Editing Engineering drawing (section)

==Media==
[[File:Typical roadway cross-section sheet in transportation engineering.jpg|thumb|A [[Cross section (geometry)|typical cross-section drawing]] of a roadway.]]
For centuries, until the 1970s, all engineering drawing was done manually by using pencil and pen on paper or other substrate (e.g., [[vellum]], [[mylar]]). Since the advent of [[computer-aided design]] (CAD), engineering drawing has been done more and more in the electronic medium with each passing decade. Today most engineering drawing is done with CAD, but pencil and paper have not entirely disappeared.

Some of the [[technical drawing tools|tools of manual drafting]] include pencils, pens and their ink, [[straightedge]]s, [[T-square]]s, [[French curve]]s, triangles, [[ruler]]s, [[protractor]]s, [[caliper#Divider caliper|dividers]], [[compass (drafting)|compasses]], scales, erasers, and tacks or push pins. ([[Slide rule]]s used to number among the supplies, too, but nowadays even manual drafting, when it occurs, benefits from a pocket [[calculator]] or its onscreen equivalent.) And of course the tools also include drawing boards (drafting boards) or tables. The English idiom "to go back to the drawing board", which is a figurative phrase meaning to rethink something altogether, was inspired by the literal act of discovering design errors during production and returning to a drawing board to revise the engineering drawing. [[Drafting machine]]s are devices that aid manual drafting by combining drawing boards, straightedges, [[pantograph]]s, and other tools into one integrated drawing environment. CAD provides their virtual equivalents.

Producing drawings usually involves creating an original that is then reproduced, generating multiple copies to be distributed to the shop floor, vendors, company archives, and so on. The classic reproduction methods involved blue and white appearances (whether [[blueprint|white-on-blue]] or [[whiteprint|blue-on-white]]), which is why engineering drawings were long called, and even today are still often called, "[[blueprint]]s" or "[[whiteprint|bluelines]]", even though those terms are [[anachronism|anachronistic]] from a literal perspective, since most copies of engineering drawings today are made by more modern methods (often [[inkjet printer|inkjet]] or [[laser printer|laser]] printing) that yield black or multicolour lines on white paper.  The more generic term "print" is now in common usage in the US to mean any paper copy of an engineering drawing. In the case of CAD drawings, the original is the CAD file, and the [[printout]]s of that file are the "prints".