A geometry modeling system for ray tracing or particle transport Monte Carlo simulation

The principles of a geometry modeling system for ray tracing or Monte Carlo particle transport simulation are presented. The model uses the boundary representation of volumes and was developed using object oriented programming. The surface is adopted as the basic element in the model. Complex structures are described using the derived concept of compound surfaces. Particle tracking exceptions caused by floating point rounding errors are discussed and robust algorithms that use geometrical reasoning to address these problems are presented.