“Irradiance rigs” by Yuan, Nowrouzezahrai and Sloan

  • ©Hong Yuan, Derek Nowrouzezahrai, and Peter-Pike Sloan




    Irradiance rigs



    When precomputed lighting is generated for static scene elements, the incident illumination on dynamic objects must be computed in a manner that is efficient and that faithfully captures the near- and far-field variation of the environment’s illumination. Depending on the relative size of dynamic objects, as well as the number of lights in the scene, previous approaches fail to adequately sample the incident lighting and/or fail to scale. We present a principled, error-driven approach for dynamically transitioning between near- and far-field lighting. A more accurate model for sampling near-field lighting for disk sources is introduced, as well as far-field sampling and interpolation schemes tailored to each dynamic object. Lastly, we apply a flexible reflectance model to the computed illumination.


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    2. Sloan, P.-P. 2008. Stupid Spherical Harmonics (SH) Tricks. In GDC ’08.
    3. Smedberg, N., and Wright, D. 2009. Rendering Techniques in Gears of War 2. In GDC ’09.
    4. Wallace, J. R., Elmquist, K. A., and Haines, E. A. 1989. A Ray Tracing Algorithm for Progressive Radiosity. In Proceedings of SIGGRAPH ’89.

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