"feestje" <fee### [at] gmailcom> wrote in message 
news:web.490ee8fda1a15775934be4af0@news.povray.org...
> I want to use a plane that emits light. This is the codeI am
> using:
>
> light_source
> { <0,0,0>, 1
>  looks_like {
>  plane {
>     z, 1000
>     pigment {
>         color White  }
>             finish {
>          ambient 1 }
>
> }  }}
>
>
> it seems the only light production from this code is because of the 
> ambient
> statement.
>
> is it even possible to have a plane emit light?

The 'looks_like' keyword adds an object with no shadow that represents what 
the light_source (which is normally invisible) looks like from the outside. 
A plane has an inside and an outside, as determined by the surface normal 
specified, so, in this case, unless your camera is at a position where 
z>1000 then it's going to be inside the plane along with the light_source, 
which gives you your first problem. Secondly the object specified using the 
'looks_like' keyword doesn't change the way the light_source illuminates the 
rest of the scene, so you'll still get light of the color specified in the 
light_source definition eminating from the location specified (ie a point 
source).

If your camera is somewhere near the origin then I suspect you need to 
adjust your plane to -z,-1000, so that the front surface is in the same 
place but so that everything beyond z*1000 is inside it, then move your 
light_source inside it (e.g. to <0,0,1001>).
To get the light to come from a broader area than a single point source you 
might want to look at using an area_light. If you want the rays to come in 
parallel you may want to check out the 'parallel' keyword in the help.

Regards,
Chris B.

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