1.3 MODELS FOR ENGINEERING DESIGN
There is a useful analogy in computing that highlights both the use of language and the central role a single artifact may take outside of the information flow model: that of the word processor. Word processing is the computerized manipulation of the basic elements of language. It facilitates the act of fleshing out thought and creating a product to reconstruct thought in the mind of the writer or the mind of another. The act of writing, which word processing supports, involves the formation of ideas and the communication of ideas.
The act of design, as with word processing, is distinguished by the basic elements of idea formation and communication. A direct correspondence between the acts and products of both writers and designers can be construed in the broadest sense of their occupations. The output of a writer's endeavors is a text based document. Correspondingly, the output of a designer is an artifact or process design. While these endeavors have elements of creativity, both operate under certain restrictions and must by the nature of their craft use a formal and specific sets of tools.
The computerized word processing environment is not just as a metaphor for computerized design processing, but contains well-formulated elements sympathetic to any human creative act. Even superficially, elements of word processing from spelling and grammar checks to thesauruses-based advising to page layout and publishing, have direct correspondence to such engineering design abstractions as design critics and rapid prototypes. Corresponding elements can be found even within other automated creation domains including music composition and illustration packages.
Before the full-screen, computerized word processors so familiar today were introduced, draft texts were initially written and edited by hand. As an act of formality, the text was then printed with a press or a typewriter, each letter formally committed to paper, mistakes painstaking to correct. Now, word processors assist the process of creation as well as formalization, with an ease and quality that far surpass the former mechanisms. Where there were once distinct stages and mechanisms in the publication process, the conception, creation, and production stages of a final artifact are now more tightly bound. Moreover, the writer can control all elements of the entire process.
Automated word processing also affects the actual process of writing. The top-down approach of outlining and organizing thought well before text was generated was long advocated in an era where pencil and paper revisions were labor intensive. Word processors now afford a generative approach to writing, where the discovery of what a writer truly wishes to express comes from reiterations of the writing process itself.
CAD environments are at the stage where the components of design and analysis are automated. But the environment is still largely not integrated or at least not as tightly bound in the cycle from conception to physical artifact. Word processing in this respect is ahead of the design environment by a few years, and can represent what design environments should strive for. Later in this paper, the concept of "design processing" will be used as a direct simile to the word processor, for the issues and specifications in the one domain have clear and identifiable analogies in the other.
None of the utilities of idea processing - to substitute the abstraction common to both text and design - seek to replace the human act of creation and decision. The tools merely augment and facilitate. Analysis and exploration tools attempt to eliminate mundane and repetitive tasks. They provide a more effective computer-based environment in which the writer or designer can explore alternatives - and perhaps even fail in the choice of some alternatives - without the cost involved with physical realization.