A dual method for constructing multi-material solids from ray-reps

Abstract

A ray-rep is an approximation of a solid using a grid of parallel rays; intervals along the ray denote various materials comprising the solid. Ray-reps have a variety of applications in computer graphics and mechanical engineering. Given a ray-rep, this paper focuses on the problem of generating a single polygonal mesh that bounds the materials forming the solid. Most investigations of this problem has focused on the two-material case. These primal methods typically build an approximating volume by connecting intersection points on the ray-rep to form curves and surfaces. In this paper, we describe a new, more flexible method that constructs polygonal approximations using a dual method. In the two-material case with normal data, this dual method typically produces better approximations than existing primal methods. In contrast to existing methods, our dual method also generalizes to three or more materials and produces reasonable polygonal approximations from ray-reps. © 2012 Springer-Verlag.