Occluder cache application?

Hi,

as I am going to add some dedicated occluder objects to a rather large scene, I would like to understand some more details of how the caching works to concentrate my work on the right parts of the scene.

I have a scene with these light sources:

- daylight by gensky, but hidden behind mkillum sources
- groups of small light sources, again hidden in bounding mkillums

Now, I guess that for the direct calculation, I will get some speed when the occluders block the small light sources. But what about the light sources generated by mkillum?

Than, my scene has one more strange feature. More or less all the outer walls are instances. So putting a big occluder around the closed parts of the building would speed-up because I do not have to test for light sources behind the wall. But the only outer light source there is the sky distribution + sun. The sky distribution is an indirect source in Radiance afaik, so will I win anything?

Thanks, hope someone can bring some light into my occluded understanding of the cache,

Lars.

Hi Lars,

I'm not quite sure how your scene is set up, but I'll try to respond...

From: "Lars O. Grobe" <[email protected]>
Date: February 13, 2007 1:56:24 AM PST

Hi,

as I am going to add some dedicated occluder objects to a rather large scene, I would like to understand some more details of how the caching works to concentrate my work on the right parts of the scene.

Just generally, there's not much point in adding dedicated occluders, unless your scene contains a lot of octree or mesh instances, which aren't included in the standard occluder cache.

I have a scene with these light sources:

- daylight by gensky, but hidden behind mkillum sources
- groups of small light sources, again hidden in bounding mkillums

Now, I guess that for the direct calculation, I will get some speed when the occluders block the small light sources. But what about the light sources generated by mkillum?

Any sources of type "glow" are already blocked by intervening "illum" surfaces. Therefore, additional occluders shouldn't make any difference.

Than, my scene has one more strange feature. More or less all the outer walls are instances. So putting a big occluder around the closed parts of the building would speed-up because I do not have to test for light sources behind the wall. But the only outer light source there is the sky distribution + sun. The sky distribution is an indirect source in Radiance afaik, so will I win anything?

Very little -- just the sun left as a light source, and testing against a single source is generally faster than any shenanigans.

-Greg

ยทยทยท

Thanks, hope someone can bring some light into my occluded understanding of the cache,

Lars.