Ken wrote:
> 
> tommaso wrote:
> >
> > Please help me,
> >
> > Declared:
> >         A = Solid  (Cone, box, cylinder)
> >         B = Polyhedron (Prism or generic surface realized with union of
> > polygons)
> >
> > I want to make
> >
> > difference:
> >                 1)      A - A    (OK)
> >                 2)      A - B   no results
> >                 3)      B - A   no surface of difference
> >                 4)      B - B   no results
> >
> >                 What is the solution for the cases 2,3,4 ?
> >
> > Excuse my english,
> >
> >                 Thanks
> >
> >                 Tst### [at] capoleucait
> 
>   Polygons, bicubic patches, meshes, triangles and a two other types
> of pov objects are considered infinitely thin objects. They have no
> well defined inside and outside. Because of this they are not allowed
> to be used in a CSG operation except for the union CSG operation.

All is not lost.  It is possible (though tedious) to construct a
polyhedron as the intersection of planes such that one could perform CSG
operations with it.

-- 
Mark Gordon
mtg### [at] mailbagcom
http://www.mailbag.com/users/mtgordon/index.html

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