Perspective (visual)

Perspective (from the Latin perspicere, see through, see through ) denotes the spatial, in particular linear relationships of objects in space: The distance ratio of objects in space in relation to the location of the observer. Thus, the perspective is always bound to the location of the viewer and can be changed only by changing the locations of the objects and the viewer in the room.

This finding is important to the effect, as that a different perspective can not be ( eg, by using a zoom lens in photography ) brought about by changing the viewing section.

The perspective view summarizes the opportunities to capture images as three-dimensional objects on a two dimensional surface that nevertheless produces a three-dimensional impression.

Species perspective view

• Geometric projection techniques. Central projection: visual rays start from a visual point, space parallel edges seem to escape in the projection to a point. Central perspective: central projection, a space is parallel to the image plane, this is image- mapped parallel and the other orthogonal to - the room surfaces are aligned in a point
• 2-point perspective ( Übereckperspektive ): central projection, the horizon parallel spatial edges are not parallel to the image plane and flee to their respective vanishing point, the verticals are mapped image in parallel.
• Frog Perspective: central projection, there is no image-plane parallel spatial edges, the eye point is below the depicted object
• Bird's eye view: central projection, there is no image-plane parallel spatial edges, the eye point is above the depicted object

• Orthogonal projection: visual rays meet at a right angle to the screen. Main crack ( three-panel projection)
• Axonometric isometric
• Dimetric ( dimetry )
• Trimetric

• Cavalier ( Cavalier perspective)
• Cabinet

Bird's-eye view

Froschperspektive

Fisheye projection

Panoramic image

Central perspective; perspective of depth as an urban design element

History

The perspective view of spatial situations can be found in the first approaches already in the Franco-Cantabrian cave paintings, such as the Cave of Chauvet 30,000 years ago. Also in other Upper Palaeolithic caves as Trois Frères to find perspective foreshortening. Technically elaborate perspective method known then the Romans (see also Skenografie ). In Pompeii frescoes were found that should continue the space into a painted garden. In the following centuries, this knowledge has not been further developed; the early Christian and medieval painting helped himself almost exclusively to the semantic perspective, that is, the size of the people and objects depicted was determined by their importance in the image, not by their spatial arrangement. Spatial effect is achieved almost exclusively by the backdrop effect that differed a foreground layer and the background.

During the Renaissance central perspective was discovered ( in connection with the camera obscura ) ( re-), which corresponds approximately to seeing with one eye or a distortion-free photographic illustration. Painters architects such as Filippo Brunelleschi ( regarded as the " inventor" of perspective), Giotto and Leon Battista Alberti created works showed the motifs of Christian iconography in a spatially correct constructed architectural sets.

Initially, the central perspective, which produces our eye, not recognized in their laws, and the preparation was carried out by means of a cord that was stretched from a fixed starting point, a simple grid in the form of a wire mesh to the imaged objects. The artist was sitting next to the grid and transferred the measurements to the grid its drawable ( " perspective pinching "). In a book published in 1436, Leon Battista Alberti explained the mathematical methods used in paintings is a perspective effect is achieved.

Albrecht Dürer published in 1525 his book Underweysung the measurement with the zirckel un richtscheyt, which was the first summary of the mathematical- geometrical method of central perspective and thus forms the basis of the perspective construction process as part of the field of Descriptive Geometry.

Examples of perspective views

Oblique projection, the so-called " military perspective"

Oblique projection, the so-called "cabinet Perspective " (or " cavalier perspective" )

Central perspective ( with a vanishing point )

Parallel Perspective view

Lines that are parallel in reality, is presented in parallel with the parallel perspective illustration likewise. Thus, a convergence of the lines is avoided in the direction of the vanishing points, so that the surfaces depicted remain clearly visible. This effect is desirable eg architects, with the purpose that the views of houses regardless of the viewing angles are always the same clearly. Architects talking about " parallel perspective ".

Axonometric representation

Axonometric representations are parallel perspective views. The vanishing point is moved to infinity. The axonometric projections are isometric and the dimetric representation.

Isometric Axonometric, to DIN 5

If the body be displayed rotated in plan view by 45 ° and then lifted into the rear side view that its surface is to the base area at approximately 35.26 ° (exactly arctan ( 1 / ) ), a three-dimensional image is projected, in which the height (h) perpendicular to the lengths (L) and depth (T) at an angle of 30 ° appears to baseline. The directions of the width ( length ), height and depth extent ( the rectangular body the directions of the edges) appear at different angles, but not at right angles to each other. All three directions are shortened equally, relate to each other as 1:1:1, ie have a common scale ( isometry ). Starting with a vertical spatial coordinate ( axis therefore " axonometric " ), all the edges or points of a body only on the, in fact perpendicular to each other, space coordinates constructed vertically or at an angle of 30 ° to the base line. Lines or edges that are not the direction of a spatial coordinate (eg the sloping gable edge of a house, the diagonals of a cube ) are not reproduced to scale, so they can not be constructed directly. The end points of these lines must be determined via a detour through the space coordinates. It is useful to plot in such a representation three line scales in the direction of spatial coordinates to clarify that only in these directions agree the dimensions is. This spatial representation is preferable in bodies with equivalent views. They are called according to DIN 5 Isometric Axonometric ( see figure ).

