Real Time Animation of Virtual Humans: A Trade-off Between Naturalness and Control

Virtual humans are employed in many interactive applications using 3D virtual environments, including (serious) games. The motion of such virtual humans should look realistic (or ‘natural’) and allow interaction with the surroundings and other (virtual) humans. Current animation techniques differ in the trade-off they offer between motion naturalness and the control that can be exerted over the motion. We show mechanisms to parametrize, combine (on different body parts) and concatenate motions generated by different animation techniques. We discuss several aspects of motion naturalness and show how it can be evaluated. We conclude by showing the promise of combinations of different animation paradigms to enhance both naturalness and control

Artificial intelligence approaches for the generation and assessment of believable human-like behaviour in virtual characters

Having artificial agents to autonomously produce human-like behaviour is one of the most ambitious original goals of Artificial Intelligence (AI) and remains an open problem nowadays. The imitation game originally proposed by Turing constitute a very effective method to prove the indistinguishability of an artificial agent. The behaviour of an agent is said to be indistinguishable from that of a human when observers (the so-called judges in the Turing test) can not tell apart humans and non-human agents. Different environments, testing protocols, scopes and problem domains can be established to develop limited versions or variants of the original Turing test. In this paper we use a specific version of the Turing test, based on the international BotPrize competition, built in a First-Person Shooter video game, where both human players and non-player characters interact in complex virtual environments. Based on our past experience both in the BotPrize competition and other robotics and computer game AI applications we have developed three new more advanced controllers for believable agents: two based on a combination of the CERA-CRANIUM and SOAR cognitive architectures and other based on ADANN, a system for the automatic evolution and adaptation of artificial neural networks. These two new agents have been put to the test jointly with CCBot3, the winner of BotPrize 2010 competition [1], and have showed a significant improvement in the humanness ratio. Additionally, we have confronted all these bots to both First-person believability assessment (BotPrize original judging protocol) and Third-person believability assess- ment, demonstrating that the active involvement of the judge has a great impact in the recognition of human-like behaviour.MICINN -Ministerio de Ciencia e Innovación(FCT-13-7848

An Actor-Centric Approach to Facial Animation Control by Neural Networks For Non-Player Characters in Video Games

Game developers increasingly consider the degree to which character animation emulates facial expressions found in cinema. Employing animators and actors to produce cinematic facial animation by mixing motion capture and hand-crafted animation is labor intensive and therefore expensive. Emotion corpora and neural network controllers have shown promise toward developing autonomous animation that does not rely on motion capture. Previous research and practice in disciplines of Computer Science, Psychology and the Performing Arts have provided frameworks on which to build a workflow toward creating an emotion AI system that can animate the facial mesh of a 3d non-player character deploying a combination of related theories and methods. However, past investigations and their resulting production methods largely ignore the emotion generation systems that have evolved in the performing arts for more than a century. We find very little research that embraces the intellectual process of trained actors as complex collaborators from which to understand and model the training of a neural network for character animation. This investigation demonstrates a workflow design that integrates knowledge from the performing arts and the affective branches of the social and biological sciences. Our workflow begins at the stage of developing and annotating a fictional scenario with actors, to producing a video emotion corpus, to designing training and validating a neural network, to analyzing the emotion data annotation of the corpus and neural network, and finally to determining resemblant behavior of its autonomous animation control of a 3d character facial mesh. The resulting workflow includes a method for the development of a neural network architecture whose initial efficacy as a facial emotion expression simulator has been tested and validated as substantially resemblant to the character behavior developed by a human actor

Behavioural facial animation using motion graphs and mind maps

We present a new behavioural animation method that combines motion graphs for synthesis of animation and mind maps as behaviour controllers for the choice of motions, significantly reducing the cost of animating secondary characters. Motion graphs are created for each facial region from the analysis of a motion database, while synthesis occurs by minimizing the path distance that connects automatically chosen nodes. A Mind map is a hierarchical graph built on top of the motion graphs, where the user visually chooses how a stimulus affects the character's mood, which in turn will trigger motion synthesis. Different personality traits add more emotional complexity to the chosen reactions. Combining behaviour simulation and procedural animation leads to more emphatic and autonomous characters that react differently in each interaction, shifting the task of animating a character to one of defining its behaviour.</p

