There is not much time before the day in the future when the human-computer interaction will approach the communication between the humans to the extent that there will be minor intellectual differences. This contention is grounded on the huge amount of investigations and the encouraging results from the developments of various intelligent virtual agents. The intelligent virtual agents (IVA) are programming autonomous agents with graphically built human face (and often a body, too), existing in either 2D or 3D virtual environment. They have capabilities to interact intelligently with the...