The following settings are recommended up to NX 11 and CoCreate Modeling 16.5.

NX – System

• Delete blanked elements before preprocessing.
• To transfer colors of assemblies the colors should be set and saved with the individual components, not the assembly.
• Note that NX uses the radius of a "tolerance tube", other CAD Systems like CATIA V4 define "tolerance" as the distance between two points.
• Select Analysis -> Examine Geometry -> all options -> all elements (up to NX2). 
• Select Analysis -> examine Geometry -> Set All Checks (up to NX8.5) The marked elements are likely to cause problems with data exchange, depending on the messages as explained below:
• Severe errors:
  data structures, consistency, face-face intersections, self-intersections
• Might cause problems:
  tiny, face smoothness, spikes/cuts, edge tolerances
• Without negative influence on data exchange:
  misaligned, sheet boundaries, edge smoothness

NX - STEP Preprocessor

• Start the external STEP processor with File -> Export -> STEP214.
• Select Data to Export and define the options:
• Object Types: One or more of the options Solid, Product Data, Surface, and Wireframe (depending on model).
• The default tolerance value in menu Advanced -> Parameters -> B-Spline Aprx. Tol. of 1.01*10-5 mm can cause to very large STEP files and should be reduced in such cases(recommended value: 10-3 mm).
• Recommended is to use the default settings in menu Translation Control (Tolerant Modeling).
• Special characters in the filename of the STEP file are not allowed. The model will not be exported.
• Validation properties are supported.

STEP File

• An adjustment of the STEP file is not necessary.

OneSpace Designer - STEP Postprocessor

• The properties for STEP import can be found in the file -> open -> options dialog
• Set the accuracy to automatic (default) to use the accuracy of the STEP file.
• If the accuracy is customized, make sure that the accuracy setting is the same or less than the accuracies setting used to generate the part being loaded.
• When associated messages are returned during the import of the STEP file the accuracy should be adjusted.
• If a product with multiple bodies is imported, Solid Designer creates an assembly.
• Blended edges are not recognized as such, and it is not possible to modify blends using standard OneSpace Designer.
• The import log file "step_load_log" gives further information.

OneSpace Designer – System

• Shaded view is helpful and gives a first impression of the model quality.
• To ensure the model quality is OK a complete model check should be performed.