Linear Perspective: A geometric constructed convention used to represent human visual perception of objects in space in the real world. The method was discovered and employed by Florentine architect and sculptor Filippo Brunelleschi (1377-1446), famous as the architect who solved the more than 100 year old engineering problem of constructing the massive dome topping the Duomo, the main cathedral in Florence. GottliebStudios.com/Classical_Glossary
The system was formalized and recorded by architect / painter/ writer Leon Battista Alberti (1406-1472) in his book De Re Aedificatoria (1450), the key theoretical treatise on architecture from the sixteenth century until the eighteenth century.
The system employs the use of the following elements:
1) The Horizon Line (HL) - the perceived line usually placed at eye level created by the meeting of the earth and the sky.
2) Vanishing Point/Points (VP) - Geometric point/points that are placed along the Horizon Line representing the farthest point from the viewer.
3) Construction or Orthogonal Lines (lines usually shown as dashed or thin lines) - lines emanating from vanishing points and radiating outward toward the viewer.
4) The Picture Plane (PP) - An imaginary plane placed paralleled to the viewer, used to project the Construction or Orthogonal Line onto.
There are three types of linear perspective. The simplest type is One Point Perspective, using only one Vanishing Point centered along the Horizon Line. Construction lines emanate from the centered VP to the Picture Plane. This type of perspective does not appear as real as two point perspective and it is recommended to be used when the object's "faces" or sides are parallel to the PP.
The second type of perspective is Two Point Perspective. This version of the method uses two Vanishing Points along the Horizon Line with the Construction Lines radiating from both points and projecting on to the Picture Plane. The further apart the VP is placed along the HL the "further" the object appears from the Picture Plane. The closer the VP's are placed along the HL the closer the object appears from the Picture Plane.
The final type of linear perspective is Three Point Perspective. This is used to give bird's-eye or worm's-eye view of an object as it distorts the view up and down as well as side to side. The third Vanishing point is placed off the horizon line either above or below it to give the desired effect.
Written and contributed by Bill Indursky, M.Arch
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