[Gmsh] Controlling the tetrahedra orientation in an extruded 3D mesh

[marco restelli]

2015-04-23 21:54 GMT+0200, Christophe Geuzaine <cgeuzaine at ulg.ac.be>:
>
>> On 14 Apr 2015, at 10:24, marco restelli <mrestelli at gmail.com> wrote:
>>
>> Dear all,
>>   I am unable to control the tetrahedra orientation in an extruded 3D
>> mesh.
>>
>> More in details: consider the following .geo file. If I set
>> "Transfinite Right" or "Left" for the surfaces 18 and 26, which are
>> two of the sides generated during the surface extrusion, this
>> orientation is followed by the 2D grids, but seems to be ignored by
>> the 3D grid, which has a rather irregular pattern. Is there a way to
>> control the 3D grid orientations?
>>
>
> Unfortunately, no: there's no way to guarantee the orientation in a general
> geometrical configuration. The seemingly random orientations you observe are
> die to swaps that are performed to recover the boundary mesh.

OK, thank you.

Could I try to control these orientations by changing the vertex
and/or line ordering of the surface that I am extruding?

Marco