Hello, I imported a mesh from gmsh and convert it using dolfin, when I compared the fenics obtained results with the results of ComsoI I found differences that disappeared when I changed the units in Comsol to “cm”. Does Fenics use “cm” as default unit for imported meshes?
Thank you.
As far as I know, FEniCS does not default to cm. How did you convert your mesh? and can you make a minimal working example illustrating the difference?
Hello, thank you for your answer. I used dolfin mesh converter from gmsh format to xml.
I have exactly the same results when I turn the unit to “cm” in Comsol, perhaps Gmsh uses cm as default I am looking how to check that.
I would not use the dolfin converter to xml, as it is no longer maintained. See Converter from GMSH to XDMF (with physical groups)
You need to check that all your units in dolfin is scales appropriately. Assume that your mesh has unit m and go from there
Thank you very much for your advices. I found the problem, I had to translate the geometry so that my first point coincides with the origin (0,0).
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You decide what units you would like to use, FEniCS does not do anything with units.
If you import your mesh, you decide if it is supposed to be mm, cm,dm,m,km etc. You then scale the other parameters of your PDE to make it non-dimensional
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No, there is no requirement for 0,0 to be in the mesh.