A Two-Pass Physics-Based Global Lighting Model

This paper describes a two-pass implementation of a physics-based global lighting model. This latter uses a physics-based reflection model, spectral distribution of light powers, and does not make any assumption on the specular behavior of materials. The scenes are discretized into points instead of patches . Hence, any kind of surface can be used without having to break down it into small planar patches. A data structure, named visibility graph, is built to efficiently evaluate the visibility between the sample points of the scene. Even though the photometric properties of surfaces (reflection, transmission , roughness, emitted powers ... ) are modified, this graph does not change, which makes it easy to produce very quickly several images. Methods for computing the Fresnel factor are given in appendix .