Agreed. I also submitted a feature request to add this to the GUI:

• https://github.com/FreeCAD/FreeCAD/issues/23782

In our case, it was caused by a mesh.

We’re working on a follow-up article now that shows how to optimize modeling meshes (eg Expanded Metal) in FreeCAD

But, yeah, it’s definitely common for volunteers to open-hardware projects to produce overly-detailed CAD contributions that don’t work at scale.

If you want a more sustainable option (read: higher density, multi-family housing) that’s actually licensed openly, checkout Eco-Libre’s designs for the Launch-Nest.

• https://github.com/eco-libre/launch-nest

The structure is designed to house 30 people (18 meters x 7 meters, 5-stories high), off-grid solar PV (energy) and thermal (heating, cooking), and walls are made of CEB pressed on-site.

Eco-Libre Launch Nest

We’re still in the design phase, but the FreeCAD files are public and licensed CC BY-SA.