Hi Michael T,

> I just had the same STEP file issue with a SolidWorks STEP
> file I downloaded from the web. I have attached it here. The
> same SAT file came in okay.
>
> Just thought I would let you know.

Thanks for posting the file Michael T - this looks like another problem with reading the units setting from the file, but it is a different problem than the previous one.

I've heard back from the STEP library author for the previous problem and he has a fix coming for it in the next version of the library. I'll also send him this other one and see if that can also be fixed.

The problem with this new one seems to be that the library thinks the units in the file are supposed to be meters, when I guess they are actually in inches. This seems to be due to some kind of alternate method used for designating the units, it's got these entries in the STEP data:

#5130 =( CONVERSION_BASED_UNIT ( 'INCH', #5131 ) LENGTH_UNIT ( ) NAMED_UNIT ( #5132 ) );

#5133 =( LENGTH_UNIT ( ) NAMED_UNIT ( * ) SI_UNIT ( $, .METRE. ) );


The library seems to be not handling or taking into account that "Conversion based unit" stuff in the file.


In order to fix this second one into MoI, you'll need to turn off the option to scale objects when the unit system changes, then change the units from meters into inches, then turn the option to scale back on and then change the units to mm to get the correct final result in mm.

- Michael

Hi Michael G.

Yep, that does it.

I will still try some of the other file conversions between these various programs, and let you know my results.

Thanks again,

Michael T.

Hi Michael T, so I found out what is going on with that second STEP file, the one from SolidWorks - it's actually a bug in MoI and not in the STEP import library itself.

It's possible for STEP files to store not only a unit system but also a scale factor that is supposed to be applied to the unit system as well, and MoI was not paying attention to this additional scale factor.

So for example that file you posted has 1 unit = 1 inch in size, but for whatever reason instead of it just directly saying that the units were inches, it instead was set to say that the units were meters with an additional scale factor of 0.0254 applied to it (which is 1 inch in meters). But MoI was only picking up on the meters setting part and not the additional 0.0254 scale factor part.

So I've added that to my list of stuff to fix in MoI. Thanks for posting the example file,

- Michael

No problem,

Always glad to try to help.

Michael T.