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I see, thanks for the clarification. After merging the duplicated vertices the non-manifold edges become evident. Incidentally, I though the input polygon soup could be represented redundantly by storing an instance of a vertex in each incident triangle, and that merging the vertices would be done by polygon_soup_to_polygon_mesh(). So from my understanding, this function "only" takes care of building the data structure and of explicitly setting the adjacency relations between its elements - correct?

Claudio

On Thu, Aug 16, 2018 at 12:12 PM Sebastien Loriot (GeometryFactory) <> wrote:

As is your model is detected as valid surface mesh.
This is because you have many duplicated vertices.
If you merge them (using something like [1] for example)
you will end up with a mesh with only one boundary cycle.
It is not stitch-able because it is would produce a set of non-manifold
edges.

 From there, depending on what you want to do with the model, you can
still try to close the model but you'll endup with some
self-intersection.

Sebastien.

[1] https://gist.github.com/sloriot/12f6ba2c5d593b1b0e2e82a07fc82df7

On 08/15/2018 11:44 PM, wrote:
> Hi Sebastien,
>
> thank you for looking into this. I've exported the polygon soup into
> .off (see attachment) - let me know if you need any further information.
>
> Claudio
>
> On Wed, Aug 15, 2018 at 12:29 PM Sebastien Loriot (GeometryFactory)
> < <mailto:>> wrote:
>
>     You probably have some non-manifold faces in your soup. If this is the
>     case, it probably needs some clean up. Can you share the input so that
>     we can give more info?
>
>
>     Sebastien.
>
>
>
>     On 08/14/2018 10:05 AM,
>     <mailto:> wrote:
>      > Hello,
>      >
>      > I'm trying to use the CGAL's PMP package to create a mesh out of a
>      > polygon soup (extracted from a spatial subdivision structure using a
>      > min-cut approach). I've usedorient_polygon_soup() and
>      > polygon_soup_to_polygon_mesh(). A subsequent call to
>      > is_polygon_soup_a_polygon_mesh() return true, but the mesh
>     produced is
>      > not closed. This also creates problems when using other functions
>     of the
>      > package, such as
>      >
>      > is_outward_oriented()/reverse_face_orientations(). Also using
>      > stitch_borders did not improve the mesh.
>      >
>      > Is this the expected behaviour of the functions?
>      >
>      > Thanks,
>      >
>      > Claudio
>      >
>      >
>      >
>
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