Auxiliary view — where it appears
Named by 2 essays across one field — each of them below, with the objects they name alongside it.
Also named here as descriptive geometry, true length — the same set of essays touches all of them, so they are one junction rather than several.
The view that makes a line a point
Descriptive geometry's first drill is to look at an edge from a direction perpendicular to it, so it draws at true length, and then along it, so it draws as a point. Both are the same identity — the imaged length is the true length times the sine of the angle to the ray — and the sine holds to 1e-12 across the whole sweep of directions.
The true shape of a cut
A plane through a box makes a hexagon of 2.8996 m². The front view draws it at 1.9966 m² — the true area times the cosine, 0.6886 — and gets its corners wrong as well, the worst by 15.60°, because a foreshortening scales one direction and not the other. The area is recoverable with one number and the angles are not, which is why a section gets a view of its own.
Named alongside it
The objects these essays reach for when they reach for this one.
Descriptive geometryForeshorteningMultiview drawingOrthographic projectionTrue lengthAnisotropyArea scaleElevationParallel projectionPoint viewProjection directionSection view