An engineering drawing communicates the geometry and manufacturing definition of a part or assembly using standardized views, symbols and annotations.

Orthographic views

A three-dimensional part can be represented by projecting it onto perpendicular planes to create front, top and side views.

Each view removes perspective so that features can be measured and related consistently.

First- and third-angle projection

First-angle and third-angle projection use different conventions for where views are placed relative to one another. The projection symbol on the drawing identifies the convention being used.

Section and detail views

A section view imagines cutting through the object so internal geometry can be shown clearly. A detail view enlarges a local region when important features would otherwise be too small or crowded.

Drawings define, not illustrate

A technical drawing is not merely a picture of a component. Together with its dimensions, tolerances, material notes and other requirements, it is a specification used to manufacture and inspect the part.