A Full Wave-based BRDF Generator

Mandy Xia (Computer Science, Cornell University)

Bidirectional Reflectance Distribution Function (BRDF) describes the relationship between reflected intensity in a given direction to the incident energy from another direction. BRDF plays an important role in light modeling in computer graphics. Researchers have been developing different BRDF models to achieve more physically realistic rendering results, but very little work has considered the full wave model of light reflection. In this talk, we describe our ongoing work on generating BRDF by numerically solving Maxwell’s Equations, which can more accurately determine the reflectance distribution and capture effects like diffraction. We apply Boundary Element Method (BEM), or called Method of Moments (MoM) to solve the integral form of Maxwell’s Equations. To accelerate to the solver, we use Fast Multipole Method (FMM). Wave optics and ray optics calculation produce noticeable difference on regular scatter tests. We plan to run experiments on some real life materials, such as silk and hair fibres, and compare wave optics simulation and ray optics simulation.