Arcs
Nearly every movement follows a slightly circular path. If not movement would be mechanical and stiff. So in animations the movement is designed along arcs. The arcs can be drawn in with key frames so that the movement can be guided along to create a more naturalistic feel. If inbetweens do not follow the arc that the key frames are on, it will ‘kill’ the essence of the movement.
Historic Example
In the historical example from The RoadRunner when the coyote is striking the match on the rocket his arm and wrist is following an arc, swiping in a circular motion. This gives is a more fluid, natural movement.
(go to 2.41 in the video)
(go to 2.41 in the video)
Contemporary Example
From Princess and the Frog, when Tiana is angry and pointing off the screen her arm is following an arc, seen particularly in her hand. So in terms of the historical and contemporary example, the uses of arcs are still important now to give animation a fluid movement.
(go to 0.45 in the video)
(go to 0.45 in the video)
Elise Townsend