Summary: Tracking and modeling people from video sequences has become an increasingly important research topic, with applications including animation, surveillance, and sports medicine. In this paper, we propose a model-based 3-D approach to recovering both body shape and motion. It takes advantage of a sophisticated animation model to achieve both robustness and realism. Stereo sequences of people in motion serve as input to our system. From these, we extract a 2\(\frac 12\)-D description of the scene and, optionally, silhouette edges. We propose an integrated framework to fit the model and to track the person's motion. The environment does not have to be engineered. We recover not only the motion but also a full animation model closely resembling the subject. We present results of our system on real sequences and we show the generic model adjusting to the person and following various kinds of motion.