A Volumetric Approach to Physically-Based Rendering of Fabrics

Efficient physically accurate modeling and rendering of woven cloth at a yarn level is an inherently complicated task due to the underlying geometrical and optical complexity. In this paper, a novel and general approach to physically accurate cloth rendering is presented. By using a statistical volumetric model approximating the distribution of yarn fibers, a prohibitively costly explicit geometrical representation is avoided. As a result, accurate rendering of even large pieces of fabrics containing orders of magnitudes more fibers becomes practical without scarifying much generality compared to fiber based techniques. By employing the concept of local visiblity and introducing the angular length density, limitations of existing volumetric approaches regarding self shadowing and fiber density estimation are greatly reduced.