Woody nous apporta ses lumieres en ce 2007/12/23 21:11:
> Can someone help me out with this scene? I'm trying to create a glowing
> cylindrical object (to look like a spotlight that fallsoff without using an
> actual light source) and I'm getting some results that look like coincident
> surfaces. Code is below.
> 
> Also, how would I go about modifying this so it does not look like a black end
> has been pasted on a green cylinder?
I would alter the scene as follow:
> 
> #include "colors.inc"
> 
> #declare cam_pos=(x*4+y*3+z*-2)*2;
> camera {
>  location cam_pos
>  look_at (x*1+y*0+z*0)*0.5
> 
> 
> }
> 
> 
> light_source {
>  cam_pos
>  color White // add *2 if this light is not bright enough
> }
> 
  cylinder { 0, <1,0,0>, 1

         pigment {rgbt 1} // No need to see the container
         hollow

         finish{ ambient 0.000 diffuse 0.000 specular 0}
         interior{
                 media{
                         emission y/2 // to prevent the oversaturation
//adjust the colour to your taste
                         density {gradient -x scale 1.01}//prevent second ramp 
from apearing
         }       }
         scale x*3
}

> 
> //remove this second light. It will make the rendering faster.
> light_source{
>         cam_pos
>         color White
> }
> 
> 
Whenever you have more than 1 light_source at the same location you should 
replace them with a single one having the sum of all the original ones. It 
render faster as you now need only 1 shadow test instead of two, or more. The 
color value of a light is not limited to 1.
light_source{0 color 2}
and
light_source{0 color 1} light_source{0 color 1}
both have exactly the same effect on your scene.

-- 
Alain
-------------------------------------------------
But I thought YOU did the backups...

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