STL file import/export scale problems

Hey all-
Not sure if there is a hidden option somewhere that’s causing this problem for me, but every time I export a Mesh into an STL file; I have to scale the Mesh size UP by 10x (exactly) in order for the exported STL to be the correct size. It’s only when I do this 10x scaling up that I can get Rhino for Mac to export a dimensionally accurate model (as seen by other tools that can deal with STL, including Netfabb, Cura, and my 3D printer.

Same thing happens when I Import STL files into Rhino is that the measured dimensions inside Rhino are 10x bigger than the object imported.

This happens every time, on every file (importing and exporting.) Of course, the workaround is totally doable: just use the scale command!

Still, it feels (to me at least) like a real bug…or perhaps someone can throw me a clue and let me know what I am missing.

Thanks very much,


STL’s don’t have units - all they have is numbers. Only two unit systems are “assumed” by software that work with stl’s - either millimeters or inches. So I suspect you are working in cm when you export or import, which would correspond with your experience more or less exactly.

Example -

If you have an object that is a 10cm cube and you export it via STL to a 3d printer program, it will assume the cube is 10mm, because all it sees is “10”.

If you have a 10mm cube in STL and you import that into a Rhino file in cm, Rhino will assume it is 10 cm.

HTH, --Mitch

Very helpful. That clarifies things quite nicely.

Thanks very much


hey. that’s Mitch!

Well, if you read the e-mail notifications and reply by e-mail, everyone is Steve… :stuck_out_tongue_winking_eye:

oh… right. i remember that being a problem for me when this discourse first started up… it’s since been fixed in the scenario i use (gmail being pushed through

… but i guess it’s still an issue for some?

For example if I reply to this via e-mail (Outlook) lets see what happens…

oh… hi steve… long time no see

I have this exact problem.