I can't get uv's to print to scale no matter how many times I apply scale and measure

I can’t get uv’s to print to scale no matter how many times I apply scale and measure.

I just took a second look and the uv parts aren’t even scaled to each other. The ring is 1 cm thick and about is supposedly 7.36 cm in outside diameter and the longest edge in the whole model is supposedly just over 6.5 cm, yet some how the longest edge is about 150% longer than the ring’s diameter.

Thanks for any help.
Tim

Attachments

scale test.blend (582 KB)

UVs have no scale.
If you are talking about the relative size to each other of lines in an exported UV try the attached file and export to SVG and scale it appropriately in a vector editor. A quick check seemed to be okay…

If you do it often I would include a small square plane of a whole number dimension to make it easier to scale the UVs to an exact size later.
In this case I measured a length in Blender’s 3Dview, 11.57cm, measured it again in the SVG of the uv export, 9.58 cm, and then scaled the SVG by a factor of 11.57/9.58.

Attachments

TRYTHIS.zip (159 KB)