12 Basic Principles of Animation

The 12 principles of Animation were first introduced in the 1981 book, 'The Illusion of Life: Disney Animation', a book by Disney animators Ollie Johnston and Frank Thomas. The content of the book was based on the work of leading Disney animators since the 1930s. The purpose of the principles is to put forward ideas and considerations to utilise when animating in order to produce more realistic and visually appealing animations. In order to do this they covered areas such as basic physical laws and the illusion of character emotion and appeal.

The principles were originally thought of and dedicated to hand drawn animation, but also translate into the modern day use of computer generated animation.

Squash and Stretch
The 'squash and stretch' principle is considered the most important of the 12 principles of animation. It implies that through animation, a materials weight and fluidity can be translated. It can be applied to a multitude of different objects and one of the simplest examples commonly used is the animated bouncing ball. When applying this principle to a realistic style of animation it's vital that the volume of the object remains unchanged despite its interaction with other objects and whether it is squashed or stretched. However, in some cases, for comical effect the volume and the objects ability to stretch can be exaggerated.

Anticipation
'Anticipation' is used in order to express to the audience that an action is about to occur and also to prepare them for it. The principle of anticipation also makes the action appear more realistic, for example, a character setting off walking need to build up momentum in order to start walking. This type of action to start a movement emulates real life, hence creating a more realistic and fluid animation style. The anticipation principle can also be applied to less physical actions such as characters anticipating the arrival of another character or event.

Staging
The principle of 'staging' applies to animation, but also to mediums such as film and theater. The purpose of staging is to direct the attention of the audience to a point of interest. Whether the point of interest be a character or action happening on screen, it's important to emphasise on the important aspects so that the audience can follow the story closely and with ease. Johnston and Thomas referred to staging as 'the presentation of any idea so that it is completely and unmistakably clear', whether this is an action, an expression or a mood. There are multiple ways to make sure the action is staged and emphasised to the audience such as positioning of characters or other important aspects of the scene, or positioning the camera accordingly. Overall, the purpose of this principle is to make what is on screen relevant to the audience and avoid any unnecessary detail. 

Straight Ahead Action and Pose to Pose
This principle refers to the two different drawing processes in animation. 'Straight ahead action' refers to drawing every individual frame of an animation start to finish. This allows for a very realistic and fluid style of animation. Overall the 'straight ahead action' approach to drawing animation gives a very dynamic illusion of movement, however some if the drawbacks include the difficulty in maintaining proportions and accuracy when drawing subtle differences between frames. In contrast, the 'pose to pose' approach to drawing means that key frames are drawn out and others added later. This style is mainly used for emotional or dramatic type scenes of large wide angle landscapes. The two types of processes are often worked in conjunction with one another. 

The use of computer animation eliminates some of the difficulties and drawbacks with straight ahead action, however pose to pose is still used when it comes to pose to pose because of the advantages it brings in terms of composition. 

Follow Through and Overlapping ActionFollow through and overlapping action are two closely related techniques that allow for movement to be rendered more realistically, and also give the impression that characters and objects abide by the laws of physics, for example the principle of inertia. The first technique, 'follow through', refers to for example loosely tied body parts to a character continuing to move even when the character themselves come to a stop, due to the momentum acting on the body part. The technique, 'overlapping action' refers to different objects moving at different speeds and times, for example if a character is walking, his arms will be moving at a different rate to their head. Both of these techniques allow for a much more realistic style of animation when applied because they apply to real life, they can also be used on inanimate objects such as a car antenna on a car.

Slow In and Slow Out
In real life for most objects and the human body, they need time to accelerate and slow down near the beginning and ending of an action. For this reason, animation has a more realistic look if near the beginning and ending of an action their are more frames or more drawings, because the action at this point is slower. Movements that this principle would apply to would be something like a character standing up from a sitting down position or starting to run from a walking pace. An example of this is the bouncing ball animation, where the ball accelerates as it falls.

Arc
In the physical world, more objects follow an arc like trajectory as appose to say a straight line trajectory and should adhere to this principle in animation in order to emulate reality and create a sense of realism to the audience. This principle is also shown in the bouncing ball example, and can apply to countless things. For example the rotation of a characters limb. However, fast moving objects travel in more or less a straight line as you observe them, for example a bullet moving through the air. If an object moves out of this trajectory generally it will appear erratic and not fluid to the audience.

Secondary Action
Secondary action is used in scenes to emphasise certain actions. A person walking will also be simultaneously moving their arms and head, this emphasises the action rather than draw attention away from it. Along with this the character could also be showing emotion or expressing a mood, which adds to the feel of the scene and develops the character and action further.

Timing
The timing principle in animation terms refers to the amount of frames or drawings for a certain action. Using the correct amount of frames for a given action allows the object to appear to have weight or be made of a certain material based on the weight it looks to have and how it interacts with other objects.

Exaggeration
Exaggeration is a technique reserved for cartoon based animation, where making it realistic would perhaps be considered dull or uneventful. The level of exaggeration is dependent on the artist and how they want their animation to be perceived, and if they want a realistic or particular style. Exaggeration defined by Disney was to remain true to reality but to make it seem more wild and extreme. However it is important to employ restraint when using exaggeration and find balance when presenting the scene.

Solid Drawing
The principle of solid drawing related to drawing objects in a given three-dimensional space with weight, volume, anatomy, light, dark etc. Traditionally, art classes were taken in order to achieve this level of skill when drawing and being able to represent forms reliably and at a high level. As an animator it's important to be constantly drawing and trying to improve your level of drawing and taking life drawing classes amongst other things to encourage improvement and accuracy.

Appeal
The appeal principle relates to the charisma and suitability of characters, just like the appeal or charisma of actors and actresses displayed in film and theater. Charisma doesn't necessarily relate to the morality or sympathy of a character. Creatures, monsters and villains can also possess certain levels of appeal due to the way they are portrayed. One suggested technique for improving the likability of a character and allow them to connect to the audience is to make their face easy to read with good symmetry.