US Patent 7348977 Subsurface scattering approximation methods and apparatus

A method for determining illumination of surface points of an object in a scene from lighting sources includes determining a first thickness map for a first lighting source for the scene, wherein the first thickness map includes a first plurality of thickness values of the object with respect to distance from the first lighting source, determining a surface point on the object, determining a first plurality of thickness values associated with the surface point on the object in response to the first thickness map, determining a first filtered thickness value associated with the surface point on the object in response to the first plurality of thickness values, and determining an illumination contribution from the first lighting source at the surface point in response to the first filtered thickness value.