The GD&T symbol for True Position defines the acceptable tolerance of a manufactured object’s location. If you’re looking for location tolerance for the center of a feature, the true position characteristic is the tool of choice in GD&T. In fact, it’s a pretty nifty alternative to “traditional” plus/minus tolerance. The ASME standard simply refers to this as “Position” although this refers to the true position of a part.
True Position Symbol:
GD&T true position tolerancing allows us to make parts that fit more cheaply because the tolerance zone in such a case is much bigger than the typical tolerance zone in case of plus-minus tolerance, often simply due to the shape of the tolerance zone itself, which, with GD&T, can be the functional shape for the application at hand – e.g. a cylindrical shaped zone for round pegs being assembled to round holes.