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[Zohar <>]

Hi Sebastien,

I read this faq already, and I'm aware that the double is less robust, but I
thought that only for complicated algorithm, I need more than it. Frankly I
expected the double to be able to intersect two segments with common edge.
Otherwise I think this should be emphasized (this specific point regarding
intersection) in the intersection / Cartesian / faq (which is too mild IMO
on this point).

Anyway I tried the exact_exact and it's terribly slow.

See if you can help me please with another approach to my problem. I'm
flipping edges in a polyhedron in order to optimize some function. Is there
a robust way to check if an edge is flippable?

1. Currently I flip the edge, then check its two consecutive facets if they
intersect other triangles in the vicinity (31). Besides being slow (due to
the exact_exact) my mesh for some reason becomes non-manifold, and has a
dangling ear in the middle of the triangulation. I still need to debug this,
probably something I've done wrong when I analyzed the triangles
intersections.

2. The next option that comes to mind is the CGAL/triangulate_polyhedron.h
that you recommended me, which estimates the normal at some neighborhood,
and project it into a 2D constrained triangulation. Then I can flip the edge
and it would warn me if it intersects anything (I think). The problem with
this is that I don't actually traverse all the possible triangulations, but
only those that are legitimate from this projection angle.




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