Game Development Reference
Figure 4.1 3D skeleton frame.
In games where audio accompanies the dialog text, facial movement is sometimes ani-
mated to provide the sense that a character or creature is speaking. Animals, monsters,
and aliens are easier to believe because many of their sounds don't rely on the lip and
jaw movements that accompany human speech.
Inanimate vehicles are expected to behave in a manner similar to organic life forms.
For example, when a car turns a corner, you expect it to dip and pull according to the
speed of the car and the traction of the road surface. When the car jumps, you expect
it to bounce when it lands.
In sports games, character animations are very important because there are specific
expectations about how a particular action should look, such as pitching a baseball,
throwing a football, or making a putt. In order not to appear robotic, there may be a
variety of animations broken into different categories for each activity. For example,
a baseball game could provide both sidearm and overhand throwing animations for
pitchers. During gameplay, the proper animation should be chosen based on the
pitcher's actual style. Some games go further by providing animations for one or more
individual players based on their specific style and equipment. Pieces of sports equip-
ment should be animated as well. Balls rotate when thrown, kicked, or hit. Bats fly
apart when they break. Helmets and mouthpieces fly off after big hits. Gloves flex and
rebound when receiving a ball.