d'Eon, EugeneWeidlich, AndreaGarces, ElenaHaines, Eric2024-06-252024-06-2520241467-8659https://doi.org/10.1111/cgf.15149https://diglib.eg.org/handle/10.1111/cgf15149We present a practical analytic BRDF that approximates scattering from a generalized microfacet volume with a von Mises- Fischer NDF. Our BRDF seamlessly blends from smooth Lambertian, through moderately rough height fields with Beckmannlike statistics and into highly rough/porous behaviours that have been lacking from prior models. At maximum roughness, our model reduces to the recent Lambert-sphere BRDF. We validate our model by comparing to simulations of scattering from geometries with randomly-placed Lambertian spheres and show an improvement relative to a rough Beckmann BRDF with very high roughness.Attribution 4.0 International LicenseCCS Concepts: Computing methodologies → Reflectance modelingComputing methodologies → Reflectance modeling10.1111/cgf.1514910 pages