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Interactive Rendering of Large Unstructured Grids Using Dynamic - - PowerPoint PPT Presentation
Interactive Rendering of Large Unstructured Grids Using Dynamic - - PowerPoint PPT Presentation
Interactive Rendering of Large Unstructured Grids Using Dynamic Level-of-Detail Steven P. Callahan , Joo L. D. Comba Peter Shirley , and Cludio T. Silva University of Utah UFRGS, Brazil Dynamic Level-of-Detail 100%
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Level-Of-Detail Background
➤ Geometric Approach
[Cignoni et al. 2004]
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Level-Of-Detail Background
➤ Texture Approach
[Leven et al. 2002]
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Level-Of-Detail Background
➤ Tetrahedra
- Farias et al. 2000
- Leven et al. 2002
- Cignoni et al. 2004
- Museth and Lombeyda 2004
➤ Regular Grids
- Danskin and Hanrahan 1992
- LaMar et al. 1999
- Weiler et al. 2000
➤ Triangles or Points
- Funkhouser and Séquin 1993
- Luebke and Erikson 1997
- Luebke et al. 2002
- Duessen et al. 2002
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Definitions Given a scalar field An approximation can be made such that and . A ray passing through the domain forms a continuous function
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Domain-Based Simplification
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Sample-Based Simplification
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Triangle Sampling
➤ Sample the triangles
- Boundary + Internal triangles
LOD B1,B2,...,Bn I1,I2,...,Im
➤ LOD index updated at each pass
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Hardware-Assisted Visibility Sorting
➤ Sort in object-space and image-space
CPU GPU
[Callahan et al. 2005, Silva et al. 2005]
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Hardware-Assisted Dynamic Level-of-Detail
CPU GPU
➤ Sample in object-space
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Ranking Strategies Topology: target continuity
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Ranking Strategies Field: target histogram
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Ranking Strategies View: target screen-space coverage
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Ranking Strategies Area: target faces that cause greater error
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Visual Quality 100% 1.3 fps 15% 4.5 fps 5% 10.0 fps
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Movie
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Movie
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Movie
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Preprocessing 15.3 s 15.3s 13.9 s 75.6 s 1.4 M Fighter 11.2 s 11.6 s 10.5 s 87.2 s 1.0 M Torso 13.9 s 5.3 s 4.5 s 17.8 s 0.8 M Spx2 Area View Field Topology Tets Dataset
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Strategy Analysis
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Strategy Analysis
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Strategy Analysis
Full Quality Topology View Field Area
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Domain and Sample Comparison Full Quality
100% @ 20 fps
Sample
50% @ 30 fps
Domain
50% @ 23 fps
g(t) g1(t) g2(t) t t t
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g(t) g1(t) g2(t) t t
Domain and Sample Comparison Full Quality
100% @ 20 fps
Sample
50% @ 30 fps
Domain
25% @ 30 fps
t
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g(t) g1(t) g2(t) t t
Domain and Sample Comparison Full Quality
100% @ 20 fps
Domain
1% @ 60 fps
Sample
10% @ 60 fps
t
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Conclusion
➤ New sampling approach which simplifies LOD ➤ Well-suited for a GPU implementation ➤ Dynamic changes to LOD are simple and require no explicit
hierarchies
➤ Tetmesh 0.1 code will be available soon at
www.sci.utah.edu/~vgc
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Open Research
➤ Better ranking strategies ➤ Handle even larger data
- Sample the boundaries
- Sample points instead of triangles
➤ Adaptive time-varying visualization
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Acknowledgments
➤ Carlos Scheidegger , Huy Vo, and John Schreiner ➤ Datasets
- Bruno Notrosso (Electricite de France)
- Neely and Batina (NASA)
- SCI Institute, University of Utah
➤ Funding
- DOE
- CNPq
- MICS
- NSF
- University of Utah