Precomputed Multiple Scattering for Rapid Light Simulation in Participating Media

• Published in: IEEE transactions on visualization and computer graphics Vol. 26; no. 7; pp. 2456 - 2470
• Main Authors: Wang, Beibei, Ge, Liangsheng, Holzschuch, Nicolas
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.07.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: Algorithms; Computational modeling; Computer Science; Computer simulation; Convergence; Graphics; Illumination; Light sources; Lighting; Mapping; Media; Multiple scatter; multiple scattering; Participating media; Photon beams; Photonics; precomputation; Rendering (computer graphics); Scattering; Participating Media; Precomputation; Multiple Scattering
• ISSN: 1077-2626; 1941-0506; 2160-9306; 1941-0506
• DOI: 10.1109/TVCG.2018.2890466

Rendering translucent materials is costly: light transport algorithms need to simulate a large number of scattering events inside the material before reaching convergence. The cost is especially high for materials with a large albedo or a small mean-free-path, where higher-order scattering effects dominate. We present a new method for fast computation of global illumination with participating media. Our method uses precomputed multiple scattering effects, stored in two compact tables. These precomputed multiple scattering tables are easy to integrate with any illumination simulation algorithm. We give examples for virtual ray lights (VRL), photon mapping with beams and paths (UPBP), Metropolis Light Transport with Manifold Exploration (MEMLT). The original algorithms are in charge of low-order scattering, combined with multiple scattering computed using our table. Our results show significant improvements in convergence speed and memory costs, with negligible impact on accuracy.