A lightweight algorithm for real-time motion synthesis

This paper presents an algorithm for interactive character animation with kinematic constraints with limited computational time. In order to reduce necessary computation, the animation is not created by procedural algorithm but synthesized by deforming and concatenating short motion examples, each consisting of a sequence of postures. A keyframe placed between two consecutive motion examples is deformed by using inverse kinematics so that it satisfies given constraints. The motion examples between the keyframes are deformed to ensure continuity of postures in position and velocity. We parameterize each posture as a set of particles in an orthogonal coordinate system. The inverse kinematics method with the particle representation realizes fast and stable deformation of keyframe postures, and the deformation of motion examples are calculated on a frame-by-frame basis by decomposing a whole-body deformation into per-particle deformations. We present some examples of character animations synthesized at an interactive rate by this algorithm.