Shading of Solid Voxel Models

Abstract

The purpose of any technique for modelling structures is to store a representation of them, and to produce two dimensional images such that a viewer correctly perceives the three dimensional nature of the structures. There are many methods for including three-dimensional visual cues in a two-dimensional image, but probably the most important one is that of shading. The intensity of light at any point on the model depends mainly on the orientation of the surface at that point with respect to the direction of the light source. In solid voxel modelling this information has to be extracted from the model. The discretisation inherent to modelling techniques has to be allowed for if successful shading is to be achieved. This paper considers the problems caused by the discretisation in solid modelling and offers compression and interpolation techniques to reduce them.