Accelerated Perspective is a form of perspective in which apparent spatial recession is deliberately increased so that a scene, structure or representation appears deeper, longer, higher or more strongly convergent than it would under its unmodified spatial conditions.
It is commonly produced through Forced Perspective or related simulated and synthetic methods that alter spatial geometry, scale or convergence. Receding lines may converge more rapidly towards their vanishing points, repeated forms may diminish more quickly with distance, or vertical structures may appear to rise or recede more strongly than they physically do.
The Dictionary of Perspective distinguishes two principal forms: Accelerated Perspective (1): Horizontal Convergence and Accelerated Perspective (2): Vertical / Upward Convergence.
Accelerated Perspective (1): Horizontal Convergence
Horizontal Accelerated Perspective increases the apparent recession of a scene along its depth direction.
This may be achieved by deliberately altering the geometry or scale of the physical scene, represented scene or perspective construction so that receding lines converge more strongly towards their vanishing points than they otherwise would.
The result is an apparently extended or exaggerated depth. A relatively shallow physical space can therefore appear much longer or deeper when viewed from the intended position.
Typical methods include:
- increasing the convergence of receding edges;
- reducing the physical size of repeated objects more rapidly with distance;
- reducing spacing between successive objects or architectural elements;
- altering the width or height of a receding passage, street or room;
- combining physical and graphical perspective adjustments.
Accelerated Perspective (2): Vertical / Upward Convergence
Vertical or Upward Accelerated Perspective increases the apparent height or vertical recession of a tower, column, façade or other elongated structure.
Instead of allowing vertical directions to converge only according to the ordinary viewing geometry, their apparent convergence can be deliberately increased so that the vertical vista approaches its vanishing point or vertex more rapidly.
The structure may consequently appear taller, steeper or more vertically extended than its actual physical dimensions would suggest.
This method can be used in architecture, scenery, theatrical environments and visual effects where an exaggerated impression of height is required.
Accelerated Perspective and Forced Perspective
Accelerated Perspective is closely related to Forced Perspective, but the two terms describe different aspects of the same possible construction.
Forced Perspective is the broader technique of deliberately manipulating physical or represented spatial relationships to produce a chosen apparent result. Accelerated Perspective describes the particular result in which apparent recession or convergence is increased.
Forced Perspective can therefore be used to produce Accelerated Perspective, but not every Forced Perspective necessarily accelerates recession.
Simulated and Synthetic Perspective
Accelerated Perspective may form part of a Simulated Perspective when altered physical or represented geometry creates an apparent spatial reality different from the unmodified scene.
It may also contribute to a Synthetic Perspective where natural and artificial perspective relationships are systematically combined.
In cinema, theatre and visual effects, accelerated perspective can therefore occur within a composite construction involving physical scenery, camera imaging, graphical backgrounds, projected images or digital elements.
Scale and Diminution
One of the principal ways of accelerating perspective is to increase the apparent rate at which forms diminish with depth.
Under ordinary viewing conditions, the apparent size of an object decreases as its distance from the observer increases. Accelerated Perspective can strengthen this effect by deliberately reducing the actual or represented sizes of successive objects more rapidly than normal spatial recession would require.
Repeated columns, windows, floor tiles, trees or other elements can therefore be progressively reduced to create an exaggerated impression of distance.
Vanishing and Accelerated Recession
Accelerated Perspective can also be understood through its relationship to vanishing.
In graphical or constructed perspective, families of receding parallel directions converge towards vanishing points. Increasing the apparent angle of convergence causes those directions to approach their vanishing points more rapidly across the image or spatial construction.
The visual result is a stronger impression of recession, even where the physical or represented depth has not increased proportionally.
Accelerated and Decelerated Perspective
Accelerated Perspective and Decelerated Perspective describe opposite manipulations of apparent spatial recession.
- Accelerated Perspective increases apparent recession, convergence or depth.
- Decelerated Perspective decreases apparent recession, convergence or depth.
A scene may therefore be made to appear substantially deeper or shallower than its physical geometry by altering the rate of scale diminution, spacing or directional convergence.
Applications of Accelerated Perspective
Accelerated Perspective can be employed wherever an exaggerated impression of spatial depth or height is useful, including:
- theatrical stage scenery;
- film and television sets;
- matte and composite backgrounds;
- architectural illusion;
- painted scenery;
- forced-perspective environments;
- digital and virtual scenes;
- visual-effects constructions.
Because the method depends upon a deliberately controlled relationship between physical or represented geometry and the intended viewpoint, its illusion is often strongest from a particular viewing position.
Why Accelerated Perspective Matters
Accelerated Perspective demonstrates that apparent depth does not depend only upon the physical depth of a scene.
By altering scale, spacing, convergence and spatial geometry, a perspective system can change the apparent rate of recession and create a spatial experience substantially different from the physical structure that produces it.
It therefore provides an important example of the distinction between Physical Form and Apparent Form, and of the wider capacity of perspective to transform rather than merely reproduce spatial appearance.