Importing a geometry to Salome

I have a geometry in .stl file format imported into Salome however, the geometry acts as one structure and I am unable to select certain surfaces.
The geometry is similar to a pipe and I want to be able to select the inlet and outlet nodes to make node sets. Is there a way that I could achieve this?
Also, if I have two .stl files, then is there a way to merge the two but still be able to individually select them?
The structure uses shell elements (zero thickness)

Would appreciate any help

Do you have the possibility to export it in another format from the place you created from? .Iges or .step? This would highly facilitate the work.

Yes, I can definitely export in those formats.
Which one would you recommend for my case?

Export it in .step, in Salome, go to geometry, import/step and then create groups with the different boundaries that you want to Distinguish and then go to the meshing module and create a mesh of the object. It will create a mesh divided in same boundaries as different groups you created.

So I am using Pointwise to export the grid and realized that it can only generate the following formats:

Would any of these work?

Several questions.
À. If you work with pointwise why you don’t do it in that software? Pointwise is a widely used and powerful tool even if I have not used I find it extremely rare that it would not have it.
B. If you generated you mesh in pointwise, there is two possibilities or you did a structured mesh and maybe you did not use a Cad geometry to create it (I insist I am not an user) or you have an unstructured mesh and therefore before generating this mesh in point wise you needed a Cad model. That what you are going to export in step format not the generated mesh of pointwise but the Cad model you used to generate it.


have I understood correctly: You are looking for coordinates of points?

This also works for *.stl files with “inspection”, see picture


I need salome because it generates a .UNV file while Pointwise does not. My end goal is to be able to convert the .UNV file to a .inp format so that I can run a simulation in CalculiX.
I tried what you said as well and imported my .STEP file to Salome and am trying to generate a zero thickness model.

I want to be able to select certain nodes and define them as a node set however, this is very helpful to know.
Thank you! @Luve

Have a look at this meshio · PyPI it could help maybe.
In any case, what do you mean by zero thickness wall. What you are looking for? A mesh where the inner and outer radius are coincident and therefore the thickness of the “tube” that is shown in the image would be one plane thick?
Please post some schematic or something as, at least for me, you are not very clear… And without all info I can not help you more.


I would like to show another possibility. The software Paraview can select groups of points from a *.stl file (see picture) and then export them as *.csv file.
Would this still be a help ?

With kind regards


Yes, exactly what you said

Thank you!
Let me try this

Then you should create the correct geometry to mesh it. You can create it in the shaper or geometry module. Have a look at cyprien rusu videos or the ones from Salome platform official channel.
This should give enough material