ENG: Intro to CAD Design
Hello everyone! David here. It sure has been a while since the last time I (or any of us, really) posted. A lot has happened since then. We've been absent mainly due to college applications since we're almost hitting those deadlines, so we have to keep those essays coming.
Anyways, it feels good to be back. Today, I'll talk a little bit about an interest I have taken up recently, and it is nothing less than CAD Design. Let's get right into it, shall we?
What the hell is CAD?
Good question! CAD stands for Computer-Aided Design, and it is essentially using computers to help in some way or another design... stuff. Anything, really.
Look around. You probably see many things around you. You got your cellphone, probably some sofas or chairs if you're at home, maybe some cars if you're walking down the street. Have you ever stopped to think about how those things were even made in the first place? If I asked you today to make me a car, how would you even start?
Well, a solid place to start would be by designing it. How will the car look like? What will be the shapes that sum up to the final product? This is all design. Of course, when it comes to Engineering, these "shapes" and "looks" aren't arbitrary - they serve a purpose. For instance, if we're talking about cars and airplanes, a lot of it comes down to aerodynamics (which, today, we can predict with CFD, for instance).
Ok, so we at least know where to start, roughly. But how do we actually design a product? You could do it on paper, that might work. The problem is that... well, some people suck at drawing. I, for example, can barely draw a stickman right. So how do we design a product in a way that we can be precise about dimensions and have good control over our design choices? CAD is a good answer.
You can use CAD to design just about anything. When I asked you to look around, odds are many of the things you looked at were, at some stage of their production, a mere CAD file, a 3D model of the real thing that your eyes are seeing right now. Cool, right?
Sure, we can design something as complex as a car. But we can also design simple wood furniture using CAD (which is, by the way, a great way to practice). See below, for instance, a wood desk/drawer furniture in my house that I decided to model using CAD for the sake of this tutorial:
Ok, great, so we know what CAD is. But how can one start actually doing some CAD Design? Well, let's first look at some CAD software options.
CAD Software
There are many options for CAD software out there. Most of them are paid but have good deals for students - and when I say good deals, I mean getting it for free.
First off, the one I recommend (and have been using) is Fusion 360. It is a complete, professional software that is free for students. It is made by Autodesk, and this company is absolutely fantastic when it comes to education licenses. If you are a student, you can register your Autodesk account as an Education Account and get access to every single Autodesk product. We're talking Fusion 360, Inventor, Maya, and many more that I had never even heard of before, which is mind-blowing to me. Even if you're not a student, you can download Fusion 360 and activate a hobbyist account, which grants you the same level of access to Fusion 360 features as the education license (everything minus Generative Design).
The second one would be SolidWorks. I believe this is the most famous CAD software and likely the most widely used in industries out there (although Fusion 360 is also used). The problem with it is that they are not so lenient when it comes to handing out education licenses. Your school needs to be registered to SolidWorks as an education distributor, and you need to go talk to your school to see if you can get a license and how to go about getting one. This is much different than Autodesk, where you just have to type the name of your school and they'll instantly grant you an education account, no questions asked.
Last but not least is FreeCAD. This is an open-source CAD software that is, as the name implies, free. I haven't even tried this one, but read that it was a great free option, especially due to its open-source nature (which means that users are constantly contributing to making it a better software).
There are many more options out there (I left out, for example, the very famous TinkerCAD due to it being simpler). I encourage you to do a little bit more research if you want to get into CAD. As I mentioned previously, I highly recommend Fusion 360. Autodesk is amazing with students, and it has been a great platform for me to get started with CAD.
Ok, so we know what CAD is, some CAD software options, and that's it. How does the process of designing something using CAD actually go? Well, let me show ya!
CAD Design Example: Let's Make a Box!
Alright, let's get into it. I'll be using Fusion 360 for this little tutorial. What really matters is the process itself, not the buttons I'll be pressing, since that changes from software to software. However, if you also want to get Fusion 360 going and maybe even follow along, I recommend this youtube video and this tutorial (the latter of which is from Autodesk themselves, by the way). They show you how to install Fusion 360 and get started with the tools you have in hands.
Let's make a box! In the end, it will look something like this:
Simple, huh? First, let's think a little bit about what a box is. What is its shape, essentially? Well, if you look at it for a little bit, you'll soon realize it's just a rectangle. What about the "walls" of the box? This one's trickier, but if you think about it for a little bit, it's just another rectangle, just an inner one that we "pulled up".
So how do we go about designing this box? Let's just do exactly what we said: a rectangle, then an inner rectangle, and pull the inner rectangle upwards to form the walls! First, let's create a "sketch", which is just the CAD/Fusion 360 term for a 2D drawing that we will later transform into a 3D shape:
There, we made a rectangle. We will make the inner rectangle later, because before we have the walls, we need the base of the box. In order to make the base of the box, we need to somehow make this 2D drawing 3D. We can do so using a tool called "extrude". This is the "pulling" action I mentioned earlier, If we have a 2D, flat rectangle and pull it up, we'll get a 3D rectangle, also known as a cuboid. Let's extrude that rectangle:
Awesome, now we have the base of our box. In order to make the walls, let's create that inner rectangle we talked about. We can, therefore, create a new sketch in the side of the cuboid where the walls will grow out of. Let's do just that:
Awesome, now let's extrude the area between the outer rectangle and the inner rectangle to get our walls:
Voila! We have a box! Let's take this box to the next level though, shall we? Let's add handles! Our handles won't be anything fancy, just a hole through the two smaller sides of the walls.
I showed you that we can extrude to "pull" surfaces outward, but what we can also do with extrude is cut through our components. To "pull" the surface, we extruded outwards, but if we extrude inwards we can cut a hole in. Let's do just that, but first let's decide the shape of our handle.
There's a sketch shape that we can use called a slot. This is essentially two arcs and a rectangle put together that gives us that nice, handle-looking shape we have in the final product. Let's create that sketch in one of the smaller sided walls:
Great, now the fun part: let's extrude inwards! We do this by selecting the sketch and the extrude tool, but instead of pulling outwards we pull inwards:
Looking good! Now we just have to add some texture to this thing. This is very easy to do in Fusion 360: simply select the entire model and click "a". The appearance menu will come up, so just choose whichever look you want your model to have. Here, I'll choose a Cherry wood look:
Voila! We now have our fully modeled box! That wasn't too hard, was it?
This is what's fun about CAD: it really isn't that complicated to get into. Everything that you see around can be achieved by putting a bunch of simple shapes together, such as circles, arcs, ellipses, rectangles, and triangles.
Closing Remarks
This is roughly it for my CAD post. Before I leave, I just want to point out one last fun fact about CAD: there are many ways to do what we did today. We could've, for instance, extruded the whole outer rectangle, which would yield us a big cuboid, and then extrude inwards an inner rectangle, that is, instead of making the base and then raising the walls, we could raise the base and cut the empty space in.
This applies to many designs. There are always many ways to achieve the same result, but with experience (and a little bit of personal preference) you start identifying the paths of least resistance, if you will (the easiest ways to achieve certain shapes and components).
That's about it! CAD is extremely fun and extremely important. Knowing how to use CAD is a great way to start your path to becoming a so-called "maker". With CAD, you can design 3D printed parts, circuits, and even woodworking pieces, all from your computer (and for free!), which comes in really handy if you want to, for example, design your own products and ideas!
Well, folks, that's it for today's post. I hope you enjoyed it and are now ready to download Fusion 360 and get CAD-ing... or whatever the term for that is. See ya soon! Peace!
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