The laws of physics and rules of animation - After Effects Tutorial

- [Instructor] Well, glossing over big ideals, such as space curvature, quantum mechanics and the architecture of the cosmos in general, we'll delve into physics and how it relates to animation, why? Well, because when you animate regardless of what you're animating, text, characters, graphics, et cetera, you are creating a world. A world that has specific characteristics with how elements animate, move and adhere to physical principles in which you establish. Basically, you have to purposely create the physics of your animated world. You might not have gravity or earth-like physics, but you must establish your own guidelines about how elements move, and then stick to those guidelines to make your style consistent and, well, believable. So to help you do that, let's quickly go over some laws of physics and rules of animation that will help you think about creating the physics of your animated world. Also, before we start, I must give a quick shoutout to Angie Taylor, whose textbook design essentials for the motion media artists I've pulled so much of this information from because she describes things much better than I generally do with a lot less rambling. You can find some fantastic courses by her in this library. Just search for Angie Taylor. Okay, let's start with the Laws of Physics. Everything has mass, or the amount of physical matter in an object. Our world has gravity, a force that pulls things down, sort of. mass and gravity in combination will give us the weight of an object. Often, we equate mass and weight to size in the animated world, but we can always play with how objects of different mass react to each other to play with our viewer's expectations. Fun, fun, fun. This brings us to the idea of Directional Force and Arc. When only worrying about gravity, the direction tends to be down, not always, but tends to be. With only the force of gravity applied, our objects move in a straight line. But if we add another force like a catapult, our objects have two directional forces working upon them, such as the direction the catapult has catapulted it as well as gravity. When we have these two different forces working on our object in tandem, we see our objects move with an arc. Everything in the organic world tends to move with an arc. The world is curved, so if you have a little bug flying across your screen, give it a little arc to make it feel more organic. Or if you have a bouncing ball across the screen, well, it definitely needs some arc to look right. What else does that bouncy ball need to look realistic? Well, it needs to adhere to damping force. As you see, our bouncy ball bounces a little less high with each and every bounce. This is because the mass of the ground absorbs energy from the mass of the bouncing ball. Any two objects that collide will transfer energy. Like, if our bouncy ball bounces into this larger square with more mass, the square moves a little as it has absorbed energy from the ball, but this slows down the motion of our ball as well, which is also a pretty good example of resistance. Pretty much everything in the world would continue moving if not for that pesky little thing called resistance. The floor, the wind, invisible particles in the air are gradually increasing slope, as such, are all examples of resistance. These things tend to slow down an object's motion, and that would bring us to Acceleration and Deceleration. As objects start and finish moving, they tend to speed up and slow down. This is known as Acceleration and Deceleration. No object just starts moving at it's top speed and suddenly stops without decreasing in speed. That's crazy pants. So, when you start an object moving, you should have it speed up to a consistent speed from a resting position and slow down to that stop. It's just physics. Now that we've covered physic, well to some extent, let's get on to some Rules of Animation, starting with Squash and Stretch. As demonstrated by our bouncy ball here, we can see that it squashes as it comes into contact with the floor, then stretches as it moves up in the air. Let's see that a little bit slower. Nice, Squash and Stretch is a distribution of mass in an object. All things do this, even people do this as they prepare to jump up and down to maybe bash color out of a computer. Yes, that is me and yes, I am wearing bear claw slippers. But, not all things squash and stretch so noticeably. And well, sure, you might not notice a bouncy ball do this in real life, but exaggerating it a little bit in animation gives it a fun and genuine look. Yes, I did say exaggeration. We use exaggeration a lot in animation. It helps us craft our world, make it fun and unique. It helps it look strangely realistic and organic, even though our exaggeration is not organic at all. Strange how that happens, right? So as we exaggerate, we exaggerate many things, such as staging, anticipation and motivation. These three ideas help to draw the viewers eye to motion. By having a ball or a car roll backwards before zooming forward, or by having a character crouch or squash down before jumping, we indicate that something is about to happen and set up expectation for things, like our character about to jump because they are crouching. We can also use staging to play with our viewers' expectations. Boom, nobody expected the crouching character to straight-up explode. And furthermore, after that explosion when the character's leg falls over, that's an example of primary and secondary action. The primary action was the explosion, which caused the secondary action a.k.a. the leg falling over. Primary actions cause secondary actions in many ways, such as a block hitting a bunch of crazy, bouncy little balls. When you see many things happening on screen at one time, which is something you very much want in your animation, you are seeing overlap, or overlapping action. This gives the viewer lots of things to take in, making the animation lively and active, and also can be used to hide some mediocre animation at times. I mean, look at all my action on screen here. I have multiple bouncy balls bouncing, all staggered in motion. I have my character dancing, wiggling her little head, shaking away, blinking and moving. Also, something to be aware of when using overlapping action, is that things don't usually start their motion, then finish before starting the next motion, and finishing and so on and so on. Many things overlap each other as they happen at all times. Having some continuing motion and overlap helps your animation stay compelling. And this idea of things not just starting and finishing brings up the idea of Follow-through. Think of our catapult. When it flings our square, it doesn't just stop when the square is hurled. No, the catapult arm continues to pull forward and swing back, and rocking a little bit before coming to rest. This is follow-through. Same with the block bouncing and rocking, too, before it comes to rest. Maybe think of when a pitcher throws a ball. She keeps rotating her arm as she lets go. Maybe when a car skids to a stop, it moves forward a touch, then jerks backwards a little. These are all examples of follow-through. The feel of your animation will strongly be influenced by timing and pacing. Faster movement will have a more urgent feel. Slower will have a more relaxed, but also, varying the pacing and timing of various elements in your animation will draw attention and give you control over the viewer's eye. Pacing an animation with repetition and change can allow you to have some great, comedic timing, like another exploding head. All and all, the way you use and combine the various laws of physics and rules of animation is what will lead to your animation having it's own style, a specific charm and unique characteristics. It's Gestalt, or as defined, and organized hole that is perceived as more than the sum of its part. This is all the result of how you combine all of these rules of animation and laws of physics. So, should you use every one of these rules and laws in every single animation you create? Well, whether you mean to or not, you pretty much will be. You see, the lack of anyone of these ideas is a use of it in and of itself. To not use damping force is an animation choice that contributes to the style, or gestalt, of your animated scenes. So, if you just accidentally use damping force, it might feel off or weird. But, if it's a predetermined choice not to use damping force, that offness, that may add to the intended feel. But remember, it's best to stay consistent with the physics that you create for your world. If one object is all bouncy and another is not, there had better be a reason for that, perhaps a different mass or intended representations of different shapes or colors. But if two of the exact same objects, same color, same shape, same everything have different physical attributes, it might come off as sloppy and not well thought through. So, there you go. Physics and animation, how they work in unison to make your already awesome stuff look even awesomer. Do it.