Editing Axonometric projection (section)

== Limitations ==
{{See also|Impossible object}}
{{multiple image
| width     = 200
| image1    = IsometricFlaw 2.svg
| caption1  = In this drawing, the blue sphere is two units higher than the red one. However, this difference in elevation is not apparent if one covers the right half of the picture.
| image2    = Impossible staircase.svg
| caption2  = The [[Penrose stairs]] depicts a staircase which seems to ascend (anticlockwise) or descend (clockwise) yet forms a continuous loop.
}}
As with other types of [[parallel projection]], objects drawn with axonometric projection do not appear larger or smaller as they lie closer to or farther away from the viewer. While advantageous for [[architectural drawing]]s, where measurements must be taken directly from the image, the result is a perceived distortion, since unlike [[perspective projection]], this is not how human vision or photography normally works. It also can easily result in situations where depth and altitude are difficult to gauge, as is shown in the illustration to the right.

This visual ambiguity has been exploited in [[op art|optical art]], as well as "impossible object" drawings. Though not strictly axonometric, [[M. C. Escher]]'s ''[[Waterfall (M. C. Escher)|Waterfall]]'' (1961) is a well-known image, in which a channel of water seems to travel unaided along a downward path, only to then paradoxically fall once again as it returns to its source. The water thus appears to disobey the [[Conservation of energy|law of conservation of energy]].