There is an Escher-like quality to these flights of steps, but it is the intricate net of shadows created by the roof structure of this sky-lit sculpture gallery, falling across a succession of vertical planes and reflecting back on the surface of the glass, which commands attention. Slender metal bars set crosswise between the rafters add their own animating rhythm. It all makes for a very complex visual arena in which to view art.
This flight of steps runs up the outside of a Modernist house in Switzerland. What is striking here is the precise construction of relationships. The gaps between steps allow crisp lines of light to fall on the darkly shadowed wall, reinforcing the subtlety of the dialogue between granite and the concrete, which has been bush-hammers to expose the stone aggregates.
...There is something hypnotic about stair climbing, and as often as I find myself thinking I ought to be at the fourth floor when I am only at the third, I think I've only gotten to three when I'm actually arriving at four.
...To my eyes (and legs) the straight run is more elegant and enjoyable to ascend.
...The narrowing is both functional and artistic, acknowledging that a stair is likely to be used by a smaller number of people as it rises and forcing the perspective narrowing of the long view upward.
...The symbolic weight of stairs is embodied in both their form and their magnitude.
For two and a half months I did not see a stairway in America. They are something that has been buried...hidden behind a door that you are not supposed to open.
The most serious model shortcoming is that the designer often has a vague, incompletely specified goal, or primary objective. In such cases, the hardest part of design is deciding what to design.
I came to realize that the most useful service I was performing for my client was helping him decide what he really wanted.
Today, we recognize that rapid prototyping is an essential tool for formulating precise requirements. Not only is the design process iterative; the design-goal-setting process is itself iterative. Knowing complete product requirements up front is a quite rare exception, not the norm. Therefore, goal iteration must be considered an inherent part of the design process.
The Goodness Function Cannot be Evaluated Incrementally
The Rational Model assumes that design involves a search of the decision tree, and that at every node, one can evaluate the goodness function of several downward branches. In fact, one cannot in general do this without exploring all the downward branches to all their leaves, which is possible in principle, but leads to a combinatorial explosion of alternatives in practice.
The explicit listing of known constraints in the design program helps here. The designer can periodically scan the list, asking, “Can this constraint now be removed because the world has changed? Can it be entirely circumvented by working outside the design space?”
Perhaps the most devastating critique of the Rational Model, although perhaps the hardest to prove, is that most experienced designers just don’t work that way.
“Conventional wisdom about problem-solving seems often to be contradicted by the behavior of expert designers. Empirical studies of design activity have frequently found ‘intuitive’ features of design ability to be the most effective and relevant to the intrinsic nature of design. Some aspects of design theory, however, have tried to develop counter-intuitive models and prescriptions for design behavior.” — Nigel Cross
Why all this fuss about the process model? Does the model we and others use to think about our design process really affect our designing itself? I believe it does. I believe our inadequate model and following it slavishly lead to fat, cumbersome, over-features products and also to schedule, budget, and performance disasters.
The Rational Model, in any of its forms, leads us to demand up-front statements of design requirements. It leads us to believe that such can be formulated. It leads us to make contracts with one another on the basis of enshrined ignorance. A more realistic process model would make design work more efficient, obviating many arguments with clients and much rework.
The Waterfall Model is wrong and harmful; we must outgrow it.