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(afaik) is a truly physically-based renderer, ie it does not employ the kinds of shortcuts that GI renderers use. Is it a good example of a GI renderer? I know of the following: Lucille, POV-Ray, Pane, Parthenon, Perceptuum, Radiance, toxic, Iguana, and those are the free ones...
The article at the very beginning references direct illumination algorithms and refers to ray tracing as an example of one. I however thought ray tracing was also a global illumination algorithm, and if you look at the wikipedia page on global illumination algorithms, it refers to ray tracing as an example of one. -- Dterei 09:22, 17 October 2006 (UTC)
I think ray tracing is used to transfere the light around the scene. How else should global illumination get its F[i,j] ? Arnero 17:41, 28 October 2006 (UTC)
I have a replacement image that I think illustrates the difference between direct and global illumimation better than the ball image. The image is from my own web site, and was generated using a radiosity renderer I wrote myself, therefore I own the copyright. Eric Pierce, what do you think? If nobody minds, I'll replace the image, and adjust the text accordingly. Rocketmagnet 18:10, 7 January 2007 (UTC)
Yes, I think this is a very good example.
EXCELLENT! -- M0llusk ( talk) 03:36, 30 July 2008 (UTC)
Hi Trevor, Thanks for that, and the other changes. From what you wrote, I think it would be good to have a section, or sections, listing or detailing several algorithms (shooting, texture mapping, etc.) If Agreed, I'll move your bit about shooting, and my bit about texturing into their own sections, which can then be expanded upon in a controlled manner by othe people. Rocketmagnet 09:43, 8 January 2007 (UTC)
Trevorgoodchild 07:10, 13 January 2007 (UTC)
Sorry Trevor, I have reverted the caption for Radiosity_Progress.jpg. From "As additional bounces are calculated in shooting radiosity the scene becomes progressively brighter." back to "As the algorithm iterates, light can be seen to flow into the scene, as multiple bounces are computed."
This is because I believe the original caption to be the more correct one. This image was not rendered using shooting radiosity. It was rendered using texture mapping radiosity. Secondly, the image is not simply getting quantatively brighter. Rather a qualitative change is happening: light flowing through the scene. Rocketmagnet 09:43, 8 January 2007 (UTC)
Trevor, I'm not sure why you deleted the line about radiosity being an iterative algorithm. The only other place I can see this mentioned is in the paragraph about shooting radiosity. I think that the fact that it's iterative is the highest level thing one can say about the working of the algorithm. Rocketmagnet 09:43, 8 January 2007 (UTC)
Early methods used a hemicube (an imaginary cube centered upon the first surface to which the second surface was projected, devised by Cohen and Greenberg in 1985) to approximate the form factor, which also solved the intervening patch problem. This is quite computationally expensive, because ideally form factors must be derived for every possible pair of patches, leading to a quadratic increase in computation with added geometry.
I don't think this is correct in all cases. If each patch takes a constant time to render to the hemicube, then it's correct. Using the texture map method, then each 'surface' takes a constant time, and the number of patches makes practically no difference. Therefore it can be linear.
I think that it would be better to have a section detailing various methods. Rocketmagnet 12:38, 8 January 2007 (UTC)
Can anyone find a reference or paper stating that hard shadows are considered to be part of Global Illumination? Rocketmagnet 14:52, 9 January 2007 (UTC)
I'm not totally sure about this statement:
Likewise, Radiosity, by Hugo Elias describes a deterministic path tracing algorithm that takes advantage of graphics hardware to accelerate irradiance gathering, by using hemicubes. While this method does indeed compute the radiosity of patches, it does not compute form factors or explicitly construct a system of equations, thus it should not be confused with the classic radiosity method.