Choreographic and Somatic Approaches for the Development of Expressive Robotic Systems

As robotic systems are moved out of factory work cells into human-facing environments questions of choreography become central to their design, placement, and application. With a human viewer or counterpart present, a system will automatically be interpreted within context, style of movement, and form factor by human beings as animate elements of their environment. The interpretation by this human counterpart is critical to the success of the system's integration: knobs on the system need to make sense to a human counterpart; an artificial agent should have a way of notifying a human counterpart of a change in system state, possibly through motion profiles; and the motion of a human counterpart may have important contextual clues for task completion. Thus, professional choreographers, dance practitioners, and movement analysts are critical to research in robotics. They have design methods for movement that align with human audience perception, can identify simplified features of movement for human-robot interaction goals, and have detailed knowledge of the capacity of human movement. This article provides approaches employed by one research lab, specific impacts on technical and artistic projects within, and principles that may guide future such work. The background section reports on choreography, somatic perspectives, improvisation, the Laban/Bartenieff Movement System, and robotics. From this context methods including embodied exercises, writing prompts, and community building activities have been developed to facilitate interdisciplinary research. The results of this work is presented as an overview of a smattering of projects in areas like high-level motion planning, software development for rapid prototyping of movement, artistic output, and user studies that help understand how people interpret movement. Finally, guiding principles for other groups to adopt are posited.Comment: Under review at MDPI Arts Special Issue "The Machine as Artist (for the 21st Century)" http://www.mdpi.com/journal/arts/special_issues/Machine_Artis

Designing Video Games and Interactive Applications to Enhance Learning in Children with Autism Spectrum Disorders

Autism Spectrum Disorders (ASD) are a group of developmental neuropsychiatric disorders that can be highly variable in their intensity and in the types of symptoms displayed among different people. Over the years, various intervention techniques using computer-based or computer-assisted therapy have been explored to help individuals with autism in their everyday lives. This paper proposes a set of special guidelines for developing computer-based interactive applications and games to assist learning in children on the autism spectrum. The guidelines proposed here form a framework of interactive and adaptive techniques to be employed in designing computer games and applications that can be used to enhance various aspects of learning and development in children on the autism spectrum. These guidelines are based on the learning activities and other peer-to-peer interactions employed by teachers in inclusive classrooms which help optimize learning in a classroom environment. Other sources of game design considerations include prior research on the limitations encountered by children with ASD in motion, sensory perception, communication and cognition. Prior and ongoing research relating to their abilities in these particular areas are also utilized in this study as important factors in designing the interactive applications and games. Lastly, studies regarding the use of technologies and augmented communication devices are used to help outline the necessary mediums of delivery for the games and applications. The guidelines created in this study are introduced to parents and researchers of children on the autism spectrum through a survey in which these participants are asked to evaluate the techniques and technologies presented in this paper. This research delves into one of the new areas of exploration that have a huge potential in intervention techniques for children with ASD. It is expected that the outlines developed here will offer helpful insight into design and development for future efforts and advancements in gaming technologies for children with ASD

Dynamic behavior-based control and world-embedded knowledge for interactive artificial intelligence

Video game designers depend on artificial intelligence to drive player experience in modern games. Therefore it is critical that AI not only be fast and computation- ally inexpensive, but also easy to incorporate with the design process. We address the problem of building computationally inexpensive AI that eases the game de- sign process and provides strategic and tactical behavior comparable with current industry-standard techniques. Our central hypothesis is that behavior-based characters in games can exhibit effec- tive strategy and coordinate in teams through the use of knowledge embedded in the world and a new dynamic approach to behavior-based control that enables charac- ters to transfer behavioral knowledge. We use dynamic extensions for behavior-based subsumption and world-embedded knowledge to simplify and enhance game character intelligence. We find that the use of extended affordances to embed knowledge in the world can greatly reduce the effort required to build characters and AI engines while increasing the effectiveness of the behavior controllers. In addition, we find that the technique of multi-character affordances can provide a simple mechanism for enabling team coordination. We also show that reactive teaming, enabled by dynamic extensions to the subsumption architecture, is effective in creating large adaptable teams of characters. Finally, we show that the command policy for reactive teaming can be used to improve performance of reactive teams for tactical situations