For 3D CAD, CorelCAD seems to provide a lot of power at a moderate price. But does it live up to its promise? Dermot Hogan gives his opinion…
One thing that you learn quite quickly about lathes, milling machines and the like is that, unlike a PC, there isn’t a delete key. If you make a mistake, you start again. Which is why it is pretty much essential to have a CAD package to produce a design – a plan – from which to work. Yes, you can use graph paper and a pencil to produce a design. You can also use a quill and ink if you like …
I’ve been using CorelDraw for a number of years as a (very) lightweight CAD package for simple mechanical drawings. It works quite well for that, in that you can add dimensions, use layers and colour items to get an idea of what you want to produce. But a 2D package that is aimed mainly at artists and illustrators doesn’t really cut it when you want to produce something like a simple right-angled mounting plate - let alone a robotic tracked vehicle. Nor, to be fair, is CorelDraw intended for that purpose.
So I started looking for something a bit more 3D-oriented which would fit in with what I had used and knew in CorelDraw. CorelCAD seemed the obvious place to start.
CorelCAD is essentially a re-packaged version of Graebert’s Ares Commander CAD system. It’s aimed squarely at AutoCAD-style users and as far as I can see does a pretty good job of it too. I’m no AutoCAD expert and, to be honest, the thought of using a command-line input to perform operations and using LISP as a programming language seem a bit, well, 1990s. But who am I to say? AutoCAD is doing very nicely thank you, and there are many happy users out there.
|This is a simple plate with a hole and a cylinder in the default wireframe view. Note the rather nice ‘ribbon’ menu which is an option over the older ‘classic’ menus.|
Design in 2D
CorelCAD works in AutoCAD’s native DWG format and you can import and work with AutoCAD drawings directly. That’s a big plus – there are many manufacturers who produce CAD drawing in DWG format for download and incorporation into your designs. But you can also import and export to CorelDraw’s native CDR format. For me, the export worked ok, but I had difficulty with importing my existing mechanical designs. CorelCAD did import them – but the dimensions were not correct (they were page dimensions, not the dimensions I had specified in CorelDraw) and in some cases the relative sizes were not correct. I was hoping that I could import my existing CorelDraw diagrams and start working on them immediately. In the end I decided that it would be simpler to start again.
With any CAD package there is going to be a learning curve. By all accounts CorelCAD is simpler to learn than AutoCAD but, even so, it’s a complicated and powerful design package and I found that it took me some time to get into producing even simple 3D objects. One of the rather strange things about CorelCAD is the help system. It really is the good old fashioned Windows XP style help. It’s comprehensive, true – but compared to the help provided with AutoCAD Fusion 360 or SolidWorks (with good short video tutorials and well laid out HTML pages on the web) it looks pretty antiquated.
2D drawings are easy, though. Even though the menus are different, I found that I could re-use much of what I knew from CorelDraw to lay out and align rectangles, etc. and specify the distance between various components – the dimensioning tools are first rate. I found the ‘Quick Input’ mechanism, where you can specify the dimensions of, say, a rectangle, on the fly to be particularly useful. As you might expect, the ability to accurately produce 2D layouts and plans is in a different ballpark to CorelDraw, and having using CorelCAD for drafting and creating 2D designs, I’d be reluctant to go back.
|You can ‘shade’ the wireframe to get an idea of what the finished item will look like. It’s ok but not wonderful.|
Into the Third Dimension
In addition to 2D work, CorelCAD also allows you to work with 3D objects. You can extrude a 2D surface to produce a 3D box, create spheres, wedges, cylinders, etc. and you can operate on them to generate holes and interiors. You can also create fillets and so on and ‘loft’ surfaces to generate 3D objects. I’m no architect, but I can see how this will work well for architectural designs in the traditional AutoCAD manner.
However, for 3D mechanical designs, there are some issues.
The first problem I had was to create a hole. Simple holes are fine, if a little unintuitive (you subtract a cylinder from a solid object), but what about an M3 machine screw hole with an 82 degree countersink? Or an M6 counter bore? Not so easy – ideally, I want a ‘hole’ menu which allows me do a number of common hole type operations. I would think that it is possible to create functions like this in CorelCAD by programming (in LISP) a routine that does exactly what you want. But I want to get on with designing my machine – not writing LISP scripts.
CorelCAD mainly operates in wire-frame mode. Typically, you would start off with a 2D ‘layout’ of a 3D design, and then extrude and move parts to where they need to be, while the display remains in wire-frame. Wire-frames, though, strike me as something of a throwback to the days when graphics cards and CPUs were not powerful enough to fully render 3D objects in real time. Times have changed and I prefer working in a fully rendered, rotatable 3D view all the time as in the Solidworks/AutoDesk Fusion 360 type of 3D CAD software. With these you create a 2D ‘sketch’ on any surface of an existing fully rendered 3D object and extrude 3D shapes from the sketch – to my mind a much more intuitive approach.
|The new QuickInput system allows you to specify dimensions ‘on screen’ rather than using the command line.|
An important feature that CorelCAD is missing for 3D work is ‘assembly’. In producing a full 3D ‘model’ of a robot, say, you would typically have a number of parts – ‘components’ – designed separately; and you then want to bring them all together as a fully functional composite object. So, you really want to be able to select a gear shaft, say, and the center of a the hole in a gear and ‘join’ them, so that they align exactly, can rotate freely about a common axis and can then be moved and placed as one component. CorelCAD does have object ‘snaps’ where you can move an object to, for example, a position close to the middle of a line and it will snap to the mid-point. But this isn’t really the same as an assembly function. For me, assembly is essential. In researching which CAD package to use for designing robots, I’ve tried several CAD packages without assembly and it takes far longer to produce a workable model than with a CAD package with it.
|This is an example of a standard CAD file made available for download by a manufacturer (in this case igus - www.igus.com). Because CorelCAD works in native DWG format, importing files like this works perfectly.|
If you want to use CorelCAD for architecture, planning, office layouts or individual component design, assembly may be pretty much irrelevant. CorelCAD is excellent at producing 2D drawings and plans and it’s also good at 3D architectural designs, but there are better products available for complete mechanical designs.
But there is one more feature of CorelCAD that you might like to consider: it has a ‘perpetual’ license. Many CAD systems – AutoCAD and SolidWorks, for example – require you to pay a yearly rental or subscription fee. For this you get the benefits of bug fixes, support and the latest releases of the software. You might think (as I do) that this is fine for the software vendor but not so good for those people who just wants to purchase something once and may consider upgrading after a few years. The CorelCAD perpetual license means that once you buy it, it’s yours to keep.
The Good1) excellent at 2D designs, layouts, drafting and drawings
2) works in DWG as native format and is cheaper than AutoCAD
3) imports and exports to CorelDraw and other Corel products
4) perpetual software license
The Bad1) importing from CorelDraw did not work well for me
2) mainly wire frame mode
3) old fashioned help system with limited tutorials
4) no assembly
…and the ugly?
No. CorelCAD is fine, as long as you are aware of its strengths and its limitations and use it appropriately. It is an excellent CAD package aimed at the AutoCAD (as opposed to full blown 3D design like SolidWorks) market. If you mainly want to produce 2D designs and 3D architectural drawings, it will serve you well. The 3D design functionality is adequate but if 3D mechanical design is your main purpose, there are better, more modern alternatives. But it’s a lot cheaper than AutoCAD (which currently costs £1,506 per year!) and it has a perpetual license. In short, I’m happy to design components and produce 2D layouts with CorelCAD, but I wouldn’t want to design a jet engine in it!