[vtkusers] a polyhedron is convex or non-convex

[Andrew Maclean]

I don't think this will work, this is, in general, a difficult problem. Look
at http://www.cs.mcgill.ca/~tflook/geo/ also hunt up the reference at the
end of the paper *Olivier Devillers, Giuseppe Liotta, Franco P. Preparata,
and Roberto Tamassia, *"*Checking the Convexity of Polytopes and the
Planarity of Subdivisions*".



On 1/22/07, PAUL <polinzhuo at 163.com> wrote:
>
>  I want to judge whether a polyhedron is convex or non-convex by an
> algorithm. The algorithm is : if every vertex of the polyhedron is convex
> then the polyhedron is convex.
>
> For each vertex, there is at least three vertexes is adjacent to it. These
> vertexes make up of a triangle which forms a plane. Because the direction of
> the plane can be gotten by the order of three vertexes according to
> right-hand-rule, the order of three vertexes must be counter-clockwise.  If
> the vertex is above the plane, the vertex is convex. If not, the vertex is
> non-convex.
>
> But I cannot assure the order of three vertexes is counter-clockwise.
>
> And have you a better way to the question?
>
> Look forward to your reply again.
>
>
>
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-- 

___________________________________________
Andrew J. P. Maclean
Centre for Autonomous Systems
The Rose Street Building J04
The University of Sydney  2006  NSW
AUSTRALIA
Ph: +61 2 9351 3283
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