Programming by Demonstration in Complex 3D Game

We have extended behavior trees to support a form of casebased reasoning by retrieving the best action to be performed according to the current state of the game. The case based was filled by programming by demonstration techniques. In this paper we demonstrate how this extension can be used to program the behavior of a non-player character in a complex 3D video game. We have also measured the perception of control that game designers have on the authoring process and conclude that designers are confident with the final result and they do not have the feeling of having lost control.