Representation On Drawings

I’ve been thinking about this topic a lot lately. There is a standard language for structural drawings – actually there are several, but that doesn’t really change the argument – and I’m wondering if we should drift from it a bit. The basics for structural drawings are framing plans everywhere, elevations where needed, and details to match up with the plans and elevations. It should be noted that plans and elevations are really the same thing – a large section cut just off of a plane of framing – with the difference between them being the orientation of that plane, horizontal or vertical. Within that very simple framework a lot of variations are possible: part plans for areas where the framing doesn’t match the regular layout or is at an odd elevation such as stairs, for example. On a project long ago, a helical stair that was an oval in plan with a major axis of 40 feet, I found that the only way I could properly show the stringers was to cut a pair of sections at the center of the treads, one looking out and one looking in, following the curve, and unroll the stair.

The axonometric framing drawing above is part of the HABS drawing set for the Avon Congregational Church in Avon, Connecticut. The church was original constructed in 1819 and repeatedly altered through the nineteenth century. It’s reasonably ordinary for a heavy-timber church of that era in New England, which is to say that the framing is quite complicated. Here’s an architectural elevation of the side:

Here’s the upper framing plan:

Finally, the details of the framing for the tower and the spire:

Complicated stuff in three dimensions, even though it’s made out of straight wood sticks. When everything was drafted by hand (the beginning of my career), adding a axonometric like the one above would be a lot of work. When most drawings were blue-printed (also the beginning of my career but extending into it a ways) everything was black and white, except that the black was blue. With CAD, and modern printing, and the fact that 99 percent of our drawings are now delivered as PDFs rather than paper, we can create axons without too much extra work and we can use color with almost no extra work. So why don’t we?

In part it’s because doing so breaks the standard language. Structural drawings have not been made in color, so there’s no common understanding of what color would mean. We could use red to indicate framing to be removed and it could be interpreted (RED IS DANGER) as meaning framing in need of repair. An axon is “fancier” than a 2-D drawing, so it might be interpreted as more important.

In part, it’s because the regulatory agency we deal with most often, the New York City Department of Buildings, has a set of standards that our drawings need to conform to. So we do our best to meet those standards.

And in part it’s because we’d have to figure out how to incorporate new forms of conveying information – which is, after all, the purpose of drawings – and what additional information we’d want to convey. And that’s the hard part. I assume we will come up with those answers, as we have before when drawing technology changed, but not yet.

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