How to generate a volumetric(tetrahedra) mesh?

[SalemTree]

I'm having a trouble of importing my own model in the elasticity scene, and I've checked up the others' posts like
#2732
or
https://www.sofa-framework.org/community/forum/topic/how-to-make-tetrahedron-msh-file-with-meshlab/

I tried the sugested ways such as gmesh software adding volume or converting with SOFA, without any luck.
I'm new on simulation and not sure about how to generate a tetrahedra mesh file properly. Here is my stl file exported with blender.
https://drive.google.com/file/d/1Cxu3wgTTlVKnNKay2f2blNUJRjffiiLB/view?usp=sharing
Any help would be appreciated.

[hugtalbot]

Hi @SalemTree

In the discussion you are referring to, I do explain that if you want to simulate a volumetric object, you need an associated volumetric mesh. A surface mesh does not suffice to compute the physics in the volume of the object.

How to generate such a volumetric mesh?

• I would suggest to always use a dedicated mesh tool. Many do exist: CGAL, Gmsh etc. As referred in this discussion, an open project shows how to use Gmsh with SOFA in a python script
• the second option mentioned in the discussion you are referring to is in SOFA, but it is maybe less robust: generating a volumetric tetrahedral mesh from a triangulated mesh using the component: MeshTetraStuffing. An example is available here

I hope this helps.

[hugtalbot]

I just realize that the object you are looking at (sclera) is a very thin object. Meshing it with tetrahedra does not really make sense for such a thin structure. I would rather go for a surface model like in the TriangleFEMForceField.scn.
Does this make sense?

FYI, I also tested your mesh in some external softwares and encountered issues because of the binary format.

[SalemTree]

Hi @hugtalbot
Thank you so much for the advice about external mesh tools and switching to a surface model. Could you elaborate on the "binary format issues" of my stl file? I exported it by blender with default setting, could it be the setting of the blender?

[SalemTree]

I found what the problem was. I used blender on windows pc and somehow its exported files cant be read by gmsh, I'm not sure how this works but by just changing to linux version of blender the problem is solved. And thank you again for the advice on mesh format.

[hugtalbot]

Just for you @SalemTree I created myself another stl mesh (same but without the import issue) from meshlab.
Here is a temporary link: https://filesender.renater.fr/?s=download&token=ed4d6ec2-9563-4a1b-a55c-169657513da9

[SalemTree]

It's very kind of you, thanks for the stl mesh! I just converted it to msh and it works fine now.