Isometric Room-House Objects are in parts.
All the parts you see are independent from each other
You can use whatever you want.
you can send a message for the question
STL (Stereolithography, filesize: 459 MB), OBJ (OBJ, filesize: 288 MB), FBX (Autodesk FBX, filesize: 140 MB), 3DS (3D Studio, filesize: 114 MB), BLEND (Blender, filesize: 22.1 MB)