Measurement accuracy depends on the skill of the user because the definition of the Alignment (Datum) for 2D users defined, but for 3D CAD Model to use to compare with.
The accuracy of the measurement depends on the skill of the operator. Since the Alignment (Datum) for its 2D users are designated for use with 3D CAD Model.
Accuracy of measurement depends on the skills of the users. Due to the Alignment (Datum) of work for 2D users determine. But for 3D are used against CAD Model.