what is geometrical tolerance
Geometric dimensioning and tolerancing (GD&T) is a system for defining and communicating engineering tolerances.D&T is used to define the nominal (theoretically perfect) geometry of parts and assemblies, to define the allowable variation in form and possible size of individual features, and to define the allowable variation between features. 1  Dimensioning specifications define the nominal, as-modeled or as-intended geometry. 2  Tolerancing specifications ...