Animation Fundamentals

[ErBoi 498]

Warning:  Yet again, this is a very long post.

Also, when I previewed this post, it was inconsistent about embedding videos so you may have to open some links.

 

Animation Fundamentals

 

Alrighty, so you may have checked out my earlier thread about professional drawing methods and tips and whatnot. You may also know that I am a professional animator (currently working on a show called Pirate Express) and, if you're reading this, I'm guessing you're interested in animating. I'll try to come across less pretentious in this thread and just delve into the content.

 

There are several different kinds of animation, but the same basic principles to acquiring appealing, expressive motion apply to all of them. For simplicity I'll be talking in terms of traditional frame-by-frame animation and trying to work in tips on achieving similar effects with puppet (i.e. Flash) style animation.

 

I've made some small example animations as well to demonstrate some of these principles.

 

Path of Action

In my previous thread, I discussed Line of Action and how it sells the motion of a character. A Line of Action is something you still use in animation but we'll get to that later; a Path of Action is a bit more literal as it's the path that the on-screen action takes. You'll see the Path of Action for a couple of my own examples further down.

 

Timing

This is a big one. Almost nothing moves at an even pace, and definitely not human beings and other living creatures. Our natural movements change momentum in frequent, but usually smooth transitions. Achieving this timing in animation means varying the spacing between your drawings. As an object speeds up, it will have travelled a farther distance in each consecutive frame of animation than the last. Of course, the opposite is true for when an object is slowing down, each consecutive frame will be closer together. These are called 'Slow-ins and Slow-outs' in animation; to be perfectly honest...I often forget which is which (pretty sure a Slow-in is when an motion starts slow and builds up speed), but as long as you know what they are, that's what's important.

 

This is a Feather Fall animation; if you study animation academically, you'll likely have to do something akin to this as one of your early assignments. When feathers fall, their path of action tends to sway back and forth, and they slow down at the extreme ends of every sway. Here is the plan of this animation:

 

The Path of Action is laid out simply as a line that the object in the final animation will follow, and each tick along the line represents a frame that will be in the animation.

Now, I cheated this one a little bit, I have too many frames in a couple places so I removed them. You'll notice near the beginning, there's a bit where it seems to stick in the same place, only rotating but not moving; that's the damage caused by having too many frames in such a spot.

 

Something else to know about timing in animation is what '1s' and '2s' are. 2D animation typically uses the commonplace video framerate of 24-frames-per-second. Feature-film animation is almost always done 'on 1s', which means that every drawing is held for 1 frame; making the animation match the framerate of the video. Doing animation 'on 2s', as I'm sure you can guess, means that every drawing is held for 2 frames; putting the animation at 12-frames-per-second.

Animation on 2s is typical of TV animation for various reasons. Obviously it's quicker to produce, and quicker to render. Additionally, a lot of TV animation often goes the route of having quick snappy actions that just tend to look better on 2s than on 1s.

It should be noted that if you are animating on 2s, if the camera has to shift, animate on 1s during that shift.  If a character is only animating every other frame while the camera is moving on every frame, the characer noticeably jitters.

 

 

Squash and Stretch

When something is in motion, velocity acts upon it's form and distorts it to a degree relative to the amount of speed (Stretch). When velocity is interrupted, the momentum inverts and the form becomes distorted in the opposite direction (Squash). This gets exaggerated to extremes in animation to help sell the on-screen action and make things more interesting to look at.

The obvious example is Looney Tunes, with the amount of times you'll see a character fly through the air, their body stretching out as they go, only to slam into a wall which immediately smushes their body the wide and flat. Additionally, while their form does distort, it still maintains the same volume; typically however much to expand something in one direction, you want to shrink it the same amount in the other.

 

Arcs

Just as nearly everything moves at an uneven pace, nearly everything moves in arcs too. The magnitude of an arc in your Path of Action can make all the difference in selling what you're expressing. A big character will typically move in big arcs, large gestures with their arms, etc. Plus, if you want some cheap laughs, inverting that, having a large gruff character move in tiny, quick movements, can result in some funny-looking animation.

