I've read about measured BDRFs and models like cook-torrance have parameters that need to be set. It isn't hard to imagine that these parameters and the measured properties would vary from point to point on a lot of surfaces.
Do artists or scans ever give us textures for these kinds of values? Where could I find or purchase models and textures for these kinds of things? What representations would textures for these models typically have? If these are hard to find is it simply because artists have yet to start using these models?