how to make tetrahedron msh file with meshlab?

[RowingMK2]

Dear users.

Hi I am beginner of Sofa-framework.
I am now try to make some tetrahedron mesh file (.msh format) with gmsh for tetrahedronFEMForceField.
But when I do Geometry-Elementary entities-Add-Volumn then Mesh-3D and save this file with .msh format, this file not work and just show ‘File ~ finally appears not to be a Gmsh file.’.
What methods other users use to make tetrahedron mesh file (.msh format)?
I heard that meshlab can do it, but I can’t find any associated information in enternet.

Thanks a lot.

[Sara]

Hi RowingMK2,

I was facing this problem last week, and have recently resolved it. I will walk you through step-by-step what I did. I roughly followed the instructions given here:

From design to mesh generation using FreeCAD and GMSH

You must first export your design file in *.brep format. This will depend on the CAD software you are using; for me, I am using SolidWorks, and so I exported my drawing as a *.igs file (keeping only the contours of my 3D body). Open this file in Gmsh, and select Tools > Options and set your 2D algorithm to MeshAdapt. You may also choose to decrease your element size to obtain a courser or finer mesh.

Then, from the left hand bar, select Modules > Mesh > 2D and this should produce a triangular and fairly homogeneous surfacic mesh. Save this as a *.msh file. Gmsh will offer you an options pop-up and there you must select ASCII Version 2. Follow the same Modules > Mesh > 3D to obtain your tetrahedral (volumetric) mesh, and save this in the same way.

I hope this helps you!

Sara

[RowingMK2]

Dear Sara.

Thanks a lot.
I followed above post (make simple rectangle .brep file with freeCAD and make .msh file with Gmsh) but my .msh file not work in SOFA.
I upload my .brep file and .msh file in following link.

https://dgistackr-my.sharepoint.com/:f:/g/personal/550160_dgist_ac_kr/EtkCoIapFw9NtGidQxGkx0ABu4aSrdH6O6O8fQxgzFE4_Q?e=dftJ5D

I think this is because of entities.
when I load liver.msh(SOFA tutorial model) in Gmsh, Info shows like bellow.
Info : 101 nodes
Info : 596 elements

but when I load my test msh file in Gmsh, Info shows like bellow.
Info : 27 entities
Info : 101 nodes
Info : 596 elements

but I don’t know how to overcome this. Is there anyone who overcome this problem?

Thanks a lot.

[Sara]

Hi again RowingMK2,

I have used your linked files to create surface and volumetric meshes and loaded them into SOFA. I did not seem to face any problems and they appeared to be fine.

I have included my mesh files in the same link you provided:

https://dgistackr-my.sharepoint.com/:f:/g/personal/550160_dgist_ac_kr/EtkCoIapFw9NtGidQxGkx0ABu4aSrdH6O6O8fQxgzFE4_Q?e=dftJ5D

Could you try load them into your scene and check if they work?

Good luck!

Sara

[Hugo]

Thanks helping @dst03251, @sara-h!

[Author]

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