A perspective axonometric, to DIN 5

The body is to be displayed rotated in the plan view and the side view of only 20 °, creating a three-dimensional image, wherein the length in an angle of 7 °, the depths are represented at an angle of 42 ° to the base line. The depths appear shortened by half compared to the heights and lengths. The spatial image is so zweimaßstäblich ( dimetric, eg H and L 1:5, T 1:10). This representation is used in one respect to the other views, particularly important front view. Taking into account the different angular scales and the body is usually drawn as in the isometric axonometric. Corresponding line standards should be drawn in the form of a spatial axis Cross To clarify here necessarily. We call this representation to DIN 5 Dimetric Axonometric (see figure).

Oblique projection

In the oblique projection, it also is a parallel projection. Unlike axonometric method, two axes can be left undistorted here, and only the third axis is oblique and (possibly) mapped shortened.

As examples, the cavalier perspective and Cabinet perspective may be mentioned. In the former, the elevation is undistorted and routes, which run perpendicular to it, are presented unabridged, in the latter, these routes are reduced to half ( as shown in the picture above).

Another name for a special type of oblique projection is the military perspective. Here, as in the cavalier perspective no shortening of the third axis. The floor plan is applied undistorted, and vertical lines are mapped to scale.

Central Perspective view

In architecture and to illustrate the so-called central perspective, also referred to as Diminishing Perspective, used. In the central perspective space parallel edges are not illustrated illustration parallel, but unite in a visually apparent, imaginary point, called the vanishing point, which is exploited in the vanishing point perspective. The vanishing point located on the horizon line can be found via the interface, caused by the extension of the parallel lying in the reality of object edges. The main feature of the central perspective is the frontal view of the object. There are no shifts in the left or right, but upward or downward. The simplest form of perspective forms the central perspective with a vanishing point. Although caused by different mechanisms of object edges multiple vanishing points, such as in the presentation of a house, these are all on the horizon line.

The surfaces facing the viewer, the object image are parallel, while leading into the depths of space object edges unite seemingly in a vanishing point on the horizon.

Other variants make prospects with two - also known as over -the-corner prospects - or three vanishing points dar. Since in perspective with three vanishing points on the horizon necessarily upward, or moves down, you call the respective figures also frog perspective or bird's eye view.

Cylindrical projection

Various artists such BMC Escher experimented with variants of perspective, such as the cylindrical projection. With this perspective panoramas are real perspective represented by 180 ° and more, are just lines, however, are distorted into curved corners. An example of this is Escher's lithograph staircase I from the year 1951 ( with " clutter animals ").

Relief Perspective view

This Perspektivart does not lead to a complete 2- D representation, but also shortens only one dimension of the 3- D space greatly. Here, the appearance of the consideration of a fixed eye point objects are not changed, since objects lying behind also be reduced accordingly when an exact relief.

Importance Perspective view

In the period before the rediscovery of the geometric perspective, the so-called semantic perspective is used in panel paintings. The size and orientation of the persons shown in the image is determined by their importance: important protagonists appear great, less important appear smaller, even if they are located spatially in front of the other person. In the image example on the right, the quasi- isometric perspective of the footrests relates only to the particular figure - in graphically - compositional sense, this arrangement allows the ( two-dimensional ) Opening of the image space to the background. The importance of perspective is already used in ancient Egyptian art: is displayed in full size While Pharaoh together with wife, one shows slaves and courtiers much smaller. In icon painting there is this type of representation as well as in the painting of the Romanesque and Gothic. The importance of perspective can be found even today in the naive painting

Air and paint Perspective view

Air and color perspective must be distinguished.

In the aerial perspective, a sense of depth is created by the contrast decrease from front to back and the brightness of the front increases to the rear. Regardless of the color is achieved simultaneously by the backward becoming indistinct outlines a set / unset contrast.

The color perspective provides a sense of depth by using different hues are used dominantly in the foreground, middle ground and background. In the foreground is dominated by warm colors (yellow, orange, red, brown), in the middle ground and the background colder green and blue tones. Instead, there may be a green or bluish tinge.

Air and paint perspective: green to blue, tired on pastel

Color perspective: reddish hue on blue, with increased contrast

Aiguilles de Popolasca (Corsica), aerial perspective in photography

Multi Perspective view

A multi- perspective refers to a spatial representation by means of several projection centers, respectively. the combination of different perspectives that give a room. In addition to the use of multi- perspective in still images, it will be applied in the digital space in moving images. By the application of several projection centers in moving images, distortions can be avoided. (Example: A ball retains its circular shape and with an elliptical shape of the ball by the camera distortion is avoided. ) The multi- perspective ( in still picture) can be found in various paintings of the history of art in varying degrees. An extreme application of the multi- perspective can be found in the works of the Swiss media artist Matthias Zimmermann. About his painting " The Frozen City" is a panoramic landscape, the space and objects from various perspectives arise ( central perspective, cavalier perspective, military perspective, a hint of a fish -eye lens, etc.).

Experience perspective

In the experience perspective, the artists try to play through accurate observation detail what they see. So you come very close to the central perspective and recognize that objects become blurred in the background and are bluish color perspective. Experience perspective represents an approximately correct vanishing point presentation before a few years later succeeded Italian artists to construct the central perspective geometrically perfect.