Remeshing in msh format

User Help
#1

Hi,square_input.mesh (501 Bytes)
square1.sol (109 Bytes)

I’m a new user of mmg and I’m trying a simple test case of refining a square 2D surface according to a scalar solution (./mmg2d_O3 square_input.mesh -sol square1.sol). I succeed to perform that with .mesh files format but I fail to do the same with .msh files (./mmg2d_O3 square.msh ? no sol file ?). Could you please advise me?

You will find attached herewith the Medit .mesh input and output files and the .msh file in which I added a Nodedata scalar field.

In the documentation you suggest to gmsh users to save their meshings into the Medit format (Save As -> Mesh - INRIA Medit (*.mesh)). I would like to point out that when I do that, the dimension in the medit file is 3 even for 2D surface. Also, it seems that mmg2d_O3 do not appreciate the 4th field in the vertices definition (see square2.mesh: output of gmsh in Medit format)

Thank you in advance for your help.

Kokoch

PS:

#2

…and the other files.

Regardssquare.msh (338 Bytes)
square.geo (407 Bytes)

#3

Hi Kokoch,

Sorry for the delay (I was on holiday) and thank you for the bug report.

  • I have broken the reading of the Gmsh data field during the last release. I think that it is fixed (master branch, commit bafe6119): due to some modifications in Mmg, now, to allow Mmg to understand that the NodeData field is a metric field, you will need to add the :metric suffix to the name of the field (the string tag that is provided). I attach the square.msh file with this modification. Please, say me if it works for you so I will release a new version of Mmg that will include this patch.

  • You are right, in 2D, Mmg asks for a “true” 2D mesh, while the .mesh output of Gmsh is a 3D mesh. You can run mmg2d on such files using the -msh 2 option of Mmg.

    mmg2d_O3 -msh 2 square2.mesh
    The output will be a mesh of the same format than the input (3D .mesh)
    The -msh option is an old option which dates from when the .msh files where not supported and I totally forgot to document it: I will do it this week.

I hope that it will helps,

Regards,
Algiane

#4

Thank you very much, it works well!

Regards

Kokoch