Proceedings: GI 2019

A Frequency Analysis and Dual Hierarchy for Efficient Rendering of Subsurface Scattering

David Milaenen (Université de Montréal), Laurent Belcour (Université de Montréal), Jean-Philippe Guertin (Université de Montréal), Toshiya Hachisuka (University of Tokyo), Derek Nowrouzezahrai (McGill University)

Proceedings of Graphics Interface 2019: Kingston, Ontario, 28 - 31 May 2019

DOI 10.20380/GI2019.03

  • BibTex

    author = {Milaenen, David and Belcour, Laurent and Guertin, Jean-Philippe and Hachisuka, Toshiya and Nowrouzezahrai, Derek},
    title = {A Frequency Analysis and Dual Hierarchy for Efficient Rendering of Subsurface Scattering},
    booktitle = {Proceedings of Graphics Interface 2019},
    series = {GI 2019},
    year = {2019},
    issn = {0713-5424},
    isbn = {978-0-9947868-4-5},
    location = {Kingston, Ontario},
    numpages = {7},
    doi = {10.20380/GI2019.03},
    publisher = {Canadian Information Processing Society},
    keywords = {Reflectance modeling, ray tracing, rendering},


BSSRDFs are commonly used to model subsurface light transport in highly scattering media such as skin and marble. Rendering with BSSRDFs requires an additional spatial integration, which can be significantly more expensive than surface-only rendering with BRDFs. We introduce a novel hierarchical rendering method that can mitigate this additional spatial integration cost. Our method has two key components: a novel frequency analysis of subsurface light transport, and a dual hierarchy over shading and illumination samples. Our frequency analysis predicts the spatial and angular variation of outgoing radiance due to a BSSRDF. We use this analysis to drive adaptive spatial BSSRDF integration with sparse image and illumination samples. We propose the use of a dual-tree structure that allows us to simultaneously traverse a tree of shade points (i.e., pixels) and a tree of object-space illumination samples. Our dualtree approach generalizes existing single-tree accelerations. Both our frequency analysis and the dual-tree structure are compatible with most existing BSSRDF models, and we show that our method improves rendering times compared to the state of the art method of Jensen and Buhler.