Arcs, Timing and Spacing

Arcs

Only the most mechanical actions follow a linear path which can work fine for animating a machine but it looks unnatural for a living creature. Most natural actions are done in a path of an arc or curve. This is especially true with humans and animals where everything from hand movements to eye movements have an arc to them. 

Importance

As an animator it's important to 'clean up' your arcs to keep them as nice flowing curves from one pose to the next to create more realistic motion. It's not uncommon for animators to use programs or sometimes even dry-erase markers on their monitors to track the arcs of different parts of a characters body such as the hips, hands, or head to ensure that they are moving in the smoothest arc possible.

Timing and Spacing

Timing and Spacing relate to how much time you put between poses. This has a great effect on how an action is understood by the audience. It can change a character's walk from someone who is slowly meandering down the road to one who is hurried or late for an appointment. 

Example

The most common example used to explain this is the head turn. Using the same head poses, a fast turn could make it seem like the character was hit in the face while a slow turn could make it seem like they are merely stretching their neck. 

Here is a lesson that was helpful to me when I was just starting to animate.

Sources

Thomas, F., & Johnston, O. (1981). The illusion of life: Disney animation. New York, NY: Walt Disney Productions.

Williams, R. (2001). The animator's survival kit. New York, NY: Faber and Faber Limited.

Goldberg, E. (2008). Character animation crash course!. Los Angeles, California: Silman-James Press.

Blair, P. (1994). Cartoon animation. Tustin, California: Walter Foster Publishing Inc.