 

Here's another animation that draws from my early college experience. And here's the plan for it:

When a ball bounces, it moves the slowest at the peak of each arc, so that's when its form is the least distorted. As it comes back to the ground, it speeds up, the consecutive drawings get further apart and the ball becomes stretched in the direction it's moving. When it hits the ground, it squashes, taking similar shape but now perpendicular to the direction of its movement.

And that impact has the momentum behind it for the ball to bounce again so it immediately returns to the air stretched, but becoming less stretched and slower as it reaches the peak. And then the process repeats, each time everything becomes a little less until the momentum is spent and the ball stops bouncing and rolls to a stop.

 

Now that we've established the core principles of movement, we can move on to the specifics of character animation.

 

Antic, Action, Overshoot, Settle

These 4 terms describe the major key poses of nearly every action a character performs.

Speaking of key poses, that's something I should probably touch base on before I continue. When animating, you will very rarely want to draw all your frames in order; that's not an efficient way to animate because you won't be able to see how your timing looks until you've already spent the effort animating the whole thing, and if it doesn't look good you'll have to do it all over again. You'll want to figure out which poses of the action your animating are the absolute necessity in conveying what that action is. For example, in the ball bounce above, the frames where the ball is either at the peak or bottom of every arc were done first. Another pass that comes after keys but before in-betweens is breakdowns. Breakdowns are sort of like semi-keys in that they're the next most important frames that exist to further define the path of action.

 

So, as for these terms for character animation:

The Antic is the motion a character performs that shows that the character is about to make the motion. This usually involves moving in the opposite direction from their planned action and doing so at a speed that is contrary to the speed of the action (so if the character is going to move really fast, their antic would be slow, and vice versa).

 

The Action is, as you may have guessed, the main action of the animation. When doing your keys, the action key will be the most pronounced frame of the action, the posing and spacing of which will describe the timing and arc that the finished animation will have.

 

The Overshoot is the polar opposite of the Antic. Before an action truly stops, it extends past the final position in a final extreme caused by the momentum of the action. Just like the antic, the timing of the overshoot is contrary to the timing of the action.

 

The Settle is the finale of the motion, pulling back from the overshoot, the character comes to rest in their final pose for that bit of animation.

 

Watch the Cat Jumping animation here:

This animation has everything talked about so far (as well as the following). And here it is as just the rough keys and breakdowns:

The first key is just our starting point. She's sitting there looking at her destination.

For the Antic, she lowers her head and raises her rear, completely opposite to what happens when she takes off (her head going up and leading the body, causing the rear to drop and drag behind).

Then there's a breakdown where she takes off and, just like the ball bounce, she stretches here and becomes less stretched as she reaches the Action key at the top of the arc.

After coming to the top of the arc, we get to another breakdown where the front of her body has contacted the ground, but the rest is still up in the air (more on that when we get to Overlapping Action). Finally we come to the Overshoot key where her whole body has hit the ground and is now squashed out.

And, very finally, we have the Settle key where her body returns to its normal shape.

Once you have all that worked out, and you're satisfied with the timing, you can go in and add your in-betweens, which are the remaining frames of animation to fill in the motion.

You'll notice that some of the rough drawings have a red Line of Action through them. I told you it'd be coming back! Having a strong Line of Action in your key poses in animation sells your posing well just the same as it does when working with still images.

 

Here's an animation I did of Spider-Man backflipping several months back. Not as good as the cat, but it still demonstrates all the same principles:

 

Every now and then, you'll have very subtle motions that your character can do without really doing an antic or overshoot, and that's fine so long as the action remains well timed.

 

Overlapping Action

Here's a small touch that is one of the major factors in selling believable and appealing motion. When characters move, things don't all move and settle in complete unison with each other. With the cat above, her body drags behind her head, her tail drags behind her body.

This is Overlapping Action: when parts of the character lag behind with less priority than the main motion.

