Patent ID: 8217955

Claim:
A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to produce effects for a computer-generated character based on surface stress, by performing the steps of receiving a representation of a surface defined by a plurality of faces; mapping a wrinkle texture to the surface in a current pose, wherein the wrinkle texture specifies high intensity regions where bulging occurs during compression of the surface and low intensity regions where crevasses are formed during compression of the surface; and for each pixel of each face defining the surface in the current pose: estimating surface stress indicating compression or stretching at the pixel by comparing a first surface vector corresponding to the surface in a rest pose to a second surface vector corresponding to the surface in the current pose, and perturbing a normal vector of the surface in the current pose at the pixel by subtracting from the normal vector a product of a gradient vector corresponding to the pixel and an output of a user-defined function, wherein the user-defined function is product of a user-specified factor and the estimate of surface stress at the pixel.