based on standard geometric shapes but in terms of composi-
tion as well.  Put simply, in order to help CAD programs move
beyond their original parameters, programmers are attempting to
install an ability to operate with a degree of “intelligence.”  
While CAD has demonstrated its shortcomings in the above-
mentioned arenas, it remains an important element of the
manufacturing sector.  Programmers, looking to remedy these
issues, are increasingly looking to other software and hardware
resources to fill in where CAD has come up short.  One area, for
example, is the introduction of “virtual reality” (VR) programs.
VR employs a degree of human-computer interface that is con-
siderably quicker than that seen in typical CAD programs. VR
therefore injects into the design and modeling process the user’s
ability to see the entire environment, including the areas the
CAD simply cannot take into account (Jezernik & Hren, 2003).  
Another issue revealed in the application of CAD to the manu-
facturing sector is one of process.  Because it has problems with
recognition of non-geometric shapes, the process of manufac-
turing design is slowed considerably.  However, by applying
another program to CAD systems, such as rule-based reason-
ing, these recognition problems may be circumvented.  Such
other programs, such as the Standard for Exchange of Product
Model Data (STEP), are used as information resources for CAD,
enabling the system to interconnect its database and link together
complex processes or multiple groups (Lau, et al., 2005).   
Medical Devices
The 21st century global economy has had a major impact on how
industries develop.  The fact that so many markets are merg-
ing into a singular, international network means substantially
increased competition.  While this has so far caused only modest
growth in competition for such established manufacturing indus-
tries as aerospace and automobiles, other growing industries are
suddenly faced with much greater amounts of pressure.  This
places heightened emphasis not only on the quality of products
manufactured (and the prices at which they are sold); it also
requires that those products be produced in higher quantities at
a much faster rate.
In the field of medical device manufacturing, for example, this
trend has become particularly evident.  Over the last few years,
this industry has seen durable rates of growth and revenue gen-
eration. In the US alone, this industry generated $75.6 billion in
2007, and an industry research leader forecasts an annual com-
pounded growth rate of nine percent through 2013 (“Advertising
with,” 2009).  Interestingly, the industry is mostly comprised
of small- to medium-sized businesses (approximately 6,400 of
the 8,000 American medical device manufacturers) that employ
fewer than 50 people.  Such volumes of small firms mean a more
dynamic industry comprised of sales teams that are eager to earn
new business.
For this reason, medical device manufacturers are increasingly
turning to computer-aided design technologies to expedite the
development and, ultimately, distribution of their products.  CAD
software has come into high demand in recent years, following
in the shoes of more established corporations in other industries
that have long enjoyed the application of such software to their
own manufacturing endeavors.
Unfortunately, the traditional applications of CAD software and
systems have to date proven somewhat daunting for the many
small companies that make up the medical device manufacturing
industry.  As mentioned, such systems have long been confined 计算机辅助机械设计英文文献和中文翻译(4):http://www.751com.cn/fanyi/lunwen_5060.html