Abstract. Virtual agents are used to interact with humans in a myriad of applications. However, the agents often lack the believability necessary to maximize their effectiveness. These agents, or characters, lack personality and emotions, and therefore the capacity to emotionally connect and interact with the human. This deficiency prevents the viewer from identifying with the characters on a personal level. This research explores the possibility of automating the expression of a character’s mental state through its body language. Using a system that animates a character procedurally, we provide tools to modify the character's body movements in real-time, so that they reflect the character’s mood, personality, interest, bodily pain, and emotions, all of which make up the current mental state of the character.