ABSTRACT
The most important difference between drawings created using GD&T and ±
dimensioning and tolerancing is that GD&T creates coordinate systems based on datum
reference frames, and all features on a part are unambiguously related to these coordinate
systems. Properly applied, GD&T specifies which part features are to be used as datum
features, creating the basis for each coordinate system. The rest of the features on the part
are related to these coordinate systems through geometric tolerances in feature control
frames.
