[Gmsh] Volume meshing an enclosure defined by STL mesh and an elementary surface defined by the GEO format

[Christophe Geuzaine]

CEM ALBUKREK wrote:
> Hello,
> 
> I am trying to mesh a volume enclosed by two surface groups consisting 
> of an STL mesh and a surface defined using elementary entities. An 
> example is a box sketched as the below:
> 
> The top in red is an STL or NAS mesh surface, the bottom and sides are 
> built using points, lines and surface loops.
>  ______
> |______|
> 
> 
> After the bottom is meshed, I am able to obtain edge nodes that match 
> the edge nodes of the STL surface perfectly. Hence at the seam of the 
> red and black surfaces there are duplicated nodes. Because of these,  
> during the volume meshing GMSH/Tetgen rightfully complains about self 
> intersections. Can I somehow force GMSH to paste the duplicated nodes 
> across the STL facets and the elementary surface facets before volume 
> meshing?  If I need to edit the code for this, what data would you 
> recommend me to modify?
> 


Hi Cem - It's definitely something that we want to do. But it's been on 
our TODO list for quite a while... :-(

Our initial plan was to clarify what the "Merge" command means, and 
provide the option to merge meshes based on node coordinates. The goal 
would be to allow to build "mixed" CAD/discrete models, and mesh them 
easily.

The exact implementation strategy is not clear yet. If you feel 
adventurous, one thing you could try is to add a method in GModel 
(Geo/GModel.cpp) that would iterate on all discrete CAD entities, and 
remove duplicate vertices based on their coordinates.




> Thank you for your help.
> 
> Best,
> 
> -- 
> Cem Albukrek, Ph.D.
> Senior Aerodynamics Consultant,
> Tel: (857) 234-1035
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> gmsh mailing list
> gmsh at geuz.org
> http://www.geuz.org/mailman/listinfo/gmsh


-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine