Wasn't it David Wallace who wrote:
>When I try to subtract a torus whose inner radius exceeds its outer radius
>from a cylinder, it leaves an ovoid behind.

Yes. What else would you expect it to do?

A fat torus is a self-intersecting shape. Under normal circumstances
there's a hole inside. When you difference the torus out of some other
object, then the bit that was the hole gets left behind.

You don't normally see the hole inside the fat torus because it's
completely inside, but you can see it if you make the surface
transparent or cut a little hole in it.

camera { location  <0, 0, -15> look_at <0, 0, 0>}

light_source {<10,10,-100> colour rgb 1}

torus {1.5,3
  rotate <90,55,0>
  clipped_by {plane {-z,3.5}}
  pigment {rgb 1}
  no_shadow
}

Post a reply to this message