Until the latter part of the twentieth century, all architectural drawings were manually produced, either by architects or by trained (but less skilled) draughtsmen (or drafters), who did not generate the design, although they made many of the less important decisions. This system continues with CAD draughting: many design architects have little or no knowledge of CAD software programmes and rely upon others to take their designs beyond the sketch stage. Draughtsmen may specialize in a type of structure, such as residential or commercial, or in a type of construction: timber frame, reinforced concrete, prefabrication etc.
The traditional tools of the architect were the drawing board or draughting table, T-square and set squares, protractor, compasses, pencil and drawing pens of different types. Drawings were made onvellum, coated linen, and on tracing paper. Lettering would either be done by hand, mechanically using a stencil, or a combination of the two. Ink lines were drawn with a ruling pen, a relatively sophisticated device similar to a dip-in pen but with adjustable line width, capable of producing a very fine controlled line width. Ink pens had to be dipped into ink frequently. Draughtsmen worked standing up, and kept the ink on a separate table to avoid spilling ink on the drawing.
Twentieth century developments include the parallel motion drawing board, and more complicated improvements on the basic T-square. The development of reliable technical drawing pens allowed for faster draughting and stencilled lettering. Letraset dry transfer lettering and half-tone sheets were popular from the 1970s until computers made those processes obsolete.
Computer-aided design
Computer-aided design is the use of computer software to create drawings. Today the vast majority of technical drawings of all kinds are made using CAD. Instead of drawing lines on paper, the computer records similar information electronically. There are many advantages to this system: repetition is reduced because complex elements can be copied, duplicated and stored for re-use. Errors can be deleted, and the speed of draughting allows many permutations to be tried before the design is finalised. On the other hand, CAD drawing encourages a proliferation of detail and increased expectations of accuracy, aspects which reduce the efficiency originally expected from the move to computerisation.
CAD programmes, for example the worldwide market leader AutoCAD, are complex and require both training and experience before the operator becomes fully productive. Consequently skilled CAD operators are often divorced from the design process. There are other more basic programmes such as SketchUp that allow for more intuitive drawing and are intended as a design tool.
CAD is used to create all kinds of drawings, from working drawings to photorealistic perspective views. Architectural renderings (also called visualisations) are made by creating a three-dimensional model using CAD. The model can be viewed from any direction to find the most useful viewpoints. Different software (for example Autodesk 3ds Max) is then used to apply colour and texture to surfaces, and to represent shadows and reflections. The result can be accurately combined with photographic elements: people, cars, background landscape.
An architectural animation is a short film showing how a proposed building will look: the moving image makes three-dimensional forms much easier to understand. An animation is generated from a series of hundreds or even thousands of still images, each made in the same way as an architectural visualisation. A computer-generated building is created using a CAD programme, and that is used to create more or less realistic views from a sequence of viewpoints. The simplest animations use a moving viewpoint, while more complex animations can include moving objects: people, vehicles and so on.
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