[Gmsh] Q-Morph algorithm on parametric space: questions related to the c++ code.

[Jean_Baptiste Faes]

Hi David,

Thanks a lot for your answer.

Yes, I know the recombine command. But it is not an advancing front method providing well-aligned rows of quadrilaterals parallel to the boundary of the domain (see Int. J. Numer. Meth. Engng. 44, 1317—1340 (1999)).

That is the reason why I have implemented this small code I would like to link to gmsh. But there is something my code is not (yet) able to do: meshing of arbitrarily curved surfaces. I thus would like (if possible) to make use of the parametric space defined in gmsh.

I would be gratefull if you could forward my mail to some of your C++ developpers, in order to have a better understanding of which part of the code I should modify to this end.

Very best regards,
JB FAES


> Hi Jean-Baptiste,
> 
> not a direct answer, but have you read this (username:
> gmsh, password: gmsh)  ?
> 
> https://geuz.org/trac/gmsh/wiki/BlossomQuad
> 
> and others related pages ? ( https://geuz.org/trac/gmsh )
> 
> Regards,
> 
> Dave
> 
> --
> David Colignon, Ph.D.
> Collaborateur Logistique du F.R.S.-FNRS
> CÉCI - Consortium des Équipements de Calcul Intensif
> ACE - Applied & Computational Electromagnetics
> Institut Montefiore B28
> Université de Liège
> 4000 Liège - BELGIQUE
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> Fax: +32 (0)4 366 29 10
> WWW:    http://hpc.montefiore.ulg.ac.be/
> Agenda: http://www.google.com/calendar/embed?src=david.colignon%40gmail.com
> 
> On 06/03/11 17:31, Jean_Baptiste Faes wrote:
> > Dear gmsh developper's team,
> >
> > I am Jean-Baptiste FAES, quantum physicist. Since some
> months, I am interested in computational fluid dynamics. I
> thus learned about it and tried to do some test cases in
> fluid-flow modeling. In most of my applications I make use
> of your software "gmsh", because it is very convenient to
> use.
> >
> > I discovered during my studies that hexahedral mesh
> offers the best support for CFD calculations using finite
> volume method. Unfortunately, gmsh doesn't offer yet an
> unstructured hexaedral mesh generator. I thus decided to do
> my own one, based on the H-Morph algorithm. My aim is to
> incorporate it in gmsh, but I faced some problems to
> understand your C++ code. I thus was wondering if you could
> help me on one or two points.
> >
> > I am currently working on Q-Morph algorithm. My
> computer code uses as input an stl file that is output from
> a triangulated surface meshed with gmsh. You can see in
> attached file some examples of 2D surfaces meshed with gmsh,
> and then converted to quad with my program (and visualized
> with gmsh in geo format). It works quite well for plane
> surfaces, or surfaces with small curvature. Now I would like
> to take advantage of the parametric coordinates used in
> gmsh. Indeed, if I could apply the Q-Morph algorithm
> directly on the parametric 2D space used in gmsh, I suppose
> that I would be able to mesh every type of surface.
> >
> > My first question is thus the following: Where in your
> code can I extract the parametric mesh ? I found that some
> 'writeMSH' routines have an argument 'saveParametric', 
> but I'm not sure the variables '_u' and '_v' correspond to
> the 2D-parametric coordinates.
> >
> > My second question is: once I have transformed the
> triangular mesh into a quad mesh, how can I put this mesh in
> gmsh in such a way it is recognized as a 3D surface mesh
> that will be further used for volume meshing ?
> >
> > I thank you very much for your attention.
> >
> > Best regards,
> > JB FAES
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > gmsh mailing list
> > gmsh at geuz.org
> > http://www.geuz.org/mailman/listinfo/gmsh
> 
>