No, it doesn't work. The media tag in radiosity is just to tell the 
radiosity on the non-media objects to sample from the media. i.e. if you 
have a glowing red media next to a white wall you'll get red radiosity on 
the wall, but if you have a white scattering media next to a glowing red 
wall the media won't pick up any of the red.

It's a matter of the complexity of the problem. With light only coming from 
light sources the media needs to trace a shadow ray for every sample point 
inside the media, then numerically integrate the samples to work out how 
much self-shadowing the media is doing, which in turn requires multiple 
samples along the shadow ray, effectively an n^2 complex algorithm (though I 
suspect the pov implementation's a little more optimal than that). Anyway, 
if you wanted to do that with radiosity you'd need to do these shadow rays 
in random directions at every point, and to get a smooth effect you'd need 
far more samples than for an opaque object, and I'd guess that the tricks 
for smoothing out radiosity on opaque objects don't work nearly as well on 
media, so you could be talking about several orders of magnitude more 
complexity than just switching radiosity off and using a few extra light 
sources.

At least, that's how I think it works.

Still, I'm puzzled that there's no option to do it in POV. Pov's happy to 
let me do any of the hundreds of other things that give me infeasibly long 
render times :)

-- 
Tek
http://evilsuperbrain.com

"Jim Charter" <jrc### [at] msncom> wrote in message 
news:43ea53a5$1@news.povray.org...
> Orchid XP v2 wrote:
>>>> Looks nice, though small objects made of marble should show some 
>>>> sub-surface scattering, which would mean using media, which then 
>>>> wouldn't work with radiosity... Ah what fun :)
>>>
>>>
>>>
>>>
>>> Why doesn't media work with radiosity?
>>
>>
>> Beats me...
> I think the idea was that it works.....eventually.

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