Real-time rendering of layered materials with linearly filterable reflectance model

Abstract

This paper proposes a real-time system to render with layered materials by using a linearly filterable reflectance model. This model effectively captures both surface and subsurface reflections, and supports smooth transitions over different resolutions. In a preprocessing stage, we build mip-map structures for both surface and subsurface mesostructures via fitting their bumpiness with mixtures of von Mises Fisher (movMF) distributions. Particularly, a movMF convolution algorithm and a movMF reduction algorithm are provided to well-approximate the visually perceived bumpiness of the subsurface with controllable rendering complexity. Then, both surface and subsurface reflections are implemented on GPUs with real-time performance. Experimental results reveal that our approach enables aliasing-free illumination under environmental lighting at different scales.