Iges conversion issue

I’m tracking down an iges translation issue.Might be coming from my end, units in one system as mm the other (NX11) Imperial, these may not playing well together.

I’m working is a very high Rhino tolerance of 0.001mm, Yes that tight, this has been done as I have never found translating anything improved quality so I didn’t have an issue of some loss. My parts are are unforced and badobject free solids in Rhino.
I’ve made a custom Iges format with 0.001 tolerance with units in millimeters.

Iges settings

The header in the iges file says this
26HRhinoceros ( Oct 22 2019 ),31HTrout Lake IGES 012 Oct 22 2019,

Here’s the question
Second line up I assume is the tolerance? if its in mm I don’t have a problem. Is there anything in the rest of this header that describes that tolerance as being in mm? Importing system, NX11 is running in imperial units.

Thanks in advance for any help or a better understanding.

Hi Ken - the “,2,2HMM” indicates mm as the unit for the file, the .001395 etc is described as the ‘resolution’

“Field 19: 0.1000000000E-003 - Minimum user-intended resolution. Used to determine if points are “coincident””

( http://www.3dmodelzone.com/iges-section-g.html)

@tim will know…


Thanks Pascal
Even the confirmation about the units been stored in the file gives me a better understanding of the issue.
I suspect the problem will be found on the steps taken on the importing procedure in the NX system that’s in inch.

@ken_miller - Tim confirmed what we were guessing about above in the IGES format…


Why not convert the file to inches in Rhino before exporting…? (then undo). Maybe Rhino is better than NX at conversion…