Editing Axonometric projection (section)

==Overview==
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"Axonometry" means "to measure along the axes". In German literature, [[axonometry]] is based on [[Pohlke's theorem]], such that the scope of axonometric projection could encompass ''every'' type of [[parallel projection]], including not only [[orthographic projection]] (and [[multiview projection]]), but also [[oblique projection]]. However, outside of German literature, the term "axonometric" is sometimes used only to distinguish between orthographic views where the principal axes of an object are ''not'' orthogonal to the projection plane, and orthographic views in which the principal axes of the object ''are'' orthogonal to the projection plane. (In multiview projection these would be called ''auxiliary views'' and ''primary views'', respectively.) Confusingly, the term "orthographic projection" is also sometimes reserved only for the primary views.

Thus, in German literature, "axonometric projection" might be considered synonymous with "parallel projection", overall; but in English literature, an "axonometric projection" might be considered synonymous with an "auxiliary view" (versus a "primary view") in a "multiview orthographic projection".

With an axonometric projection, the scale of an object does not depend on its location (i.e., an object in the "foreground" has the same scale as an object in the "background"); consequently, such pictures look distorted, as [[human vision]] and [[photography]] use [[perspective projection]], in which the perceived scale of an object depends on its distance and location from the viewer. This distortion, the direct result of a presence or absence of [[foreshortening]], is especially evident if the object is mostly composed of rectangular features. Despite this limitation, axonometric projection can be useful for purposes of illustration, especially because it allows for simultaneously relaying precise measurements.