His primary area of interest is Computer Animation, with an emphasis on generating realistic motion using physically based simulation and motion capture techniques. He has authored numerous papers on these topics. In addition to his research pursuits, Prof. O'Brien has worked with several game companies on integrating advanced simulation physics into game engines, and his methods for destruction modeling were recently used in the film Avatar. He received his doctorate from the Georgia Institute of Technology in 2000, the same year he joined the Faculty at U.C. Berkeley. Professor O'Brien is a Sloan Fellow and ACM Distinguished Scientist, Technology Review selected him as one of their TR-100 for 2004, and he was recently awarded research grants from the Okawa and Hellman Foundations. He is currently serving as ACM SIGGRAPH Director at Large.