Do you have a reference for this? Where do you get the definition of "classic radiosity"? Perhaps "full matrix" radiosity was the method described in the first paper on the technique, but the hemicube method is still considered radiosity. Surely a radiosity method would be any which computes the radiosity of patches. What the algorithm does then is up to it. Indeed, SIGGRAPH 1993 Education Slide Set: Radiosity Overview Page 2, by Stephen Spencer talks about both "full matrix" and "progressive" methods. and the next page talks about "Progressive Radiosity Variants". Therefore pointing to one implementation of radiosity and calling it something else seems odd. Unless a reference can be found, I'll revert this in a couple of days. Rocketmagnet 07:36, 10 May 2007 (UTC)
User:Ryulong has been reverting my edits on an attempt to move this page to Radiosity (computer graphics). In my view, radiosity (should that be capital R?) does not deserve to hold this page title.
First and foremost this is a term borrowed from physics. The term that describes a fundamental phenomenon in physics with applications in engineering, optics, thermodynamics, and astronomy. In terms of the broad population or wikipedia users, it seems clear to me that this more fundamental meaning should precede the specialised use relating to this computer graphics algorithm. A disambiguation page is the correct approach.
Without the physical concept described by the physics term, there would *be* no computer algorithm. These are not two different meanings. The computer algorithm is an implementation of computation directional specular radiative transfer that borrows the name of one of the phenomena it models. It does not usurp the name.
My reference is the *very* popular (for mechanical engineers) undergraduate text Incropera and Dewitt, Fundamentals of Heat and Mass Transfer. The term 'radiosity is introduced in the first few pages of the radiation topic, as one of the foundation concepts of radiative transfer. Jdpipe 10:31, 11 June 2007 (UTC)
I think you missed one important thing: calculation results are viewpoint-independend. —Preceding unsigned comment added by 83.25.52.170 ( talk) 19:08, 27 February 2008 (UTC)
The result of the move request was: moved to Radiosity (computer graphics). Favonian ( talk) 23:12, 12 February 2012 (UTC)
Radiosity (3D computer graphics) → ??? – Disambiguator is overly precise. Radiosity (computer graphics) or Radiosity (algorithm) are acceptable. Pnm ( talk) 21:09, 5 February 2012 (UTC)
This is the
talk page for discussing improvements to the
Radiosity (computer graphics) article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find video game sources: "Radiosity" computer graphics – news · newspapers · books · scholar · JSTOR · free images · free news sources · TWL · NYT · WP reference · VG/RS · VG/RL · WPVG/Talk |
![]() | This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to multiple WikiProjects. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
(afaik) is a truly physically-based renderer, ie it does not employ the kinds of shortcuts that GI renderers use. Is it a good example of a GI renderer? I know of the following: Lucille, POV-Ray, Pane, Parthenon, Perceptuum, Radiance, toxic, Iguana, and those are the free ones...
The article at the very beginning references direct illumination algorithms and refers to ray tracing as an example of one. I however thought ray tracing was also a global illumination algorithm, and if you look at the wikipedia page on global illumination algorithms, it refers to ray tracing as an example of one. -- Dterei 09:22, 17 October 2006 (UTC)
I think ray tracing is used to transfere the light around the scene. How else should global illumination get its F[i,j] ? Arnero 17:41, 28 October 2006 (UTC)
I have a replacement image that I think illustrates the difference between direct and global illumimation better than the ball image. The image is from my own web site, and was generated using a radiosity renderer I wrote myself, therefore I own the copyright. Eric Pierce, what do you think? If nobody minds, I'll replace the image, and adjust the text accordingly. Rocketmagnet 18:10, 7 January 2007 (UTC)
Yes, I think this is a very good example.
EXCELLENT! -- M0llusk ( talk) 03:36, 30 July 2008 (UTC)
Hi Trevor, Thanks for that, and the other changes. From what you wrote, I think it would be good to have a section, or sections, listing or detailing several algorithms (shooting, texture mapping, etc.) If Agreed, I'll move your bit about shooting, and my bit about texturing into their own sections, which can then be expanded upon in a controlled manner by othe people. Rocketmagnet 09:43, 8 January 2007 (UTC)
Trevorgoodchild 07:10, 13 January 2007 (UTC)
Sorry Trevor, I have reverted the caption for Radiosity_Progress.jpg. From "As additional bounces are calculated in shooting radiosity the scene becomes progressively brighter." back to "As the algorithm iterates, light can be seen to flow into the scene, as multiple bounces are computed."
