C hapter 3 the Design Context
72
section on structured design processes that follows). In formal
methodologies in product design, early steps often include decomposing the problem into as many subproblems as possible (sometimes creating a subsolution importance hierarchy). Not all
subproblems necessarily have to be solved at once by a proposed
design. Some subproblems may have preexisting solutions, whereas
others do not. Many are ultimately more important than others in
determining the critical design essence of a final solution.
Concept development stages follow. Generating initial design proposals is a straightforward task to a design professional; it involves its
own internal structures and logics. (The process is not nearly so
mysterious as is sometimes portrayed.) For an overall project, many
designers typically internalize fundamental product requirements
and goals as well as characteristics of prior design precedents and
then identify, quickly explore, and rapidly delineate one or more
generative design concepts. Frequently, new material characteristics
will suggest original design solutions.
Preliminary and design development stages follow, whereby the
functionality and physical form of the promising concepts are
increasingly resolved and studied. (This is sometimes called the
embodiment stage in product design or preliminary design in architecture; see Figure 3.19.) A series of geometric and functional
modeling and technical evaluation studies are normally undertaken, as are initial cost studies. Subsequent steps include defining
in detail the series of related systems and subsystems that provide
a given function or set of functions. A result of the first part of
this general process is to have a set of design requirements for each
system or element detailing what it needs to do in unambiguous
terms. These specifications are normally performance oriented but
are much more technically directed than the more generic target
requirements used in preliminary designs, which typically relate
more to user need perspectives. For some subsystems, input and
output values must be within specified ranges. Other examples
might be those of specifications for a mechanism that require it
to provide a given pushing force over a specified stroke distance.
A pressure vessel might have to be able to contain a specified
internal volume and pressure.
By this stage of the process, there should also be clear understanding of the maximum envelope dimensions of any particular
assembly of subsystem components and where (in a physical layout
sense) connections are made to related subsystems. The detail or
design development and engineering phase of the development process
72
section on structured design processes that follows). In formal
methodologies in product design, early steps often include decomposing the problem into as many subproblems as possible (sometimes creating a subsolution importance hierarchy). Not all
subproblems necessarily have to be solved at once by a proposed
design. Some subproblems may have preexisting solutions, whereas
others do not. Many are ultimately more important than others in
determining the critical design essence of a final solution.
Concept development stages follow. Generating initial design proposals is a straightforward task to a design professional; it involves its
own internal structures and logics. (The process is not nearly so
mysterious as is sometimes portrayed.) For an overall project, many
designers typically internalize fundamental product requirements
and goals as well as characteristics of prior design precedents and
then identify, quickly explore, and rapidly delineate one or more
generative design concepts. Frequently, new material characteristics
will suggest original design solutions.
Preliminary and design development stages follow, whereby the
functionality and physical form of the promising concepts are
increasingly resolved and studied. (This is sometimes called the
embodiment stage in product design or preliminary design in architecture; see Figure 3.19.) A series of geometric and functional
modeling and technical evaluation studies are normally undertaken, as are initial cost studies. Subsequent steps include defining
in detail the series of related systems and subsystems that provide
a given function or set of functions. A result of the first part of
this general process is to have a set of design requirements for each
system or element detailing what it needs to do in unambiguous
terms. These specifications are normally performance oriented but
are much more technically directed than the more generic target
requirements used in preliminary designs, which typically relate
more to user need perspectives. For some subsystems, input and
output values must be within specified ranges. Other examples
might be those of specifications for a mechanism that require it
to provide a given pushing force over a specified stroke distance.
A pressure vessel might have to be able to contain a specified
internal volume and pressure.
By this stage of the process, there should also be clear understanding of the maximum envelope dimensions of any particular
assembly of subsystem components and where (in a physical layout
sense) connections are made to related subsystems. The detail or
design development and engineering phase of the development process