Subject: CGAL users discussion list
List archive
Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?
Chronological Thread
- From: Mael <>
- To:
- Subject: Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?
- Date: Fri, 3 Aug 2018 10:02:13 +0200
- Authentication-results: mail3-smtp-sop.national.inria.fr; spf=None ; spf=None ; spf=None
- Ironport-phdr: 9a23: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
Hello, Assuming you are using a basic Delaunay_triangulation_2: for the maximal alpha value, the alpha shape is the Delaunay triangulation of the point set, thus the status of a vertex cannot be exterior since the Delaunay triangulation is a triangulation of the convex hull of the point set.If you are using a weighted triangulation (Regular_triangulation_2), things are bit trickier: if the point has a weight such that it does not appear in the (weighted) Delaunay triangulation, then its status should be exterior, even at the greatest alpha value of the family. However, there is a known bug in Alpha_shape_2 when using the General mode that makes it so a vertex is never marked as exterior. I am not sure if its also present in regular mode. Best, Mael On 03/08/2018 09:46, nsoonhui wrote:
I have the following (Pseudo) code: 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); for(fit=A->finite_faces_begin(); fit!=A->finite_faces_end(); ++fit) { A->set_alpha(alphaLevel); auto classType2 = A->classify(fit); //can this be EXTERIOR? } I know that if alphaLevel is not maximum, then A->classify(fit) can be EXTERIOR. But, my question is that, is it even possible for the maximum alpha level to classify one of the face as EXTERIOR? -- 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, 08/03/2018
- Re: [cgal-discuss] Does maximum Alphalevel always guarantee that all of the elements are classified as EXTERIOR type?, Mael, 08/03/2018
Archive powered by MHonArc 2.6.18.