[Gmsh] Problem with Reading the mesh generated into freefem.

[Jacob Abdelfatah Ndioubnane]

According to your first reply, I extracted the points of the boundaries and I noted that, as you said, the points are ordered in a clockwise sens(Freefem only reads in a counterclockwise sens). So I created a Matlab script that reads the points in .xyz format and creates a .geo file with the points and lines:

When I imported the points into a matrix, I reversed the order using the comand “flip”. Then I defined the points and lines according to the gmsh nomenclature, and when I created the mesh and exported in a .mesh format, FreeFem reads it without problems.

Thanks for your reply, it helped me to find another way to solve the problem.

I attach the .m script, the .xyz points and the generated .geo file.

Best Regards,
Jacob

________________________________
De: G. D. McBain <gdmcbain at protonmail.com>
Enviado: Monday, May 20, 2019 3:31:21 AM
Para: Jacob Abdelfatah Ndioubnane
Cc: gmsh
Asunto: RE: Problem with Reading the mesh generated into freefem.



I checked also that when the program generates the mesh it displays a warning error due to It can’t orient the normal of the Surface.

Yes, on running 'gmsh -2 Dominio.geo', I see this too:

    Warning : Could not orient normal of surface 1

I'm not immediately sure why though...  I continue to suspect that this warning is associated with the error from FreeFEM about triangular elements having negative areas, but I haven't been able to work out what the problem with Dominio.brep is, i.e. why Gmsh can't orient the Plane Surface.

I even get the same warning from Gmsh when trying to make a simple Plane Surface from either of the two Curve Loops separately.  That does seem odd to me since the second, which looks like an island (or is it a lake) is simple enough to be inspected manually in the Gmsh GUI and it looks fine.

Sorry, I'm not sure what to suggest from here...

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