cgal-discuss - [cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?

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[cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?

From: Christopher Mitchell <>
To:
Subject: [cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?
Date: Sat, 10 Sep 2016 12:31:00 -0400
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I'm attempting to determine if two Polygon_2s overlap in anyway, ie, share any portion of their interiors, including one being entirely contained by the other. In most cases this works, but for a few polygon pairs, do_intersect() returns false unexpectedly. I make sure (1) all polygons are simple (2) all polygons are not oriented CGAL::CLOCKWISE (I call .reverse_orientation() on the polys if they are CGAL::CLOCKWISE), and (3) that the starting vertex is not duplicated. I have attached an example of a polygon pair for which do_intersect() returns false. Thanks in advance for any insight; I'd be happy to provide additional information as necessary.

Attachment: do_intersect.png
Description: PNG image

[cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?, Christopher Mitchell, 09/10/2016
- Re: [cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?, Efi Fogel, 09/11/2016
  - Re: [cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?, Christopher Mitchell, 09/12/2016
    - Re: [cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?, Efi Fogel, 09/12/2016
      - Re: [cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?, Sebastien Loriot (GeometryFactory), 09/12/2016
        
        Re: [cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?, Christopher Mitchell, 09/12/2016
        
        Re: [cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?, Efi Fogel, 09/13/2016
        
        Re: [cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?, Christopher Mitchell, 09/13/2016
        Re: [cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?, Efi Fogel, 09/14/2016
        Re: [cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?, Andreas Fabri, 09/14/2016

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[cgal-discuss] Unexpected Polygon_2 do_intersect() Behavior?