Graphic Representation

Perspective elevation of the Fifth Avenue front of the New York Public Library:

This article at ArchDaily on the graphic representation of construction details is interesting in two ways, one serious and one frivolous. The frivolous issue is that only six of the original ten illustrations are present, because the article is an incomplete translation; listicles are a well-established form on the web, but I usually expect the number of items in the list to match the stated number in the headline.

The serious issue is how should we represent complicated three-dimensional assemblies on a piece of paper or a computer screen? Since the goal of a project is to actually build the structure in question, the main purposes of the drawings are (a) to communicate with contractors and other designers and (b) to persuade people that the design is worthwhile. The second purpose can include anything from persuading government agencies that the design is safe and feasible to persuading banks to lend money to persuading prospective tenants to move in.

As a historical oddity, design drawings for buildings don’t use the exploded views that are popular with mechanical engineers, eve though they might help. Our details show components in their permanent positions.

The six options in the article are of varying degrees of usefulness. Freehand sketching as a form of communication, for example, depends on a person’s ability to draw. My ability is lacking, so I try to limit my freehand sketches to my own use or to very basic discussions. The second and third items on the list are ordination details and building sections as are commonly used. Axonometric drawings (labelled in the article as “3D”) have been made more common by the near-universal use of CAD. My experience of them is that they do not often add information that is not accessible from ordinary 2D details, and cannot substitute for 2D details, but that they can be sometimes be helpful. Perspective 3D drawings, on the other hand, are useful to architects to visualize an unbuilt space but of little use to others in the AEC community. Similarly, models are useful to architects and their clients, but not in construction.

The most interesting idea in the article is shown but not explicitly discussed, and that is the use of now-common computer techniques to integrate drawings and photographs. We regularly use photos as backgrounds and as locators for detail drawings, something that was theoretically possible to do before CAD but was laborious and expensive. Computer technology has made real changes in the way we work and this is one of the most important: enabling better communication by allowing us to sue photos of the existing buildings as part of our drawings describing the work to be performed.