Plant3D can export to SDNF2.0 and PCF, but has no intelligent solution to import Piping / Structure. I am not a capable to write ObjectARX tools but how can we import ?;
PCF (Piping Component File) files
SDNF files
IFC2x3 files
XML iso15926 files
At this time Plant 3D 2014 can only import certain files types. Here is a list of all the files that are currently importable.
http://docs.autodesk.com/PLNT3D/2014/ENU/filesACD/GUID-81A5EE76-39A7-40A4-A5C5-E4921C03B33A.htm
If you do not see the file format you are needing in the list, you are more than welcome to submit a request here.
Autodesk Product Feedback:
http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=1109794
Quentin Contreras
Technical Support Specialist
There are partners that have written importer for various formats. I've heard that more than one has written PCFin. See what you can find with a little bit of googling.
Wouldn't you just Xref it rather than go through SDNF out/in?