Direct Visualization of Quadrics

Abstract

Today, most of the powerful graphic systems are based on 3D-triangle display methods.However, this approach generates well-known problems, like the low quality ofcontours and shading, and the necessity to have large amounts of primitives to displaycomplex scenes. A way to solve these problems is to use higher level primitives,among which a very interesting one is the quadric surface. We study here directvisualization of quadric surfaces (quadrics for short) .Although we study all the rendering process, we focus on the scan conversion stage.First, we present mathematical and modeling backgrounds where we show that aquadric surface can easily be rendered in scan-line. Then we give the general algorithmand details about the difficult part, i.e. the bounding plane algorithm. A functionaldescription of a scan converting processor is proposed, using a modular approach.In the last part, we give a hardware implementation of each module and the wholeprocessor. We also do an estimation of the silicon cost. The conclusion is that ourquadric patch scan converter can actually be realized.