Motion modeling for on-line motion synthesis

Abstract

In this thesis, we propose an example-based framework for on-line motion synthesis. Our framework consists of three parts: motion modeling, behavior modeling and motion synthesis. In the motion modeling part, an unlabeled motion sequence is first decomposed into motion segments, exploiting the contact forces against the ground. Those motion segments are subsequently classified into groups of motion segments such that the same group of motion segments share an identical structure. Finally, we construct a motion transition graph by representing these groups and their connectivity to other groups as nodes and edges, respectively. In behavior modeling, we build a motion transition model that connects motion segments according to on-line motion specifications, while adapting to the (time-varying) environment. In motion synthesis, given a stream of motion specifications in an on-line manner, our system generates a corresponding motion while traversing the motion transition graph guided by the motion transition model. Based on the framework, we first address the issues in motion dynamics and transition that arise from the cyclic nature of locomotions. We then generalize the idea to two-character motions, in particular, motions for martial arts performed by a pair of characters. Although the focus of the present work is on locomotve motions and martial arts motions, we believe that the framework of the proposed approach can be conveyed to other footstep driven motions as well.