Unbiased Caustic Forecasting

[Zom-B]

Caustic Forecasting: Unbiased Estimation of Caustic Lighting for Global Illumination

We present an unbiased method for generating caustic lighting using importance sampled Path Tracing with Caustic Forecasting. Our technique is part of a straightforward rendering scheme which extends the Illumination by Weak Singularities method to allow for fully unbiased global illumination with rapid convergence. A photon shooting preprocess, similar to that used in Photon Mapping, generates photons that interact with specular geometry. These photons are then clustered, effectively dividing the scene into regions which will contribute similar amounts of caustic lighting to the image. Finally, the photons are stored into spatial data structures associated with each cluster, and the clusters themselves are organized into a spatial data structure for fast searching. During rendering we use clusters to decide the caustic energy importance of a region, and use the local photons to aid in importance sampling, effectively reducing the number of samples required to capture caustic lighting.

http://graphics.idav.ucdavis.edu/~bcbud ... ustics.pdf

[CTZn]

We discussed sampling importance based techniques in another forum a few months ago, first practical feedback was rather positive... hey I was just an observer, even if your truely started the talk on this

Btw photons are a quick way to estimate importance, but I'm sure one can imagine other agents. I guess a pre-pass must happen anyway to build the importance sampling, unless the estimation is con-evolutive with light paths(not sure about unbiasedness in that case, might be difficult to find a balance then).

Scrap that. Importance sampling rocks, now reading that paper is another story for me

[oodmb]

wooo! I love it.

perfect timing too. Just after i refactored the core of my renderer.