/* Hi, Christoph

I don't think the root solver is the problem, because it
works perfectly with, for example, standard spheres, but not
with the *same* spheres modeled by a poly.
I have continued to experiment with polys and I'm irritated
even more -- just look at my intersection of three orthogonal
semitransparent poly-planes. Even these _most_simple_ polys
create cutting-faces that are too large (by _exactly_ 0.0001 --
compare with the white sphere: the same value as with my drop).
Replace the polys by the equivalent planes and everything will
be perfect. Do you understand the shadows? Especially: where do
the small triangular "shark shadow" on the white sphere and the
big one at the bottom left corner of the picture come from? Not
to mention the bizarre patterns on the white box!

    Sputnik

P.S. The 'origin' of the checker pattern isn't <0, 0, 0>, it
is -- you guess it -- <0.0001, 0.0001, 0.0001>! Why? Also a
root solver accuracy? Where does this magic number come from?


fr### [at] computermuseumfh-kielde


*/
// VERY simple example of poly error
intersection {
  poly { 2, < 0,0,0, 1, 0,0,0,0,0,0 > sturm } // plane { x, 0 }
  poly { 2, < 0,0,0,0,0,0, 1, 0,0,0 > sturm } // plane { y, 0 }
  poly { 2, < 0,0,0,0,0,0,0,0, 1, 0 > sturm } // plane { z, 0 }
  texture  { 

    pigment { color rgbt < .6, .7, 1, .5 > }
    finish { ambient .3 specular .2 }
    }
  }

// white sphere, just as landmark and size-comparator
sphere { 0, 0.0001 texture { pigment { color rgb 1 } } }
//white box, to catch bizarre shadows
box { <0, 0, 0.0002>, <0.00045, -0.0008, 0.00021>
  texture { pigment { color rgb 1 } }
  }

light_source { <-1, 1, -1> color rgb 2 }
camera {
  location <1, 1, -1>/2000 // also use "/200": _seems_ to be OK
  look_at -0.0002*y
  }

// E N D ======================
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