"Marc-Hendrik Bremer" <Mar### [at] t-onlinede> wrote in message
news:39d71e43@news.povray.org...
| Here is the scene file which renders a black media object under the clouds
| in front of a blue background. (See p.b.I. for an example image with has a
| different background). Please try if you get the same results or if it is
| white in your case.

Well, this much is fairly certain.  It's the polygon primitive causing it,
or at least something about it is.  I thought perhaps odd/even number of
them at first but no, that didn't make any difference.
Using the plane instead is fine as you probably know.
Nothing I can really say definite about it.  I mean, it sure doesn't seem to
be a inside/outside hollow problem since it's not disappearing only getting
darkened.
There might be previous mention of polygon not coexisting well with media
but if there is I don't know about it.

Addendum:
Wrong!  Well, partly wrong anyhow.  I'm leaving the first part of my reply
to prove how mistaken a person can be while trying to debug their scene
files (everyone knows that, don't they...?)
I was curious why I didn't see it the same this time as before.  Because I
had used my own light and camera!  Apparently the light location has a lot
to do with it, although it's still related to polygon in some way.
If the light source is further away from the camera line of sight the media
becomes darker.  Much like media type 5 (Henyey-Greenstein) would do I
guess, where it is less or more scattering depending on light direction.
Even absorption might behave similarly, however since none of these are used
it still remains the polygon in question.
It could be something to do with the high density amount too possibly but
that's pure conjecture from me.
Hope I've shed some light (pun) on the problem anyway.

Bob

Post a reply to this message