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Choosing CAD software
It is possible to use a wide range of
different software on Windows based computers to produce Computer Aided Design (CAD) drawings. The software available ranges in price from
free software, to shareware software (often
costing less than $100 when you register
it), to $395.00 for IntelliCAD, an
AutoCAD clone, solid modelling software (SolidWorks, Autodesk Inventor) and finally to software that
costs as much as $30,000 a seat requiring very powerful computer workstations
in order to run it.
There are many different CAD programs on the
Australian market AutoCAD, AutoCAD LT, Caddsman,
IntelliCAD, Design Cad 3D,
TurboCAD, Qikdraw, Catia, Solidworks, IronCAD,
MicroStation, MiniCAD, Foresight, LisCAD, WESCOM,
Adobe Illustrator to name but a few. They all have various strengths and weaknesses. Perhaps the most
important thing to note is that they mostly save their drawing file in their
own particular
file formats, variously called .DWG, .DGN, .CTA etc. Because the file format
differs, moving data from one CAD program to another is not necessarily a trivial
task, so you need to 'get it right' when making the choice.
If you are running a business, it is obviously important to make the correct choice of software.
This article attempts to help you make an informed judgement?In Australia, there is no question that
IntelliCAD and Autodesks AutoCAD software dominate the market.
Our guess is that >80% of CAD
files created in Australia use the .DWG format. Let's discuss these
CAD programs before attempting to choose a particular piece of software.
IntelliCAD costs $A395,
AutoCAD LT $2200 and the full version of AutoCAD ($6500). Rather
obviously, one needs to know the limitations of each.
AutoCAD and IntelliCAD software in
their native form what are called are surface modellers. The figure
below shows a typical 2D drawing produced using IntelliCAD.
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A typical set of CAD drawings -
polycarbonate pipe fittings used by plumbers, each drawn accurately to size
using simple entities such as lines and arcs. |
Here is a link to our eLearning web site where you can learn to
produce models such as these. Choose the blue link alongside the
'Introduction to CAD - QuickStart CAD' course in the CAD group to view
the syllabus.
This is a common question. When it comes to 3D work, AutoCAD and
IntelliCAD these programs work in what is called a surface modelling
mode. The figure below shows what one can do in IntelliCAD when you
learn to model in 3D.
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3D model
created and rendered in IntelliCAD. |
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Models created in AutoCAD or IntelliCAD
can be moved into other software for rendering, 'fly
throughs' and 'walk arounds'. Here the model has been moved
to Google SketchUp a modeller free for non-commercial use. |
You should dismiss AutoCAD LT if you want to do 3D work. AutoCAD LT does
not render 3D objects properly. The choice is between IntelliCAD at $395
and AutoCAD at $6500. Download a free trail copy of IntelliCAD from
http://www.siacad.com.
Here is a link to our eLearning web site where you can learn to
produce models such as these. Choose the blue link alongside the 3d
course in the CAD group.
There are also a number specialty architectural
and building CAD programs - some of
these are 'add-ons' to the above CAD 'engines', while others are stand alone products.
Examples of software of this type are: KarelCAD, DRCAuto,
AutoPLAN, SmartArchitect, SIACAD and ArchiCAD, Form Z, etc.
These add-on
architectural CAD packages are sometimes sold by the developer to
another company. When this happens, there is often a change of name - AutoPLAN
is, we believe, in this category, and has been sold to a Canadian firm
and renamed.
Autodesk (the makers of AutoCAD) also
produce two of its own architectural products - REVIT and
AutoCAD Architect, but they use the AutoCAD engine. By that we mean
that the underlying program is AutoCAD which you use to place lines,
circles etc. but when it comes to (say) inserting a window in a wall and
automatically cutting the wall as you do so, these add on program do
just that. [The base CAD program can also do it, you just have to learn
how - so we do not think that the extra expense incurred in buying these
add-ons is justified].
There is a strong
possibility that only one of these (REVIT and Auto Architect) will survive in the market place.
