A Facial Expression Parameterization by Elastic Surface Model
Figure 8
The blue vertex is the fixed bony attachment point, and the red vertex is the skin attachment point. The green vertex is a facial control point within the zone of influence. When the muscle contract, the red point is moved along the muscle endpoints. Rs: radial distant at the muscle's registration, Rf: radial fall off distance, : angular fall off, : angle of the control point from the muscle.
