FreeCAD is a great software used for 3D modeling physical objects of any scale, including buildings.
FreeCAD is open-source BIM software that offers several benefits over commercial competitors. Things like walls and flooring, for example, are not required to have any certain "typical" shapes. This affords you the opportunity to design novel shapes, such as a floor slab that gradually rises to become a wall. Including features like these is helpful while developing futuristic buildings.
There are a bunch of decent tools out there that offer the same array of services as FreeCAD. And it can sure get confusing to choose the best from the lot. Luckily, we've got you covered with our curated lists of alternative tools to suit your unique work needs, complete with features and pricing.