CGAL users discussion list

[Andreas Fabri <>]

Hello,

Besided exactness issues, note that you are in charge to initialize the
planes associated to the faces. The data structure only provides the
storage.

andreas

Max wrote:
> > I am using CGAL::Simple_cartesian<double>  as Kernel. for Polyhedron_3.
> > In my algorithm I need to compute the intersections of the planes
> > induced by the faces of the polyhedra. That seems to work fine.
> > But when I try to compute the intersections of the resulting
> > intersection lines there seems to be a problem.
> > CGAL says there is no intersection, but when I display the lines there
> > is an intersection.
> >
> > I guess what I need is an intersection test which accepts a delta value
> > to be more stable.
> > I tried to find a function which computes the minimum distance between
> > the lines and the point where this minimum distance occurs, but without
> > success.
> >
> > Do I need to implement my own tests or can I do this with CGAL? A hint
> > would be nice :)
> >
> > Best Regards,
> > Matthias
>
> CGAL will give the exact result, more exact than what you can see with your
> eyes, as long as you are using an exact kernel.
>
> Generally, you should use exact kernel types playing with (nef_)polyhedra.
>
> The predefined Exact_predicates_exact_constructions_kernel is a good choice.
>
> HTH.
>
> B/Rgds
> Max