Basics of mechanical drawing include use of perspective, dimensioning and sectioning. These skills provide the fundamentals for executing basic diagrams and assembly drawings, including where and how to reference dimensions on a drawing.
Mechanical drawing is similar to drawing proofs in planar geometry, in which instruments such as drafting compasses and protractors are used to reproduce exact angles and curves in drawings of specific dimensions. In addition to these tools, mechanical drawing also uses AutoCAD, computer-aided design software especially useful for rendering 3-D drawings.
Much of mechanical drawing relies on orthogonal lines, which intersect at right angles, to create perspective. Whether drawing diagrams that explain the parts of an electrical component or illustrating assembly instructions, mechanical drawings must clearly display an object from a specific, informative perspective. For instance, one-perspective mechanical drawings, which use only one vanishing point to establish perspective, require that all vertical lines are parallel to one another, all horizontals are parallel to one another and that they intersect at 90-degree angles. While one-perspective drawing isn’t as accurate as multi-perspective forms, it gives viewers a good sense of basic spatial relationships.
Likewise, use of dimensioning and sectioning are important to basic mechanical drawing because learning these skills teaches draftsmen how to break down an object visually to explain its function or construction systematically.