This is a separate architectural element, a skybridge, ready to be put into your building. Its great detail allows makes it perfect for indoor and outdoor renderings as well. The model is structurally correct. It's also modular so you can create a bridge as long as you want.
3ds Max version has correct materials in the default scanline and the Vray version too. The other conversions are just geometry.
Previews were rendered with 3ds Max - Vray version.