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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Architectural drawing | 3/7 | https://en.wikipedia.org/wiki/Architectural_drawing | reference | science, encyclopedia | 2026-05-05T13:59:18.327822+00:00 | kb-cron |
An isometric 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. Cabinet projection 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, but has virtually disappeared from general use. An axonometric 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, and allows freedom to choose any suitable angle to present the most useful view of an object. Traditional drafting techniques used 30–60 and 45 degree set squares, and that determined the angles used in these views. Once the adjustable square became common those limitations were lifted. The axonometric gained in popularity in the twentieth century, not just as a convenient diagram but as a formal presentation technique, adopted in particular by the Modern Movement. Axonometric drawings feature prominently in the influential 1970's drawings of Michael Graves, James Stirling and others, using not only straightforward views but worms-eye view, unusually and exaggerated rotations of the plan, and exploded elements.
=== Detail drawings === Detail drawings show a small part of the construction at a larger scale, to show how the component parts fit together. They are also used to show small surface details, for example decorative elements. Section drawings at large scale are a standard way of showing building construction details, typically showing complex junctions (such as floor to wall junction, window openings, eaves and roof apex) that cannot be clearly shown on a drawing that includes the full height of the building. A full set of construction details needs to show plan details as well as vertical section details. One detail is seldom produced in isolation: a set of details shows the information needed to understand the construction in three dimensions. Typical scales for details are 1/10, 1/5 and full size. In traditional construction, many details were so fully standardized, that few detail drawings were required to construct a building. For example, the construction of a sash window would be left to the carpenter, who would fully understand what was required, but unique decorative details of the façade would be drawn up in detail. In contrast, modern buildings need to be fully detailed because of the proliferation of different products, methods and possible solutions.
== Architectural perspective ==
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:
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 horizon, which is a horizontal line at eye level. Verticals converge to a point either above or below the horizon. The basic categorization of artificial perspective is by the number of vanishing points:
One-point perspective where objects facing the viewer are orthogonal, and receding lines converge to a single vanishing point. Two-point perspective reduces distortion by viewing objects at an angle, with all the horizontal lines receding to one of two vanishing points, both located on the horizon. Three-point perspective introduces additional realism by making the verticals recede to a third vanishing point, which is above or below depending upon whether the view is seen from above or below. 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. 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.
== Sketches and diagrams ==