Normal Distribution Mapping

Abstract

Normal distribution mapping is an extension of traditional texture mapping methods to normal and shading information. The surface normal direction and shading for a patch of surface are represented by a statistical distribution of normal directions. The normal distribution map is a map of these distributions as they vary over the surface. Normal distribution mapping admits considerable freedom in the choice of probability density function. We propose using a distribution based on a 3D Gaussian for this purpose. This distribution can be easily filtered for map antialiasing and cheaply evaluated for surface shading.