When motion capture is used on line, it is possible to create applications based on a full 3-D interaction metaphor in which the specifications of deformations or motion are given in real-time. This new concept drastically changes the way of designing animation sequences. Thalmann [1993] calls all techniques based on this new way of specifying animation VR-based animation techniques. He also calls VR devices all interactive devices allowing to communicate with virtual worlds. They include classic devices like head-mounted display systems, DataGloves as well as all 3D mice or SpaceBalls. He also considers.
