Practical product sampling for single scattering in media

EGSR 2021


Efficient Monte-Carlo estimation of volumetric single scattering remains challenging due to various sources of variance, including transmittance, phase-function anisotropy, geometric cosine foreshortening, and squared-distance fall-off. We propose several complementary techniques to importance sample each of these terms and their product. First, we introduce an extension to equi-angular sampling to analytically account for the foreshortening at point-normal emitters. We then include transmittance and phase function via Taylor-series expansion and/or warp composition. Scaling to complex mesh emitters is achieved through an adaptive tree-splitting scheme. We show improved performance over state-of-the-art baselines in a diversity of scenarios.

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BibTeX reference

  author = {Keven Villeneuve and Adrien Gruson and Iliyan Georgiev and Derek Nowrouzezahrai},
  title = {Practical product sampling for single scattering in media},
  booktitle = {Proceedings of EGSR},
  year = {2021},
  month = jun,
  publisher = {The Eurographics Association}