Serban D. Porumbescu, Brian C. Budge, Zhi Feng, and Ken Joy
A shell map is a bijective mapping between shell space and texture space that can be used to generate small-scale features on surfaces using a variety of modeling techniques. The method is based upon the generation of an offset surface and the construction of a tetrahedral mesh that fills the space between the base surface and its offset. By identifying a corresponding tetrahedral mesh in texture space, the shell map can be implemented through a straightforward barycentric-coordinate map between corresponding tetrahedra. The generality of shell maps allows texture space to contain geometric objects, procedural volume textures, scalar fields, or other shell-mapped objects. Once the correspondence is established, a variety of rendering techniques can be used to render surface with shell maps. This method opens up new avenues of research in geomtry textures, generalized displacement maps, and three-dimensional volumetric textures.