Engineering Graphics with AutoCAD 2023

Chapter 10

Geometric Tolerances

10-1 Introduction

Geometric tolerancing is a dimensioning and tolerancing system based on the geometric shape of an object. Surfaces may be defined in terms of their flatness or roundness or in terms of how perpendicular or parallel they are to other surfaces (Figure 10-1, right).

Geometric tolerances allow a more exact definition of the shape of an object than do conventional coordinate-type tolerances. Objects can be toleranced in a manner more closely related to their design function or so that their features and surfaces are more directly related to each other.

Figure 10-1 (left) shows a square shape dimensioned and toleranced according to plus and minus tolerances. The resulting tolerance zone has an outside ...