Hi everyone!

I have a problem with the Looks_Alike feature of light sources. Please see 
here an excerpt of my code:

#declare Signal=sphere // Signal Light
{
 < 0.0, 0, 0.0 > 0.05
 pigment { rgb < 0.8117647,  0.8941176,  0.5607843 > * 10 }
 finish { ambient 1.0 }
// no_shadow
}

#declare SignalLight=light_source
 {
  < 0.0, 0.0, 0.0 > color rgb < 0.8117647,  0.8941176,  0.5607843 > * 100
  looks_like { Signal }
  fade_distance 0.9
  fade_power 3.0
 }

Okay. When I now place such a "Signal Light" object, there is still no light 
effect. If I remove the Looks_Alike, the light is there. What is it I do 
wrong?

Thanks for your help.

Sven

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"Sven Littkowski" <sve### [at] jamaica-focuscom> wrote in message 
news:45571fc3@news.povray.org...
> Hi everyone!
>
> I have a problem with the Looks_Alike feature of light sources. Please see 
> here an excerpt of my code:
>
> #declare Signal=sphere // Signal Light
> {
> < 0.0, 0, 0.0 > 0.05
> pigment { rgb < 0.8117647,  0.8941176,  0.5607843 > * 10 }
> finish { ambient 1.0 }
> // no_shadow
> }
>
> #declare SignalLight=light_source
> {
>  < 0.0, 0.0, 0.0 > color rgb < 0.8117647,  0.8941176,  0.5607843 > * 100
>  looks_like { Signal }
>  fade_distance 0.9
>  fade_power 3.0
> }
>
> Okay. When I now place such a "Signal Light" object, there is still no 
> light effect. If I remove the Looks_Alike, the light is there. What is it 
> I do wrong?
>
> Thanks for your help.
>
> Sven

Hi Sven,

I'm not sure what you're saying is wrong with this.
I just added the following lines and I get a white sphere as I'd expect 
given the very high brightness of the values you have set for the colors, 
(the values get clipped and you lose the subtle green shading).

camera { location <0,0.1,-0.5> }
light_source { SignalLight }
plane {y,0 pigment {color rgb 0.01} translate -y*0.2}

I tried moving the light source around the scene a bit in case that was what 
you meant, but I still get both the lighting effect and the visible light 
source.
I'm on the Windows 3.6 Version.

Regards,
Chris B.

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Hi Chris B.,

I am using the latest beta 3.7. My problem is, that the little sphere is 
enlighted, but that there is no light spot at the underground I put the 
little sphere atop. Usually, it should behave light a tiny lightbulb. But 
just the sphere is bright, the environment near to the sphere is still 
dark...

It looks like the sphere blocks the flow of the light.

Sven

Post a reply to this message

"Sven Littkowski" <sve### [at] jamaica-focuscom> wrote in message 
news:4557cacf$1@news.povray.org...
> Hi Chris B.,
>
> I am using the latest beta 3.7. My problem is, that the little sphere is 
> enlighted, but that there is no light spot at the underground I put the 
> little sphere atop. Usually, it should behave light a tiny lightbulb. But 
> just the sphere is bright, the environment near to the sphere is still 
> dark...
>
> It looks like the sphere blocks the flow of the light.
>
> Sven

Hi Sven,

Hmm. I do get a light spot on the plane that I put beneath the light_source. 
Obviously it has to be within range of the 'fade' specified, so anything 
more than a couple of POV-Ray units away isn't going to get much light, but 
that would be the case with or without the 'looks_like' clause, so I'm 
assuming that's not your problem.

Just a thought;- did you check the release notes for the 3.7 Beta to make 
sure the various features that you're using are fully implemented?  As well 
as the 'looks_like' clause I'd recommend checking for any surface features 
or media features that you're using that might be incomplete in that Beta 
test version.

Regards,
Chris B.

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