Efficient Radiosity Methods for Non-Separable Reflectance Models
Determination of interreflection of non-diffuse environments looks back to a few years. In case of N patches, separable (or, in particular, diffuse) reflectance leads to an equation system of N unknowns; in case of general bidirectional reflectance there are O(N 2) unknowns. This paper will describe two new, efficient methods for this latter extended, sparse matrix problem. Applying decomposition to diffuse + specular, sorted gathering + shooting methods is rather effective in case of small specular cones. The other method, relying on albedo-equivalent separable reflectance, offers a fast approximating radiosity solution, primarity suiting specular reflectances, with flat, undistinctive characteristics, for that any method is too slow. The two methods may be combined, the error term for the iterative solution of the first method defines a problem, offered a rapid approximate solution by the second method.
KeywordsConjugated Gradient Method Separable Model Bidirectional Reflectance Jacobi Iteration Albedo Function
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