-- Before measure --
Datum A Fix + Rotated
Can also be used on flat surfaces perpendicular to the datum axis
-- records --
Point 1 = -10,+15
-- After measure --
If tolerance of GD&T on drawing , limit 30
It can use , Because this work piece is limit +15 (oversize), -10(lowersize) = 15 + 10 = 25.
But . . .
If to tolerance of GD&T on drawing , limit 20
It can't use .
![](https://i.ytimg.com/vi/s2WIU7cPdZY/mqdefault.jpg)