Animated intelligent agents play an important role in dynamic virtual environments. They are able to perform behaviours based on internal states and external stimuli. Animation techniques are crucial to agent behaviour visualization in order to achieve effective interaction between agents and human users. This paper proposes a new animation procedure to visualise realistic intelligent agent behaviours. The animation system consists of three parts, namely synthetic vision, FzFSM with memory and an animation library that uses mesh skinning techniques. The agent is capable of exhibiting non-repetitive behaviours to reflect change from both its internal states and its environment. The system is implemented on a PC platform with modern 3D acceleration hardware. The result of this work can be applied to real time 3D graphics applications in the field of entertainment and multimedia.