I've used CAD professionally in all of its forms since the beginings of the technology. Since I started designing & making knives, I have designed on my high end, 3D system. I find that if I'm not careful, the tool (CAD) leads the design process, creating a knife that was easy to draw in CAD, but not the optimum design. You would be faced with the additional problem of learning the program.
I would not discourage you from trying the technology, however. You will find it extremely useful if you design folders at some point. Just bear in mind the pitfalls that have been mentioned.
I tried the link posted above, and was not able to get in. I'll try again later. If your willing to buy a program, TurboCAD 3D is available for $100 at most of the large computer stores. It's easy to use in 2D, and it has pretty good 3D capability for a $100 product. Unfortunately, in the 3D world, you get what you pay for. The highen end, professional programs run into thousands of dollars.
Hope this helps.
Bob Couture