FreeCAD is definitely a good tool for construction and design

My guess would be FreeCAD but I’ve never used it so I’m not sure.

https://blenderbim.org/

Maybe this can serve you, it generates buildings in 3D (Procedural), yoy can export as OBJ, (Html5)

https://watabou.itch.io/procgen-mansion

See also the other projects from the author

https://watabou.itch.io

https://wiki.freecadweb.org/Arch_Workbench

https://wiki.freecadweb.org/BIM_Workbench

https://blenderbim.org/

I use freecad for General 3d modeling… piracy is always an option