I have been testing how the radiosity in Vue 5 works for interior scenes. It seems like light just doesnt bounce of the surfaces as it should, and the renderings become to dark. Here I placed a spotlight in the corner of a room. The material is Flat White. I rendered the room with Global Radiosity. In the first image I had gain at 1, in the second at 9,75. In the firs image everything outside the spotlight remains almost black. In the second one the light is too bright and the room is still darker than it should be. On the right I added a heat map to better show the difference in lighting. Can someone help me with the correct settings, or is Vue just not made for real interior radiosity?

Regards,
Heikki

You might try experimenting with different kinds of lights, I'm not a big fan of spotlights myself as they never seem to provide the right effect for me. That's pretty much the only thing I'd suggest off hand until I can get into radiosity a little more.

First, before raising the gain control (which is a boost and has the limitation of all boost controls), you should adjust the balance of ambient-sunlight more (or completely) towards the ambience. Then, you have to play with the amount of ambient light in the material editor for each material involved. This is the control that lets you individually fine tune the responsiveness of each material to the radiosity engine. After you have set all that, if the result isn't still what you want, you can adjust the - skydome lighting gain (if your interior has open windows) - gain value - bias value in SMALL quantities (the gain excursion is too much). Especially the bias color is very sensitive, a gray color that is even slightly lighter than black will have a great influence. Radiosity in Vue 5 has several parameters, not as many as you would find in a professional application, but many enough to require careful adjustment. As a rule of thumb, use this (it is valid for all similar situations): if you have, say, 5 parameters that can influence a result, and your aim is to obtain "10", you will always get a better and more balanced result by distributing the 10 over all five parameters (e.g. setting all five parameters to "2") than by setting only one parameter to "10" with all the others left at "0". Hope this helps. If you like to share the scene, I will set up parameters for you with which to have a better result.

This test was done in a completely closed box. The light slider was all the way to ambient, spotlight power to 90 and falloff to 30.

The light seems to bounce around pretty much as I'd expect, though there is something a bit odd going on where the walls meet in the corner.

"The light seems to bounce around pretty much as I'd expect, though there is something a bit odd going on where the walls meet in the corner." I believe that's caused by sampling artifacts, a rather well known issue with radiosity at low sampling. I raised this issue before in here, and it seems Vue 5 lacks certain user control over the radiosity solution that would help clean that up without stressing the calculations unnecessarily. Vue 5 Pro might have more detailed control over the radiosity solution, and allow this to be cleaned up easier.

maxxxmodelz; you could be right, but that's where it gets complicated! In Vue 5 Radiosity settings are represented as lighting models in the atmosphere editor, sampling is a function of the render quality editor.

I've minimised the strangeness here by getting rid of "lighting from sky" in the atmosphere editor. It's still not 100% correct, but good enough that I don't feel inclined to start upping the sampling rate in the renderer too. I think Vue 5 could improve on this, I just don't have the patience. :)

John

The forum wont let me post attach the Vue file (?). How does distance affect the lighting when using radiosity, is my box to big? (In the real world the result is different if you put a 100W light in a dollhouse or a sports arena). Is then 1 unit in Vue close to one inch? Heikki

hey ! try with object in your room ! place some chairs and play with shadows and light... you can see the results on radiosity... in an empty room result could be always strainge...

"How does distance affect the lighting when using radiosity, is my box to big? (In the real world the result is different if you put a 100W light in a dollhouse or a sports arena). Is then 1 unit in Vue close to one inch?"

I don't think that would have an affect in this case. What you are speaking of is known as "photometric lighting". Vue doesn't support this type of real world accurate lighting to scale that I know of, and radiosity is not the same as this either. Message edited on: 10/20/2004 16:35

"The forum wont let me post attach the Vue file (?)."

No, I think just jpg or gif, not even png! It has to do with php and streaming MIME types into a database, but that's boring...

"Is then 1 unit in Vue close to one inch?"

It's just a 'logical unit' as it really is in any 3D app. It has no relationship to any 'real world' measurement. You can, I think, do a reasonable job of simulating light decay by modifying settings on indivdual lights though.

"hey ! try with object in your room ! place some chairs and play with shadows and light... you can see the results on radiosity... in an empty room result could be always strainge..."

True, if you add some objects and textures then the inaccuracies are totally unimportant! If you're really into rendering empty, flat white, rooms with single lightsources though... :)

John.

Full support for photometric IES Lighting Systems is available in other apps, and does come in handy when modeling to scale for architectural design, but such a thing really isn't applicable here. I don't even think the Pro version will support .ies file format. ;-)