CGAL users discussion list

[Mael <>]

Hello,

Thanks for the data set. I can't reproduce the issue neither with the 
4.6 release nor with CGAL's master branch. I do get the 545 faces, but 
they're all marked as 'interior' for the max alpha value (~1e14).

It's probably a good idea to update your version of CGAL in any case as 
4.6 is a couple years old and there have been bug fixes and new features 
in Alpha_shape_2 and in other packages.

Best,
Mael

On 07/08/18 06:51, nsoonhui wrote:
> Hi, I attach my dataset ( note that it is in Point3D format, but it shouldn't
> matter as the z is 0 always and you can easily convert to Point2D).
>
> And this is the gist of my code:
>
> typedef CGAL::Triangulation_vertex_base_2<Kernel>                      VbT;
> typedef CGAL::Triangulation_face_base_with_info_2<FaceInfo2,Kernel>    Fbb;
> typedef CGAL::Constrained_triangulation_face_base_2<Kernel,Fbb>        FbT;
> typedef CGAL::Triangulation_data_structure_2<VbT,FbT>               TDS;
> typedef CGAL::Exact_predicates_tag                                Itag;
> typedef CGAL::Constrained_Delaunay_triangulation_2<Kernel, TDS, Itag>  CDT;
>
> typedef CGAL::Alpha_shape_vertex_base_2<Kernel> Vb;
> typedef CGAL::Alpha_shape_face_base_2<Kernel>  Fb;
> typedef CGAL::Triangulation_data_structure_2<Vb,Fb> Tds;
> typedef CGAL::Delaunay_triangulation_2<Kernel,Tds> Alpha_Triangulation_2;
> typedef CGAL::Alpha_shape_2<Alpha_Triangulation_2>  Alpha_shape_2;
>
> Alpha_shape_2 *A =new Alpha_shape_2(first,last, 100000,Mode.Regular);
>        auto maxLevel =  A->number_of_alphas()-1;
>        auto alphaLevel = A->get_nth_alpha(maxLevel);
>       int i=0;
>          for(fit=A->finite_faces_begin(); fit!=A->finite_faces_end(); ++fit)
>          {
>
>
>                       A->set_alpha(alphaLevel);
>                     auto classType2 = A->classify(fit);   //i==504 is
> EXTERIOR
>                 i++;
>                          
>          }
>
>  From what I can tell, there is an element at i==504, which is EXTERIOR. (
> there are 545 elements).
>
> Do let me know whether you can reproduce the problem with the dataset and
> the above pseudo code. If not I will prepare a fully working sample.
>
> I am using CGAL 4.6.2. Not sure whether it matters or not
>
> coordinate.csv
> <http://cgal-discuss.949826.n4.nabble.com/file/t212754/coordinate.csv>
>
>
>
>
>
>
> --
> Sent from: http://cgal-discuss.949826.n4.nabble.com/