Some of the rules for architectural lettering are to use a minimum lettering height of 3 millimeters, single-stroke vertical letters, a standard Gothic-style font and to make all lettered information the same height. The goal is to create clear, legible, uniform, dark, black letters.
Architects communicate their ideas visually through lines and letters. Using architectural lettering enables an architect, engineer or designer to communicate what the end product being designed looks like through additional written details. A visual image of the object is drafted, and it gives the client an idea of its end appearance. Without lettering, only the shape of the object or building being designed is visible to the client. Lettering is used to detail the size of the object, meaning dimensions such as length, width and height, the location of features such as holes and cutouts, and the building materials needed to make the object.
The standard lettering used by architects and engineers has been designated by the American National Standards Institute and is a Gothic alphabet. A more-stylized Gothic font is used for title and cover pages. Since lettering is done freehand, anyone entering the engineering, architecture or design fields of work needs to learn how to draft letters efficiently.