Abstract

Three properties of trees produce distinctive visible characteristics of wood: the cylindrical growth rings, the vertical pores, and the radial planes that compartmentalize the tree to protect it from disease or injury. Such a model of a tree was the basis for rendering a wooden surface. With this first approximation, the growth rings will appear as elliptical contours on a planar cut, streaked by dark lines that arise from the rays, and speckled by pores. These three properties of wood capture its salient visual attributes. The particular form of the ring albedo function is not important, nor is it necessary to model the radial rays exactly. We speculate that the pattern of radial rays and elliptical rings, and possibly their intersection, allow the observer to make the inference of wood, for few other natural structures will produce this characteristic surface texture.

© 1985 Optical Society of America