Automatic Generation of Animated Population
in Virtual Environments

Keywords

population, crowd simulation, informed virtual environments, autonomous agents.

Overview

The necessity to model virtual population appears in many applications of computer animation and simulation. Such applications encompass several different domains - representative or autonomous agents in virtual environments, human factors analysis, training, education,simulation-based design, and entertainment. Reproduce in simulation the dynamic life of virtual environments in realtime is also a great challenge.

Simulating virtual environments populated with virtual but realistic crowds requires dozens of different face and body geometries. In this course, we will present methods that allow automatic generation of desired population models. In particular, we will explain a method which generates any population group that is statistically calculated to satisfy given properties. We divide the population generation module into the face part and the body part. Each of them is based on a database, which is an organization of information collected and processed from the real population dataset. We will also explain how to automatically modifying an existing model by controlling the parameters provided. On any synthesized model, the underlying bone and skin structure is properly adjusted, so that the model remains completely animatable using the underlying skeleton.

It requires at most to enable several hundreds of virtual humans to navigate inside the mockup. Navigating is for a real human one of the most basic behaviour but for behavioural animation it requires to integrate different technologies. First to allow people to navigate, they should be able to perceive their environment but not only in a geometric way. Studies in psychology and urbanism has shown that visibility and topology are also important in the navigation task. We will show how to build automatically a hierarchical topologic map of the environment (indoor and outdoor) from a 3D database. This structured environment can then be used for path planning and reactive navigation of several hundreds of virtual humans in real time. Another aspect in the navigation process concerns the mental representation of the environment to introduce differences in behaviour between people who use to navigate in a specific area and others who discover it. We will present a spatial memory model for pedestrian navigation inside virtual cities.

The course will also explore essential aspects to the generation of virtual crowds. In particular, it will present the aspects concerning information (intentions, status and knowledge), behavior (innate, group, complex and guided) and control (programmed, autonomous and guided). It will emphasize essential concepts like sensory input (vision, audition, tactile), versatile motion control, artificial intelligence level, and rendering techniques. The course will also presents the new challenge in the production of realtime crowds for games, VR systems for training and simulation. Techniques for rendering a very large number of Virtual Humans will be emphasized. The course will be illustrated with a lot of examples from recent movies and real-time applications in Emergency situations and Cultural Heritage (like adding virtual audience in Roma or Greek theaters).

Agenda

Introduction (Daniel Thalmann, 10 minutes)

• Objectives, Applications, State-of-the-Art

Creation of population (Nadia Magnenat-Thalmann, 40 minutes)

• Automatic construction of population models
• Animation ready and textured models
• Anthropometric modeling
• Individual deformation operators

Informed Virtual Environments (Stephane Donikian, 45 minutes)

• State of the art
• Path planning and reactive navigation
• Individual and collective pedestrian behaviours
• Animation chain for indoor and outdoor virtual environments

Virtual Humans models for crowds (30 minutes)

• Facial animation and motion capture (Nadia Magnenat-Thalmann)
• Motion models (Daniel Thalmann)

Crowd simulation (Daniel Thalmann, 30 minutes)

• Crowd models
• Artificial life techniques
• Impostor Rendering and Texture Generation
• The paintbrush approach

Case studies (all speakers, 15 minutes)

Conclusions (all speakers, 15 minutes)

Presenters

Daniel Thalmann is Professor and Director of The Virtual Reality Lab (VRlab) at EPFL, Switzerland. He is a pioneer in research on Virtual Humans. His current research interests include Real-time Virtual Humans in Virtual Reality, Networked Virtual Environments, Artificial Life, and Multimedia. Daniel Thalmann has been Professor at The University of Montreal. He is coeditor-in-chief of the Journal of Visualization and Computer Animation, and member of the editorial board of the Visual Computer and 3 other journals. Daniel Thalmann was Program Chair of several conferences including IEEE VR 2000. He has also organized 4 courses at SIGGRAPH on human animation. Daniel Thalmann was the initiator of the Eurographics working group on Animation and Simulation which he cochaired during more than 10 years. Daniel Thalmann has published more than 250 papers in Graphics, Animation, and Virtual Reality. He is coeditor of 30 books, and coauthor of several books including the recent book on "Avatars in Networked Virtual Environments", published by John Wiley and Sons. He received his PhD in Computer Science in 1977 from the University of Geneva and an Honorary Doctorate (Honoris Causa) from University Paul Sabatier in Toulouse, France, in 2003.

Nadia Magnenat-Thalmann has pioneered research into virtual humans over the last 20 years. She obtained several Bachelor’s and Master’s degrees in various disciplines and a PhD in Quantum Physics from the University of Geneva. From 1977 to 1989, she was a Professor at the University of Montreal in Canada. She moved to the University of Geneva in 1989, where she founded MIRALab. She has received several scientific and artistic awards for her work in Canada and in Europe. In l997, she has been elected to the Swiss Academy of Technical Sciences, and more recently, she was nominated as a Swiss personality who has contributed to the advance of science in the 150 years history CD-ROM produced by the Swiss Confederation Parliament, 1998, Bern, Switzerland. She has been invited to give hundreds of lectures on various topics, all related to virtual humans. Author and coauthor of a very high number of research papers and books, she has directed and produced several films and real-time mixed reality shows, among the latest are CYBERDANCE (l998), FASHION DREAMS (1999) and the UTOPIANS (2001). She is editor-in-chief of the Visual Computer Journal published by Springer Verlag and editor of several other research journals.

Stephane Donikian got a Graduate Degree in Computer Science in 1989 and a PhD in Computer Science in 1992. He is currently Research Scientist for CNRS (French National Center for Scientific Research) and member of the Computer Graphics Research Team at IRISA in Rennes, France. His research interests include Reactive and Cognitive Behavioural Animation, Informed Virtual Environments, Scenario Authoring, Interactive Fiction, Animation and Simulation Platform. Stephane Donikian is co-animator with Jean-Pierre Jessel (IRIT) and Catherine Pelachaud (Paris 8) of the French national research action on virtual humans and is also co-animator of the french working group in animation and simulation. He is author of several papers in journal and conference in the fields of computer graphics and autonomous agents. He is this year member of the program committee of EG'04, AAMAS'04, TIDSE'04, CAVW'04, and AFRIGRAPH'04.