Import and Export object dimensions and translations scaled by changes to Unit Scale.

[Adrian Giddings]

When Blender is correctly set up in millimetres (scale_length = 0.001 and length_unit = millimeters) exported 3mf files are 1000 times too small and on import 1000 times too large as are the object positions in relation to the world origin.

While this is easily fixed by exporting at 1000 scale and importing at 0.001 I think this is unexpected behaviour.

This is not an issue with import and export of STLs with the same Blender settings.

I have tried changing the code of the Addon locally but that always seems to break it, probably because I have no idea how Addons work other than how to install them.