Papers

In this paper we present a system which allows a virtual character to display multimodal sequential expressions i.e. expressions that are composed of different signals partially ordered in time and belonging to different nonverbal communicative channels. It is composed of a language for the description of such expressions from real data and of an algorithm that uses this description to automatically generate emotional displays. We explain in detail the process of creating multimodal sequential expressions,... Read more

How to create effective body animations for virtual agents with emotions remains the state of the art for human animators and a great challenge for computer scientists. In this paper, we propose to use a model of hierarchal parameters to represent body animations: emotional, style, motion, and procedural parameters. Based on this model, we have created motions for a virtual character with generic animation procedures and mapped these procedural parameters into style parameters as proposed... Read more

Moral emotions have been argued to play a central role in the emergence of cooperation in human-human interactions. This work describes an experiment which tests whether this insight carries to virtual human-human interactions. In particular, the paper describes a repeated-measures experiment where subjects play the iterated prisoner's dilemma with two versions of the virtual human: (a) neutral, which is the control condition; (b) moral, which is identical to the control condition except that the... Read more

Psychology suggests highly synchronized expressions of emotion across different modalities. Few experiments jointly studied the relative contribution of facial expression and body posture to the overall perception of emotion. Computational models for expressive virtual characters have to consider how such combinations will be perceived by users. This paper reports on two studies exploring how subjects perceived a virtual agent. The first study evaluates the contribution of the facial and postural expressions to the overall perception... Read more

With the increase in the development of autonomous agents, there is a bigger demand on their capability of interacting with other agents and users in ways that are natural and inspired by how humans interact. However, cultural aspects have been largely neglected so far, even though they are a crucial aspect of human societies. Our goal is to create an architecture able to model cultural groups of agents with perceivable distinct behaviour. In particular, this... Read more

Many researchers associate a culture with some form of knowledge; other scholars stress the importance of the environment inhabited by the knowledge carriers; while archaeologists learn about cultures through the objects produced in the environment as a result of utilizing this knowledge. In our work we propose a model of virtual culture that preserves the environment, objects and knowledge associated with a certain culture in a 3D Virtual World. We highlight the significance of virtual... Read more

In realistic looking game environments it is important that virtual characters behave naturally. Our goal is to produce naturally looking gaze behavior for animated agents and avatars that are simply idling. We studied people standing and waiting, as well as people walking down a shopping street. From our observations we built a demo with the CADIA Populus multi-agent social simulation platform. Read more

We introduce a physically-based facial animation system for natural-looking emotional expressions. Our system enables creation of simple facial expressions using Facial Action Coding System (FACS) and complex facial expressions by blending existing expressions. We propose a method for blending facial actions, based on a parameterization that combines elements of FACS and MPEG-4 standard. We explore the complex expression space by examining the blends of basic emotions produced with our model. Read more

In human-human conversation, the first impression decides whether two people feel attracted by each other and whether contact between them will be continued or not. Starting from psychological work on flirting, we implemented an eye-gaze based model of interaction to investigate whether flirting tactics help improve first encounters between a human and an agent. Unlike earlier work, we concentrate on a very early phase of human-agent conversation (the initiation of contact) and investigate which non-verbal... Read more

Displaying facial motions such as crying or laughing is difficult to achieve in real-time simulations and games. Not only because of the complicated simulation of the physical characteristics such as muscle motions or fluid simulations, but also because one needs to know how to control these motions on a higher level. In this paper, we propose a method that uses the MPEG-4 Facial Animation standard to control a realistic crying face in real-time. The tear... Read more