All sketches are prepared very rapidly [ball-point pens are the best] mostly to lock in an idea, and to extract from the mind any thought as early as possible and bring this into the project, often as soon as the brief or the site is known and the brief has been assessed. Most often these are then used to guide the next steps, and phases of work thereby establishing the framework for design development. Sketches and first cut drawings can take up anything from five minutes [sometimes within a minute] to about five hours, but rarely more than a day’s worth to settle.
“God created paper,” Aalto wrote, “for the purpose of drawing architecture on it. Everything else is, at least for me, an abuse of paper.”
Unlike computer aided drawings, I find sketches to be much more immediate, and readily presentable and accessible to consenting colleagues and learned Clients alike and they can be rendered very quickly making their way into my projects very early into the scheme, particularly if I have an impatient Client or if time happens to be of the essence to the contractual relationship.
I keep my sketches mainly as record, and I go back frequently to them to review and assess the work in hand right up until the detail design phase. For Duyong [latest restaurant design] the application using initial sketches are obviously very direct and spontaneous.