Alright ... I just don't understand photons, I guess.
If I have read correctly, the use of photons will allow light to be focused
by a lens

I have tried, but failed!  Below is a transparent 'fog box' with a red light
shining through it.  There is a convex lens in the center.

If I set the photon 'target' value of the lens to anything except 0, it
blocks the light entirely.  If I set the target value to 0, then light
passes through without refraction.

What am I doing wrong, folks?

Alan Walkington
----------------------------------------------
#version 3.5;
#include "colors.inc"
#include "textures.inc"
#include "glass.inc"

global_settings {
  photons {
     count 20000
     autostop 0
     jitter .4
     gather 20, 100 //100, 100
     expand_thresholds 0.2, 30
  }
}

camera
{ orthographic
  location  <-60 *.7, 60 * .7, -60 *.7>
  look_at   <0, 0, 0>
}


box {    // fog box
   <-30,-15,30>,<30,15,-30>
   pigment { White filter 1 }
    hollow on
    interior{
        media {
        scattering { 1, rgb 0.03}
        intervals 1
        samples 5
        method 3
        }
    }
}

light_source {
    0*x
    color Red * 20
    spotlight
    translate <-60, 0 ,0>
    point_at <0, 0, 0>
    radius .1
    tightness 85
    falloff 5
    photons {
        refraction on
        reflection on
    }
}


light_source
{
  0*x
  color White * .8
  translate <0, 100, 0>
}

intersection {// lens
    sphere {
        <0, 49.25, 0>, 50
    }
    sphere {
        <0, -49.25, 0>, 50
    }
    cylinder {
        <0, 3, 0>,
        <0, -3, 0>,
        7.05
    }
    material {M_NB_Glass}
    photons {
        target  0
        refraction on
        reflection on
        collect off
    }
    rotate z*90
}
----------------------------------------------

Post a reply to this message