Here I will document my research into animation, I'll be looking at the principles of animation, how to create natural, fluid and expressive human motion in animation as well as I'll look into the process of exporting animations into a game engine, most likely Unity since it's the engine I've had the most experience with.
The Principles of Animation and How They Help To Create Natural, Fluid and Expressive Human Motion in Animation
The 12 basic principles of animation are the most important techniques you must master as an animator. Apparently originating from Disney, they may have come up before, the 12 principles should be the best possible guide for creating appealing and realistic character animations.
Here are the 12 principles of animation in no particular order:
- Timing and Spacing
- Squash and Stretch
- Anticipation
- Ease in Ease Out/Slow In and Slow Out
- Follow Through and Overlapping Action
- Arcs
- Exaggeration
- Solid Drawing
- Appeal
- Straight Ahead and Pose to Pose
- Secondary Action
- Staging
Timing and Spacing
Timing and Spacing in animation is what gives objects and charcters the illusion of moving within the laws of physics. Timing refers to the number of frames between poses e.g. if a ball moves from one side of the screen to the other, left to right, in 24 frames that would be the timing. You can set the amount of frames to be in one second, a common number of frames per second is 24 when animating.
Spacing refers to how a ball is placed in each of the individual frames e.g. in the same example as I used before, the spacing would be how the ball is positioned in the 23 frames before the 24th. If the spacing is close together, then the object would move slower and if the spacing was further apart across the frames the object would move faster.
Squash and Stretch
Squash and stretch is what gives objects flexibility. Believe it or not, there’s quite a lot of squashing and stretching happening in real life that you may not notice and in animation this can often be exaggerated. For example, there’s a lot of squashing and stretching in the face when someone speaks, when the jaw moves up and down it stretches your cheeks and lips and then you move your mouth if you were to whistle, it squashes.
Another example would be if you were to watch a bouncing ball, as the ball falls and gathers speed it stretches and when the ball impacts the floor it will squash and then when it takes off, it stretches again.
Squash and stretch can be implemented in many different areas of animation such as when a character gets surprised, their face would squash down then stretch. Squash and stretch is a good principle to help exaggerate animations and add more appeal to movement.
Example of squash and stretch as a character gets surprised:
Anticipation
Anticipation is to prepare the viewer for an action that is about to happen. For example the character could be about to kick a football but to make the viewer anticipate this, as well as to gather momentum for the kick, the character would first move their foot backward. Another example would be if a character was to jump, they would first bend their knees and then push themselves upward off of the ground.
Ease In Ease Out/Slow In Slow Out
When an object or character is going to move or stop there needs to be time for them to accelerate and decelerate. Why is this necessary? Because movements can appear very robotic and unnatural. For example, as a car starts and stops moving they would first need to accelerate before reaching top speed and then decelerate when coming to a stop as going from 0mph to 100mph in one frame would look ridiculous as well as going from 100mph to 0mph.
This is where spacing comes into this, having the each frame begin closer together then space further apart when it comes to the middle of the action then gradually become closer together as its coming to the end creates the effect of easing in and out. An example given by digital tutors would be if a character was standing up from a sitting position, the spacing will start off closer together easing them into the movement, and as they stand up, they will ease out of the movement. Without this acceleration and deceleration of the actions everything would be very abrupt and jerky.
Example Image:
As you can see, the frames begin closer together as if you ease the character's movement in.
Follow Through and Overlapping Action
According to digital tutors, follow through and overlapping actions are sometimes considered two different principles, but they're closely related.
Follow through is when certain parts of a character continue moving after the character has stopped. A great example digital tutors gave was; as a character comes to a stop from a walk, every part of the body won't stop at the exact same time, the arms may continue to sway forward and then back before coming to a stop. This could also apply to clothing that continues to move as the character comes to a stop.
My example of follow through is if a character was running and tried to come to a stop as soon as they could, my hair would fly forward whipping my face as it was still carrying momentum.
Overlapping action is very similar in that it means different parts of the body will move at different times. For example if a character was to lift their foot in front of them to place it on a box, the top of their leg would have to bend along with their knee or if the character was to raise their arm up the shoulder would move first then the arm then the elbow possibly causing the hand to lag behind a few frames. Other terms for this incude "dragging" or "lead and follow". Another example would be if someone were to nudge a small tree, for whatever reason, first the area around the point of impact would move followed by the rest of the tree giving you a waving motion.
"In real life, everything moves at different speeds and at different moments in time, and that is why follow through and overlapping action is so important for capturing realistic and fluid movement."
