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Importing STL

Posted: 12 Dec 2021, 22:40
by astendah
Hello all!

So while im sure my issue is trivial for many of you it is very much not for me. I have been tasked with simulating some magnetic fields and have zero experience with Elmer. I have been given a STP file that i need, and now I desperately need to know how exactly i import that to Elmer correctly. The file has multiple parts with different materials so i need to keep parts separated. I have tried to use FreeCAD so any solution based on that program is greatly apprechiated. Im also using a Linux based machine so dont really have access to windows based programs.

So in short: How do i import a multipart STP file to Elmer, assuming I have zero knowledge of Elmer or 3d in general. The more detailed the better. A bit of a weird situation and no easy thing to ask i know, but anything is greatly apprechiated.

Thanks, Alex

Re: Importing STL

Posted: 13 Dec 2021, 01:06
by kevinarden
If you want to learn some Elmer you should work through some of the tutorials

https://www.nic.funet.fi/pub/sci/physic ... orials.pdf

A STP file is geometry and Elmer uses a finite element mesh. You need a tool to import the STP file, mesh it, and export the mesh. You can then use the mesh file in Elmer. Several tools will do it including FreeCAD, other popular ones are gmsh, and salome.

Re: Importing STL

Posted: 14 Dec 2021, 12:38
by astendah
Thank you for the reply. I have worked through some examples in Elmer, so that im on board with. However its the importing of the mesh that is the primary consern. So it is possible to export the correct type of mesh from FreeCAD? Is there some guide on all the steps from importing STL to exporting the correct mesh that is available?

Re: Importing STL

Posted: 14 Dec 2021, 13:21
by kevinarden
There is a detail description in chapter 9 for salome and gmsh. FreeCad forum has information on using Elmer in Freecad
https://www.nic.funet.fi/pub/sci/physic ... dElmer.pdf

just google
elmer in freecad

Re: Importing STL

Posted: 14 Dec 2021, 19:40
by fjimenez
Just my two cents. This is what I do. I do not work directly with stl but with step files. Whenever the geometry is relatively simple, I do the geometry and meshing in Salome. Salome is great for meshing but their CAD interface is not that great. If what I need to do is more complex, I do the geometry in Freecad because it is way easier to work with the sketches. Once I have the geometry in Freecad, I exported it as a step file so I can work with it in Salome. This way I have full access to all the great options Salome offers in terms of generating meshes that are very easy to work with in Elmer. I have worked with very complex designs using this workflow. It is even great is someone sends you the geometries from solid works or inventor.

Re: Importing STL

Posted: 14 Dec 2021, 21:14
by kevinarden
Thanks, unfortunately the title says Importing STL but in the text it is stated that it is actually a step file STP. STL files are not very good for meshing since the geometry definition is not precise, STL files are used for graphics to make CGI animations for movies. STP files are used for definition of engineering parts. It is good a STP file is the starting point.