As an alternative to buying the software, the StairFile Lite service (free of charge to Full members) will include the 3D DXF files as well as the full set of 2D DXF stair and parts files.
Do any of the paid versions of StairDesigner have a possibility to export the whole stair as a 3D dxf project? Is there any examples I could see? From other posts I could see only 2D dxf files.