POV-Ray : Newsgroups : povray.beta-test : light_group+media bug Server Time
31 Jul 2024 06:13:12 EDT (-0400)
  light_group+media bug (Message 1 to 4 of 4)  
From: Lutz-Peter Hooge
Subject: light_group+media bug
Date: 11 Sep 2001 09:45:48
Message: <MPG.160834111f191173989688@news.povray.org>
scattering media seems to be always and only illuminated by global 
light_sources, even if "global_lights off" is specified.

Also, Pov always gives a warning "no pigment type given" when using 
light_groups.

here a small scene to demonstrate it

#version 3.5;

global_settings
{
	assumed_gamma 1
	ambient_light 0
}

camera
{
	location <0,0,-5>
	look_at <0,0,0>
}

#macro light_marker(rad,col)
sphere
{
	0,1
	hollow
	pigment{color rgbt 1}
	interior
	{
		media
		{
			emission 1/rad*col
			density{spherical}
		}
	}
	scale rad
	
}
#end

light_source
{
	<1.5,1.5,-1>
	color rgb <1,0,0>
	looks_like{light_marker(.5,<1,0,0>)}
}

light_group
{ 
	
	light_source
	{
		<-1.5,1.5,-1>
		color rgb <0,0,1>
		looks_like{light_marker(.5,<0,0,1>)}
	}
	
	sphere
	{
		<0,0,0>,.5
		hollow
		texture{pigment{color rgbt 1}}
		interior
		{
			media
			{
				scattering{1,color rgb 10}
				intervals 3
			}
		}
	}
	
	global_lights off
}


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From: Mr  Art
Subject: Re: light_group+media bug
Date: 12 Sep 2001 00:35:29
Message: <3B9F1E55.85A6A12A@chesapeake.net>
It's almost as if it expects the light group to have a pigment:
the no pigment given error is reported even when there are no objects in
the group.

Lutz-Peter Hooge wrote:
> 
> scattering media seems to be always and only illuminated by global
> light_sources, even if "global_lights off" is specified.
> 
> Also, Pov always gives a warning "no pigment type given" when using
> light_groups.
>


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From: Ken
Subject: Re: light_group+media bug
Date: 12 Sep 2001 01:29:50
Message: <3B9EF3C4.C694168A@pacbell.net>
"Mr. Art" wrote:
> 
> It's almost as if it expects the light group to have a pigment:
> the no pigment given error is reported even when there are no objects in
> the group.

The POV-Team is fully aware of this problem and should have a fix in
the next release (I think).

-- 
Ken_Tyler_POV_Ray_Technical_Assistance_Group


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From: Thorsten Froehlich
Subject: Re: light_group+media bug
Date: 12 Sep 2001 10:45:37
Message: <3b9f7511$1@news.povray.org>
In article <3B9F1E55.85A6A12A@chesapeake.net>, "Mr. Art" 
<mra### [at] chesapeakenet> wrote:

> It's almost as if it expects the light group to have a pigment:
> the no pigment given error is reported even when there are no objects in
> the group.

Because internally light_groups are handled like a special kind of CSG
object.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

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