1. A method for use in simulation of a material, comprising the steps of: establishing a polygon mesh for the material with each polygon in the polygon mesh having a first area equal to its area in a resting position; animating the polygon mesh, the animation resulting in each polygon in the polygon mesh having a second area; for each polygon in the polygon mesh, calculating a polygon wrinkle ratio by dividing the second area by the first area; for each vertex in the polygon mesh, calculating a vertex wrinkle ratio as an average of the polygon wrinkle ratios for each polygon attached to the vertex; and using the vertex wrinkle ratios in a process of altering lighting of pixels representing polygons in the polygon mesh.