ABSTRACT
When reproducing visual elements found in nature, it is crucial to have a mathematical theory that models real-world light transport. In real-time graphics, the interaction of light and matter is often reduced to local reflection described by bidirectional reflectance distribution functions (BRDFs), for example, describing reflectance at the surface of opaque objects [Kurt 09]. In nature, however, many
objects are (partly) translucent: light transport also happens within the surface (as shown in Figure 4.1).
