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Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?
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- From: Mael <>
- To:
- Subject: Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?
- Date: Tue, 7 Aug 2018 10:05:48 +0200
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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/
- [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?, nsoonhui, 08/03/2018
- Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?, Mael, 08/03/2018
- Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?, nsoonhui, 08/03/2018
- Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?, Mael, 08/03/2018
- Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?, nsoonhui, 08/07/2018
- Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?, Mael, 08/07/2018
- Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?, nsoonhui, 08/07/2018
- Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?, Mael, 08/03/2018
- Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?, nsoonhui, 08/03/2018
- Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?, Mael, 08/03/2018
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