Game Development Reference
Follow-through and overlapping action:
This is the way in which momentum acts on a moving object to cause
extra motion even after the initial force has stopped; for example, a
baseball pitcher's arm does not stop moving the moment the ball
leaves his hand. In addition, his legs and body also move in response
to the action. Overlapping action occurs when secondary objects
move with the main object.
Slow in and out:
Natural movement in which there is a change in direction decelerates
into the change and accelerates out; for example, a car turning a
corner slows into the corner and accelerates out. A person jumping
will slow into the impact with the ground and speed up as he pushes
off the ground with his legs.
Motion in animals and humans occurs along curved paths. This
includes the rotation of limbs and the rise and fall of a body when
walking. The same curved movement is also found in the trajectory
of thrown objects.
These animations support the principal animation. They give a scene
more realism; for example, a person walking along the street won't
just be moving his legs. His arms might swing, he may be talking,
and his hair could be flowing with the breeze.
This refers to the speed of actions. It is essential for establishing
mood and realism; for example, a fast-moving character will
appear to be in a hurry, whereas a slow-moving character
portrays lethargy or disinterest. For realism, the correct timing of
actions with motion and sound is critical. Slow animated walking
characters can look like they are slipping across the ground if
their forward movement and leg cycles are not matched.
A delay between an action and a sound, such as a bomb exploding
and the associated sound effect, adds to suspension of disbelief.
Perfect imitations of the real world in animation can appear
dull and static. Often it is necessary to make things bigger, faster,
and brighter to present them in an acceptable manner to a
viewer. Overexaggeration is also used in physical features of
characters for the effects of physics; for example, in Warner Bros.'
coyote and roadrunner films, when the coyote is about to fall
from a great height, the time he spends in the air realizing his
predicament is exaggerated far beyond what normal gravity
This is the term given to an animator's ability to consider and draw a
character with respect to anatomy, weight, balance, and shading in