This is because I believe the original caption to be the more correct one. This image was not rendered using shooting radiosity. It was rendered using texture mapping radiosity. Secondly, the image is not simply getting quantatively brighter. Rather a qualitative change is happening: light flowing through the scene. Rocketmagnet 09:43, 8 January 2007 (UTC)
Trevor, I'm not sure why you deleted the line about radiosity being an iterative algorithm. The only other place I can see this mentioned is in the paragraph about shooting radiosity. I think that the fact that it's iterative is the highest level thing one can say about the working of the algorithm. Rocketmagnet 09:43, 8 January 2007 (UTC)
Early methods used a hemicube (an imaginary cube centered upon the first surface to which the second surface was projected, devised by Cohen and Greenberg in 1985) to approximate the form factor, which also solved the intervening patch problem. This is quite computationally expensive, because ideally form factors must be derived for every possible pair of patches, leading to a quadratic increase in computation with added geometry.
I don't think this is correct in all cases. If each patch takes a constant time to render to the hemicube, then it's correct. Using the texture map method, then each 'surface' takes a constant time, and the number of patches makes practically no difference. Therefore it can be linear.
I think that it would be better to have a section detailing various methods. Rocketmagnet 12:38, 8 January 2007 (UTC)
Can anyone find a reference or paper stating that hard shadows are considered to be part of Global Illumination? Rocketmagnet 14:52, 9 January 2007 (UTC)
I'm not totally sure about this statement:
Likewise, Radiosity, by Hugo Elias describes a deterministic path tracing algorithm that takes advantage of graphics hardware to accelerate irradiance gathering, by using hemicubes. While this method does indeed compute the radiosity of patches, it does not compute form factors or explicitly construct a system of equations, thus it should not be confused with the classic radiosity method.
Do you have a reference for this? Where do you get the definition of "classic radiosity"? Perhaps "full matrix" radiosity was the method described in the first paper on the technique, but the hemicube method is still considered radiosity. Surely a radiosity method would be any which computes the radiosity of patches. What the algorithm does then is up to it. Indeed, SIGGRAPH 1993 Education Slide Set: Radiosity Overview Page 2, by Stephen Spencer talks about both "full matrix" and "progressive" methods. and the next page talks about "Progressive Radiosity Variants". Therefore pointing to one implementation of radiosity and calling it something else seems odd. Unless a reference can be found, I'll revert this in a couple of days. Rocketmagnet 07:36, 10 May 2007 (UTC)
User:Ryulong has been reverting my edits on an attempt to move this page to Radiosity (computer graphics). In my view, radiosity (should that be capital R?) does not deserve to hold this page title.
First and foremost this is a term borrowed from physics. The term that describes a fundamental phenomenon in physics with applications in engineering, optics, thermodynamics, and astronomy. In terms of the broad population or wikipedia users, it seems clear to me that this more fundamental meaning should precede the specialised use relating to this computer graphics algorithm. A disambiguation page is the correct approach.
Without the physical concept described by the physics term, there would *be* no computer algorithm. These are not two different meanings. The computer algorithm is an implementation of computation directional specular radiative transfer that borrows the name of one of the phenomena it models. It does not usurp the name.
My reference is the *very* popular (for mechanical engineers) undergraduate text Incropera and Dewitt, Fundamentals of Heat and Mass Transfer. The term 'radiosity is introduced in the first few pages of the radiation topic, as one of the foundation concepts of radiative transfer. Jdpipe 10:31, 11 June 2007 (UTC)
I think you missed one important thing: calculation results are viewpoint-independend. —Preceding unsigned comment added by 83.25.52.170 ( talk) 19:08, 27 February 2008 (UTC)
The result of the move request was: moved to Radiosity (computer graphics). Favonian ( talk) 23:12, 12 February 2012 (UTC)
Radiosity (3D computer graphics) → ??? – Disambiguator is overly precise. Radiosity (computer graphics) or Radiosity (algorithm) are acceptable. Pnm ( talk) 21:09, 5 February 2012 (UTC)