General Information and Techniques for Improving STEP Translation Success


  • Use entity types that are supported by your translator or defined in exchange agreements

  • Wherever possible use basic geometry and primitive solids to create the model

  • Avoid modeling practices that can create geometry which cannot be exchanged, as in constructing solids where topological edges converge at a single degenerate point

  • Use the highest precision when creating a part

  • Most CAD vendors today implement AP 203 (configuration managed 3D design data), Conformance classes 2, 4, and 6

    - Class 6 is advanced boundary representation solids

    - Class 4 is topologically bounded surfaces

    - Class 2 is geometrically bounded wireframe and surfaces

  • AP 214 implementations so far have mainly copied AP 203 geometry

  • Use b-rep solids since facetted boundary representation solids corresponds with the little-implemented AP 203 class 5

  • If you must use wireframe, make it geometrically bounded since topologically bounded wireframe corresponds with the virtually unimplemented AP 203 class 3

Importing STEP Files

  • Confirm that files are defined to the agreed standard

  • Verify that files have not undergone any conversions that may have corrupted them, e.g. ASCII to EBCDIC conversion can convert special characters, which have a meaning in STEP files

  • Ensure that files have not been truncated, e.g. to 80 character records, or in length

Exporting STEP Files

  • For assemblies, confirm that all component files are in the same directory

  • Make all geometry visible and selectable

  • Remove unnecessary geometry, layers, annotation from the file(s)

  • Use tools available in the native system to validate geometry prior to export

  • Ensure that the STEP translator can support the nature of the data to be exchanged


  • Modify UNCERTAINTY_UNIT to match IDEAS’(“.1”)



  • Run autostitch after import

  • If prompted to deal with open edges, give tolerance of the original CATIA model


@ 2000 KFKI ISYS Informatikai Kft.