The difference between 2D and 3D animation


4 minute read // Animation

When you watch an animated film, it’s very easy to notice the difference between 2D and 3D animation. Anyone can point out that this is 2D and this is 3D. But what is the core difference between the two, other than the visual result? What does it mean to make a 2D animation as opposed to making a 3D one? Well, actually the making process is very different.

To draw or not to draw

For starters, to make a 2D animation, you need to be able to draw. Everything you see in a traditional 2D animation had to be drawn. Usually frame by frame. For a 3D animator, while being able to draw, well, is definitely an advantage, it is not mandatory. When you’re animating in a 3D environment, you move the character kinda like a puppet right down on the computer.

Alright, so what does it really mean? In 2D animation, you draw the first key pose. And then the rest of the key poses. Now you need to draw all the frames in between them. Notice when the guy’s arm is covered by its body, it’s actually gone.

If something is not shown in 2D animation, you don’t have to draw it. If a character closes his eyes, the eyeballs do not exist anymore until I draw them again. This concept is one of the big differences between the two types of animation. That’s because when you’re working in a 3D environment, all the parts of your character are always there, and you have to be aware of them.

While in 2D you just draw whatever is seen and the rest is gone.

Okay, so we all know that animating in 2D means drawing a lot. But what does it really mean to animate in 3D? How does it look? Well, let’s see. A 3D model, it is rigged. That means that he is programmed with all the right virtual bones and controls to make it as easy for animators as possible to go ahead with animating it. You can grab one of the controls and move it around. 3D animation is all about graphs and curves. You know math and formulas don’t belong to an artistic thing like animation, but here it is. Now, this might seem a little overwhelming but most of these controls have six different curves you need to manage. All at once. They translate curves X, Y, and Z for up, down, left, right, closer, and farther away.

The rotation curves (X,Y, Z)

There are three curves for rotation X, Y, and Z, also for the three axes of rotation. We have these curves for both hands, two legs, knees, elbows, neck, back, pelvis, hips, and each part of each finger. That’s a lot of curves. Some of the controls have even more than six curves. So yeah, an animator spends a lot of his time looking at these graphs and curves.

The animation process

So now we know about the curves, but we still didn’t cover the animation process. So let’s say a character wants to raise his hand. We’ll go for the first frame in the timeline and make a keyframe. A keyframe is when you tell the program you want the hand to be in this position, at this time period, at this frame. You can see in the graph editor that there is a curve on the Y-axis of the hand going up. That’s because the computer interpolates the difference between the first and second keyframes we made. So an animator will do what we just did, but he will also move most parts of the body for every keyframe and offset some of them and tweak them for hours and hours.

Well, 2D animators mostly look at drawings. Another difference is the frame rate and what happens on moving holds. What do we mean by that? Well, in animation we usually work in 24 frames a second. In 2D animation that means that there is a drawing every frame 24 times a second.

That sounds like a lot of drawings, but it’s actually not that many. Because when there are no big or fast movements, you can settle for one drawing lasting for two frames. So that’s actually 12 drawings per second.

Working on ‘two’s’

This is called working on two’s because you’re making a change or a new drawing every two frames. When the movement is very still, you might even work on three’s and four’s making a new drawing every three or four frames.

You see that a lot in Japanese animation and stop motion. Sometimes they would hold the same drawing for many frames. In 3D though it doesn’t really work that way. When a 3D character doesn’t move at all, even for one frame, it seems kinda wrong. It seems dead.

This makes it a challenge to do what is called a moving hold in 3D animation. A moving hold is whenever you need a character to do nothing, but still, feel like it’s alive.

While in 2D and stop motion you can settle for a new drawing every three to five frames, or even not have a new drawing at all for a few seconds, in 3D we always got to keep the character moving, even a little bit. And that’s not easy. Well, that’s it for now. There are, of course, a lot more differences between the two kinds of animation. But we hope this short overview gave you a basic understanding of what it means to animate in 3D as opposed to animate in 2D.

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