Association of Game Events with Facial Animations of Computer-Controlled Virtual Characters Based on Probabilistic Human Reaction Modeling

Abstract

Computer-controlled virtual characters are essential parts of most virtual environments and especially computer games. Interaction between these virtual agents and human players has a direct impact on the believability of and immersion in the application. The facial animations of these characters are a key part of these interactions. The player expects the elements of the virtual world to act in a similar manner to the real world. For example, in a board game, if the human player wins, he/she would expect the computer-controlled character to be sad. However, the reactions, more specifically, the facial expressions of virtual characters in most games are not linked with the game events. Instead, they have pre-programmed or random behaviors without any understanding of what is really happening in the game. In this paper, we propose a virtual character facial expression probabilistic decision model that will determine when various facial animations should be played. The model was developed by studying the facial expressions of human players while playing a computer videogame that was also developed as part of this research. The model is represented in the form of trees with 15 extracted game events as roots and 10 associated animations of facial expressions with their corresponding probability of occurrence. Results indicated that only 1 out of 15 game events had a probability of producing an unexpected facial expression. It was found that the “win, lose, tie” game events have more dominant associations with the facial expressions than the rest of game events, followed by “surprise” game events that occurred rarely, and finally, the “damage dealing” events.

Evaluations of Software Developed as Research Tools to Analyze Trends of Educational Videogames Characters

“…Thus, the development of educational games apps involves working with interdisciplinary groups of professionals, including software developers, designers, video producers, psychologists, and pedagogues. The intention is to fill the gap between computer science, psychology, design, artificial intelligence, and other disciplines involved in digital game production [10], [11]. In the case of videogames for young learners as they are starting to read, solving visual communication issues in mobile apps is the primary concern of the referred professionals.…”

“…Virtual characters are crucial parts of virtual environments but especially computer games. The interaction between these characters and human players directly impacts the application's credibility and engagement [10]. In this visual setting, creating characters involved in a game's animation is a complicated task.…”

“…In this visual setting, creating characters involved in a game's animation is a complicated task. It implies defining the cartoon character's formal representation animated with visual and physical aspects, including facial expressions and movements, vital to these interactions that make an attractive identity for young learners [10]. Animated characters can improve children's experience, increase concentration, bring motivation, and accomplish more effective outcomes related to the use of the game [7], [12].…”

“…The design task includes phenotypes, archetypes, racial characteristics, biometric and anthropometric maneuvers, costume proposals, and accessories [13]. Furthermore, the designer must be sure that characters and scenarios in the games reflect the reality and feelings of prospective users, including facial expression related to the game situation [10)The design task includes phenotypes, archetypes, racial characteristics, biometric and anthropometric maneuvers, costume proposals, and accessories [13]. Furthermore, the designer must be sure that characters and scenarios in the games reflect the reality and feelings of prospective users, including facial expressions related to the game situation [10].…”

“…The production of educational games used for active learning encloses multidisciplinary knowledge and skills from practitioners and stakeholders involved [10], [19]. Thus, the practice of utilizing software as research analysis tools or as part of techniques to evaluate the design and use of this type of game is a challenge.…”