Exploring the potential of layered BRDF models

Abstract

The key advantage of using layered BRDFs over traditional, more general shading-language constructs is that the automatic result is highly plausible. This course is a survey of the considerable potential of layered surface models. On a simple layered surface model that combines several traditional BRDF components, it demonstrates how a surprisingly large number of interesting and important surface types can be efficiently represented by using the same, not particularly complex, BRDF code. It also shows how handy such an approach is for the eventual end user, whose main concern is the ease of describing object appearance based only on a few intuitive parameters. The course begins with a discussion of layered surface models in computer graphics and the constraints of modelling object appearance in a physically plausible fashion, then demonstrates the techniques that can be used to efficiently evaluate layered BRDF models and presents examples of the surface types that can be described in this way. The course goes beyond plain-surface models to showcase how a texture-based combination of layered surface components can be used to describe highly complex object-appearance attributes, while implicitly remaining physically plausible. In particular, we demonstrate on a simple layered surface model that combines several traditional BRDF components how a surprisingly large number of interesting and important surface types can be efficiently represented by using the same, not particularly complex, BRDF code. We also show how handy such an approach is for the eventual end user, whose main concern is the ease with which one can describe object appearance based only on a few intuitive parameters. We first discuss layered surface models in computer graphics and the constraints of modelling object appearance in a physically plausible fashion. We then demonstrate the techniques that can be used to efficiently evaluate layered BRDF models, give examples of the surface types that can be described in this way. We also go beyond plain surface models, and showcase how a texture-based combination of layered surface components can be used to describe highly complex object appearance attributes, while implicitly remaining physically plausible.