Design Realization/Detailed Design - Medical Device Design: Innovation from Concept to Market - page 172

workstations running bespoke software. Nowadays personal desktop computers are
extremely powerful, and the software is extremely user friendly and affordable. Hence,
the rise of computer-aided design has been equally relentless. There are a few front-runners
in the CAD field, which are:
AutoCAD ®
CATIA ®
ProEngineer ®
SolidWorks ®
All have their pros and cons, and I do not dare to demonstrate any preference over one or
the other. But the one thing they all have is the ability to produce realistic 3D visualizations
of the design and transfer electronic information over the Internet. Why are these two items
so important? Let us go back 20 years. A draughtsman would produce a two-dimensional
engineering drawing that had to be copied to be transferred; you had to know how to read
the drawing to understand it; and you had to have extremely good 3D spatial awareness
to imagine the 3D shape drawn out as a 2D plan drawing. Not really conducive to
collaborative work!
Let us now compare the modern equivalent. The CAD draughtsman produces a 3D
object perfectly representing the component; this is transferred to 2D drawings for
manufacture or to a 3D model for rapid-prototyping (see later); an electronic email
version can be sent to all partners who do not need the software to see the design and do
not need to be able to read drawings. I think you can imagine the power I am trying to
demonstrate.
Nowadays we are also able to have online discussions around the design; you can have
someone produce an electronic circuit in Japan and then integrate this with your model (in
front of you online) and check if it fits! Yes, this is all possible. If you are not using CAD in
your design work, then you really are in the dark ages.
It is difficult to convey the power modern CAD systems have. It is only when you have seen
a system in action that you begin to realize just what you can do. Also, when you think that a
good desktop PC may cost between $2000 and $3000, and the software may cost $6000, it's
not really anything to balk at. Modern CAD systems really do save time and are worth the
investment ( Figure 8.9 ).
Before we go any further we need to understand two concepts: solid models and
surface models. A solid model is just that: if you draw a cube you have a solid cube.
Hence solid modelers produce solids. A surface model system still produces a solid
component, but it is hollow. Hence, when you draw a cube you do not get a solid cube,