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

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

3.  3D Models represented as mesh of polygons http://www.pixolator.com/zbc/attachment.php?attachmentid=15162

4.  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

5.  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

6.  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

7.  Triangle Decimation  Schroeder et al. 1992  Multiple passes over mesh to remove vertices that meet decimation criteria; patch hole http://www.emeraldinsight.com/fig/1560020102012.png

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

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

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

11.  Metrics  Geometric similarity ▪ Topology  Time  Space

12.  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 http://www.webreference.com/3d/lesson57/57-1.jpg

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

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

15.  Metrics  Visual similarity  Time  Space http://ja.gram.pl/upl/blogi/264034/img_wpisy/2008_05/postacie.jpg

16.  The combination of simplification and appearance preserving algorithms allows detailed models in drastically less time http://upload.wikimedia.org/wikipedia/commons/3/36/Normal_map_example.png

17.  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]

18.  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

20.  CIGNONI, P., MONTANI, C., ROCCHINI, C., AND SCOPIGNO, R. 1998. A general method for preserving attribute values on simplified meshes. In Visualization '98. Proceedings, 1998, 59-66.  COHEN, J., OLANO, M., AND MANOCHA, D. 1998. Appearance-preserving simplification. In Proceedings of the 25th annual conference on Computer graphics and interactive techniques, 1998, ACM,, 115-122.  SCHROEDER, W.J., ZARGE, J.A., AND LORENSEN, W.E. 1992. Decimation of triangle meshes. In Proceedings of the 19th annual conference on Computer graphics and interactive techniques, 1992, ACM,, 65-70.  KRISHNAMURTHY, V. AND LEVOY, M. 1996. Fitting smooth surfaces to dense polygon meshes. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, 1996, ACM,, 313-324.  RONFARD, R. AND ROSSIGNAC, J. 1996. Full-range approximation of triangulated polyhedra. Computer Graphics Forum 15, 67-76.  CLARK, J.H. 1976. Hierarchical geometric models for visible surface algorithms. Commun. ACM 19, 547-554.  HOPPE, H., DEROSE, T., DUCHAMP, T., MCDONALD, J., AND STUETZLE, W. 1993. Mesh optimization. In Proceedings of the 20th annual conference on Computer graphics and interactive techniques, Anaheim, CA, 1993, ACM, Anaheim, CA, 19-26.  HOPPE, H. 1996. Progressive meshes. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, 1996, ACM,, 99-108.  WILLIAMS, L. 1983. 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, 1-11.  TURK, G. 1992. Re-tiling polygonal surfaces. In Proceedings of the 19th annual conference on Computer graphics and interactive techniques, 1992, ACM,, 55-64.  REDDY, M. 1996. SCROOGE:Perceptually-Driven Polygon Reduction. Computer Graphics Forum 15, 191-203.  COHEN, J., VARSHNEY, A., MANOCHA, D., TURK, G., WEBER, H., AGARWAL, P., BROOKS, F., AND WRIGHT, W. 1996. Simplification envelopes. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, 1996, ACM,, 119-128.  GARLAND, M. AND HECKBERT, P.S. 1997. 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.,, 209-216.  HECKBERT, P. 1986. Survey of Texture Mapping. Computer Graphics and Applications, IEEE 6, 56-67.