CGAL users discussion list

[Michel Audette <>]

Hi Laurent,

this polyline code was taken verbatim from the example

examples/Mesh_3/mesh_two_implicit_spheres_with_balls.cpp

  Polylines polylines (1);
  Polyline& polyline = polylines.front();
  
  for(int i = 0; i < 360; ++i)
  {
    Point p (1, std::cos(i*CGAL_PI/180), std::sin(i*CGAL_PI/180));
    polyline.push_back(p);
  }
  polyline.push_back(polyline.front()); // close the line

  // Insert edge in domain
  domain.add_features(polylines.begin(), polylines.end());
  
I don't understand why what is admissible for the implicit function example is inadmissible for the polyhedral surface input. Can you elaborate? Sorry to be a pest... 

Cheers, 

Michel




On Tue, Jun 14, 2011 at 5:32 AM, Laurent Rineau (GeometryFactory) <> wrote:
>
> On vendredi 10 juin 2011 23:20:31 Michel Audette wrote:
> > Hi Laurent,
> >
> > I'm seeing the following error, with a number of different choices for mesh
> > size...
> > *
> > terminate called after throwing an instance of 'CGAL::Assertion_exception'
> >  what():  CGAL ERROR: assertion violation!
> > Expr: sq_d > 0
> > File: /usr/local/include/CGAL/Mesh_3/Protect_edges_sizing_field.h
> > Line: 416
> > Aborted
> > *
> > I've been using the following code... See below. So far, I'm trying to get
> > a result with constant tet size, even though the surface mesh size has
> > edges varying between about 10 and 40mm.
> >
> > Is this a bug related to the new boundary faithfulness implementation or a
> > consequence of a mismatched size objective?
>
> The set of polylines that you specify with domain.add_features(...) must be a
> graph. The vertices of this graph are the endpoints of the polylines (not all
> points, just the two endpoints of each polyline), and the edges of this graph
> are the polylines. The polylines must not intersect but at their endpoints.
>
> I had a look at your code, and I saw that, as set of feature curves, you
> entered only one polyline with all vertices of the input polyhedron, in the
> order of the vertices iterator. Depending on your polyhedron, that polyline
> probably intersects itself.
>
> --
> 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
>



--
Michel Audette, Ph.D.
R & D Engineer,
Kitware Inc.,
Chapel Hill, N.C.