Multiple-Scattering Microfacet BSDFs with the Smith ModelThe paper "Multiple-Scattering Microfacet BSDFs with the Smith Model" is available here: https://eheitzresearch.wordpress.com/240-2/ Update: it is being added to Blender's Cycles! - https://developer.blender.org/D2002 Modeling multiple scattering in microfacet theory is considered an important open problem because a non-negligible portion of the energy leaving rough surfaces is due to paths that
