RADIOSITY out of memory...?

[bobo]

I have recently upgraded to a decent P4 with 2GB ram, top line graphics card etc... :D, however when I go to calulate radiosity on my house design i get an out of memory message with a recomendation to save and reset my section box.., which I have... Any ideas on what else to do? :(

[beegee]

Check out the discussion in this thread (www.zoogdesign.com/forums/phpBB2/viewtopic.php?t=1117&highlight=radiosity) about radiosity and section boxes.

Larry Greenberg also shared some good tips about radiosity in another thread.


1. Always try and include some form of daylighting in the solution. Lights only tend to create jagged shadows and some serious artifacting problems. I have found daylights, even if the sky is turned down or the time of day is set in the evening, really helps.
2. Use the “best” radiosity setting as this will mesh the model with a finer grid, reducing some artifacting problems.
3. Do NOT use backface and view culling (if you can help it) as this interferes with shadow and reflection accuracy in the final render.
4. When doing a final render, also use “best” and wait for the render to complete for a much better result. I generally use 3 transparency and reflection bounces, but YMMV.

The residual is the amount of light energy left to distribute (“shoot”) in the scene. You can go again (hit “Continue”) to keep distributing the residual, but it eventually becomes an exercise in diminishing returns. Just shoot till the scene looks illuminated correctly.

[bobo]

Well, thanks for the reference, I suspect it is to do with a combination of things... model size...exterior aspects, etc.... The model has a door open to the outside, perhaps this is the cause... pretty limiting aspect unfortunately... thaks all the same.. lets hope 6 will address huh

[hand471037]

Actually, rietveld, this isn't something that can be 'fixed' with 6.0, for this is a problem inherant with Radiosity as a rendering process. Even people using VIZ or Lightscape run into problems of what's within the 'boundry' of the calculation. Unless you are either using a GI rendering plug-in, like Vray or Brazil, that 'fakes' the global illumination, or using Radiance, which actually calcs out the global illumination for the total scene, you're gonna run into this problem...

Radiosity is simply a work-around for the fact that a standard ray-tracer can't account for how light and materials properly interact within a model. Radiosity tries to account for the 'bounced' light within the space by drawing a mesh over everything, and then sampling each square to see how it interacts with all the other squares, and hense figures out where the 'bounced' light is going within the room. However, the larger the scene, and the more complex the scene, the more complex this mesh becomes until it goes beyond the ability of your computer to produce. It's common in other rendering packages to 'exclude' things like furniture, landscaping, and more from the radio calc to help this process out, as well as 'bounding' the scene to only part of the model that you wish to render.

In order to do what you want, i.e. have an open door to the outside that light is coming into your space via, I would make a dummy bit of glazing immedately on the other side of the door from your view, that fills the whole doorway & with a material that makes it perfectly clear (so you don't see it), and set it as a daylighting source. This will bring the light into the room, but make it so that the radiosity calc doesn't have to 'think' about the whole of your outside model... :)

This is a large part of why I'm learning Radiance, for it doens't run into the same limitations as the radiosity process does...