clipka <nomail@nomail> wrote:
> If the mesh is open I'd expect whacky results from CSG operations. For example,
> if you intersect an open mesh and a solid object, the resulting object will
> *not* behave like a "cut-out" piece of the mesh; instead, I'd expect certain
> parts of the other object's surface to be visible as well, namely all those
> areas where a ray, when shot along the inside vector, would enter through a
> "hole" into the inside of the mesh. (This is just a guess, but be prepared to
> get something like this or similar.)

  There's nothing really strange about solid meshes which do not form a
closed surface, as long as the inside_vector is defined properly.

  Sure, you'll get odd behavior sometimes, but so you do with other solid
primitives which are not closed surfaces, such as planes and heightfields.
(I assume that many povray users don't realize the heightfields *are* solid
and can be used in CSG. Everything under the heightfield is considered to
be inside. The same goes for planes.)

  If you have a planar mesh, then simply define an inside_vector for it which
is perpendicular to its surface, like you would do with a plane. This way one
side of the mesh will be inside and the other outside, exactly like with a
plane.

-- 
                                                          - Warp

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