Linear perspective tutorials like drawabox often mention distortion, but never define it. Wikipedia defines distortion for photography and optics and they seem related, but I want a definition specifically for drawing.
The distortion discussed in the Drawbox article are related to using a two point perspective in a manner that makes the object in the drawing look distorted.
Wikipedia has a nice article on the limitations of the two point perspective.
Perspective images are calculated assuming a particular vanishing point. In order for the resulting image to appear identical to the original scene, a viewer of the perspective must view the image from the exact vantage point used in the calculations relative to the image. This cancels out what would appear to be distortions in the image when viewed from a different point. These apparent distortions are more pronounced away from the center of the image as the angle between a projected ray (from the scene to the eye) becomes more acute relative to the picture plane.
The work shows a scene that provides many deliberate examples of confused and misplaced perspective effects. Although the individual components of the scene seem self-consistent, the scene itself can be classed as an example of an impossible object.
Partial list of "errors"
- The man in the foreground's fishing rod's line passes behind that of the man behind him.
- The sign is moored to two buildings, one in front of the other, with beams that show no difference in depth
- The sign is overlapped by two distant trees.
The wiki article goes on to list many more errors in the picture - these are all examples of distortion