Page "Engineering drawing" Paragraph 48

Not all views are necessarily used.

Generally only as many views are used as are necessary to convey all needed information clearly and economically.

The front, top, and right-side views are commonly considered the core group of views included by default, but any combination of views may be used depending on the needs of the particular design.

In addition to the 6 principal views ( front, back, top, bottom, right side, left side ), any auxiliary views or sections may be included as serve the purposes of part definition and its communication.

View lines or section lines ( lines with arrows marked " A-A ", " B-B ", etc.

) define the direction and location of viewing or sectioning.

Sometimes a note tells the reader in which zone ( s ) of the drawing to find the view or section.