POV-Ray : Newsgroups : povray.general : media interaction problem Server Time
4 Aug 2024 02:23:09 EDT (-0400)
  media interaction problem (Message 1 to 6 of 6)  
From: Slime
Subject: media interaction problem
Date: 30 Aug 2003 22:16:15
Message: <3f515a6f$1@news.povray.org>
I have some clouds in my scene (scattering media). They're lit by a single
"sun" light source.

For a separate lighting effect, I have some large area_lights in the scene.
They have media_interaction off because I don't want them to make the clouds
brighter - I only want them to light up the solid surfaces in the scene.
This is easy enough.

Unfortunately, despite the "media_interaction off," the clouds are still
casting a shadow from the area_lights. I don't really mind the shadow so
much, but what I *do* mind is that the varying shadow is causing the
adaptive area_light sampling to be useless, making my scene extremely slow
to render.

Does anyone know of a way that I can force the area_lights to ignore the
media when shadows are being calculated?

Thanks for your help. Let me know if I need to describe the problem better.

 - Slime
 [ http://www.slimeland.com/ ]


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From: Warp
Subject: Re: media interaction problem
Date: 31 Aug 2003 08:39:45
Message: <3f51ec91@news.povray.org>
Slime <fak### [at] emailaddress> wrote:
> Does anyone know of a way that I can force the area_lights to ignore the
> media when shadows are being calculated?

  I wonder if light groups could help here.

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -


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From: Slime
Subject: Re: media interaction problem
Date: 31 Aug 2003 11:50:16
Message: <3f521938$1@news.povray.org>
>   I wonder if light groups could help here.

I thought of that... but I'm pretty sure that no matter what light group an
object is in, the object will always cast a shadow for every light in the
scene - even if that light is in another light group. All light groups can
do is keep lights from illuminating other objects.

I did think of one solution which would *almost* work: projected_through. If
I put an object between the area light sources and the solid surface, and
projected_through it, then the clouds wouldn't interfere. However, this
would only work in the case where the clouds are separate from the solid
surface, and in my scene, the surface is *inside* the clouds. So no matter
how close I put the projected_through object, there'll still be media
between it and the surface.

Still thinking...

 - Slime
 [ http://www.slimeland.com/ ]


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From: Christopher James Huff
Subject: Re: media interaction problem
Date: 31 Aug 2003 18:05:42
Message: <cjameshuff-5C59B0.18054231082003@netplex.aussie.org>
In article <3f515a6f$1@news.povray.org>, "Slime" <fak### [at] emailaddress> 
wrote:

> Does anyone know of a way that I can force the area_lights to ignore the
> media when shadows are being calculated?

Have your lights fade with distance. When they reach the clouds, they 
will be too dim to show up. POV may be able to avoid doing the full 
lighting calculations when distant enough, if not it is something that 
probably should be added.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


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From: Slime
Subject: Re: media interaction problem
Date: 31 Aug 2003 20:22:17
Message: <3f529139$1@news.povray.org>
> Have your lights fade with distance. When they reach the clouds, they
> will be too dim to show up.


The clouds are between the lights and the surfaces.

 - Slime
 [ http://www.slimeland.com/ ]


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From: Christopher James Huff
Subject: Re: media interaction problem
Date: 31 Aug 2003 21:03:25
Message: <cjameshuff-F29D49.21032431082003@netplex.aussie.org>
In article <3f529139$1@news.povray.org>, "Slime" <fak### [at] emailaddress> 
wrote:

> > Have your lights fade with distance. When they reach the clouds, they
> > will be too dim to show up.
> 
> The clouds are between the lights and the surfaces.

Oh...maybe you should describe what you're trying to do a little more.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


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