Cylindricity is a geometric tolerance that measures how closely an object resembles a perfect cylinder. It assesses the uniformity of the cylindrical shape by evaluating the distance between the outer and inner surfaces of the object. This tolerance is important in manufacturing and engineering, ensuring that parts fit together correctly and function as intended. To determine cylindricity, a cylindrical feature is compared to an ideal cylinder using specialized tools. The measurement considers factors like roundness and straightness, which are essential for components in machines and assemblies. Proper cylindricity ensures that parts, such as shafts and bearings, operate smoothly and efficiently.