Roll and Rig a Cube in After Effects

Joey Korenman : What's up Joey here at school of motion and welcome to day 19 of 30 days of after effects. Today's video is going to be half an animation class and half a class about rigging and expressions. What we're going to try to do is tackle the problem, which was actually much trickier than I thought it would be. Uh, how do you make a cube or a square that can roll accurately? You know, if you think about it, there's a lot of logistical problems involved in doing something like that. So, first I'm going to show you how to animate the cube. Once you have it rigged then for the geeks out there. And I know there are some geeks out there I'm going to walk you step by step through how I built the rig. I'm going to show you the expressions and explain how they work. Then of course, I'm going to give you everything you need to build the rig for free.
Joey Korenman : Or if you just want to practice your animation skills, you can grab the completed rig too. All you need to do is sign up for a free student account. So you can grab the project files from this lesson, as well as stuff from any other lesson on the site. Now I want to go into after effects and show you some cool stuff. So let's go do that. So for the first part of this video, we're just going to talk about how to animate a cube kind of tumbling. Once you have the rig set up. And then after we do that, I will walk through how I actually came up with and made this rig and I'll copy and paste the expression code onto the site. So if you guys don't want to watch that part, feel free to just copy and paste the code and it should work for you.
Joey Korenman : So there's a lot of things going on here that make this animation work and the rig is part of it. There's also just a lot of animation principles and really precise, key framing and animation curve manipulation. So I wanted to talk about that first. So what I have here is a copy of the scene with no animation on it. And I do have my rig set up. So the way this rig works is there's a bunch of NOLs in the nose, all do different things. And we'll talk about that in the second part of this video, but the one that you control is this Knoll here, box control. Oh one. And I labeled this oh one because in the demo I had two boxes. So I had two sets of controls. So this Knoll, literally, if you just move it left to right, like this, the box roles correctly, based on where that knowledge is.
Joey Korenman : So if you just wanted the box to just kind of simply roll across the screen, all you need to do is move the nuts real easy. I wanted it to feel like the box got kicked or something and sort of landed like this. So the good thing about having a rig that takes a lot of the manual labor out is I literally only have to key frame one thing, the exposition, the rotation, uh, and really the trick is that the box has to move up and down a little bit as it rotates to always keep it touching the ground. If you look at this B this box adjust, why not right here, um, that actually moves up and down. Let me move this box back and forth. If you keep an eye on it, it's this snow right here. It actually moves up and down as the box rolls.
Joey Korenman : That's kind of, what's doing the trick there. So why don't we start out by just animating the exposition of this box? So we'll have it start off screen. I'll put a key frame here and then let's go forward. I don't know, a couple of seconds and we'll have it roll out to the middle of the screen. And I want to make sure that it lands totally flat on the ground. And it's, it's going to be pretty tricky to do that because all I'm animating is the exposition and I can kind of eyeball it and say all that looks right, but how do I actually check and make sure that it's flat on the ground? Well, let me unlock this and all this and all here. The be rotate for box rotate. If I open up the rotation properties of that Knoll, the zero station has an expression on it.