"Mike Hough" <Ama### [at] aolcom> wrote in message
news:3cead5cf$1@news.povray.org...
> I tried using photons in a scene recently and was suprised at how long it
> took to render it in 3.5 RC5.  I'm posting in this group in case I'm
missing
> some subtle change in the photon syntax. The following scene at 320x240,
AA
> 0.3 takes 19 seconds to render in MegaPOV 0.5 and 3 minutes 37 seconds to
> render in RC5.

That's interesting. I hadn't made any such comparisons.
Reposting your script below because it lacked a couple braces and maybe
slightly easier for people to try that way.
But also, you hadn't put a photon block into the light source... so I did
and turned reflection off since there isn't any reflective objects present.
Doing a quick 160x120 without AA I had the following results:

Only refraction on (photons {} in light)
Parse = 0s
Photons=3s
Trace=80s

Reflection and refraction (or no photons{} in light)
Parse = 0s
Photons=3s
Trace=82s

Not exactly anything significant. However, I tried again with a
        photons {
                collect off
                }
added to only the union of that cylinder pair which is differenced from the
remainder cylinder and the render time increased 8 fold.
I stopped there because I couldn't figure the logic in your CSG creation.
:-)

________________

/* #version Unofficial MegaPOV 0.5; */
global_settings {
   photons {
     count 100000
     autostop 0
     }
 }

#declare WATERMAT =
material {

texture {
        pigment {color rgb <1, 1, 1> filter .9}
        finish {
        ambient 0
        }
        normal {bozo scale 1 bump_size 5}
}
interior
        {
        ior 1.33
        }
}

disc {<0, 0, 0>, <0, 1, 0>, 5
material {WATERMAT}

photons{
  target
  refraction on
  collect off      /* 3.5 */
  /*ignore_photons*/ /* mega */
}
}

camera {location <5, 15, -25> look_at -2*y angle 27}

light_source {<0, 0, -100> color 1*<1, 1, 1>
rotate 55*x rotate -170*y
        photons {
                reflection off
                refraction on
                }
}

difference {
cylinder {<0, -2, 0>, <0, .6, 0>, 6.5
pigment {color rgb <1, 1, 1>}
}

union
        {
cylinder {<0, -3, 0>, <0, 2, 0>, 5}
cylinder {<0, -3, 0>, <0, 2, 0>, 6 inverse}
pigment {color rgb <1, 1, 1>}
}
finish {ambient 0}
}

plane {y, -2
pigment {color rgb <1, 1, 1>}
finish {ambient 0 diffuse .5}
}

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