Most animation for games is done in short little segments, which are strung together as the game is played to give the illusion of continuous motion. Most games have a stock inventory of cycled motions that cover the basic needs of the game: running, jumping, standing, fighting, and so on.
Moves must be short to preserve interactivity. If a player moves the joystick, he doesn't want to wait several seconds for an action to complete before the character responds. No matter how good it looks, the gamers of the world will loathe your animation if it takes too long to play back and spoils their control of the character.
Basic moves for most characters in a game include these:
Idle. The idle is the motion that the character does when the player is not using the joystick. The character is typically standing in a moving hold, as shown in Figure 1. This might involve shifting weight, breathing, scratching, looking around, and so on. Idle motions should be cycled over approximately 3040 frames.
Run. In most games, the character always seems to be in a hurry to get somewhere or get away from some threat. The run, shown in Figure 2, is very much a staple of gaming, and almost every game has a run cycle, usually about 18 or fewer frames. Sometimes there also is a separate jog and a sprint version of a run.
Walk. For those times when a character is not running, you need a walk (see Figure 3). This usually involves about 24 or fewer frames. Sometimes you also need a crouching walk, an injured walk, or some other type of walk.
Other locomotion. Depending on the game, you might need other gaits, such as a sneak (shown in Figure 4), a somersault, a leap, a crawl, or a skip. Most of these involve 24 or fewer frames.
React. For added realism, it's a good idea to animate your character reacting to something, as shown in Figure 5. This reaction could be anything from a head turn to a full-body take. The reaction depends on what is interacting with the character, such as react to bite, react to shot, react to fire, and so on. This usually involves about 15 or fewer frames.
Death. If your character gets shot, stabbed, shocked, or clobbered with a mallet, he needs to die (see Figure 6). Death can take many forms, and a single game is likely to have several ways for your character to die. This usually isn't a cycle, and it takes about 15 or fewer frames.
Knock down. Those times when your character gets hit but doesn't die, he might be knocked on his face or rear end (see Figure 7). This motion is typically used in fighting games, is not cycled, and takes 12 or fewer frames.
Get up. If a character reacts to something and falls to the ground because of it, he needs to get up, as shown in Figure 8. The first frame of this motion should hook up with the last frame of the react motion. The last frame usually hooks up with the first frame of the idle motion. Getting up usually takes about 30 or fewer frames.
Attack. This involves a cycle of your character punching, kicking, clobbering, and so on. Each game has different requirements. In a fighting game, for instance, the attack move might be a kick or a punch (see Figure 9); a creature game might use a bite or claw, and an armed game might use the aiming and firing of a weapon, as follows:
Aim: Usually 10 or fewer frames
Shoot: Usually 14 or fewer frames
Bite: Usually 14 or fewer frames
Punch: Usually 14 or fewer frames
Kick: Usually 14 or fewer frames
Figure 1 Standing idle
Figure 2 Running
Figure 3 Walking
Figure 4 Sneaking
Figure 5 Reacting
Figure 6 Dying
Figure 7 Getting knocked down
Figure 8 Getting up
Figure 9 Attacking
All these frame counts obviously depend on the console that you are developing for, the programmers involved, the game engine, and so on.
Of course, characters in games might need to open doors, climb ladders, drive cars, swim, and fly, among many, many other types of motion. Each game is different and requires many of its own custom motions.