Irradiance Gradients in the Presence of Participating Media and Occlusions

Wojciech Jarosz Matthias Zwicker Henrik Wann Jensen
UC San Diego


In this paper we present a technique for computing translational gradients of indirect surface reflectance in scenes containing participating media and significant occlusions. These gradients describe how the incident radiance field changes with respect to translation on surfaces. Previous techniques for computing gradients ignore the effects of volume scattering and attenuation and assume that radiance is constant along rays connecting surfaces. We present a novel gradient formulation that correctly captures the influence of participating media. Our formulation accurately accounts for changes of occlusion, including the effect of surfaces occluding scattering media. We show how the proposed gradients can be used within an irradiance caching framework to more accurately handle scenes with participating media, providing significant improvements in interpolation quality.

Computer Graphics Forum (Proceedings of the Eurographics Symposium on Rendering 2008)

irradiance_gradients_participating_media.pdf [4MB]

Last update: Dec. 16, 2008
Henrik Wann Jensen