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# Problem with Mesh of a Divided Disk

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### Problem with Mesh of a Divided Disk

Posted by Giorgio Bornia at October 01. 2019
Dear all, I am trying to mesh a Divided Disk. I need to have only quadrangle finite elements. I mesh each face separately (at the end, I will put them together). Since I want to have a different number of divisions in the two directions of each of the 5 faces, I use: - Quadrangle mapping; - two Submeshes on two adjacent edges, with the Hypothesis "Propagate 1d hyp. on opposite edges" on each of them. After computing, I get a weird mesh that seems to start well but then generates a bunch of small triangles towards the end... In attachment is the python dump, if it helps. How can I achieve my goal? Any help is very much appreciated. Best, Giorgio
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### Re: Problem with Mesh of a Divided Disk

Posted by Saint Michael at October 01. 2019

Hi

I attach a script which meshes the whole divided disk according to your hypotheses. Your way is also possible but you missed Propagation hypothesis on nsubs_radial.

St.Michael

### Re: Problem with Mesh of a Divided Disk

Posted by Giorgio Bornia at October 01. 2019
Sure, I clearly forgot that hypothesis but I had it in mind, I think I was way too tired I don't see your attachment for your alternative way, perhaps you forgot it. Could you please reattach it? I also have a question: since I need to do 2 Submeshes for each of the 5 faces, and several of these Submeshes are in common, is there a way to avoid repeating them, something like "Sharing of Submeshes"? What I did was to create variables in the Notebook to be used to discretize the coincident Submeshes in the same way. Thanks a lot for your help, Giorgio

### Re: Problem with Mesh of a Divided Disk

Posted by Saint Michael at October 01. 2019

Oops

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### Re: Problem with Mesh of a Divided Disk

Posted by Giorgio Bornia at October 01. 2019
Actually, to be correct, I defined my variables as Hypotheses variables. Is it better to do like this and do "Edit hypothesis", or to do an "Update study" for variables defined in the Notebook? I've experienced some problem when doing "Update study", like segfaults, so my opinion would be that the best practice is the first one. Giorgio

### Re: Problem with Mesh of a Divided Disk

Posted by Saint Michael at October 01. 2019

In my opinion it is better to avoid "Update study".

St.Michael

### Re: Problem with Mesh of a Divided Disk

Posted by Giorgio Bornia at October 02. 2019
Thanks a lot, St. Michael. Now that the mesh of the Divided Disk is made, I have a bunch of internal edge elements that I would like to remove since my boundary of the differential problem is only the external circle. Is there a way to do that besides manual erasing? Best, Giorgio

### Re: Problem with Mesh of a Divided Disk

Posted by Saint Michael at October 02. 2019

Hi Giorgio

You can easy remove them using a filter. In Remove Elements dialog click [Set Filter] and set up parameters as in the picture.

The same thing is possible in a script as well.

### Re: Problem with Mesh of a Divided Disk

Posted by Giorgio Bornia at October 02. 2019

Thanks a lot!

My initial goal was actually to create a Divided Dome mesh with quadrangle elements.

I finally made it. I had some problem with removing extra edges from faces (whenever a face has more than 4 edges I guess some of these become an obstacle for Quadrangle Mapping). From what I understood from a forum post, I created an auxiliary volume in the Geometry, removed extra edges then extracted the "clean" face.

My solution is in attachment. I used your method of "crossed" Propagation of edge hypotheses instead of my method of meshing 5 faces.

Perhaps one day Salome will also have Divided Dome or Divided Sphere buttons

Was there any other way to remove extra edges from faces?

Giorgio

Attachments

### Re: Problem with Mesh of a Divided Disk

Posted by Saint Michael at October 02. 2019

In Geometry module there is a dedicated function that removes extra edges: menu Repair > Remove Extra Edges.

St.Michael

### Re: Problem with Mesh of a Divided Disk

Posted by Giorgio Bornia at October 02. 2019

I tried to use "Remove Extra Edges" on a Face, but it didn't work. Actually I couldn't even select that Face (it was a face coming from an Explode of a Common).

So are you telling me that I have to use the function on the Volume father?

What if the face didn't have any Volume father?

Giorgio

### Re: Problem with Mesh of a Divided Disk

Posted by Saint Michael at October 02. 2019

If the face has no solid father, a workaround is to put the face into a compound.

St.Michael

### Re: Problem with Mesh of a Divided Disk

Posted by Giorgio Bornia at October 02. 2019

Thanks! That works too.

g.