The majority of actions follow arcs. Using an arc allows you to ensure your animation have a continuous flow. For example, when you swing your arm upwards, the wrist leads in an arc shaped motion, dragging the hand behind with it.
One of our tasks is to animation a pendulum. In this task, the path of action needs to be in an accurate arc. If it is not, then the cord in which it is hanging from will look as though it changes length throughout the animation.
Sometimes, instead of using an arc, a straight line is used. In the example here, you can see that the arrow has a short distance to travel and enough force has been used so it only travels in a straight line, giving it a meaning of power and force. The other arrow has furthrer distance to travel and does not have enough power to reach the target. This is where an arc has been used
Arcs are significantly shown in Richard Williams' Jesseica Rabbit (based on Tex Avery's 'Red'. The curvatious motions in this case are emphasised on her legs, hips and waist.
Written by Elizabeth Foley