The short video below is a work flow that I've used to export Infraworks to DWF, with the help of 3ds MAX.
Key workflow points
- Exporting is done by sending the model to 3ds MAX by the send to 3ds function. (3ds need to be installed on the PC for the function to be available)
- 3ds MAX now has the selected region of the model and exporting dwf is as simple as export to dwf.