modeling the interaction of light between diffuse surfaces cindy m. goral, keenth e. torrance,...
TRANSCRIPT
![Page 1: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/1.jpg)
Modeling the Interaction of Light Between Diffuse Surfaces
Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile
Presented by:Chris Wassenius
![Page 2: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/2.jpg)
Outline
● Introduction / Motivation– Local vs Global Illumination
● Method● Results● Conclusion● Acknowledgments
![Page 3: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/3.jpg)
Introduction / Motivation
● Accounting for global illumination is central in producing realistic scenes.
● Most surfaces reflect light diffusely back into the environment.
● Diffuse reflections of objects account for most of the lighting in a scene.
![Page 4: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/4.jpg)
Introduction / Motivation
Ray Tracing– hard shadows – ambient term needed
to simulate global illumination
![Page 5: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/5.jpg)
Introduction / Motivation
True Global Illumination– soft shadows– color bleeding– no need for ambient
term
![Page 6: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/6.jpg)
Introduction / Motivation
● The proposed method, Radiosity, accounts for indirect light surfaces.
● Related Work:– Thermal Engineering
Radiant heat exchange
Energy transport and conservation principles
![Page 7: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/7.jpg)
Outline
● Introduction / Motivation ● Method
– Radiosity Equation– Form Factors– Putting It Together
● Results● Conclusion● Acknowledgments
![Page 8: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/8.jpg)
Method
● Diffuse reflectors / emitters● Enclosures
– Set of surfaces that define the illuminating environment
● Form factors– Fraction of the radiant light energy leaving one
surface that strikes another surface
![Page 9: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/9.jpg)
Method
Bj = radiosity of surface j
Ej = rate of direction emmision from surface j
ρj = reflectivity of surface j
Hj = incident radiant energy arriving at surface j
![Page 10: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/10.jpg)
Method
What is the incident radiant energy arriving at surface j?
This gives:
![Page 11: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/11.jpg)
Method
Computing Form Factors– The intensity of light reflected is constant and
uniform from all viewing directions.– Total energy leaving a surface is found by
integrating over the hemisphere.– Intensity of light drops proportionally with the
distance squared.
![Page 12: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/12.jpg)
Method
Computing Form Factors (continued)
Putting all this together...
![Page 13: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/13.jpg)
Method
Computing Form Factors (continued)
Identity Shortcuts
1
2
3
![Page 14: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/14.jpg)
Method
Implementation
Step 1 - Read in polygon data
Step 2 - Subdivide polygons into patches
Step 3 - Compute form factors
Step 4 – Solve Radiosity Equation
Step 5 – Render scene
![Page 15: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/15.jpg)
Outline
● Introduction / Motivation ● Method● Results● Conclusion● Future Work
![Page 16: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/16.jpg)
Results
![Page 17: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/17.jpg)
Results
![Page 18: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/18.jpg)
Results
![Page 19: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/19.jpg)
Results
![Page 20: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/20.jpg)
Outline
● Introduction / Motivation ● Method● Results● Conclusion
– Pros and Cons– Future work
● Acknowledgments
![Page 21: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/21.jpg)
Conclusion
● Pros– Approached realism with global illumination– View independent solution
● Cons– Computationally expensive– Does not account for occluded surfaces– Does not taking into account specular reflections
![Page 22: Modeling the Interaction of Light Between Diffuse Surfaces Cindy M. Goral, Keenth E. Torrance, Donald P. Greenberg and Bennett Battaile Presented by: Chris](https://reader031.vdocument.in/reader031/viewer/2022032722/56649cee5503460f949bc349/html5/thumbnails/22.jpg)
Conclusions
Future Work:– Account for occluded surfaces (hemicube method)– Optimal polygon subdivision method– Hierarchical storing of patches– Faster form factor calculations