[mcockbu9]

Hi - I am currently trying to mesh this geometry with all hexahedral elements, but I keep running into the issue where the outer perimeter will only mesh with tetrahedra. Does anyone know what I can do to move forward? I created an o-grid and it has worked before, but now I am unable to mesh this properly. Please let me know any ideas you guys may have

Screenshot 2024-10-17 150530.jpg

[mcockbu9]

I am able to get the mesh refined enough to look like this - but am still not able to make any hexahedral elements in the surroundings. Let me know if you have any ideas please!

Screenshot 2024-10-17 153214.jpg

[Gert-Jan]

You should first check of all bodies are sweepable.
You can check this using the RMB on Mesh and then select Show>sweepable bodies.
Every body that highlights Green, is sweepable.

The other have problems. Most likely you have additional vertices on edges. You can make all vertices visible in mesher. If you have them, go back to the CAD and make sure you have removed them there.

[mcockbu9]

Hi Gert-Jan,

I checked my geometry and it shows that every body is sweepable. Could you please advise me what to do next?

[Gert-Jan]

Difficult to say. There are many things that might cause problems. The only way to find out is to change things and check the mesh to see their effect.

E.g. it might be that initially the mesher thinks one volume is sweepable in the x-direction and the other in y-direction. Then individually you get a nice mesh, but not together.

Therefore, what happens if you:
1) delete all mesh
2) click on Mesh in the tree (this way you activate mesh options behind your RMB)
3) click on the large volumes
4) click on your RMB select "Mesh the selected volumes"

If these do not give the mesh you want, then something is wrong in those volumes.
If these give the mesh you want, then mesh the other volumes.
Then if these do not give the mesh you want, then their connection is the problem.

Generally speaking, it is not clear to me which volume the mesher takes first if you blindly select "Generate Mesh". It starts in a certain volume and ends .... somewhere I don't know. This random sequence might not be the most logical since the mesher cannot think by itself (no AI yet). By manually meshing volume by volume, you can help the mesher in the best mesh sequence (from inside to outside, or the other way around). This will help to get a mesh you want or to find what is causing the problem.
If, at the end of the day, the consequence of this all is that you always need the manual sequence to get a succesful mesh, then you should look in the help on Worksheet. This records your manual actions, and allows you to replay the actions when loading a new geometry.

Can't help you more without having the goemetry or multiple pictures of individual volumes.

Good luck, Gert-Jan