Dimensions are a type of annotation that you can use to add information to a layout. Using the Dimension tool or the Ordinate Dimension tool, you can dimension any type of entity. When you edit the value of a dimension the entity updates. Alternatively, you can override the value with a different one and the entity does not update. You can also set the number of decimal places for the dimension.

You can lock a dimension in a layout so that the value of the dimension does not change when you drag a vertex or entity. The locked or unlocked state of the dimension is retained when you save a layout file.

Use the Dimension tool to dimension lines, angles, diameters, radii, arcs, and ellipses. Depending on the type of dimension that you create, you can choose one or two references. You can dimension an entity in multiple ways. For example, you can dimension an arc by its radius or diameter, or by its arc length.

Use the Ordinate Dimension tool to create a series of dimensions that reference a single start point or baseline. You can select one or more entities as references for an ordinate dimension.