Understanding GD&T

Geometric dimensioning and tolerancing (GD&T) complements traditional dimensional tolerancing by letting you control 14 different geometric characteristics. It applies tolerances to the form of features, instead of just to their dimensions.

This videos covers the different geometric characteristics and other key aspects of GD&T including datums, material modifiers (MMC, LMC and RFS), the Envelope Principle (also called GD&T Rule #1), and the Independency Principle.