Comprehensible rendering of 3-D shapes

TLDR

Shape features can be readily understood if certain geometric properties are enhanced. The authors propose a new rendering technique that produces 3‑D images with enhanced visual comprehensibility by developing drawing algorithms for discontinuities, edges, contour lines, and curved hatching. The method realizes all enhancement operations with 2‑D image processing on G‑buffers that store per‑pixel geometric properties, thereby separating enhancement from geometric and physical rendering steps and enabling efficient post‑processing. The approach allows users to rapidly test combinations of enhancement techniques without excessive recomputation, yielding highly comprehensible images, and is applicable to edge enhancement, line drawings, topographical maps, medical imaging, and surface analysis.

Abstract

We propose a new rendering technique that produces 3-D images with enhanced visual comprehensibility. Shape features can be readily understood if certain geometric properties are enhanced. To achieve this, we develop drawing algorithms for discontinuities, edges, contour lines, and curved hatching. All of them are realized with 2-D image processing operations instead of line tracking processes, so that they can be efficiently combined with conventional surface rendering algorithms.Data about the geometric properties of the surfaces are preserved as Geometric Buffers (G-buffers). Each G-buffer contains one geometric property such as the depth or the normal vector of each pixel. By using G-buffers as intermediate results, artificial enhancement processes are separated from geometric processes (projection and hidden surface removal) and physical processes (shading and texture mapping), and performed as postprocesses. This permits a user to rapidly examine various combinations of enhancement techniques without excessive recomputation, and easily obtain the most comprehensible image.Our method can be widely applied for various purposes. Several of these, edge enhancement, line drawing illustrations, topographical maps, medical imaging, and surface analysis, are presented in this paper.