AN APPLICATION OF THE MONTE CARLO RAY-TRACE METHOD WITH BIDIRECTIONAL REFLECTION
Surface bidirectionality must be considered when high accuracy is required of a radiative exchange model. Presented is an adaptation of the Monte Carlo ray-trace (MCRT) method for treating bidirectional reflections. Each incident ray is split into a family of reflected rays whose power and direction are determined based on a new four-component model for the bidirectional reflectance distribution function (BRDF) of Z302, an optical coating widely used in aerospace applications. The model is based on BRDF data available in the literature. We validate the model by using it to simulate the performance of a device for measuring the BRDF of a Z302 sample. We find that the difference between the original BRDF, upon which the bidirectional reflectivity model is based, and the BRDF recovered from the simulation depends on the physical resolution of the detector geometry and the number of rays traced.