CGAL users discussion list

[Stephane Tayeb <>]

Joe C wrote:
> Just one more question on the third template parameter 'Dummy_kernel'. I
> cannot see it is really used anywhere in the code. So why would changing it
> from Simple_cartesian_kernel to IGT solve the first issue when remeshing the
> cube?
>
> template <class Polyhedron, class Kernel, class Dummy_kernel>
> class AABB_polyhedral_oracle : public Polyhedron
> {
> ...
> }
>
>
>
> Joe
>
>
> please correct me if there is anything I missed:

Hi,

You are right. The following typedefs should be used (where Dummy_ could 
be any type):

typedef CGAL::Mesh_3::Robust_intersection_traits_3<Kernel> IGT;
typedef CGAL::AABB_polyhedral_oracle<Polyhedron,IGT,Dummy_> Input_surface;

Best regards,
Stéphane.

> On Tue, May 25, 2010 at 2:48 AM, Laurent Rineau (GeometryFactory) <
> >
>  wrote:
>
> > On Friday 21 May 2010 09:27:10 fp2008 wrote:
> > > Hi Andreas,
> > >
> > > I attached three OFF files. The remeshing tool crashes quickly when
> > > processing box.off and glass-mug.off, though it gets stuck instead with
> > > flash.off.
> > There are several issues.
> >
> > ** First, there is a non-exact use of the AABB_tree class, in the
> > Polyhedron demo. Please apply the following patch:
> >
> > --- demo/Polyhedron/Polyhedron_demo_remeshing_plugin_cgal_code.cpp.~BASE~
> >     2010-05-25 11:24:12.000000000 +0200
> > +++ demo/Polyhedron/Polyhedron_demo_remeshing_plugin_cgal_code.cpp
> >  2010-05-21 15:12:43.000000000 +0200
> > @@ -110,10 +110,10 @@
> >  //
> >  // Types for meshing
> >  //
> > -typedef CGAL::Simple_cartesian<double> Simple_cartesian_kernel;
> > +// typedef CGAL::Simple_cartesian<double> Simple_cartesian_kernel;
> >  // input surface
> > -// typedef CGAL::Mesh_3::Robust_intersection_traits_3<Kernel> IGT;
> > -typedef
> > CGAL::AABB_polyhedral_oracle<Polyhedron,Kernel,Simple_cartesian_kernel>
> > Input_surface;
> > +typedef CGAL::Mesh_3::Robust_intersection_traits_3<Kernel> IGT;
> > +typedef CGAL::AABB_polyhedral_oracle<Polyhedron,Kernel,IGT> Input_surface;
> >
> >
> >  // A base non-templated class, to allow
> >
> >
> > That will prevent the Surface_mesher from crashing on a simple cube
> > surface. Actually, a cube a something particularly difficult to mesh:
> >  - there are a lot of coplanar points,
> >  - there are sharp edges (that the Surface_mesher package cannot mesh
> > properly).
> >
> >
> > ** Second, your file glass-mug.off is not a triangulated surface. Please
> > use the menu entry Operations->Triangulate facets before launching the
> > remeshing function.
> >
> > ** Third, your file flash.off is triangulated, but quite difficult to mesh:
> > it has two cylindrical patches of surface that are very close from each
> > other. It means that the least feature size of this surface
> > is very small. You need to decrease the sizing field by a magnitude.
> > However, I agree there is a problem in the surface mesher, because I have
> > not been able to mesh that object without the assertion. Again, I
> > know that the problematic feature is the coplanar facets at the bottom of
> > the object. We have solutions for that, but the merge with the branch of
> > CGAL-3.6 is not easy.
> >
> > --
> > Laurent Rineau, PhD
> > R&D Engineer at GeometryFactory           http://www.geometryfactory.com/
> > Release Manager of the CGAL Project       http://www.cgal.org/
> >
> > --
> > You are currently subscribed to cgal-discuss.
> > To unsubscribe or access the archives, go to
> > https://lists-sop.inria.fr/wws/info/cgal-discuss


--
Stephane Tayeb
Software engineer - INRIA Sophia Antipolis
Geometrica Project-Team