The driving force of a motion usually comes from a specific body part and that's the part that will move with the most priority. When a cat pounces, it leads with its head, as is the case in that animation.

On human characters, there are all kinds of things to create overlapping action: Hair especially, but also clothing, earrings, flab on fat characters, breasts on women (may sound dirty, but it's true and even Disney does it; see Ursula in The Little Mermaid), etc.. As with all things animation, overlapping action can be made more interesting to look at with exaggeration, and you can create appealing overlapping action with body parts you wouldn't even normally consider for it: Ears, fingers, noses, jaws, and whatever else about your character's design you might find that can do it.

 

Secondary Action

Last but not least, Secondary Action is another relatively self-explanatory term in that it is action during another action that is secondary to it. For example, a character running across screen might wave to a friend as they go; the run being the action and the wave being the secondary action. These are the kinds of little touches that help make characters more believable as living, breathing entities.

During dialogue animation, you can create good secondary with subtle touches in the eyes such as blinks or bulges timed to accents in the voice-over. This is one reason why it's a better idea to have the voice acting before you animate. The delivery in the voice work can help you animate your character more believably and when you do the animation first, you limit the actor to performing within the confines of the existing animation.

 

Well, since I've been talking in terms of traditional animation and since I assume most of you reading this are most interested in puppet animation, I'll touch on that for a bit now.

One of the great things about puppet-style animation is that you get the ability to finesse your motion, and especially your overlapping action, like crazy without having to completely redraw frames.

Also, creating attractive overlapping action in that style of animation can be really easy. After you've got your animation flowing, find the keys for the specific pieces of a character that you want to move out of sync and simply shift them a couple frames back or forward in the timeline.

For instance, if a character is pointing, go through the hierarchy to get to the keys for the pointing arm and shift them 2 frames earlier than the rest of the body. This way the point drives the motion by leading the body. Also, with a lot of actions, shifting the keys for the head 2 frames later than the rest of the body can create some nice overlap on the animation as well. I find myself doing this a lot on Pirate Express and it can really boost the appeal of your animation.

That said, I get to use Toon Boom Harmony (<3) on Pirate Express and said software really lends itself to tweaking animations like that with quite a bit of ease. Your experience with other software, like Flash, may be somewhat more tedious.

 

A few quick tips for animating dialogue. First off, focus on the body acting of the character first before your worry about the face. Once the acting looks good, then move on to the face animation. Also, don't animate the mouth perfectly in time to the dialogue, have the mouth hit the right shapes 2-3 frames early. Sometimes you'll have dialogue where the actor has simply talked too fast for you to animate every syllable; in those cases, try to get an approximate 'combination' mouth shape, or use the shape for the syllable that is the most pronounced.

 

A quick tip when animating a character blinking: Put a bit of subtle squash and stretch in the eyes (squash as they close, stretch as they open, then settle to their original shape a couple frames later). It's just some of that nice-looking exaggeration. You can also make blinks even more expressive by having the character's eyebrows lower and raise in time to the blink (y'know, if they have eyebrows that is).

 

One final aside: Using the manipulator tool on your character, stretching, squashing and skewing, is a good way to hit your extremes like overshoots and such; I only implore you not to skew your entire character completely uniform. You can start a pose that way, but go in and continue to distort individual pieces of the character. When a character's whole form suddenly skews with no variation, it can really kill the believability of the motion, and, quite frankly, I see it a lot in fan-made MLP animations.

 

Just like I said with drawing, in animation things can always be better. I look back at that cat and realize her tail gets thicker and shorter when it settles, and I'm a little bothered by that. But you do your best to get everything looking good within the time you have (meeting deadlines if you work in a studio, or if you're doing an independent project, then simply finishing things when you want to be done with them) and hopefully the end result is pleasing to your audience.

 

Well I do believe that's everything I wanted to cover. Of course, there's still tons more I could talk about, but I think I've covered the most important aspects. Hopefully this was helpful to you. And now I will leave you with funny in-betweens!

 

Edited March 3, 2015 by ErBoi