Active Time Battle
From Free net encyclopedia
Image:Activetimebattle.jpg The Active Time Battle (ATB) system in a computer role-playing game is an alternative to a turn-based system. It has been used primarily in Square Enix's Final Fantasy franchise, although it has appeared in a few other games, including Square's own Chrono Trigger.
In battle, each character in a party has a time meter, which counts down to his or her turn to use an ability or attack. Some abilities require time to charge before attacking, while others, such as a standard attack, work immediately with a recovery time afterwards. If a character uses a charged ability, and then a no-wait ability, he or she can attack twice in a row. Sometimes an action will require both charging time and a recovery period.
On the battle screen, there are different coloured bars displaying various status, such as health of the character. One of the bars represents the length of time left before that character can perform his attack, and this is the ATB meter.
The main deciding factor in the length of the time meter is the ability that is used. More powerful abilities will take longer to charge and recover from than normal attacks. The length of the time meter and the speed in which it charges is also affected by a character's "speed" attribute, which can be altered by certain items, equipment, abilities, spell effects (Haste, Slow, etc.) or levelling up.
Not all of this applies to every role-playing game that uses Active Time Battle, and some are much less complex, but it is a general idea of how this battle system works.
Though not technically called Active Time Battle, the battle systems of the Grandia series of video games uses a battle system very similar in concept to ATB systems.