JOURNAL OF INFORMATION SCIENCE AND ENGINEERING 22, 843-861 (2006) 843 A Novel Cache-based Approach to Large Polygonal Mesh Simplification HUNG-KUANG CHEN 1,3 , CHIN-SHYURNG FAHN 2 , JEFFREY J. P. TSAI 4 AND MING-BO LIN 1 1 Department of Electronic Engineering 2 Department of Computer Science and Information Engineering National Taiwan University of Science and Technology Taipei, 106 Taiwan 3 Department of Information and Design Asia University Taichung, 413 Taiwan 4 Department of Computer Science University of Illinois at Chicago Chicago, IL 60637, U.S.A. Traditional iterative contraction based polygonal mesh simplification (PMS) algo- rithms usually require enormous amounts of main memory cost in processing large meshes. On the other hand, fast out-of-core algorithms based on the grid re-sampling scheme usually produce low quality output. In this paper, we propose a novel cache- based approach to large polygonal mesh simplification. The new approach introduces the use of a cache layer to accelerate external memory accesses and to reduce the main memory cost to constant. Through the analysis on the impact of heap size to the locality of references, a constant sized heap is suggested instead of a large greedy heap. From our experimental results, we find that the new approach is able to generate very good quality approximations efficiently with very low main memory cost. Keywords: cache-based polygonal mesh simplification, large mesh, iterative half-edge collapse, quadric error metrics, independent queuing 1. INTRODUCTION The rapid advancements in 3D scanning technology have introduced a great chal- lenge: the processing and rendering of large meshes. Recent examples such as the Digital Michelangelo Project [1], the Forma Urbis Romae Project [2] at Stanford University on culture heritages preservation and the Visible Human Project [3] of the National Library of Medicine for medical applications, have created large, unsegmented 3D surface meshes over tens of million faces. Rendering and processing such meshes usually ex- ceeds the capability of current computer systems. Therefore, mesh simplification algo- rithms capable of converting an input mesh into various level-of-detail (LOD) represen- tations are becoming extremely important. Polygonal mesh simplification (PMS) has been studied intensively. A host of works have been proposed. Among these works, three types of PMS algorithms are most widely Received April 7, 2004; revised February 1 & August 2, 2005; accepted August 29, 2005. Communicated by Pau-Choo Chung.