design programs were Computer Vision, baby food-manufac-
turer and supplier Gerber, and McDonnell Douglas. Thanks
to the work of such figures as Hanratty and Sutherland, early
versions of CAD systems became increasingly popular among
large corporations. Unfortunately, the size and cost of computer
systems in general, along with the costs of systems specific to
this purpose, left CAD applications largely beyond the reach of
smaller businesses.
In the latter 1970s, computer technology became more compact
and affordable. With this came an evolution of CAD programs,
which increased in terms of capability and versatility. By the
early 1980s, CAD programs were able to create more complex,
inter-linked models as well as design in clearer 3-D settings (pre-
vious incarnations utilized a simpler, 2-D format). Such modified
systems led to greater interconnectivity among design models
(Raj, 2007). By the late 1980s, CAD technology was consider-
ably more sophisticated and more widespread in its use than it
had been only two decades earlier. An example may be found in
the introduction of PTC Pro/Engineer, a system that used para-
metric design programs, which allow for greater connectivity
with other design models through the application of historical
data. This “history-based” approach became, for a few years,
popular among engineers who had previously used 3-D model-
ing in their work. The debate over these programs is ongoing
(Stackpole, 2009). Introduced in the 1970s, the personal computer saw a rapid evo-
lution over the next two decades. The prevalence of smaller,
multiple-unit computer terminals allowed a larger number of
engineers, computer scientists and design professionals to both
use existing CAD programs as well as create modified versions
for their own purposes. CAD systems became more common
and had greater capabilities – some systems allowed the user to
manipulate 3-D shapes, while others created greater parametric
connectivity that allowed for the development of extensive and
more complex design models.
Today, computer-aided design systems are some of the most
popularly used computer programs by major corporations and
certain industries of all sizes and industry areas. This paper will
next turn to a few examples of how CAD is employed in the 21st
century global economy.
Applications
Architecture
Prior to the introduction of computer software, architects relied
on careful, manual mathematic calculations and drawings.
Architectural drawings and blueprints have long been essential
for those doing the work and the clients who seek to have the
work done. Such drawings are also useful for government offi-
cials who may or may not approve funding and/or zoning for
such work, and also prove practical for other contractors who are
performing landscaping or other external work.
Central to any construction or manufacturing industry is the
design stage. In this phase, the engineer is expected to create
from a visual ideal a valid structure or mechanism that will
appear in a certain way while it performs the task for which it
is created. In architecture, the design is crucial, for it not only
enables all parties involved (the construction contractors, the
client and others) to see the realized schematic – it helps them
understand the structural integrity and viability of the building.
In the global economy, architecture is essential to the manu-
facturing industry. Factories and production plants require
configurations that are conducive to the manufacturer’s needs and
budgets. Architects must take into account energy source distri- 计算机辅助机械设计英文文献和中文翻译(2):http://www.youerw.com/fanyi/lunwen_5060.html