What exactly is the incorrect value?
Some dimensions act differently depending in Which entity is selected first.
One example:
If you select, from a cylindrical face, the center-line as the 1st and the edge as the 2nd object, the dimension value will be doubled.
Second Example:
If you select a symbol on your sheet as a 1st object and an edge as the 2nd, the dimension value will be the measured distance on the sheet. (not the 3D model)
Ronald van den Broek
Senior Application Engineer
Winterthur Gas & Diesel Ltd
NX9 / TC10.1.2
Building new PLM environment from Scratch using NX12 / TC11