Drawing Pulled In Two Directions

by Don Friedman on July 31, 2017


I found this to be an interesting article on the use of iPads in creating and working with drawings. We use iPads pretty heavily for field survey work – taking notes on PDFs of drawings, taking notes in general, creating annotated photos – but have not got very far into using them as drawing tools. We will shortly be replacing our iPads (most of which are three to four years old) with the next generation of hardware, which includes the electronic “pencil” that is really designed for drawing.

This development is the opposite end of the scale from a question we get asked all the time, which is if we use BIM (Building Information Modeling). We do not, for a very specific reason: BIM is inefficient for existing-building work. In an ordinary 2D draining, you can hint at unknown structure around the area of work, or you can draw it with incomplete information. If we know an existing beam is present but don’t know its size, we can draw it as a dashed line and be done with it. BIM standards want us to provide a size for that beam, leaving us with the options of (a) performing more investigatory work that we may not have the time, budget, or access for, or (b) guessing. Option a is often not available to us but option b is the insidious danger. Drawings in general look authoritative, and we make a point of putting “verify in field” or similar notes to discourage people from assuming that just because we show something it must be true. A BIM model showing a I-beam in three dimensions looks that much more authoritative even though it may be based on the same partial information. The only way to completely avoid this problem is to spend a lot of extra time getting the information that has to be input in BIM so that the model is reasonably accurate.

It may sound like I’m anti-BIM, but I’m not. When used in the field it was developed for – new buildings – it can be a fantastic tool for collaboration between architects, engineers, and builders. I just don’t work in that field.

In any case, BIM models are big files that need a lot of computing power to work with and are meant to be complete pictures of buildings. They are not so much incompatible with iPad sketching as they are unrelated to it. Just because both activities are “drawing” doesn’t mean they are or should be compatible. A napkin sketch was never a measured drawing and field notebooks were never presentation sketches. Drawing, as a design profession’s activity, has always been pulled in two directions and this continues under the new regime of CAD everywhere.

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