Edge flip creates a non-manifold

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Edge flip creates a non-manifold

Zohar
Example mesh (connectivity only):
f 1 5 2
f 1 4 5
f 3 2 4
f 4 2 5

If I flip 1-5, then the mesh would be non-manifold (2-4 would be incident to
4 triangles). Polyhedron_3::flip_edge() would be happy to do it for me.
Polyhedron_3::is_valid() would return that everything is fine. Only when I
save and load the mesh again, it would find the problem.



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Re: Edge flip creates a non-manifold

Zohar
Maybe a full example would help.

src.off

-----
*OFF 5 4 0

0 2 0
2 2 0
2 0 0
0 0 0
1 1 1

3 0 4 1
3 0 3 4
3 2 1 3
3 3 1 4*
-----

Flipping 0-4

flip.off

-----
*OFF 5 4 0

0 2 0
2 2 0
2 0 0
0 0 0
1 1 1

3 0 3 1
3 1 3 4
3 2 1 3
3 3 1 4*
-----
 



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Re: Edge flip creates a non-manifold

Zohar
Using the operations split_edge, join_facet, join_vertex, one can flip an
edge. Therefore, these operations are also compromised (at least the
join_vertex) concerning non-manifoldness.



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