Geometric Dimensioning & Tolerancing (GD&T) is the modern standard of design. Every Mechanical designer and engineer needs to understand the modern global language of Engineering Design. Among other modern practices, the knowledge of GD&T is considered to be a must for every mechanical engineer wanting to work in the global engineering platform. The GD&T standards for drawing and designing are published by the American Society of Mechanical Engineers (ASME Y14.5) and ISO.

GD&T aims at defining methods and symbols so that the designer’s intent is expressed on the drawing without ambiguity. To a Mechanical engineer, the ability to read and use a GD&T based drawing is almost becoming as important as the ability to read and write.