Brief Theory of Design
Design is the thinking that accompanies any intentional arrangement and construction. It's not a special branch.
Writing is a form of design. Movie-making is a form of design. Music is a form of design. Architecture is a form of design. Even politics can involve design.
ASPECTS, FEATURES, and RAMIFICATIONS
Aspects are parts which cannot be separated. Features are parts of a design which can be separated.
This is a vital distinction. Consider the example of a conventional word processor (yaargh). It is an aspect, or inseparable part of the design, that it deals with text and keyboard input. But separable features of some particular word processor design could be a spelling checker, some particular viewing mode, etc.
Principles are aspects and overall characteristics which are intentionally chosen and shaped in a design, such as the upstairs passenger lounge on a 747, "watertight compartments" on the Titanic.
Ramifications are additional properties that unfold (sometimes unexpectedly) from particular aspects, principles and/or features, separately or together. A small number of design ideas can produce a forest of ramifications.
Ramification conflict occurs when two different ramifications of a design idea do not work well together.
Harmonizing ramifications is a big problem in the design process. Fixing the conflicts among ramifications of various principles and features can be long and difficult. Different parts of the plan have to be changed, replaced, moved around, made bigger or smaller, etc. The overall effect has to be looked at and considered again and again and again. This happens throughout the design process.
STAGES OF THE DESIGN PROCESS
The actual steps that different designers go through can be very different. However, in general the following stages are popular:
A design can begin in several ways. Often they are combined.
1. Requirements. Sometimes there is a directive from
management saying what has to be done.
2. Evolution from a pre-existing design.
3. Wish list and desiderata ("desiderata" is the Latin plural of "desideratum", meaning "that which is desired")
The designer(s) consider different possible things that might be done. Sometimes they consider many, sometimes few.
What I call the "jingle method" refers to considering a lot of possibilities together-- like jingling coins in your hand. When you jingle coins, they tend to line up. When you jingle desiderata, you find the ones that go together and line up according to some overall design or principle.
In this phase, ideas are tried out together and their ramifications studied.
PRODUCTION BEFORE DESIGN IS COMPLETE?
In some areas, such as building skyscrapers and airplanes, the entire design is completed before the structure is actually created. In other areas, such as movies and software, the design process and detailing continue to the very end of the production.
A detailing phase may take place before production, or (as in movies and music) the detailing is part of the final production.
Typically, in software, work continues until all too near the shipping date, there is not enough time to check it, there is not enough time to document it, and it is shipped with both bugs and bad documentation.
It's not that software is that different from other creative processes, but that it is definitely harder to plan.