Right now, direct dxf export only works in Windows, and requires the installation and setup of some external programs:
- Download and install the following
- pstoedit(64-bit) - do the full install
- Add the path of both to the system path
- Make sure the path to pstoedit is correct in popupcad preferences(File->Preferences).
This should enable the dxf option in File->export... to work.