Provided a set of acquired BRDF data, realistic image synthesis requires evaluation of the rendering equatuation over a hemisphere of directions on a surface. We store the basis representation of the BRDF, acquired directly from the sample material, in a pair of three-dimensional textures to offload the work to the GPU. For materials that produce artifacts in the basis representation, we use
data fitted to the D-BRDF model as an alternate method of rendering the BRDF. We discuss the usage of environment maps and importance sampling algorithms as a method of representing complex natual illumination. Through this approach, the solution of the illumination integral can be approximated for real-time and interactive applications that opt to use measured BRDFs.