Animation Principles - Action Analysis for Animators - page 60

upward, the ears trail behind, facing downward. As the head begins to move
downward, the action of the ears continues to move upward—in other words,
the action follows through . When the dog comes to a halt, the ears will once
again continue to move forward until the action is arrested, because of the
ears' attachment to the head. One action stops, the second continues to move
in the direction of the force. The action has followed through .

Overlapping action describes how various parts of a figure in motion move at
different rates and at different times. As a standing figure turns to walk away,
the action may start with a slow turn of the head followed by the upper torso,
the hips, and then the legs. There are often no hard and fast rules as to how a
figure will behave or the exact sequence in which the separate elements will
move; it is enough to state that these separate parts of a figure will almost
always move at different times. The actions will overlap one another.

Arcs

In nature, objects seldom move in straight lines. This kind of action is more
associated with mechanical actions like those of human-made objects such as
machines, engines, and robots. Linear actions may be exactly the right ones
for abstract actions, but such movements will look very unnatural in more
organic subjects. If you look at the arm action of a human figure throwing
a ball using an overarm motion, you will see that the hand describes a very
large arc, starting from behind the figure and progressing to a position
directly over the figure before extending in front of the body, then finally
moving downward, then back toward the body.

However, arcs are seen in all manner of movements, not just the more
extreme actions such as a throw. Consider the hand action in a walk cycle. The
main action is obviously with the legs and the swinging arms, but through

FIG 3.12 The arc of the movement
of the ribbon is clearly seen in this
example.