1. Definitions

GPS (Geometrical Product Specification – ): set of ISO standards used to define requirements related to product geometry, as well as those related to measurement systems used for verification purposes.

Nominal geometry of a part: set of surfaces bounded by portions of simple geometric surfaces (planes, cylinders, cones, spheres, tori) or complex geometric surfaces (e.g., Bézier surfaces).

Nominal geometric feature: point, line, or surface that is related to the nominal geometry of a part.