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Import 1D-2D elements issue - Salome 8.5.0 on Linux

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Import 1D-2D elements issue - Salome 8.5.0 on Linux

Posted by Mattia at December 07. 2018
Hello everyone,
I'm struggling trying to mesh a partitioned geometry using "import 1d-2d elements" hypothesis.
I'll try to explain everything in a clear way as unfortunately I can't share the geometries.
I have a standalone geometry which has been 3D meshed and used to inspect performance. Minor changes usually occur to provide best aeraulic results. This is stage 1.
Once the results are fine, I need to "insert" only the boundary 2D mesh of this final geometry in a bigger domain. Stage 2.
The domain is processed using partion between the very domain and the final object's geom in order to preserve faces and obtain, but this operation is made only after stage 1 is done (I don't get the very domain before stage1 results)
I tried to use "import 1d-2d elements" on a submesh of the domain but I'm facing the same error mentionend in this old post:
I already tried to use projection with no success.
As the documentation doesn't tell much, is there a proper way to mesh something small and use it's 2D surface mesh as part of another mesh that actually includes this first stage object without pre-partition them (as I have only one stage object at a time)?
Sorry if I wasn't fully clear, I'll make some simple geometries if you need to reproduce the problem.

Re: Import 1D-2D elements issue - Salome 8.5.0 on Linux

Posted by Saint Michael at December 07. 2018

Hi Mattia,

Maybe the following approach is suitable for you.

1) 2D mesh the domain

2) Join the 2D domain mesh and 2D mesh of the final geometry using Build Compound mesh.

3) 3D mesh the Compound mesh. BUT Viscous Layers can't be applied this way.



Re: Import 1D-2D elements issue - Salome 8.5.0 on Linux

Posted by Mattia at December 09. 2018

Hello St.Michael,

first of all thanks for fast response. I didn't think about this kind of approach, even if it makes perfect sense and it's actually very easy!

This is good and it works well. Already tried on sample geometry and it reminds me Pointwise's approach :D

Unfortunately viscous layer is something I usually have to compute, therefore I can't really use this method while useful. Al least not all the time.

Anyways I found the solution and I post it for future reference.

I was wrongly grouping faces in the geometry modules. The correct way to obtain face group that can be used with 1d-2d imports is the following:

1. Process original geometry (obj_A), creating whatever groups you need and make at least one group containing all the faces shared between obj_A and the domain it will be partitioned with.

2. Use this geometry as tool for domain partition (at least in my case)

3. Extract / Explode the domain to be meshed (obj_B)

4. Create face groups on obj_B using "geometrical parts of the second shape" pointing to the face groups previously created on obj_A and click "select all". This way Salome does a 1:1 map. This was my mistake as I was creating obj_B's groups from scratch, even if the faces were the very same.

5. Create groups from geometry entities on obj_A's mesh. Here you can create the "global shared faces" group

6. Use those groups as source faces with import 1d-2d elements hypo on obj_B's 2D submeshes.

Testend on both 8.3 (Windows 10) and 8.5 (Linux) with 4.5 million cells tethra grid. Not a single error printed, the meshes are perfectly matching.



Re: Import 1D-2D elements issue - Salome 8.5.0 on Linux

Posted by Mattia at December 10. 2018

Ok forget it, I got the same error processing another geometry with the same method.

I'll try to reproduce the error with sample geometry and I'll post them so you can check if everything works or not.


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