"Michael Raiford" <mra### [at] hotmailcom> wrote in message
news:40cc619e@news.povray.org...
>
> From what I have seen the coincident surfaces problem usually manifests
> itself as a random speckling of the object and/or light source. In
reality,
> the spotlight should not affect the cabinet above them. I am a bit
suprised
> I didn't see the usual coincident surfaces issue before in this scene.

Yeah, well, I wouldn't place any light at a surface even if it is a
spotlight pointing away from it. Just asking for trouble.
:-)

> All in all, this has the hallmarks of an accuracy problem. (i.e. really
far
> away objects viewed with a really narrow camera angle seem to have
drop-out
> like this). But in my case, the values are within practical limits..

It definitely merits looking into, I believe. What I thought was fixed by
moving the light sources actually remains artifact-prone when changing
resolutions. Very peculiar. Has me baffled since the scene file isn't what
I'd call extreme, so worries me a little. A couple area lights, three spot
lights, some primitives like box, plane, cylinder, sphere... I checked using
a simple pigment {color rgb 1} in place of the textures, and the blanking
out parts stayed so I figured it couldn't be related to max_trace_level.

Just now, I found out the 'media on' in radiosity will cause the blanking.
Commenting it out I can render the scene okay even though all lights are in
their original positions. I should have tried that before. In fact, there's
a relation with 'count' too, because count 50 clears it up while media is
on.

It's times like this I wish I had done more beta testing.

Bob H.

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