Courses

Data-driven animation using motion-capture data has become a standard practice in character animation. A number of techniques have been developed to add flexibility on captured human motion data by editing joint trajectories, warping motion paths, blending a family of parameterized motions, splicing motion segments, and adapting motion to new characters and environments.

Even with the abundance of motion-capture data and the popularity of data-driven animation techniques, programming with motion capture-data is still not easy. A single clip of motion data encompasses a lot of heterogeneous information including joint angles, the position and orientation of the skeletal root, their temporal trajectories, and a number of coordinate systems. Due to this complexity, even simple operations on motion data, such as linear interpolation, are rarely described as succinct mathematical equations in research papers.

This course provides not only a solid mathematical background, but also a practical guide to programming with motion-capture data. It begins with a brief review of affine geometry and coordinate-invariant (conventionally called coordinate-free) geometric programming, which generalizes incrementally to deal with three-dimensional rotations/orientations, the poses of an articulated figure, and full-body motion data. Then it identifies a collection of coordinate-invariant operations on full-body motion data and their object-oriented implementation. Finally, it explains the practical use of this programming framework in a variety of contexts ranging from data-driven manipulation and interpolation to state-of-the-art biped locomotion control.