I came across this problem when trying to dimension something in LayOut and saw that when drawing in inches you can't dimension in a tighter tolerance than 0.01". I was digging around to find out what was going on with that, and came across this post from Google employee John Bacus:
As you can imagine, we do care quite a lot about precision/accuracy in LayOut's dimensioning system. In fact, we limit the precision for decimal inches to .01" because we can't certify that values in the thousandths of an inch are correct in all cases. For the majority of our users, this isn't an issue– they are doing either architectural or furniture scaled work where thousandth of an inch are just not relevant. But I can easily understand how unsatisfying this is for those working at a machinist's tolerances.
Unfortunately, this isn't just an issue in LayOut. SketchUp can't really work to .001" precision either. As you approach entities of .001" in length or less, you'll find that faces in the model won't close and SketchUp will begin reporting validity problems. The only real solution to this is to scale the entire model up by some multiplier.
nspies: If you haven't already found it, you can limit the precision of your dimensions in LayOut by choosing 1/8" from the "Precision" menu in the Dimension Style panel.
hope this helps-
The dimensions in LayOut is not that big of a concern for me, but I am a little worried about his statement that SU won't work to 0.001" precision and once you go that small things don't really work right.
When I go to WINDOW > MODEL INFO > UNITS, I am able to select tolerances MUCH smaller than 0.01", and when I import items as .DXF files everything seems to measure out to the dimensions that they were originally drawn in (originals were drawn in TurboCAD).
So my question is this: Has this issue has been resolved with the update from SU7 to SU8, or is drawing things to 0.001" tolerance still unreliable as John stated in his comment?
I know some people use the workaround where they draw everything in feet and then scale down by a factor of 12, but obviously I'd like to avoid doing that if I can.
Thanks in advance for your help.