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[cgal-discuss] problem/bug with CGAL::Polygon_mesh_processing::is_outward_oriented()


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  • From: Hugo Ledoux <>
  • To:
  • Subject: [cgal-discuss] problem/bug with CGAL::Polygon_mesh_processing::is_outward_oriented()
  • Date: Thu, 6 Apr 2017 11:27:56 +0200
  • Authentication-results: mail2-smtp-roc.national.inria.fr; spf=None ; spf=Pass ; spf=None
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Greetings,

I have one mesh whose normals are pointing outwards, but the function
CGAL::Polygon_mesh_processing::is_outward_oriented() returns
otherwise.

I have checked the code and the average of the normals of the faces
incident to the min-vertex is used, which conceptually I doubt should
work… And it doesn’t work in my case (unless I made a mistake
somewhere), you can download my OFF file, along with the code I used,
there:
https://www.dropbox.com/sh/49as9yt139v6kxk/AABXI3Nh4ZfqCEDWHyv8Q-Zja?dl=0

If other ways to compute the normal were used (eg by using the area of
the face as a weight), then the x-component of the vector could be
negative (as is used by cgal), but I am wondering if that would always
work. I think not.

Any comments appreciated, cheers,
Hugo Ledoux

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