Planning-Based Narrative Generation in Simulated Game Universes

An agent-based social simulation is one way to add a story to simulated game universes within the game mechanics while preserving the autonomy of nonplay characters (NPCs). In this paper, we add a social reasoning element behind NPC actions to make their plans more story like. An AI planner is developed to combine plan search and logic inference about others´ minds. An NPC agent equipped with the planner uses actions to change others´ minds, and uses such mental changes to achieve its goal. We review the question of whether stories do arise from agent-based simulations by examining actual narrative segments generated by our NPC agents, and by an experimental exploration of the frequencies and lengths of narrative segments. A story facilitator, named divine intervention operator service (DIOS), makes stories happen when they are impossible via on-the-fly adjustment of character personalities.