Arcs
It's unnatural for people to move in straight lines, we tend to move in some form of arcing motion. In animation this principle of arcs helps to ensure animation is smooth and moves in a realistic way.
For example, as we walk out feet don't move in a somewhat straight/square motion, it's more or a rounded circular motion, an arcing motion or if we were to turn our head from left to right, it would normally dip a bit downward during the turn, creating an arcing motion which looks much less robotic and more natural.
Exaggeration
Exaggeration pushes movements further and adds more appeal to an action. Depending on how much exaggeration you use can either make an animation appear more cartoony or robotic. If you're animating to a realistic degree even a little exaggeration is necessary to keep the action from looking unnatural. This also helps when you're trying to enhance movements or help to demonstrate the weight of the character.
For example a lighter/weaker character would hace to put more of their body into pushing a heavy car than a larger/stronger character as its harder for them to push, demonstrating the weight of the car to be difficult for a smaller character to push than a larger one.
Solid Drawing
This mostly applies to 2D animation but still somewhat applies to 3D animation. With solid drawing you should think about how you're posing your 3D character rig, ensuring there is correct balance and weight in the pose, as well as a clear silhouette. You don't really want to have the post you have created mirrored across to the other side.
When the average person stands, they tend to put their weight on one leg more than the other as balancing weight between both legs is somewhat uncomfortable and interesting and a bit unappealing in a sense that it doesn't give a character much personality.
Appeal
This principle comes down to making the viewer be able to connect or relate to the character, an overly-complicated or strange character design may not be as appealing. Some ways to generate appeal in a character is to, for example, give the viewer something to remember about your character like if the character pushes out his chest a lot or has a cocky grin on his face a lot of the time.
Straight Ahead and Pose to Pose
Another joint principle! Straight ahead and pose to pose refers to a couple of different ways for how you could go about animating. With straight it gives you a more linear approach and can feature many different aspects as each post of the animation will be created one after the other. An example given by digital tutors is: if you’re animating a character jumping in the air you would create the pose where he’s standing, the next where he is beginning to kneel down, the next would be him completely crouched, and so on. You’re working through the animation as you’re going.
As for pose to pose it's much more planned out, there's more of a set path with the most important poses required to properly express the action. Their example of this is: you could approach the exact same action as the example before with four poses, the character standing, crouched, in the air, and back on the ground. It allows you to work much simpler, and ensure the posing and timing is correct before going into each individual frame and adding detail.
Secondary Action
When you add a secondary action to support the main action it helps to breathe more life into the animation to make it move convincing and lifelike.
The secondary action is usually something subtle such as while a character is walking their shuffling around in their bag or pockets for something or just looking around, something that doesn't distract the viewer too much from the main action. Another example would be characters waiting in like taking a step along the line every once in a while, that would be the main action, but while they're in the like their could have their arms folded, tapping their finger creating the secondary action. These actions are subtle yet powerful when making the animation more lifelike.
Staging
Staging is when you make the animation's purpose clear to the viewer, its when you set up your scene, from where the characters are placed to where the background and foreground elements are placed as well as where the camera is and it's angle. This could be setting up a character and an object or two characters so that they are easily seen from the angle you place the camera in. You don't want to confuse the viewer so keep the focus of the camera on the purpose of the shot and what you want to show the audience. For example you could should the face of a character as well as an object they want, then the viewer can easily see that the character is focused on the object and judging by his expression what he wants from or to do with the object.
Exporting Animations Into A Game Engine
For this example I'm going to use Unity as the game engine I'm going to export my animation into from 3DS Max.
For bone structure based animations you first import the character and create any animation you want, using both Forward Kinematics and Inverse Kinematics. Next select all of the bones and/or the Inverse Kinematic solvers and go to Motion then trajectories and press collapse. Unity makes a key filter, so the amount of keys you export is irrelevant.
Next go to export or export selected as newest FBX format, the default export settings should be fine. Once the exporting has finished you can then just drop the FBX file into the Assets of your Unity project. In Unity you need to reassign the texture to the material in the root bone.
When you export a rigged model with a bone hierarchy from 3DS Max into Unity the GameObject hierarchy in Unity will be the same as the hierarchy you can see in the "Schematic vew" in 3DS Max. Unity will place a GameObject as the new root, containing the animations and will place the model and material information in the new root.
Bibliography:
Surprised Image, easing example + image and follow through + overlapping quote and examples taken from: http://blog.digitaltutors.com/understanding-12-principles-animation/
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