Beehave
https://gyazo.com/f807e2d0986d7f8b0b59a76d37cbacb5
Behaviour trees are a modular way to build AI logic for your game. For simple AI, behaviour trees are definitely overkill, however, for more complex AI interactions, behaviour trees can help you to better manage changes and re-use logic across all NPCs.
AIの実装等に使える
https://www.youtube.com/watch?v=n0gVEA1dyPQ
ゴブリンが木に近づいて、伐採して、運ぶ Action を組み立てるサンプル実装の紹介
Condition を組み立てて、伐採置き場がいっぱいの場合は動かないように条件チェックをできる