Linear-time CSG rendering of intersected convex objects

Abstract

The Sequenced Convex Subtraction(SCS) algorithm is a hardware based multi-pass image-space lgorithm for general purpose Constructive Solid Geometry (CSG)Rendering. Convex objects combined by volumetric intersection, difference and union are rendered in real-time without b-rep re-processing. OpenGL stencil and depth testing is used to determine the visible surface for each pixel on the screen. This paper introduces a specialised algorithm for CSG Rendering of intersected convex objects,we call SCS-Intersect. This new technique requires linear time with respect to the number of intersections. SCS-Intersect is primarily of interest as an optimisation to the SCS algorithm for rendering CSG trees of convex objects. A revised formulation of the SCS CSG Rendering algorithm is presented in this pape.