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A set of 2D plans for a simple dwelling
created using AutoCAD LT 2005. No add on tools were used,
just the base program itself. These are plans in what is
called model space. Paper space (or layout) is used when a
'proper' printed set of plans is required. |
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The same drawing in IntelliCAD. Although
IntelliCAD will open most AutoCAD drawings without
difficulty, you should not take it as axiomatic that this
will always occur perfectly. |
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The very same set of plans can be viewed
from above if the external walls are extruded. No special 'add
on' architectural software is required. |
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An architectural add-on in use in the
IntelliCAD environment. This makes cutting in doors and
windows very easy. |
The first step is to decide
exactly what it is that you want to achieve with
your use of CAD software. It is important to write this down
along the lines set out below:
"Our company needs a simple 2D
CAD drafting tool to create shop drawings. We will not need to exchange
drawings with any third party".
or
"Our company needs a 2D
drafting tool to create shop drawings. We will certainly need to
exchange drawings with third parties and have a real need to export
drawings to a laser cutting firm".
or
"We are determined to
work in 3 dimensions, but only require wire frame models of our designs.
We wish to be able to generate 2D views directly from the model."
or
"We work closely with
automotive manufacturers who use the solid modelling software package
called CATIA. Any
product that we choose must be able to generate solid models and accept CATIA drawing files
from our clients."
Can you see that there
are very many possibilities? You need to write these down and
communicate the information to management!
If for example, your company was a group
of professional planners who wanted to generate
and present concept plans quickly and easily so that clients could interpret
planning proposals, the CAD tool that they might select should be strong in
generating 2D drawings and have good presentation capability. The diagram below shows part of a plan created
using CAD software that we believe is appropriate for a planner. This
example consists of a base map (which was scanned from a street
directory) with
lines and text overlaying the base map produced by the CAD program. The drawing was constructed very quickly indeed
because the drafter was relying on a lot of pre-existing information which
was simply
scanned in and acted as a back drop.
Although not used in the example above, we
find the combination of aerial photographs of a site combined with vector information a
particularly useful way of conveying information to non-technical people.
It is possible to combine photographs taken with a digital camera with drawing data as shown below.
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The photo shows an old steam
generator located close to our offices. It was imported from the
UK in the 1920's. The green rectangle in the map adjacent was
produced in a CAD program and shows the location of the
generator. Clearly, the CAD tool used here is suitable for a
planner/facilities manager. |
Our mythical company
might want to dress their designs up with some interesting graphics. We
find Adobe Illustrator
an invaluable tool for this purpose.
If our hypothetical planning
firm needed to produce high quality
reports on (say) an ISO size A3 sheet, then CAD software tool chosen might need to be combined with with
an application such as Adobe's InDesign and
PhotoShop to produce a
result similar to that shown below.

So in
this case, the company
needed the right choice of CAD software and a number of software tools to satisfy their aims.
A
designer of industrial products would certainly have an entirely
different set of criteria for selecting software in order to produce
an image similar to
that shown below.
Here the
software might need to be capable of solid modelling and have built in ray-tracing facilities
when rendering the image.
It is likely that such software will be quite expensive. Some software
of this type even requires the user to type in the dimensions of the design
and when (and only when) enough dimensional information has been entered, the model is suddenly
built.
If we were an architect and wanted to model our new company car
(grin), we might model the new car using software with surface modelling
capabilities, render it and superimpose the model onto a photo of the staff
car park!
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Wire frame image rendered and blended with a
background photograph of our car park. |
The choice of software is of course
yours, but we cannot stress enough, the value of writing down your requirements
and communicating this to management.
The table below may assist in this.
We are of course biased, but once you have
chosen and installed your software, we believe that you need to be taught to use it
correctly. Considerable increases in productivity can come if the
software is utilized to its full potential. Visit our
courses pages for more information.
Many of our courses
allow you to take them using our unique
broadband or
distance learning system -
it's time and cost-efficient.
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