You should be very careful when using measurement command in the NX. The result might be different from the real value.
This problem occurs because of the option selected in the measurement command by the default.
In Measure command, the measure will be seen on the screen after the faces are selected. But you will see the “Minimum distance” on the screen. Change the option as “Minimum Perpendicular Distance” to see the perpendicular distance between faces. (Shown in the figure.)Note: Be careful Sometimes “Minimum Perpendicular Distance” might give a false result, and “Minimum distance” might give the right result.