Choosing CAD software

 

This paper discusses some of the issues involved in choosing and implementing CAD software.

Why CAD?

The availability of low cost CAD software has radically changed the way professionals work. Most project managers now expect that some type of CAD software will be used to create drawings describing design work. Managers and clients also assume that the work you do, will be delivered in both printed and electronic format.

So, in most design professions, producing design work on paper drawings alone is no longer acceptable; you really need CAD.

This change in attitude has major implications for many of us. If you are working, or intend to work, in the Architecture, Surveying, Engineering or Construction industry, you need to be able to produce CAD drawings if required. It goes without saying that you need to learn to do this efficiently, making the CAD software work hard for you, not the other way around.

Learning CAD

Learning to use CAD software is not a trivial task. You really need to allocate some serious time to acquiring a new skill. The news is not all bad though, you will have a marketable skill. Simply purchasing expensive CAD software will not make it easier to learn.

Tip# 1: Do not spend money on software first - get some experience with free CAD software first

We suggest downloading free CAD software that mimics the way the CAD market leader (AutoCAD) works and access training materials on the Internet before putting any money down. There are many possible software options, but we believe you should choose one that has quite a simple interface and is easy to learn. An example is Windows software called gCADPlus, which although it is focused on the needs of landscape architects, it can be used to make CAD drawings in any discipline. It does have tools in its gCADPlus drop down menu that automate many CAD task that are tedious to do. In our view, you should look for CAD software in your discipline that has sets of automated tools designed for your discipline.

Visit http://www.plus. designcad.net to get a copy of gCADPlus. The software and interface is functionally similar to AutoCAD, DraftSight and IntelliCAD the most common CAD software tools in use professionally - the commands and method of operation in all four software tools mentioned are almost identical) can be used in any design field.

Note that gCADPlus works on Intel based Macintosh computers using the CrossOver plugin or Paralllels so you can certainly experiment with CAD on your Mac.

Free learning materials

Here is a link to an online learning course on CAD. Again, it is focused on the needs of landscapers, but the principles are the same, no matter what CAD software is in use.

Examples of CAD drawings

The CAD designs shown below were produced using gCADPlus.

Detailed landscape design.

Mechanical services drawing

Instrument loop drawing

Simple garden design plan produced using GardenCAD.

Here a hand sketch and some images of suitable plant were assembled in GardenCAD using the insert raster tool.

More complex landscape design

So, you can gain some considerable experience in CAD and get access to a comprehensive suite of training materials (including many on-screen movies that show how things have been done) by visiting the learning link above. For a more detailed and a more structured free online course http://www.gardencad.net/web/?q=node/250. There are some 2o modules giving a good idea how things are done in the CAD world.

Now back to choosing CAD software - spending money after some experimentation

There are many different CAD programs on the market – AutoCAD, AutoCAD LT, GardenCAD, gCADPlus, MicroDraw, DraftSight, Caddsman, IntelliCAD, Design Cad 3D, TurboCAD, Qikdraw, Catia, Solidworks, IronCAD, MicroStation, MiniCAD, Foresight, LisCAD, WESCOM, to name but a few. They all have various strengths and weaknesses and their cost varies. Perhaps the most important thing to note is that they mostly save their drawing file in different file formats, variously called .DWG, .DGN, .CTA, .VEC, .AI, etc. Because these file formats differ, 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 of software for you or your company, especially if you need to accept work from others and pass your work on to associates.

Determine your organization 'sits' in the scheme of things'

In selecting CAD software, our advice is to first define where you or your organization sits in the ‘flow of information’ for the design work that you carry out. This will be different for each business. A firm of mechanical engineers who manufacture their own products and designs and develop ‘in-house’, can choose any CAD program that suits their needs; they don’t care what others are using as long as the software they choose suits their staff and the job is done efficiently.

However, others such as landscapers architects and garden designers, by the very nature of their profession, must recognize that they are invariably dealing with drawing files that come from other design professionals (surveyors, civil engineers, architects etc). Thus there is a need to consider not only their own requirements, but it is critical to be aware of the CAD software that others in the 'supply chain' are using.

Most vendors of CAD software will tell you that they have included an export function to create what is called a Drawing Exchange Format (DXF) file which makes drawing translation a simple task. Be aware however that the translators providing for the generation (and importation) of DXF files are not perfect and do not deliver seamless translation. Although we have tried to make our software (gardenCAD and gCADplus) talk to CAD software like AutoCAD we concede that the transfer is not always seamless. It often depends how well the drater of the original CAD drawing has done.

As an example, most CAD programs do not understand polylines used by IntelliCAD and AutoCAD. These get converted into short line segments as the DXF file is generated. Flexibility of editing in a subsequent drawing session in the 'receiving' environment is then compromised. This drawing file incompatibility issue is not a trivial concern. We have experience in a job where profitability was severely compromised because (as we discovered at a very late stage) the survey software used for the base drawing (WESCOM) uses AutoCAD text shape files to place tree symbols – letters appeared in the AutoCAD drawings where we expected to see existing trees. Many hours were lost trying to track down the source of the problem.

Many CAD programs now claim the ability to open DWG files without conversion. Again, be wary of this claim; try this claim by downloading a trial version of the software before you buy. There may be an ability to do this, but the software may not open the DWG files generated by the latest release of AutoCAD.

