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.