RISA-3D allows you to append, or merge, multiple models into a single model file. This may be helpful if you model single floors in separate files and want to stack them together.

Absolutely; RISAFloor, RISA-3D, and RISAFoundation all allow the user to export a model as a DXF file for use in most major CAD programs.

You can import a building into RISAFloor one level at a time using a DXF file. First, save your CAD drawing in the DXF file format.