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[Sukhraj Singh <>]

Okay,

Assuming I don't use connected_components().

And I directly create Polyhedrons from the segments, i.e.

- Iterate through polyhedron.
- Create polyhedron of a segment using Polyhedron_incremental_builder_3.

Is this correct way to do ? Or there is some better approach in CGAL.

 

On Mon, May 23, 2016 at 1:18 PM, Sebastien Loriot (GeometryFactory) <> wrote:

What I mean is if you need both clusters and segments but want to save on computation time, you can run the segmentation algorithm to extract
segments and then clusters using `connected_components()` (instead of
another run of segmentation).

Sebastien.

On 05/22/2016 02:32 PM, Sukhraj Singh wrote:

Thanks for your answer, Sebastien
Do I really need to use connected_components()

I already have the "segment_pmap", where the value is the segment id to
which that particular face belongs.
And one could parse the Polyhedron and collect all the faces having
particular segment ID.(Of-course I need to check, how to implement the same)
Is my understanding correct ?



Further, quoting from my previous email:

    Two spatially apart areas( i.e. not having
    common edges) of a Mesh may fall into same segment, since they had
    comparable SDF values.


I am not sure about it, they of-course may fall into same cluster, but
may not be to the same segment.  In such a case if, faces that don't
share edge, will fall into different segment always, even though they
were in same cluster, using connected_components() may not be required ?




On Thu, May 12, 2016 at 6:00 PM, Sebastien Loriot (GeometryFactory)

< <mailto:>> wrote:

    On 05/12/2016 02:16 PM, Sukhraj Singh wrote:

        Salut,

        The "Triangulated Surface Mesh Segmentation" module allows one to
        segment a surface mesh using the SDF values.
        It creates a Property Map which is colorized according to the
        indices,
        resulting into segments. Two spatially apart areas( i.e. not having
        common edges) of a Mesh may fall into same segment, since they had
        comparable SDF values.

        My question is, how can one extract these segments. Since I want
        to do
        further processing on a segment separately. Also I would like
        further
        divide a segment, into say sub-segments , where a sub-segment
        will have
        faces which are not spatially apart, i.e.  a subset which is having
        common edges only.



    Set the parameter output_cluster_ids to true when calling the
    segmentation function

    http://doc.cgal.org/latest/Surface_mesh_segmentation/group__PkgSurfaceSegmentation.html#ga8533ea7b1062ebbabe3bf23fed303f24

    If you need also the segments, then set the option to false and
    use the function connected_components() considering as constrained
    edges the edges between two faces belonging to different
    segments.

    http://doc.cgal.org/latest/Polygon_mesh_processing/group__keep__connected__components__grp.html#gabe2052b2281e1e628e68d8fea94be2d9


    Sebastien.



        Thanks to inform.




        P.S. I am a newbie.
        --
        Sukhraj Singh



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Sukhraj Singh

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