Datasheet

Weight
Weight is an implied facet of design and animation. The weight of your subject in the
frame rests on how it is colored and its contrast, shape, and location in the frame and the
negative space around it. In animation, the idea of weight takes on a more important role.
How you show an object’s weight in motion greatly affects its believability. As you’ll see in
the axe tutorial in Chapter 8, creating proper motion to reflect the object’s weight goes a
long way toward creating believable animation.
Weight in animation is a perception of mass. An object’s movement and how it reacts in
motion and to other objects need to convey the feeling of weight. Otherwise the animation
will look bogus, or as they say, “cartoonish.”
Weight is created with any number of techniques developed by traditional animators
over the years that in some ways distort the shape of the character to make it look as if it
is moving. Although it may seem strange to distort an object’s dimensions as with squash
and stretch, it lends more realism of motion to the character. Chapter 8 will touch more
on creating weight in animation; here’s a quick preview.
SQUASH AND STRETCH
This technique makes a character responds to gravity, movement, and inertia by literally
squashing down and stretching up when it moves. For example, a cartoon character will
squeeze down when it is about to jump up, stretch out a bit while it is flying in the air, and
squash back down when it lands to make the character look as if it is reacting to gravity.
EASE-IN AND EASE-OUT
Objects never really suddenly stop. Everything comes to some sort of rest in its own time,
slowing before the complete stop in most cases. This is referred to as ease-out.
As objects don’t suddenly stop, they also don’t immediately start motion either. Most
everything needs to speed up a bit before reaching its full speed. This is ease-in. The
bouncing ball tutorial in Chapter 8 illustrates ease-in and ease-out.
FOLLOW-THROUGH AND ANTICIPATION
Sometimes exaggerating the weight of an object is necessary in animation. Objects ending
an action typically have a follow-through in some way. For example, a cape on a jumping
character will continue to move a bit even after the character lands and stops moving. This
is similar to the movement of gymnasts. When they land, they need to bend a bit at the
knees and waist to stabilize the landing.
Likewise, you can create a little bit of movement in your character or object before
it moves. Anticipation is a technique in which a character or object winds up before it
moves, like a spring that coils in a bit before it bounces. The axe tutorial in Chapter 8
will introduce you to these two concepts.
26 ■ chapter 1: Introduction to Computer Graphics and 3D
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