“Gaussian quadrature for photon beams in Tangled” by Johnson, Lacewell, Selle and Jarosz

  • ©Jared M. Johnson, Dylan Lacewell, Andrew Selle, and Wojciech Jarosz




    Gaussian quadrature for photon beams in Tangled



    We implemented the recent Photon Beams [Jarosz et al. 2011] algorithm in Photorealistic RenderMan to efficiently render artistically-directed volumetric lighting effects for the feature-length animated movie Tangled [Nowrouzezahrai et al. 2011]. Photon beams generalize volumetric photon mapping by storing the entire path of a photon instead of just the scattering location. Conceptually, each photon beam represents a truncated conical beam of light through the medium. Jarosz et. al formulated several ways to compute a radiance estimate from photon beams, promoting the so-called Beam x Beam 1D estimate which interprets each beam as a flat axial billboard.


    1. Jarosz, W., Nowrouzezahrai, D., Sadeghi, I., and Jensen, H. W. 2011. A comprehensive theory of volumetric radiance estimation using photon points and beams. ACM Transactions on Graphics 30 (January), 5:1–5:19.
    2. Nowrouzezahrai, D., Johnson, J., Selle, A., Lacewell, D., Kaschalk, M., and Jarosz, W. 2011. A programmable system for artistic volumetric lighting. ACM Transactions on Graphics (Proceedings of SIGGRAPH).
    3. Pegoraro, V., and Parker, S. G. 2009. An Analytical Solution to Single Scattering in Homogeneous Participating Media. Computer Graphics Forum (Proceedings of the 30th Eurographics Conference) 28, 2, 329–335.
    4. Stroud, A. H., and Secrest, D. 1966. Gaussian quadrature formulas. Prentice-Hall series in automatic computation. Prentice-Hall, Englewood Cliffs, NJ.

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