The 12 Principles of Animation
These 12 principles help to make animations look more realistic and comply to the basic rules of physics.
1.) Squash and stretch is used to give the illusion of weight and volume to moving characters it is also used when animating dialogue as it adds realism to facial expressions. An example of when squash and stretch is commonly used is when animating a bouncing ball and the ball is stretched into an egg shape across the frame.
Source: http://en.wikipedia.org/wiki/File:Squash_and_Stretch.svg
2.) Anticipation is used to prepare the audience for a movement or action and also to make that action look more realistic. This is done by for example when someone hits a tennis ball they first have to draw the arm and the racket back in anticipation, before swinging it forwards to make contact with the ball. However Anticipation can also be used to prepare the audience for something that is not a physical movement such as a character being introduced to the scene. This can be done by a character looking off screen for example.
Source: http://www.evl.uic.edu/ralph/508S99/gif/batter.gif
3.) Staging is used to focus the attention of the audience on a certain character, movement, expression or mood and make clear what the most important in the shot. This is done by selecting what things are in the frame and where they are placed, lighting and camera angles.
4.) Straight ahead action and pose to pose are methods of the actually drawing animations. Straight ahead action is when you draw each frame from beginning to end and an example of this is when you draw each page in a flip book. This method is used more for action scenes as it creates a more fluid illusion of movement. The other approach is pose to pose this when you only draw a few key frames and then add the intervals later. This method is used more to convey emotion and create drama however the two methods are often combined.
5.) Follow through and overlapping action this is used to render movement more realistically, these also give the impression that the characters and their movements obey the laws of physics. Follow through is used to show for example when someone stops walking some body parts keep moving like the arms. Overlapping action is when body parts don't move in unison or at the same rates as arms tend to move at a different time to your head etc.
Source: http://upload.wikimedia.org/wikipedia/commons/e/e3/Anim
horse.gif
6.) Slow in and out this is needed to show movement more realistically by having more frames before and after a movement as movement cant instantly take place, and it takes time for limbs and other objects to speed up and slow down. The bouncing ball above also uses this principle but so does changing from one extreme pose to another for example going form sitting down to standing up.
7.) Arcs used in animation also to add to the realism as most natural actions tend to follow an arched trajectory. Like a limb moving by rotating a joint however there is an exception to this which is mechanical movement as that moves in straight lines to seem robotic. Arcs are also done to make the movement more fluid.
8.) Secondary actions are added to main actions to give animations more life, and also the support the main action being performed. For example a person walking is the main action and then the person swinging his arms is the second as it is happening simultaneously to him walking. A secondary action doesn't have to a physical action it could be someone walking and singing to him self at the same time, for example. Though secondary action never take away from main actions they only add and emphasize them.
9.) Timing is simply talking about how many frames or pictures are used in a action, this in turn dictates the speed of the action on film. Timing is also key in order to make objects appear to obey the laws of physics and can be used to show a characters mood or personality. For example if a character moves slowly that can give the impression that they are depressed or sad.
10.) Exaggeration is an effect or technique that can be very useful in animation especially in comedic animations. Also because exact imitation of reality can look static and dull in cartoon form. An example of animation that uses a lot of exaggeration is Tom and Jerry where frequently Tom is exaggerated on.
Source: http://squonkblog.files.wordpress.com/2011/01/missing-mouse-2.jpg
11.) Solid drawing is the principle of three-dimensional drawing and how you take take into account space, volume and weight. For this it is important that the animator understands basic anatomy and how shapes and shadows move.
12.) Appeal in a cartoon character is the equivalent to charisma in an actor, just because a character is appealing does not necessarily mean that he's nice, bad guys can also be appealing. The main purpose is that the character acts realistic and interesting.
