In article <q2ipet4cijb6s9vn1bv6mkbrvo13qrlb4e@4ax.com>, akong@povrayNO-
SPAM.org says...
> On Sun, 29 Apr 2001 21:32:17 -0000 Bjorn Jonsson wrote:
> 
> >I'm having trouble getting a torus object to render properly. I've tried 
> >adding the sturm keyword but it seemed to have absolutely no effect on 
> >the torus' appearance. The torus appears "noisy", it's as if some of the 
> >rays do not hit it even though they should.
> 
>   Where's the rest of your scene code? I rendered what you gave and added a
> camera and light source but the resulting 90 degree 'elbow' looks fine to
> me. Without seeing the cylinders in the union it looks to me that you might
> be experiencing coincident surfaces. What do you see when you comment out
> the other objects?

Here is a greatly simplified (my original POV file is about 2500 lines) 
version of what I'm doing:

#include "colors.inc"

camera  {
   location <-5000,-25000,-40000>
   look_at <300,-1300,-1500>
   angle 1
//   location <-500,-2500,-4000>
//   look_at <300,-1300,-1500>
//   angle 10
}

light_source {
  <-5000,-16000,-30000>
  color White
}

torus  {
   66,33 sturm
   rotate x*90
   translate <-66,116,0>
   rotate z*90 rotate y*180 translate <175.5,-970,-1027>
   pigment {White}
}

This reproduces the problem. However, if I change the camera/angle to the 
one that's commented out in the above code the problem disappears ??! 
This problem appears in most/all of the renderings I have made of the 
complete object. In many of these angle is close to 10 degrees and the 
camera is 5-10 times farther away from the object than in this 
example. This is the only POV primitive I'm having problems with in this 
particular model which contains many POV primitives (spheres, cylinders, 
cones, prisms, triangle meshes, CSG objects etc.). Does anyone know of a 
workaround ?

Bjorn

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