc." + Untangling Cloth

Michael Kass
Monday, April 21, 2003, 4:15PM
TCSeq 200


"Monsters Inc." marks Pixar's first extensive use of physical simulation in a feature film. Pixar animators directly controlled the movements of the characters' bodies and faces, but much of their hair and clothing movement was computed using simulations of Newtonian physics. In this talk, some of the details of the simulations will be described, as well as their impact on the production process. Physical simulation allowed a degree of realism of motion that would not have been possible with traditional methods. Nonetheless, adding this type of simulation into the Pixar production pipeline sometimes caused surprising and amusing results -- both successes and bloopers will be shown. One of the key developments that allowed clothing simulation to go smoothly during the production was a set of algorithms for untangling simulated clothing when it was excessively tortured by the animators. The algorithms allowed the simulator to handle a range of non-physical situations like character interpenetrations without producing unpleasant visual artifacts. An overview of these algorithms will be presented to preview the paper "Untangling Cloth" by Baraff, Witkin and Kass which will appear in Siggraph '03.

About the Speaker

Michael Kass is a Senior Scientist at Pixar Animation Studios where he worked with David Baraff and Andrew Witkin to develop the physically-based clothing and hair animation software that was used in "Monsters Inc." He received his B.A. from Princeton in 1982, his M.S. from M.I.T. in 1984, and his Ph. D. from Stanford in 1988. Dr. Kass has received numerous awards for his research on physically-based methods in computer graphics and computer vision including several conference best paper awards, the Prix Ars Electronica for the image "Reaction Diffusion Texture Buttons," and the Imagina Grand Prix for the animation "Splash Dance." Before joining Pixar in 1995, Dr. Kass held research positions at Schlumberger Palo Alto Research and Apple Computer.

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