Is CAD essential to all teams?

[evoluti1]

Let's take a step back: the D in CAD stands for "Design." If you had asked instead, "Is design essential to all teams?", I think the answer is obviously yes. Whether you're a rookie with no mentors or an IFI team, you should do some amount of design before you start building.

So the real question is, "Is it essential for every team to design some or all of their robot on a computer?" First I want to qualify this: NO team should do ALL of their design in CAD. For instance, a large part of your design should be your
strategy for playing the game, and that's not exactly a task for Solidworks or Inventor. Also, CAD should not get in the way of prototyping - every year I see lots of robots which clearly took lots of time to model, but aren't effective playing the game because the underlying design idea wasn't refined enough through prototyping and iteration. In other words, CAD is just one part of the design process and should be understood and utilized as such. (Perhaps if you're wondering how to make your design more "legit" you should spend some time learning about how design iteration works and how the best teams use it, rather than just focusing on the CAD aspect).

That said, I don't think there's a team in FIRST that wouldn't benefit from using CAD software. To restate the question I posed earlier, we might ask, "in FRC, how does Computer Aided Design compare with Cardboard Aided Design or even Paper Aided Design?"

A lot of people say that CAD is difficult to use because it's harder to learn than doing design on paper. I totally disagree with this, at least I totally disagree with the notion that drafting by hand is significantly easier to master than CAD. Learning to use CAD effectively and learning to draft by hand effectively should both be viewed as large time commitments (it's why drafting used to be an entire high school class!). If you're currently making drawings by hand, but you haven't invested that time and effort, chances are almost 100% that your drawings aren't very good, and you should be investing serious time an effort in a new skill anyway. And if you have to learn a new skill, why not choose the one that's more versatile or applicable in your future career?

With the main drawback out of the way, what are the benefits of CAD over other types of design? For all but the simplest parts, I find that CAD is quicker than hand-drafting. Of course this is largely a function of how much practice you have. But again, if you're not practiced, drawing (well) by hand won't be very quick either. For more complex parts (even if you don't have access to CNC equipment), CAD starts to really shine. Parts that contain anything more than one or two rectangular profiles or square hole patterns quickly become more time consuming to draw by hand than to lay out on a computer.

But one thing a lot of people miss is that CAD isn't just about designing complicated parts with really cool-looking CNC-cut lightening pockets - it's really a tool that can improve any robot. For determining layout of an assembly, you just can't beat CAD, especially in a game like this year where lots of teams found it important to pack all of their hardware into a small space. In addition to 3-D assembly layout, CAD can also help you determine 2-D mechanism geometry before you even start designing any parts. This year, our team was confident we could build an arm that could tackle all of the defenses before the team versions were even finished, all because we could lay out the relevant geometry and constraints in an Inventor sketch. I don't know of a better way to do that kind of planning before you start cutting metal and spending money. (And in case I haven't beat the CAD-is-only-for-fancy-parts horse enough, I should mention that when the time did come to design parts for our arm, CAD helped us figure out how to make it work with only a band saw and a drill press.)

CAD is also more forgiving than drawing by hand. Mistakes can be corrected far more quickly (and often more thoroughly) than on paper. In fact, I'd argue that the ability to correct mistakes alone makes CAD an indispensable tool to have in your repertoire. After all, what is "design" but a process of repeatedly making mistakes in a controlled way and correcting them? Anything that helps you iterate faster is a good thing.

There are lots of other aspects of CAD that make it appealing and worth your time to learn, but if you do decide to pursue it, I think these are the main features that you will soon find indispensable. Like I said, I don't think there's a single team in FIRST that wouldn't benefit from being able to do high-level design and correct mistakes before it's too late. For these and lots of other tasks you simply can't do better than CAD.