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[Biswajit Biswas <>]

Hi Sebastien,
Thanks a lot for your help.
Have a good day,

On Wed, Dec 13, 2017 at 9:07 PM, Sebastien Loriot (GeometryFactory) <> wrote:

If you have been able to build a Polyhedron or a Surface_mesh it means
that it is not a polygon soup.

I guess you do something different than just loading the two files
posted. If you have a minimal example showing the pb it would help
to tell you exactly what the pb is.

Sebastien.

On 12/13/2017 03:33 PM, Sean Hardesty wrote:

I was able to compile the polyhedron demo and duplicate the results you described. However, I don't understand how I would test for this in my own program. I generated the .off files I sent from CGAL::Surface_mesh - how do I check whether such an object is a polygon soup (as is done in the demo)?

All of the following look okay:

mesh.is_valid() = 1
CGAL::Polygon_mesh_processing::does_bound_a_volume(mesh) = 1
CGAL::Polygon_mesh_processing::does_self_intersect(mesh) = 0
CGAL::Polygon_mesh_processing::is_outward_oriented(mesh) = 1
CGAL::is_closed(mesh) = 1

I wanted to try something from the polygon soup example, like this

CGAL::Polygon_mesh_processing::is_polygon_soup_a_polygon_mesh

but I haven't been able to figure out how to call that on a CGAL::Surface_mesh object.

     Thanks,
     Sean Hardesty

On Wed, Dec 6, 2017 at 2:24 AM, Sebastien Loriot (GeometryFactory) < <mailto:>> wrote:

    When I open you files in the CGAL polyhedron demo, it is telling me that
    your meshes are polygon soups (meaning you have non-manifold edges).
    If I duplicate those edges to make it a self-intersecting surface
    I have the following set of intersecting faces.

    Sebastien.

    On 12/05/2017 05:22 PM, Sean Hardesty wrote:

        I have a collection of meshes that overlap slightly, so I am
        going through a loop removing overlapping pieces. It works for a
        while, but eventually I run into trouble. I am calling
        PMP::corefine_and_compute_difference(CGAL 4.11) on a pair of
        meshes that satisfy

        !CGAL::Polygon_mesh_processing::does_self_intersect
        CGAL::Polygon_mesh_processing::does_bound_a_volume

        and I get the following:

        terminate called after throwing an instance of
        'CGAL::Assertion_exception'
            what(): CGAL ERROR: assertion violation!
        Expr: hedge!=start
        File:
        /usr/local/include/CGAL/Polygon_mesh_processing/internal/Corefinement/Visitor.h
        Line: 663
        Aborted (core dumped)

        They are fairly small, so I wrote them to .off format and
        attached them to this message. I am aware from your
        documentation pages that there can be problems with sequential
        boolean operations, so I am using the kernel with exact
        predicates and exact constructions. Maybe the precision in the
        .off format is inadequate to diagnose the problem. I would be
        grateful for any help that can be provided.

              Sincerely,
              Sean Hardesty


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thanks and regards 

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