Visually-Uniform Reparametrization of Material Appearance through Density Redistribution

Variations of material parameters such as roughness, sheen, etc. do not usually produce visually-uniform changes in rendered images. This might make it detrimental to artistic edition or prefiltering. In this work, we provide a methodology to reparametrize non visuallyuniform parameters, by uniformly distributing the visual changes across the range of parameter values. For 1D and 2D parameters, our solution boils down to inverting a Cumulative Distribution Function. We provide three concrete applications of this method to reparametrize the complex refractive index, roughness and sheen.