You can export 3d pdms to STEP file using Mechanical Equipment Interface and with STEP file you can transfer to many 3d software like AutoCAD. User must be in one of the Design modules before export the models.
Here is the example of the commands you need to type in command line or save as a macro and run it. With save as macro you can run in the device TTY mode it will be a lot quicker to output the files rather than the graphics mode of the Design module if the models that you are going to export is large.
Here is the example of the commands export 3d pdms to STEP :
repre level 6
repre level pipe 6
repre level nozz 6
repre level stru 6
export system /explantmcad
export file /D:\PDMSid\ExportedModels
export system /explantmcad *Load the export driver.
export file /D:\PDMSid\ExportedModels *Specify the target directory for the exported files.
Read another way to export 3d pdms to 3D AutoCAD DGN or DXF using Explant !!