Precision control

 From:  Michael Gibson
1848.13 In reply to 1848.12 
Hi Burr,

> Is the MM thing an internal file format or are you under the
> impression that my interface is set to mm?

It's what was set as the unit system in the .3dm file - the .3dm format has a place in it to mark what unit system is being used, in the bobcad file that is set to mm. (and coordinate values have been scaled so that they are in mm units instead of inches).

If you open that file up in MoI, then go to Options, you'll see Unit system: Millimeters, also same thing if you open it in Rhino.

> Could there be a version issue with open nurbs. MoI is on
> version 3 and bobcad using 4? (Am I mistaken? I am
> getting this from the toolkit)

It's true that MoI is using v3 of the OpenNURBS toolkit, but files written by OpenNURBS v3 are able to be read in by OpenNURBS v4 without any problem... I can't think of anything that would introduce error in coordinate values for example.

Maybe Bobcad does not like to get files with Inches as the units in the file?

I guess another test you could do would be to start a new file in MoI, set units to mm, then create a sphere of radius 127 mm - then import this into BobCAD - does this then show a value of exactly 5 inches in Bobcad? If so then maybe there is a possibility that BobCAD has a bug when importing files with inches as the unit system and converting it to mm...

- Michael