ABSTRACT

Behavior trees and state machines were originally separate techniques—each with their own positive and negative points. The intent behind behavior trees is to make a series of character behaviors, whereas the intent behind finite-state machines (FSMs) is to make a stable cycle of character actions. For FINAL FANTASY XV, develops a new decision-making system that combines behavior trees and state machines into a single structure using the LUMINOUS STUDIO. This chapter explains the AI Graph structure, operation principle, and examples from FINAL FANTASY XV. The new decision-making system, which it calls the AI Graph, extends the node formalism to enable sharing nodes between FSMs and behavior trees, provides advanced techniques for code reuses using trays that organize code reuse and behavior blackboards, and also provides many features for integrating with detailed low-level character behaviour. AI Graph allows the developers to leverage both techniques in a nested hierarchical node structure, enabling a very flexible architecture.