The following settings are recommended up to CATIA V5R24 (V5-6R2014) (Dassault) and I-DEAS 12 NX Series.

CATIA V5 (Dassault) – System

• Model should be cleaned of all unlinked information
• Delete unused elements from the NOSHOW area.

CATIA V5 (Dassault) - STEP Preprocessor

• Recommended settings in the STEP export options (Tools -> Options...-> Compatibility…-> STEP) :
• Choose the respective Application Protocol (AP): AP203, AP242 or AP214 (recommended).
• When exporting assemblies choose One Step File, because CC6 (External references) is not supported from all STEP processors.
• Do not export the NO SHOW area (set Export all entities: off).
• Optionally define the Header of STEP file.
• Validation properties are supported.
• If export a CATProduct:
• The option "work with cache system" has to be switched off (Tools -> Options -> Infrastructure -> Cache Management)
• The root node has to be selected, otherwise only the node of the CATPart will be exported

STEP File

• An adjustment of the STEP file extension is not necessary.

I-DEAS NX - STEP Postprocessor

• Save reminder (Options/Preferences/Data Management/ Save reminder every) should be turned off since the translator stops for every alike message.
• In Menu STEP Export Settings AP214 several options for the used units of functionality can be set. A change of the default options is only necessary in case of unsuccessful results.
• If the import was successful, you will get a confirmation message.
• Two log files are generated (filename.ipr and stepoi.ipr):
• filename.ipr includes the import settings
• stepoi.ipr includes an import log
• The log files are written in the same directory as the STEP file.

I-DEAS NX – System

• A part is automatically generated from the filename on import. 
• If the part name duplicates an existing part name, the part is renamed "Duplicate Part Name X", where X is a sequential number (X=0 for the first duplicate).
• On each import, a new part is created even if the parts are identical. Therefore, the part names must be different.
• Shaded view gives hints about possible defects.
• Use the Automatic Stitch-mechanism for information about open gaps and remaining free edges. It is found in Master Surfacing Module in Menu Surface Operators.
• If free edges are found in solid models, the Automatic Stitch-mechanism can be applied to merge free edges by changing default accuracy. For surface models, the edges that build the contour of the model remain free edges.