How to divide a surface to subdomains, which can be recognized in msh file? Avoiding duplicated nodes is necessary.

In general I have geo file which contains definition of smaller and bigger region, now I would like to assign different physical surfaces (tags) to both - but right now is impossible due to only one plane surface.

Is it possible to assign tag to cells directly in mesh module (but not manually in file)?


is there a reason why you are trying to avoid creating two surfaces? The points on lines shared by the two surfaces should not be duplicated.

Gmsh GUI enables the user to define physical surfaces (see Geometry->Physical Groups->Add->Surface), but you can only mark existing (elementary) surfaces with a physical tag. You cannot select some cells of existing surface and tell gmsh that they should belong to a new physical surface.

Maybe it would be better to ask a question like this on Gmsh mailing list.

Best regards,


  • $\begingroup$ I have solved my problem using 'Coherence' keyword, which prevents duplicating nodes in grid. Right now it doesn't matter how many surface I have. $\endgroup$ – Krzysztof Bzowski Aug 15 '13 at 7:17

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