Presented By Greg Gire Advised By Zoë Wood California Polytechnic State University

 Introduction  Problem  Simplifying Polygonal Meshes  History  Metrics  Normal Mapping  History  Metrics  My Thesis

 3D Models represented as mesh of polygons

 What is the optimal simplified mesh to apply appearance preservation to make it appear the most visually similar to the original mesh? 558 quads 65 quads 225,467 quads

 My thesis will focus on generating the best simplified mesh that will be most visually similar to the original high resolution mesh 43,850 quads

 Problem:  Rendering complex meshes requires a large amount of memory, processing power, and time  This is bad for interactive graphics applications such as animation and video games  Solution:  Reduce the level of detail (polygon count) while maintaining its overall shape

 Triangle Decimation  Schroeder et al  Multiple passes over mesh to remove vertices that meet decimation criteria; patch hole

 Re-tiling  Greg Turk 1992  Create new vertices that approximate the curvature of a model; re-triangulate [Turk 1992]

 Progressive Meshes  Hughes Hoppe 1996  Iterative collapse of an edge into a single vertex; stores collapses to adjust LOD [Hoppe 1996]

 Quadric Error Metrics  Garland and Heckbert 1997  Collapse two vertices into one; use of quadrics to approximate cost of collapse [Garland and Heckbert 1997]

 Metrics  Geometric similarity ▪ Topology  Time  Space

 Problem:  Simplified meshes may work for animation, but not so good for video games  Solution:  Preserve appearance from complex mesh and “paint” it on simplified mesh using existing graphics hardware

 Displacement mapping  Krishnamurthy et al  User defines patches that approximate surface; stores distance for displacement [Krishnamurthy et al. 1996]

 Normal mapping  Cignoni et al  Sample complex mesh and store normals into texture image [Cignoni et al. 1998]

 Metrics  Visual similarity  Time  Space

 The combination of simplification and appearance preserving algorithms allows detailed models in drastically less time

 Problem:  There are many techniques and levels of detail for model simplification, and not all look equal when a normal map is applied  Solution:  Optimize simplified mesh for normal mapping [Garland and Heckbert 1997]

 My Thesis 1) Add visual similarity metric to QEM simplification 2) Generate normal maps using MELODY 3) Compare visual similarity of high resolution mesh to optimized mesh and other simplified meshes

 CIGNONI, P., MONTANI, C., ROCCHINI, C., AND SCOPIGNO, R A general method for preserving attribute values on simplified meshes. In Visualization '98. Proceedings, 1998,  COHEN, J., OLANO, M., AND MANOCHA, D Appearance-preserving simplification. In Proceedings of the 25th annual conference on Computer graphics and interactive techniques, 1998, ACM,,  SCHROEDER, W.J., ZARGE, J.A., AND LORENSEN, W.E Decimation of triangle meshes. In Proceedings of the 19th annual conference on Computer graphics and interactive techniques, 1992, ACM,,  KRISHNAMURTHY, V. AND LEVOY, M Fitting smooth surfaces to dense polygon meshes. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, 1996, ACM,,  RONFARD, R. AND ROSSIGNAC, J Full-range approximation of triangulated polyhedra. Computer Graphics Forum 15,  CLARK, J.H Hierarchical geometric models for visible surface algorithms. Commun. ACM 19,  HOPPE, H., DEROSE, T., DUCHAMP, T., MCDONALD, J., AND STUETZLE, W Mesh optimization. In Proceedings of the 20th annual conference on Computer graphics and interactive techniques, Anaheim, CA, 1993, ACM, Anaheim, CA,  HOPPE, H Progressive meshes. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, 1996, ACM,,  WILLIAMS, L Pyramidal parametrics. In Proceedings of the 10th annual conference on Computer graphics and interactive techniques, Detroit, Michigan, United States, 1983, ACM, Detroit, Michigan, United States,  TURK, G Re-tiling polygonal surfaces. In Proceedings of the 19th annual conference on Computer graphics and interactive techniques, 1992, ACM,,  REDDY, M SCROOGE:Perceptually-Driven Polygon Reduction. Computer Graphics Forum 15,  COHEN, J., VARSHNEY, A., MANOCHA, D., TURK, G., WEBER, H., AGARWAL, P., BROOKS, F., AND WRIGHT, W Simplification envelopes. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, 1996, ACM,,  GARLAND, M. AND HECKBERT, P.S Surface simplification using quadric error metrics. In Proceedings of the 24th annual conference on Computer graphics and interactive techniques, 1997, ACM Press/Addison-Wesley Publishing Co.,,  HECKBERT, P Survey of Texture Mapping. Computer Graphics and Applications, IEEE 6,