Hi Jason,

> I then imported the file into Pro/ENGINEER which comes
> in fine but with errors (Geom Check, which could mean
> sliver edges).

Well, it's certainly possible to create small edges in MoI, in any number of ways - for example if you boolean together 2 objects that are slightly misaligned that will usually create some small sized edges in the result.

Is it possible for you to send me the particular file that Pro/E is complaining about so I could take a look at it?

re: cylinders - when MoI writes out surfaces to the STEP file, it just writes them as generic "NURBS surface" entites (which do have an exact cylindrical shape though if it was a cylinder), and not as a special cylinder entity.

Often times if a program needs to do something special with particular kinds of primitive objects, they may detect if the imported NURBS surface has the exact shape of an analytic primitive when they read the file - it sounds like the newer version that you were importing into has that analytic detection in it, and the older version does not have analytic detection. Does that help explain what you are seeing?

- Michael