Making the choice

There may be tension between your needs and those of the supply chain. On the one hand, you may want the ability to implement 3-D rendering, to output rendered images in a format suitable for a commercial printer, the capability to paste aerial photographs as a backdrop to your drawings and the ability to smoothly work with multiple views of drawing files which are greater than 10 Mb in size (in a design for a very large wetland  for instance).

In our opinion, MicroStation software, from Bentley Systems, certainly meets these criteria far better than does Autodesk's AutoCAD, DraftSight or IntelliCAD. However, in many states of Australia, MicroStation has less than 10% of the market share (in Western Australia MicroStation holds >50% of the market) so you might have to eliminate MicroStation from your list of potential CAD programs, because it is unlikely to be used in your supply chain.

Making a logical choice - let's focus on landscape professionals

As mentioned the first step in choosing CAD software for landscape professionals is to look at the local market and then at your own supply chain.

Local Market

In most states of Australia there is no question that IntelliCAD and Autodesk’s AutoCAD software dominates the market. [In the USA, MicroStation and AutoCAD run nearer 50:50.] Our guess is that in Australia, >80% of CAD files are created in .DWG format used by IntelliCAD and AutoCAD in these states. This leads to the conclusion that after downloading and trying out the free CAD software and getting a feel for CAD, the first piece of software purchased by a landscape office operating in Australia could be gCADPlus (cost around $A325.00). This software contains many automated landscape tools for reducing drafting time. A second choice might be the Lite version of AutoCAD - AutoCAD LT (cost around $2000).  The latter software does not contain any automated landscape tools.

Focus on your supply chain and think about the availability of skilled staff

Suppose that your supply chain is a little unusual in that 50% of your work comes from a firm of architects who used to use VersaCAD or VectorWorks on Macintosh computers and now use VerctorWorks on a Windows computer. Ask yourself the following questions. "Are you getting drawings from these architects presently? Do they work well enough in (say) the IntelliCAD/AutoCAD environment you currently use (through DXF or DWG exchange)? Is it absolutely crucial to have at least one copy of VersaCAD or VectorWorks in your office?" "Is there a pool of qualified landscape architects who are VersaCAD competent who you can draw on for a project?" "What would be the real cost if you had to complete a project entirely in VectoWorks? "

Second purchased - is the CAD software to be AutoCAD, AutoCAD LT, GardenCAD, or gCADPlus?

Having established that the .DWG format used by AutoCAD (and tried out gCADPlus and the Lite version of AutoCAD), a choice then has to be made between buying one of these or the full AutoCAD (at $6000.00) - perhaps so you can do 3-D modelling and another copy of AutoCAD LT or IntelliCAD (see below).

Final purchase

Now it is time to look at your own specific requirements more closely. If you have chosen AutoCAD, you need to decide which version of AutoCAD will do the job for you? The list of questions below (in no particular order of importance) should assist in decision making.

Image files:

Is there an absolute requirement for pasting carefully registered scanned images into drawings? In AutoCAD, images can be placed in drawing files, but, like XREFs, they are not actually part of the drawing file. The image is linked to the drawing file through a path name or a data management document ID. Linked image paths can be changed or removed at any time. By attaching images using linked image paths, you can place images in your drawing, only slightly increasing the drawing file size. Early versions of AutoCAD LT did not have the ability to load this type of composite drawing, but LT now does with some limitations. If you need this feature, then perhaps you can get an associate company with a full AutoCAD to create the base drawing with its attached image files and then use LT for your design work. LT can handle pasting .GIF, .JPEG and .PCX files into a drawing, but it may not give you the degree of control that you are after.

 It pays to keep checking on the features in the current version of AutoCAD LT, it tends to leapfrog the full AutoCAD. The development of IntelliCAD and BricsCAD is also remarkable.

Programming:

AutoCAD LT is not programmable. Ask yourself "Do you have a requirement for using any of the programming languages that come with the full AutoCAD (AutoLISP, VBA, ARX etc.)?" If you choose LT then you cannot run (say) a program to read a data file of points and create a (rectangular) surface mesh with facets to give you the surface topography of a site including contours. In the same way, you cannot use AutoLISP to create a new command (we call it VERIFY) to enable you to audit a finished drawing against a project or company standard. the VERIFY command checks fonts and blocks used, layer names etc. The ‘Pack and Go’ feature of AutoCAD is a great feature where project files are being exchanged, but relies on AutoLISP being present.

3-D Design:

Do you need to work in 3D? You may like to, but have you got the skills now? AutoCAD LT can read and display drawing files with 3D information in them, but it cannot create some very complex 3D shapes. Can you create and manipulate these complex 3D shapes in the full AutoCAD now, or is it a pipe dream? Do you need solid modelling?

Rendering: 

AutoCAD LT does not allow rendering (creating photo realistic 3-D images with light sources with (say) a sky) with clouds as a background. Before you say 'yes I must have this feature', are you willing to spend the time to learn to draw in 3-D? It is not a skill quickly acquired.

Is there and alternative? Can you learn to use your digital camera more effectively and then use Photoshop to dress up images, pasting them back into AutoCAD for final presentation? Maybe you can learn to build simple 3D geometry as a wire frame image and then 'dress it up' using Paint Shop Pro. SketchUp might be a better alternative. The figures below shows a garden and warehouse design created in SketchUp.

Model created in SketchUp (by Yardstick Designs)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cost: 

How much money does your budget allow? Each CAD seat needs a software licence. The full AutoCAD has a hardware and/or a software lock, so you can have the program loaded on several computers and simple move the lock around as needed while  AutoCAD LT and IntelliCAD need to be licensed for each computer on which they are loaded.