Architectural drawing

An architectural drawing or architect's drawing is a technical drawing of a building (or building project) that falls within the definition of architecture. Architectural drawings are used by architects and others for a number of purposes: to develop a design idea into a coherent proposal, to communicate ideas and concepts, to convince clients of the merits of a design, to assist a building contractor to construct it based on design intent, as a record of the design and planned development, or to make a record of a building that already exists.

Architectural drawings are made according to a set of conventions, which include particular views (floor plan, section etc.), sheet sizes, units of measurement and scales, annotation and cross referencing.

Historically, drawings were made in ink on paper or similar material, and any copies required had to be laboriously made by hand. The twentieth century saw a shift to drawing on tracing paper so that mechanical copies could be run off efficiently. The development of the computer had a major impact on the methods used to design and create technical drawings,^[1] making manual drawing almost obsolete, and opening up new possibilities of form using organic shapes and complex geometry. Today the vast majority of drawings are created using CAD software.^[2]

History[edit]

The oldest architectural elevation drawing was found in a piece of white terracotta crucibles unearthed in China, dated 7400 years ago. It shows 2 stilted watch towers (or light houses) with spiral staircase above water. ^[3]

An uses a plan grid at 30 degrees from the horizontal in both directions, which distorts the plan shape. Isometric graph paper can be used to construct this kind of drawing. This view is useful to explain construction details (e.g. three dimensional joints in joinery). The isometric was the standard view until the mid twentieth century, remaining popular until the 1970s, especially for textbook diagrams and illustrations.^[8]^[9]

isometric

is similar, but only one axis is skewed, the others being horizontal and vertical. Originally used in cabinet making, the advantage is that a principal side (e.g. a cabinet front) is displayed without distortion, so only the less important sides are skewed. The lines leading away from the eye are drawn at a reduced scale to lessen the degree of distortion. The cabinet projection is seen in Victorian engraved advertisements and architectural textbooks,^[8] but has virtually disappeared from general use.

Cabinet projection

An uses a 45-degree plan grid, which keeps the original orthogonal geometry of the plan. The great advantage of this view for architecture is that the draftsman can work directly from a plan, without having to reconstruct it on a skewed grid. In theory the plan should be set at 45 degrees, but this introduces confusing coincidences where opposite corners align. Unwanted effects can be avoided by rotating the plan while still projecting vertically. This is sometimes called a planometric or plan oblique view,^[10] and allows freedom to choose any suitable angle to present the most useful view of an object.

axonometric

Perspective is the view from a particular fixed viewpoint.

Horizontal and vertical edges in the object are represented by horizontals and verticals in the drawing.

Lines leading away into the distance appear to converge at a .

vanishing point

All horizontals converge to a point on the , which is a horizontal line at eye level.

horizon

Verticals converge to a point either above or below the horizon.

Perspective in drawing is an approximate representation on a flat surface of an image as it is perceived by the eye. The key concepts here are:

The basic categorization of artificial perspective is by the number of vanishing points:

The normal convention in architectural perspective is to use two-point perspective, with all the verticals drawn as verticals on the page.

Three-point perspective gives a casual, photographic snapshot effect. In professional architectural photography, conversely, a view camera or a perspective control lens is used to eliminate the third vanishing point, so that all the verticals are vertical on the photograph, as with the perspective convention. This can also be done by digital manipulation of a photograph taken with a standard lens.

Aerial perspective is a technique in painting, for indicating distance by approximating the effect of the atmosphere on distant objects. In daylight, as an ordinary object gets further from the eye, its contrast with the background is reduced, its color saturation is reduced, and its color becomes more blue. Not to be confused with aerial view or bird's eye view, which is the view as seen (or imagined) from a high vantage point. In J M Gandy's perspective of the Bank of England (see illustration at the beginning of this article), Gandy portrayed the building as a picturesque ruin in order to show the internal plan arrangement, a precursor of the cutaway view.^[12]

A montage image is produced by superimposing a perspective image of a building on to a photographic background. Care is needed to record the position from which the photograph was taken, and to generate the perspective using the same viewpoint. This technique is popular in computer visualization, where the building can be photorealistically rendered, and the final image is intended to be almost indistinguishable from a photograph.

's Vitruvius Brittanicus, illustrations of English buildings by Inigo Jones and Sir Christopher Wren, as well as Campbell himself and other prominent architects of the era.

Colen Campbell

The , founded in 1894 by Charles Robert Ashbee and now available through English Heritage. A record of notable streets and individual buildings in the former County of London.

Survey of London

records of notable buildings drawn up during the 1930s Depression, this collection is held by the Library of Congress and is available copyright-free on the internet.