[Gmsh] Extrude 2D quadrilateral mesh and get hexahedrals

Christophe Geuzaine cgeuzaine at ulg.ac.be
Wed Apr 9 21:47:29 CEST 2014

On 09 Apr 2014, at 19:44, Matteo Parsani <parsani.matteo at gmail.com> wrote:

> Excuse me, this is the right .geo file
> On Wednesday, April 9, 2014 1:42:32 PM UTC-4, Matteo Parsani wrote:
> Dear gmsh users and developers,
> I have mesh a square cylinder in an unstructured way using only quadrilateral elements.
> However, when I extrude it in 3D I get triangle, pyramids and hexahedrals. My goal is to only get hexahedral.
> Could you please advice?

Your 1D "Transfinite" meshing contraints are not compatible with having a even number of triangles in some surfaces. Two solutions:

- fix it by hand
- or use the "magic" option "Mesh.FlexibleTransfinite = 1;", which will try to do it for you.

Attached is a modified version of your file, which works fine here.

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> Please find in attachment the .geo file I am using
> Thank you
> <square-cylinder.geo>_______________________________________________
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Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science