Mechanical and structural engineering drawings define the objects to be created. To make these drawings unambiguous, a comprehensive set of standards has been established, agreeing on basic standards and types of drawings. Formats, scales, and elevations are presented, along with lines and representations such as line types, letters, numbers, and typeface. Hatching and dimensioning are also included. For structural engineering drawings, the representation of building materials and building elements is shown. In tool engineering drawings, technical surfaces, roughness designations, limit dimensions, and fits are of interest. Welding designations and samples of machining marks are also included. For technical systems, parts lists are addressed. Form and position tolerances ensure the geometric accuracy of the component to be manufactured.