Once drawing objects have been established at the proper size, scale, and orientation, annotation generally begins. Adding dimensions, symbols, and notes to a drawing (sometimes referred to as detailing) conveys intent when it is time for the drawing to become something real. A dimension is a label in a design showing a linear, angular, or radial measurement.
OpenUtilities Substation has many dimensioning tools. For example, the Element Dimensioning tool can be used to quickly dimension most elements.