Three-point perspective is usually used for buildings seen from above (or below). In addition to the two vanishing points from before, one for each wall, there is now one for those walls recede into the ground. This third vanishing point will be below the ground. Looking up at a tall building is another common example of the third vanishing point. This time the third vanishing point is high in space. Three-point perspective gives a casual, photographic snapshot effect. In professional architectural photography, conversely, a perspective control lens is used to eliminate the third vanishing point, so that all the verticals are vertical on the photograph.
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