Presented ByGreg 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

http://www.pixolator.com/zbc/attachment.php?attachmentid=15162

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. 1992

Multiple passes over mesh to remove vertices that meet decimation criteria; patch hole

http://www.emeraldinsight.com/fig/1560020102012.png

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

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

Displacement mapping Krishnamurthy et al. 1996

User defines patches that approximate surface; stores distance for displacement

[Krishnamurthy et al. 1996]

Normal mapping Cignoni et al.

1998Sample

complex mesh and store normals into texture image

[Cignoni et al. 1998]

Metrics Visual similarity Time Space

http://ja.gram.pl/upl/blogi/264034/img_wpisy/2008_05/postacie.jpg

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

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 Thesis1) Add visual similarity metric to QEM

simplification2) Generate normal maps using MELODY3) Compare visual similarity of high

resolution mesh to optimized mesh and other simplified meshes

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.