Which Structural Analysis application are you using?
Geometry Gym has some tools that help with this, although it’s far from trivial to get this 100%.
Walls have door “openings” and many software simply want the meshed surface.
Then there is “healing” a model, a structural analysis model is a simplification and aproximation, ie columns might be preferred to be on the slab perimeter curve, rather than the column mid axis which might cause a mesh with vertex in close proximity to the perimeter. Or wall axis might need to be projected onto the perimeter.
I tried it for the tunnel part and it didn’t work. I asked because I often work with such structures. In fact, there are much more complicated models like tunnel junction structures. I’m trying to find an easier way to prepare these models.
I mostly use Sap2000 and actually installed Geometry Gym and started using it a while ago. I’m working with the second method you mentioned. My main purpose is to transfer the structural walls as a shell elements, columns as a frame elements etc.
Even if some of the structures I am working on are too complex, would Geometry Gym be useful for simpler models?