Acknowledgments: The authors would like to thank Wei Xu, Brian Dawson, Dwayne Mason, and James Scarafone of Sony Computer Entertainment America for their support and generous help collecting motion capture data for this paper, as well as Nick Van der Horst as a motion capture talent. We would also like to acknowledge the very helpful discussion and remarks of Nancy Pollard, Christian Shelton, and the SIGGRAPH reviewers that made this paper stronger and more comprehensible.