Conservation of certain areas

[Turbomichi]

Is there a way to conserve certain areas or shapes of my object?

For example if I have a rectangular beam, I want to still have the rectangular shape and only within there should be a topology optimization?
This kind of optimization can be done for example in Z88Arion.

Like you did in Example 3 with the non-design spaces but with the FreeCAD.

Thanks and greetings.

[fandaL]

Optimization domain is defined by the elset_name in the beso_config.py Elements which are not in this elset are not optimized.
If you use FreeCAD macro, it can be done as well. When preparing the model, create a separate material object for what you want to optimize and separate material object for areas not intended for the optimization. In the beso_fc_gui.py you then select only the material object to be optimized. Or, you can use also the column Domain 1 or Domain 2 and untick As design domain so that this area will be visible in the resulting mesh, but not optimized.

[Turbomichi]

What exactly do you mean by separate material object? I can create seperate bodies in FreeCAD but how does the *.inp-file know which are the different Domains. I always only have one Domain. How do I create different Domains in FreeCAD so that the GUI can distinguish them? And is there an in depth explanation of the complete GUI?
Thank you so far.

[fandaL]

When preparing the geometry, you need to make partitions
FEM_Geometry_Preparation_and_Meshing
It will make parts which can be selected, when you are creating a material object
FEM_MaterialSolid
The GUI does not have a manual. There are only tool tips when you hover a mouse.

I used very course mesh, but preserved domain in the middle is clear in the resulting mesh:

FreeCAD file
multidomain.zip