SimScale CAE Forum

Base Mesh Size and Unresolved Faces

I am modeling a pool with a very small inlet and outlet face. When I use the default base mesh, the inlet and outlet faces disappear during the meshing process (i.e. less faces post mesh). Even if I try to use a refinement for those faces, they are still removed. However, if I increase the number cells for the base mesh, with a fine enough resolution, the faces will appear and then the refinements work fine.

So I think I understand what is going on here but it seems to me that the meshing process should be smart enough to know that when a face is refined, it should never be removed no matter what the base mesh resolution might be.

Is this a known limitation of the meshing algorithms (i.e. snappyHexMesh)?

Hi @mas985,

could you share the project with us so that we can have a look at that?

Thanks and cheers!


I shared it with support but here it is:

Have a look at “Mesh- Bad”. This is the default base mesh case where several faces disappeared. “Mesh - Good” is where I tripled the base mesh and then all faces were meshed properly.

Hi @mas985!

Let me get back to you as soon as I have figured out the issue.



Hi @mas985!

The main problem in this case is that your inlet/outlet face(s) are very small making it hard to mesh them properly. You can have a look at one try from me trying to mesh the geometry:

But still I am not satisfied with the result as the faces are either deleted (if the mesh is too coarse) or need a super fine refinement (which is like taking a sledgehammer to crack a nut…).

Let me make some experiments with it and I will get back to you if I got something that is good enough :+1:



Support generated this one:

It works but is really over refining the edges and the small parts which I guess is ok. I may try some variants of this one.

Hi @mas985.

Yes that looks satisfying. I would use this and adapt the parameters in the mesh settings accordingly. :slight_smile:

Have a nice weekend!