Techniques for reducing Boolean evaluation time in CSG scan-line algorithms

Abstract Atherton's scan-line hidden surface algorithm for Boolean combinations of plane-faced primitives is intended for fast image generation of complex models. An important step in the algorithm is the Boolean evaluation at the required positions on each scan-line. This step, however, can be very time consuming if performed in a straightforward way. Some techniques are presented here that considerably reduce the time needed for the Boolean evaluation. These include a fast bottom-up evaluation technique and partial backface elimination.