POV-Ray : Newsgroups : povray.unofficial.patches : 'normal' is not taken into account in radiosity Server Time
2 Sep 2024 22:15:15 EDT (-0400)
  'normal' is not taken into account in radiosity (Message 21 to 23 of 23)  
<<< Previous 10 Messages Goto Initial 10 Messages
From: Margus Ramst
Subject: Re: 'normal' is not taken into account in radiosity
Date: 17 Nov 1999 05:53:23
Message: <383289CC.E033425E@peak.edu.ee>
By the way:
For an inter-reflection model to be considered physically correct, for one it
would have to be able to treat diffuse and specular reflection as one, i.e. it
should also be able to model inter-reflections of semi-diffuse surfaces. While
forward Monte Carlo tracing could _theoretically_ do this, I see no way of doing
it with a manageable number of samples.
AFAIK, POV's radiosity can do recursion because its sample rays are always
distributed around the surface normal, so it can terminate recursion for the
current ray when this ray hits an already-calculated sample. With specular
properties, the bias of the new sample rays would start to depend on the
direction of the incoming ray. So old samples could not be reused - they would
be taken from a different direction.
I'm wondering if backward tracing, like photon mapping, could overcome this
problem...
If I'm not mistaken, Radiance can do it. But Radiance uses the wavelet method,
which is completely alien to me. I don't know if (true) radiosity can model
non-diffuse reflection. For some reason, I doubt it.

Margus


Post a reply to this message

From: Nieminen Juha
Subject: Re: 'normal' is not taken into account in radiosity
Date: 17 Nov 1999 05:53:24
Message: <38328924@news.povray.org>
Btw, if you haven't seen me pov3.1g vs. uvpov6 radiosity speed
comparison yet, see my post in p.b.images.
  The difference in speed is marvelous.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/


Post a reply to this message

From: Mike
Subject: Re: 'normal' is not taken into account in radiosity
Date: 22 Nov 1999 01:51:33
Message: <3838E580.4CF28AC2@aol.com>
> It would be nice if we could get it precalculated for the whole scene and
> then you could just render and render without having to figure it out again
> for each and every frame.

I explained how to do this in the thread "UVPov alpha 6" in case anyone feels
like doing it.  Unfortunately time doesn't permit me to it myself right now.

-Mike


Post a reply to this message

<<< Previous 10 Messages Goto Initial 10 Messages

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.