HowTo Talk:Use radiosity

A description of the parameters might be a documentation sort of thing, but seeing what changes to parameters do is sort of a How To thing...

I am working on a few demonstration scenes for the following:

1. a scene demonstrating when radiosity could be used to improve realism.
   • When I was new to POV, I didn't know when to use radiosity, and I think different examples showing the difference between using the ambient light for global illumination and radiosity would be helpful in making such a determination.
2. Using radiosity with lightsources
3. Using radiosity without lightsources (glowing object method)
4. Effects ok sky_sphere or background on radiosity
5. possibly a 10 x 10 grid of images with parameter changes (and render times) to demonstrate some of the main speed/quality ratios.
6. ???

Input would be appreciated! --Reactor 22:32, 27 December 2007 (UTC)

It makes sense to cover the typical problems and artifacts that people run into, and how to avoid those pitfalls.
Maybe something like a Cornell box for a test scene?
TimA 23:34, 27 December 2007 (UTC)

In response:The Cornell box is a pretty good one, but I think we should have several examples, especially different types. The Cornell Box is an indoor scene with all objects very close together. The one I envisioned for an example of when to apply radiosity is a simple outdoor architectural scene that includes both wide areas, smaller objects, and light reflected off of walls farther away.

Included are two images side by side that I think would be helpful to those new to POV in deciding when there scene would benefit from radiosity:

• 

  Without Radiosity

• 

  With Radiosity

The Cornell Box in various forms would be very good for indoor examples, but I think variations of a scene similar to this would be helpful for outdoor examples, especially because a new user may not be aware that the sky_sphere can influence radiosity.

--Reactor

Split into more than one article?

Most of the things I've added under tuning radiosity focus on use of light sources and the background for scene lighting. The use of objects with high ambient values is essentially similar, but it really has its own set of issues that need to be addressed. Then there is using a combination of both, which requires a good understanding of when to raise the brightness in a radiosity block, and when to increase light intensity or ambient values.

In short, I'm thinking that this article could be split into at least 3 or 4 articles:

• Basics about radiosity
• Radiosity Using light_sources
• Radiosity Without light_sources
• Advanced Radiosity (using light_sources, bright objects, light groups, etc)
• Speeding up and Troubleshooting Radiosity

Or something.

--Reactor 05:57, 13 January 2008 (UTC)

Article definitely needs to be split into multiple articles

The info in this article is all based on official version 3.6 (although it doesn't say it at this time), and the behavior and image output is slightly different between official 3.6 and 3.7 current beta(s). While many of the techniques are the same, there are more than enough differences to warrant this article being split (since future versions of POV may continue to change as improvements are )

Taking from the list above, I'm thinking the Radiosity article(s) should probably be in a Global Illumination Category, with the main article being a general description of how POV-ray can simulate it via radiosity, with links to subtopics (i.e. version specific info, tricks and techniques, etc. That way, the informational article can describe how and why it may change, allowing the user to select the appropriate version specific info. The article can also have a bit about MCPov, which, while not an official version, is widely used as a reference renderer.

Anyway, from the list above:

Global Illumination Category

Main Article - Simulating Global Illumination, which contains

General descriptions about what global illumination is, and how POV-ray does it

Slightly more specific info for each version, with link to version-specific page

Other category articles

• Tabled comparison between version 3.6 and 3.7 radiosity
  (behavior differences, image output differences, render time differences, etc.)

• MCPov and why it can be used as a reference
• Techniques for indoor scenes
• Techniques for outdoor scenes
• Radiosity Using light_sources
• Radiosity Without light_sources
• Controlling the brightness and contrast of your light in radiosity-lit scenes
• Speeding up and Troubleshooting Radiosity

--Reactor 21:49, 1 February 2009 (UTC)