Which geometric concept specifies the circularity of a feature?

The concept that specifies the circularity of a feature is Geometric Dimensioning and Tolerancing (GD&T). This system allows precise communication of design intent and specifies the exact geometric requirements for the features of a part. Circularity, specifically, is defined as a feature of size where all points on the boundary of a cross-section of that feature must lie within a specific tolerance zone, which is a circular area at a given distance from the center point. GD&T provides the framework to ensure parts fit together correctly and function as intended by establishing relevant tolerances that account for manufacturing variations.

While material condition relates to the state of the material (such as maximum material condition or least material condition), it does not directly specify geometric characteristics like circularity. Assembly specification refers more to how parts are assembled together rather than describing the geometry of individual features. Functional limit is concerned with operational aspects of a part, rather than explicitly detailing its geometric properties. Therefore, GD&T is the most direct and appropriate choice for specifying the circularity of a feature.