Principles of Animation: Arcs

Arcs as an animation principle are used to make fast movement and rotations appear more realistic, or to emphasize weight and gravity.

Here are some examples of arcs used in animation:

Pikmin - Occupational Hazards [00:01:42 - 00:02:13]

https://www.youtube.com/watch?v=233Z0WhDrak

This scene is a good example of using arcs for comedic effect and to show weight as the Pikmin descend and ascend, with the Yellow Pikmin slowing down and stopping midair before gently coming down to land on the backhoe. Arcs shown are consistent, such as when the movement of the thrown nail is conserved between cutting from the top to the bottom as it hits the White Pikmin in the head. An arc is also seen when two Blue Pikmin land on the seesaw, failing to launch the Purple Pikmin (who remains perfectly stationary), while both go flying in an arc to the side. Conversely, a near-straight arc is seen when two Purple Pikmin land and launch the White Pikmin into space, done to help emphasize their power for comedic effect.

Professor Layton and the Eternal Diva [01:19:48 - 01:21:06]

https://www.youtube.com/watch?v=J26uI-NkqLQ

Arcs can also be used to greatly exaggerate tension and drama, especially during a fight scene. As Descole and Layton fight, a mix of fast and slow arcs are used as the duel proceeds; slow, tense arcs are used when they cross swords in order to emphasize tension as the music swells, and fast, blurred arcs are used in order to emphasize the speed and ferocity of their attacks. Arcs are also used to help accentuate Descole's dramatic nature as a character and as a fighter, such as when he draws his sword, throws away his cape into the wind, and backflips out of reach of Layton's weapon.