Answer:
With the release of program version RFEM 5.23.01, a new option, "Simulate and Generate Wind Load", is available in the settings of RWIND Simulation. This allows you to export 3ds files inserted in RFEM as a terrain model or a surrounding model to RWIND Simulation. It is also possible to consider an IFC or STEP file imported as a CAD/BIM model in RWIND Simulation.