material question: gold mosaic


I wish you a happy new year!

I am working on a simulation of a certain phase of a historical building. My
job is to do the light sim, and of course I try to do this with radiance :wink:
While I am getting more and more successful concerning the reuse of big and
bad CAD-models, I am getting some problems with materials now...

I have got quite a lot of material data of the building. Most of the
interior has marble surfaces, in different colors, which we have documented and
which should be well representable by radiance modifiers.

But the really difficult part seams to be the gold mosaic. E.g. there is a
dome which has a surface of gold mosaics, afaik with glass in front of the
gold pieces afaik. Now I could use a gold material, but this is far from the
real interior (while it might be ok to get the light simulation, the impression
of the dome wouldn't be the same). So I wonder how to define this.

So should I try to use gold with roughness? I know this is a different
effect, but as I view from quite a distance (in most cases), it might be
sufficient to get quite close to it.

The best solution seams to be the use of brdfs, as those could really
represent the behaviour of the gold pieces. Do you think this would be necessary,
and is there anyone who has such data?

Maybe someone tried similar things in radiance before and might give me a

Thank You, CU, Lars.

BTW: I compiled the 3r4 yesterday on an x86 (K6-2 3D) with gcc on SuSE Linux
7.0 (kernel 2.2.1x) and this seamed to be ok, I couldn't really verify that
everything works, but I was able to render a quite big scene.


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