POV-Ray : Newsgroups : povray.beta-test : Media photons too bright : Re: Media photons too bright Server Time
30 Jul 2024 08:21:22 EDT (-0400)
  Re: Media photons too bright  
From: Nathan Kopp
Date: 2 Dec 2001 00:50:31
Message: <3c09c127@news.povray.org>
"Slime" <noo### [at] hotmailcom> wrote...
> I posted this bug a *long* time ago, and although Nathan said he was
> "looking into it", that was four betas ago. So, if someone could confirm
> this, that'd be great, or if not, i'd at *least* appreciate if someone put
> it on the unconfirmed bugs list. Thanks, I just want to make sure
> something's being done, this is the only bug I really care about right
> now... *sniffle*...

I apologize.  I've been so busy with "Real Life" recently that I've somewhat
neglected work on POV 3.5.

Anyway, the issue here (if I remember correctly) was with the interaction of
no_shadow and photons.  There are many different ways that this interaction
could be defined.  The reason for the darkness with "no_shadow" is that the
photon ray ignores the media object when no_shadow is enabled.  It does that
to avoid causing a shadow in the photon map.  I think this is probably a
bug, since the photon ray should hit the object, but then somehow the
intensity cannot be decreased... but then we must ask how IOR should
interact with no_shadow... argh, now I'm starting to remember how complex
this whole no_shadow issue is!!!!  The problem is that photons are
inherently physically CORRECT, but no_shadow is by definition physically
INCORRECT, which makes consistency rather difficult (if not impossible).

Anyway, I still don't know why the media is so bright.  Hopefully I'll get
some time to look into it soon, but if someone else wants to try (with the
MegaPov source code), go ahead!

-Nathan


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