Hi Mike, maybe you have not set any unit system at all in MoI?

Several file formats like STEP I think does not really have the equivalent of a "no unit system" setting, it wants to have an actual unit system set and I think if you do not have any units set in MoI then it will default to inches in the STEP file.

So if you had been modeling with intending to use units as cm or something like that, but you did not ever actually set the unit system in MoI to actually have that value and left it just at "No unit system", then that might be your problem with you generating a STEP file with its units actually in inches.

If that's the problem then the fix is to just go to the Options dialog in MoI and set the unit system to the unit system that you are intending to use instead of leaving it at the generic "No unit system".

If you just leave it at "No unit system" then MoI will not understand what units your objects are supposed to be at - it's fine to leave it at "No unit system" if you're just modeling stuff only in MoI but when you are exchanging data with other CAD systems you should set the unit system so that you know what units will actually be set in the generated file.

- Michael