Large Steps in Cloth Simulation

David Baraff

Pixar Animation Studios


Animating cloth for 3D computer graphics has been a vexing problem for many years. Giving an animator direct control of the cloth is difficult, because the excessively large number of degrees of freedom inherent in even a single piece of clothing make traditional hand-animation techniques impractical. An obvious alternative is to animate clothing through physical simulation. However, the running time of cloth simulation algorithms has been too slow to make such an approach practical. In this talk, I will describe our methods for simulating cloth that for the first time allow for realistic cloth motion with reasonable runtime performance. The talk will outline the basic mathematics behind cloth simulation and summarize previous results, discuss the obvious speedups stolen from the numerical algorithms community, and describe the additional enhancements we added to make it all work. Video examples made using the cloth simulation system at both an amateurish level (translation: my internal research animations) and at professional level (translation: actual production work by real animators using a commercial version of the system) will be shown with the talk.

David Baraff joined Pixar Animation Studios in 1998. Prior to his arrival at Pixar, he was an Associate Professor of Robotics and Computer Science at Carnegie Mellon University. David Baraff received his Ph.D. from Cornell University in 1992, where he was a graduate student in Cornell's Department of Computer Science and the Program of Computer Graphics. Before and during his graduate studies he also worked at Bell Laboratories' Computer Technology Research Laboratory on real-time 3D interactive computer graphics animation and games. After receiving his Ph.D., he joined the faculty of Carnegie Mellon University. In 1995, he was named an Office of Naval Research Young Investigator. His research interests include physical simulation and modeling for computer graphics, robotics, and animation.

His web page is at and he can be contacted at

Edited by Leonidas Guibas