CGAL users discussion list

[Olivier Devillers <>]

Le 4/19/12 3:32 PM, ochyomdu a écrit :
> Hallo Dimitris.
>
> The easiest way to calculate intersection of two polyhedrons is using of
> class Nef_Polyhedron_3.
>
> If You need to use some functions from Polyhedron_3 You can just convert
> Polyhedron_3 into Nef_Polyhedron_3 (using constructor), calculate
> intersection of polyhedrons and convert the resulting Nef_Polyhedron_3 into
> Polyhedron_3 back (using function convert_to_polyhedron()).
>
> Intersection is calculated with operation *
> N1*N2
>
> You find more information about Nef_Polyhedron_3 here:
> http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Nef_3/Chapter_main.html

yes,
but it will be quite inneficient if the two polyhedra ere known to be 
convex.

by dualization and convex hull you will do it in (N1+N2)log(N1+N2)

(and nef-polyhedra deals with very special cases (degenerate) but for that
they require exact arithmetic and it costs some time)