| When we simulate a large number of virtual humans in virtual worlds we encounter a point where it is no longer feasible to simulate all of them in full detail. In the case where some of them never interact with the user it is useful to distinguish between main virtual humans and background virtual humans. The main purpose of background virtual humans is to engage the user in the immersive environment. Their main objective is to be believable to the user and allow him to suspend disbelief. To achieve this, the background virtual humans must be able to perform various behaviors, with conversational behavior being one of the most commonly required.;In this dissertation we present a framework for believable simulation of conversational behavior for background virtual humans based only on a small number of parameters. It was developed over the course of four major iterations based on computational models derived from literature review and analysis of video corpus data. It takes into account the role of proxemics, gaze, turn-taking and pause on believability of conversational behavior and how context such as culture and conversational task affects believability.;We report on a number of evaluations performed during the development of the simulation and show that simulations appear believable to the subjects. We describe the applications where the simulation has been employed and show what role it can play in a larger framework covering multiple levels of detail. |
