In a new Gamasutra bonus feature
, Introversion developer Gary Chambers recalls the creation of the AI systems in the indie studio's Darwinia
and its multiplayer successor Multiwinia
, as well as the upcoming Xbox 360 compilation Darwinia+
Among other topics, Chambers describes how the scope of Multiwinia
grew over time from a simple additional mode to a full-fledged game, and how that necessitated a new AI system rather than simply piggybacking on the one developed for he original game:
"It soon became apparent that the existing AI was no longer sufficient to provide a player with a fun, challenging game. Even in Domination and King of the Hill, which simply involves capturing and holding points around the map -- the exact purpose for which the original AI was designed -- a number of problems arose.
"In Darwinia, each of the levels in which this AI was actually used (enemy Darwinians only appear in 2 or 3 levels later in the game), the islands were small enough that each AITarget placed on the map represented an actual objective.
"Maps in Multiwinia tend to have much more open area however, and so some AITargets had to be placed to serve as ‘connectors', simply filling open space in the network to allow the AI to properly navigate a level. The result of this was that groups of Darwinians would often be found standing around in the middle of nowhere, basically wasted.
"This was solved by introducing the concept of ‘importance' to the AITarget. An AITarget is deemed important if it is placed near some other building of interest -- a Spawn Point, or a Hill zone in King of the Hill, for example -- and unimportant otherwise.
"This simple solution solved a number of problems with the basic AI. When a group of Darwinians now arrived at an AITarget that was not important, they could simply continue straight on to the next target, and conversely, the AI knew to defend AITargets it already had control of if they were important.
"This means that, not only did the AI stop leaving Darwinians milling around in the middle of nowhere, doing nothing, but because they are able to move straight over these unimportant targets, the AI was able to much more efficiently supply reinforcements to important targets that needed a boost."
In the full feature
, Chambers goes on to discuss the goal of player simulation, dynamic targets for the AI, and an ambitious game mode that was eventually dropped from development.