Quadrilateral Perspective


In the text below, the Architect and Architecture Course Professor at Pernambuco Federal University explains briefly and realistically the difficulties faced with the traditional perspective by conic projection.


“The conic perspective has several inconveniences: the static view point, the lateral deformation, the parallelism of the verticals and the small visual angle. The two latter can be partially corrected by using an inclined square, but this is exhausting when we have to draw on a drawing board. We may use a graphic computer to overcome this inconvenience … but this is hardly accessible.

Assuming that we accept the recent theories about vision and brain functioning, we would be inclined to the adoption of the following new foundations: the view point (eye) moves itself, travels all over the objects (like television) in successive lines and points that are located and focused. A complete image is formed in the brain, a sum of many partial images. Since each image has its own visual angle, the angular openings will be defined by arches and not by straight lines. (It is not by chance that this idea coincides with the Universe structure modern theory!) And the arches should be represented on a spherical surface. The same happens in Photography with the big angular lens “fish eye” type.

The Spherical Perspective theory is not more complicated than the Conic Perspective theory which we have just studied. However, the spherical perspective representation is not handy, it is not adequate to the traditional instruments: ruler, squares and compass.

The graphic computer overcame this inadequacy. Therefore, the scholars have a vast field ahead”.

Page 150 – excerpt from the book “A PERSPECTIVA DOS PROFISSIONAIS”, by Gildo A. Montenegro – 1983 – Editora Edgard Blucher Ltda.
(Free translation)

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