[Gmsh] Unstructured hexahedra mesh from STL geometry

Meiner Auchmeiner auchmeiner at googlemail.com
Wed Nov 24 20:11:16 CET 2010

I just wanted to drop you all a quick note that I finally found a
solution for generating hexahedra meshes out of STL surfaces (with an
intermediate tetrahedral mesh step). Unfortunately, this solution is
not GMSH but an external program :(. As a further drawback this tool
is not even OpenSource... Fortunately, the academic license of it is
quite affordable. So everybody who runs into the same problems I did
should take a look at CUBIT (from Sandia National Labs). I hope it's
ok that I point towards this external solution - please excuse any
inconvenience caused.



2010/11/23 Meiner Auchmeiner <auchmeiner at googlemail.com>:
> Hello again,
> thank you very much for your quick reply.
> 2010/11/23 Jean-Francois Remacle <jean-francois.remacle at uclouvain.be>:
>> Le 23-nov.-10 à 17:25, Meiner Auchmeiner a écrit :
>> Hi gmsh group,
>> Hello,
>> I was wondering if anybody here succeeded to mesh a STL geometry with
>> an unstructured mesh consisting of hexahedra elements. I'm trying to
>> mesh following file(s) using standard settings, except for the
>> subdivision algorithm "All hexas": 500.stl & 500.geo (see attachment).
>> I'm always getting the error messages "Error: Cannot evaluate point on
>> discrete face" and "Error: Cannot compute parametric coordinates on
>> discrete face".  Whereas meshing the STL geometry with tetrahedron
>> elements work like a charm. Is there any intermediate step necessary
>> to optimize (maybe with e.g. MeshLab) the input STL geometry? Or is
>> there any gmsh preprocessing option/conversion I overlooked ?
>> There is actually NO automatic hexaedral mesher in GMSH.
>> For doing a better STL, you can use the reparametrization tools, see
>> https://geuz.org/trac/gmsh/wiki/STLRemeshing (username wiki, password wiki).
>> JF
> Hmm, so do I get you right, there is no way (yet?) of generating
> hexahedral meshes out of STL files in gmsh? In all my naivety I
> thought it would be possible in GMSH to subdivide tetrahedra elements
> in hexahedra elements... Say, what about the manual hexahedral mesher
> in GMSH you just mentioned, is it - with the right manually input -
> capable of meshing closed STL surface geometries with hexas?
> Uwe
>> Thanks
>> Uwe
>> P.S.: The skeleton data have been obtained by courtesy of S. Van Sint
>> Jan, Laboratory of Anatomy, Biomechanics and Organogenesis, Université
>> Libre de Bruxelles.
>> <500.stl><500.geo>_______________________________________________
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>> ------------------------------------------------------------------
>> Prof. Jean-Francois Remacle
>> Universite catholique de Louvain (UCL)
>> Ecole Polytechnique de Louvain (EPL) - Louvain School of Engineering
>> Institute of Mechanics, Materials and Civil Engineering (iMMC)
>> Center for Systems Engineering and Applied Mechanics (CESAME)
>> Tel : +32-10-472352 -- Mobile : +32-473-909930