Computing visibility from folded surfaces

摘要

This paper presents an algorithm to estimate what parts of the surrounding environment are visible from each of many sample points on a surface, which may be highly folded and may contain holes. The results can be used to estimate how much of an extended light source is visible from each sample point and, thus, the shading of the surface. Examples are presented of shaded cloth. Unlike shading methods that use a local illumination model, the new method accurately estimates the darkness of deep folds in the cloth.