Precomputing Sound Scattering for Structured Surfaces

Abstract

Room acoustic simulations commonly use simple models for sound scattering on surfaces in the scene. However, the continuing increase of available parallel computing power makes it possible to apply more sophisticated models. We present a method to precompute the distribution of the reflected sound off a structured surface described by a height map and normal map using the Kirchhoff approximation. Our precomputation and interpolation scheme, based on representing the reflected pressure with von-Mises-Fisher functions, is able to retain many directional and spectral features of the reflected pressure while keeping the computational and storage requirements low. We discuss our model and demonstrate applications of our precomputed functions in acoustic ray tracing and a novel interactive method suitable for applications such as architectural walk-throughs and video games.