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Re: [cgal-discuss] Meshing implicit surfaces creates inside out meshes.


Chronological Thread 
  • From: "Sebastien Loriot (GeometryFactory)" <>
  • To:
  • Subject: Re: [cgal-discuss] Meshing implicit surfaces creates inside out meshes.
  • Date: Tue, 12 Jun 2018 12:44:29 +0200
  • Authentication-results: mail2-smtp-roc.national.inria.fr; spf=None ; spf=Pass ; spf=None
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We added some functions in PMP to handle this kind of issues.
See CGAL::Polygon_mesh_processing::orient()

https://doc.cgal.org/latest/Polygon_mesh_processing/group__PMP__orientation__grp.html#gafe035adcc4ff061b4438cc9dae591d00

Sebastien.

On 06/12/2018 11:31 AM, Raphael Grimm wrote:
Hi,
i am meshing implicit surfaces and sometimes the result is inside out (the vertex order of triangles is wrong).

I attached three meshes and the code to show what i mean:
 *  'sphere_r_const_1_1.000000.off' is correct
 *  'sphere_r_const_2_1.000000.off' is inside out
 *  'sphere_r_const_4096_1.000000.off' is correct

In both cases i meshed a unit sphere.
The only difference when creating the spheres is the squared radius i passed to 'Sphere_3' when creating my 'CGAL::Implicit_mesh_domain_3'.
The first sphere got the exact squared radius '1' and the second the larger value '2' and the third the value '4096'.
Hence i the issue can't be a too large bounding sphere.

Why does this happen and how can i prevent this?

Best regards,

Raphael


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