EXPORTING CONTOURS IN 3D PDF

I am trying to export DWG (3D contours) to 3D PDF. Whilst exporting in 3d PDF file, some contours are being displayed as regions. Is there any way I can export them as polylines instead? I have worked around with Entity Mapping settings already but no luck. I would appreciate if someone could help me out with correct process/settings for exporting?

Thank you