Troubles navigating in Elmer to find body ID

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bptsj
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Troubles navigating in Elmer to find body ID

Post by bptsj »

I'm having trouble in Elmer navigating the image to find body numbers. When I had a 3D assembly of 4-5 parts of similar size it was easy. My new project has 18 parts and the relative sizes very from very small to large. When I show body #'s the characters all overlap and I can't discern the #'s for small features. Also, I can only rotate the image and not translate it so it makes it difficult to zoom in on small features. Is there a better way to identify body numbers? Is there any file I could look at to correlate Salome group # to the Elmer body #?

Thanks in advance for your help.
Brian
bptsj
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Re: Troubles navigating in Elmer to find body ID

Post by bptsj »

More info,
Here is a dropbox link to a picture showing a thin diagonal strip of material I'm trying to identify the body # of,https://www.dropbox.com/s/dkzg3cym2xmdw ... 4.png?dl=0 You can see the body #'s overlap & obscure themselves.

This feature is in the center of a large object. There are similar objects (not shown) on the far left and right of the overall assembly. Because I seem to only be able to rotate the view and not translate I can't zoom in on the other objects.

Regards,
Brian
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: Troubles navigating in Elmer to find body ID

Post by mzenker »

Hi Brian,

navigating in a geometry with ElmerGUI is indeed not very comfortable.

There are three possibilities to work around that problem:

1. Convert the Elmer mesh to gmsh format: from the command line, navigate to the directory where the Elmer mesh resides (it is generated after the first project save with the GUI) and say

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elmergrid 2 4 mesh
Then there will be a mesh.msh file which you can open with gmsh. Navigation is by far better in gmsh, so you will quickly find out which number corresponds to which body/boundary.

2. Use the names from Salomé in Elmer, following an indication by Peter Raback here: http://elmerfem.org/forum/viewtopic.php ... 220#p14925. Drawback: you cannot do that with ElmerGUI.

3. Convert your unv file with elmergrid from the command line. If your mesh file is named mymesh.unv, you say

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elmergrid 8 2 mymesh.unv
Elmergrid spits a list showing the correspondances between Salomé names and Elmer indices.

All that is not entirely satisfactory. It would be good to have a possibility to import the names given in Salomé in a way that ElmerGUI can display them...

HTH,

Matthias
mark smith
Posts: 215
Joined: 26 Aug 2009, 18:20
Location: Peterborough, England

Re: Troubles navigating in Elmer to find body ID

Post by mark smith »

Hi Brian,
My preferred solution is to convert the Elmer mesh to vtu format
Go to the folder where your mesh.boundary etc files are & open a command window then type
elmergrid 2 5 mesh

this will write out a vtu file which you can open in paraview ( a great free postprocessor) Now in paraview you can threshold by GeometryIds to see what numbers have been assigned to each of the boundaries by the meshing software you used to create it.
HTH
Regards
Mark
mzenker
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Location: Germany

Re: Troubles navigating in Elmer to find body ID

Post by mzenker »

Interesting alternative, I was not aware of that one.
I just tested that method and did not manage to display the boundary IDs correctly. They have an offset of 100, and the boundaries are not distinguished as such. Maybe I have used the wrong method.
For the moment I prefer gmsh which can display bodies and boundaries selectively with their IDs. However, gmsh sometimes has difficulties to display the mesh correctly when it was originally in unv format.
So still this does not replace a better interface between Elmer and Salomé...

Matthias
mark smith
Posts: 215
Joined: 26 Aug 2009, 18:20
Location: Peterborough, England

Re: Troubles navigating in Elmer to find body ID

Post by mark smith »

yes boundary conditions have 100 added to them whereas body number are as given, this is just for the vtk output, the BC numbers in the sif would be as intended without the 100 added.
Regards
Mark
annier
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Re: Troubles navigating in Elmer to find body ID

Post by annier »

mzenker wrote: 3. Convert your unv file with elmergrid from the command line. If your mesh file is named mymesh.unv, you say

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elmergrid 8 2 mymesh.unv
Elmergrid spits a list showing the correspondances between Salomé names and Elmer indices.
An addendum to Matthias' suggestions:

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elmergrid 8 2 mymesh.unv -autoclean
Autoclean flag has to be added for the mesh conversion by ElmerGrid from unv format.

Yours Sincerely,
Anil Kunwar
Anil Kunwar
Faculty of Mechanical Engineering, Silesian University of Technology, Gliwice
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: Troubles navigating in Elmer to find body ID

Post by mzenker »

annier wrote: An addendum to Matthias' suggestions:

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elmergrid 8 2 mymesh.unv -autoclean
Autoclean flag has to be added for the mesh conversion by ElmerGrid from unv format.
Not always - I just run simulations where I did not use autoclean. I use ElmerGUI where this is not the default. But I agree that autoclean often can avoid trouble.
Anyway, If you use autoclean on the commandline, then either open the converted mesh directly with ElmerGUI (file->load mesh) or set the -autoclean option in ElmerGUI under mesh->configure->Elmergrid String (_before_ you open the mesh). Otherwise you will have a different numbering.

Matthias
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: Troubles navigating in Elmer to find body ID

Post by mzenker »

Hi,

I just have (re-)discovered something interesting:
mzenker wrote: 3. Convert your unv file with elmergrid from the command line. If your mesh file is named mymesh.unv, you say

Code: Select all

elmergrid 8 2 mymesh.unv
Elmergrid spits a list showing the correspondances between Salomé names and Elmer indices.
Not only does Elmergrid spit a correspondence list in the terminal, but it also writes a file entities.sif with a skeleton for body and boundary sections, and also a file mesh.names. Both files show all the names from the unv and their numbering in Elmer. Very practical!

HTH,

Matthias
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