[Gmsh] stl and prism extrusion

[David Colignon]

On 11/12/09 15:00, Hoessler, Julien wrote:
> Good afternoon all,
> First of all, thanks for writing this code, I'm using it a lot to generate 2D/3D meshes for DNS and stability analysis. I was wondering if it is possible to extrude a layer of prisms using the surface normals instead of a specific direction. I need to generate a layer of prisms out of a wall which is curved and there is more than 80 degrees of angular difference between the two extreme locations of the surface (it is smooth, but twists a bit like a sinh).


Hi Julien,

it is still experimental and quite hidden in the documentation
  ( http://www.geuz.org/gmsh/doc/texinfo/gmsh.html#Structured-grids ),
but you can try:

Extrude { Surface { expression-list }; layers }

which extrudes a boundary layer along the normals of the specified surfaces (if they are smooth and do not form acute 
angles).

> My second question is about the stl importation. I have a stl file which is a 3D box that I can read and visualise without problems, but I'd like to remesh it

The undocumented "Compound Surface" command is also very experimental, but you can try the attached file (reparam.geo) 
which here use a .msh file but should also work with a .stl file.


, mesh the volume inside  and split the box surface to assign different physical groups for boundary conditions (and add 
a layer of prisms on one of the surfaces). Is it possible with Gmsh? I've searched through the questions in this mailing 
list, do I need the opencascade support for this?


Regards,

Dave


-- 
David Colignon, Ph.D.
Collaborateur Logistique du F.R.S.-FNRS
CÉCI - Consortium des Équipements de Calcul Intensif
ACE - Applied & Computational Electromagnetics
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