stm31415 wrote:

> I believe the problem is with your isosurface, not the gammma. There is
> artifacting on the upper half as well. As to waht to do about that, I am
> not sure. Are you doing anything odd w/ your functions?
> 

Don't think so.  Pretty much straight from Mike Williams.

Here's the exact file I tested with:

global_settings {
         assumed_gamma 1.0
}

camera {
   location  vrotate ( <0,0,-12>, <10,0,0> )+<-1,0,0>
   look_at   <0.0, 0.0,  0.0>+<-1,0,0>
   right     x*image_width/image_height
   angle 20
}

light_source {
   0*x                  // light's position (translated below)
   color rgb <1,1,1>    // light's color
   translate vrotate ( <0,0,-20>, <40,60,0> )
}


isosurface {

         function { x*x + z*z - .45*.45 }

         contained_by { box { -1, 1 } }
         accuracy 0.001
         //max_gradient 2.772
         evaluate 5, 1.2, 0.95

         texture{
                pigment {
                         rgb <1,.9,.7>
                }
                finish {
                         ambient 0
                         diffuse 1
                }
         }
}


cylinder {

         <-2,1,0>, <-2,-1,0>, .45

         texture{
                 pigment {
                          rgb <1,.9,.7>
                 }
                 finish {
                          ambient 0
                          diffuse 1
                 }
          }
}

BTW if I set assumed_gamma to 2.2 I get the same result as if
I don't specifiy it at all.

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