CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Qianqian Fang wrote:
> On 03/21/2011 10:47 AM, Sebastien Loriot (GeometryFactory) wrote:
> > > http://nmr.mgh.harvard.edu/~fangq/temp/post_extract.off
> >
> > Your off file contains triangles that are not consistently oriented
> > to describe a polyhedron. You need to reorient triangles.
> >
> > If you use the Polyhedron demo of CGAL, do:
> > "Operations -> Orient polygon soup"
> > To produce a 3D mesh you can then do:
> > Save in back to an off file and reload it.
> > Then do:
> > "Operation -> Create a tetrahedral mesh"
> >  or directly use your code.
>
> I used JMeshLib (http://jmeshlib.sourceforge.net/) to reorient
> all triangles, but the output surface mesh still crashed the
> polyhedral mesher. The surface meshes before and after
> the reorientation can be found here
>
> http://nmr.mgh.harvard.edu/~fangq/temp/pre_cgalpoly.off
> http://nmr.mgh.harvard.edu/~fangq/temp/pre_cgalpoly_reorder.off
>
> any more comments?
>
> thanks
>
> Qianqian
Can you provide the code, because it is working fine for me.

If you copied-pasted an example, you should adapt the parameter
values of the criteria because those in the example are proper to the
hard-coded model (in particular size criteria).

The demo and the following worked for me:

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>

#include <CGAL/Mesh_triangulation_3.h>
#include <CGAL/Mesh_complex_3_in_triangulation_3.h>
#include <CGAL/Mesh_criteria_3.h>

#include <CGAL/Polyhedral_mesh_domain_3.h>
#include <CGAL/make_mesh_3.h>
#include <CGAL/refine_mesh_3.h>

// IO
#include <CGAL/IO/Polyhedron_iostream.h>

// Domain
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Polyhedron_3<K> Polyhedron;
typedef CGAL::Polyhedral_mesh_domain_3<Polyhedron, K> Mesh_domain;

// Triangulation
typedef CGAL::Mesh_triangulation_3<Mesh_domain>::type Tr;
typedef CGAL::Mesh_complex_3_in_triangulation_3<Tr> C3t3;

// Criteria
typedef CGAL::Mesh_criteria_3<Tr> Mesh_criteria;

// To avoid verbose function and named parameters call
using namespace CGAL::parameters;

int main()
{
  // Create input polyhedron
  Polyhedron polyhedron;
  std::ifstream input("pre_cgalpoly_reorder.off");
  input >> polyhedron;

  // Create domain
  Mesh_domain domain(polyhedron);

  // Mesh criteria (no cell_size set)
  Mesh_criteria criteria(facet_angle=25,
                         facet_size=3.5,
                         facet_distance=3.5,
                         cell_radius_edge=3);

  // Mesh generation
  C3t3 c3t3 =
  CGAL::make_mesh_3<C3t3>(domain,criteria,no_perturb(),no_exude());


  return 0;
}