Hi!

I wanted to cut a "pyramid without a top" out of a box. This is for a
backround of a game so I used an orthographic camera.
  But the shading is all wrong. To show the problem, I squeezed the
prism to have a really shallow angle (see the scale-statement in the
prism), so nearly no difference in the shading of the box and the cutted
out surface should be visible. Uncommenting the first three lines in the
camera-statement shows the problem.

On a sidenote, if you change the perspective camera to a location 37000
y-units far away, and an angle of 1, the problem is turned around. (I
guess, this is due to precision issues... - But there are no gigantic
numbers in the orthographic case.)

My POV-Ray Version is 3.6.1.icl8 on WinXPSP2
Any Ideas?
Thank you!
Kalle

//Sourcecode starts here

camera {
//  orthographic
//  right <650,0,0>
//  up <0,490,0>
   location <320,500,240>
   look_at <320,000,240>
}

difference {
   box {<0,-1,0>,<1+1/3,0,1>}
   prism {
     conic_sweep
     1.1,0.8,4
     <-0.5,0.5>,<-0.5,-0.5>,<0.5,-0.5>,<0.5,0.5>
     translate -y
     scale <1,.000005,1>
     translate y
     translate <0.5,-1,.5>
   }
   pigment { green 1 }
   scale 480
}

light_source {
   <240,500,-240>
   color rgb 1
}

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