Efficient finite-edge diffraction using conservative from-region visibility

We present a fast algorithm to accelerate geometric sound propagation in complex 3D scenes. Our approach computes propagation paths from each source to the listener by taking into account specular reflections and higher-order edge diffractions around finite edges in the scene. We use the well known Biot–Tolstoy–Medwin (BTM) diffraction model along with efficient algorithms for region-based visibility to cull away primitives and significantly reduce the number of edge pairs that need to be processed. The performance of region-based visibility computation is improved by using a fast occluder selection algorithm that can combine small, connected triangles to form large occluders and perform conservative computations at object-space precision. We show that our approach is able to reduce the number of visible primitives considered for sound propagation by a factor of 2–4 for second order edge diffraction as compared to prior propagation algorithms. We demonstrate and analyze its performance on multiple benchmarks. To the best of our knowledge, this is the first algorithm that uses object-space visibility algorithms to improve the performance of finite-edge diffraction computation for geometric sound propagation.