University of Illinois at Urbana-Champaign Department of Computer Science Thomas M. Siebel Center for Computer Science 201 North Goodwin Avenue Urbana, Illinois 61801-2302 USA COMPUTER SCIENCE COLLOQUIUM Recent Progress in Visual Surface Deformation Yizhou Yu Computer Science Department University of Illinois, Urbana-Champaign http://www-faculty.cs.uiuc.edu/~yyz/ October 20 (Monday), 2008 at 4:00 p.m. 1404 Siebel Center for Computer Science Abstract: I will review our recent progress in two types of visual surface deformation. Detailpreserving deformation based on differential coordinates exploits the Laplacian in graphical mesh editing. A brief introduction is given to mesh deformation based on the Poisson equation. The distinctive feature of this approach is that it modifies the original mesh geometry implicitly through gradient field manipulation. It can produce desired results for both global and local editing operations. To reduce computational cost, we have developed a multigrid algorithm specifically tailored for geometry processing. We have also generalized Laplacian-based editing to deforming mesh sequences and designed efficient user interaction techniques. The second type of surface deformation can be generated in a data-driven way using a set of examples. Such results are desired when the deformation needs to observe a predefined style. Solutions to this task can find many applications in data-driven skin animation, computer puppetry, and computer games. I present an intuitive and powerful animation interface to simultaneously control the deformation of a large number of local regions on a deformable surface with a minimal number of control points. Our method learns suitable deformation subspaces from training examples, and generate new deformations on the fly according to the movements of the control points. Our run-time algorithm can be implemented on GPUs and can achieve a few hundred frames per second even for large datasets with hundreds of training examples. Bio: Yizhou Yu is currently an associate professor in the Department of Computer Science at the University of Illinois at Urbana-Champaign. He received his PhD degree in Computer Science from University of California at Berkeley in 2000. He is a recipient of the best paper award in ACM Symposium on Computer Animation, NSF CAREER Award and Microsoft Fellowship. His current interests include data-driven computer animation, texture analysis and synthesis, visual analytics, and image processing.