US Patent 7289124 Facial animation method

A 3D imaged head consisting of a set of meshes is animated by modelled facial muscles. For natural animation of the lips in speech, the lower and upper lips are distinguished in a set of lip mesh based on the nodes of the mesh on a boundary of the lip corner and mouth opening, and lower and upper zones of the head are divided by the boundary. Modelled muscles attached to the upper lip, with intersecting zones of influence in the upper zone, and attached to the lower lip, with intersecting zones of influence in the lower zone, displace nodes of mesh respectively in the upper lip and under the nose and in the lower lip and the chin. Other muscles have zones of influence in the lower and upper zones.