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### Course: Storytelling>Unit 1

Lesson 4: Lesson 3: Bringing characters to life

# Actuators

Building the muscles of a character. Copyright The Walt Disney Company.

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## Video transcript

Once we have an armature for a character that is capable of all the functions we need to make the character believable, the next step is to add actuators to actually make it move. Actuators are the motors and pistons that drive the movement of the character, kind of like the characters muscles. There are three main types of actuators: pneumatic, hydraulic, and electric motors. They create motion by different means and have different characteristics. Pneumatic is actually one of the simplest and easy to do, even at home to get a pneumatic function running. They're typically lower force than a hydraulic or an electric actuation, and can have some squishiness or some springiness in the in the action, but for some, some things we do, it's actually perfect for that, for the application. Hydraulics on the other hand much more force in the same size, so if we need some really dynamic or heavy loading or a very responsive motion, hydraulics are the quick way to achieve that. So electric motors on the other hand, they're, they're quite close to the amount of power you can get to hydraulics. They're actually not quite as powerful per size, but there's a fair amount of controls advantages, performance advantages. Then you start thinking of the physics and and in the physics you start thinking, "Okay, what is the inertia of these armatures?" And you know inertia tells you how hard is it to move something and to keep it moving. And, and the the other thing is how much force do I really need to make this move? And the other thing is if this thing really heavy, because if it is I'm gonna need some really big motors or hydraulics so all these things start coming playing together. And, and, actually how do I combine all these things to make this move. But no matter what type of actuator we use, there are only two kinds of motions they provide. Linear motion, that is motion along a line, like an up-and-down, or an in-and-out. Or rotary motion, that is a spinning motion. The magic is how we combine these basic motions in our armatures in order to breathe life into our characters. When we did Davy Jones, it's a mixture of electronic and hydraulic. We use hydraulics for the really big movements, the really big things that had to move or had to move fast the arms, the body, all of those those big functions are hydraulic. But then, like, facial functions, and facial moves, and hands, those are electric. The future of animatronics is electric. The electric actuators are getting so much better that we can do some amazing new things and much smaller packages and with much greater detail of movement. Jake's neck has a simple armature in it. It is a stack of motors and brackets that work together to give him all the expressiveness that you see. One motor is just responsible for turning the head, like this, and turning the other two motors along with it. And then one motor is responsible for just tilting his head, like this, and another motor is responsible for just tilting his head, like this, and those three motors and the order in which they're positioned, determine how Jake can move and what kinds of expressions we can get out of him. So the tiny life figures are eight-function animatronics it's an all-electric figure. So every motor inside these little guys are electric so it's got a nose up and down, that's the first one, we've got full motion in the head so we have a head rotate. We also have tilts and up and down and those motors actually sit inside the characters tummy. And there's two rods that help us get all of that motion. We have a squash and stretch, which makes the whole body kind of squish up and go up and down, which ends up being super critical, we think, for kind of being able to express emotion. We have a body tilt side to side, that they can get close to their friends. We have a lean forward and a lean back, so that people, you know, they can really lean in and say 'Hi' to people that they see. And then we have a tail wag in the back. One of the challenges of creating great animatronic characters is balancing creative demands with technical feasibility. s\ Rocket's wrists are really, really tiny. They're like the size of a penny. And unfortunately, they don't make motors that small. Generally speaking, an arm will have, a fully functional arm, will have about eight functions we only really had space to put two motors to accomplish all his arm functionality. So, we had to figure out a way to make Rocket have arms, that even though he only had two functions, make it look like he had eight. Basically was like this, so Rocket's arms are posed like this in kind of a, like, you know, off angle things. So this arm was capable of moving this way, and then this part was split over here, and he could move this way. And if you pay attention when you're animating and in kind of just make sure to follow arcs and various things that look more natural. You can kind of get these swinging functionality things that look like you're getting a fully functional arm. So there's a part of the show where Rocket turns and he's like, you know, and you guys need to help me with the thing. And we basically just have him, he swings around like this, and most people see you and they're like, "oh yeah, he totally pointed at me," and yet none of his fingers moved. His wrist didn't move. His His shoulder didn't move. He just has this one capability here, and this other one. But linked together, you get something that's more fluid and looks like it's totally working the way that you would expect. Remember, each function is there for a reason. It helps to deliver the performance that tells a story - a story that connects with guests. In the next exercise, we will provide you with an animatronic simulator. that will allow you to build a digital armature for your character. When choosing your functions, think about why each function is important to be able to tell the story driven performance for your character. Whatever you make, just have fun!