Path Finding and Collision Avoidance in Crowd Simulation

Motion planning for multiple entities or a crowd is a challenging problem in today’s virtual environments. We describe in this paper a system designed to simulate pedestrian behaviour in crowds in real time, concentrating particularity on collision avoidance. On-line planning is also referred as the navigation problem. Additional difficulties in approaching navigation problem are that some environments are dynamic. In our model we adopted a popular methodology in computer games, namely A* algorithm. The idea behind A* is to look for the shortest possible routes to the destination not through exploring exhaustively all the possible combination but utilizing all the possible directions at any given point. The environment is formed in regions and the algorithm is used to find a path only in visual region. In order to deal with collision avoidance, priority rules are given to some entities as well as some social behaviour

Towards an engineering approach for advanced interaction techniques in 3D environments

National audienceIn recent years, Virtual Environments have appeared in new areas such as mass-market, web or mobile situations. In parallel, advanced forms ofinteractions are emerging such as tactile, mixed, tangible or spatial user interfaces, promoting ease of learning and use. To contribute to the democratization of 3D Virtual Environments(3DVE) and their use by persons who are not experts in 3D and occasional users, simultaneously considering Computer Graphics and Human Computer Interaction design considerations is required. In this position paper, we first provide an overview of a new analytical framework for the design of advanced interaction techniques for 3D Virtual Environment. It consists in identifying links that support the interaction and connect user’s tasks to be performed in a 3DVE with the targeted scene graph. We relate our work to existing modeling approaches and discuss about our expectations with regards to the engineering of advanced interaction techniqu

Smartphone Based 3D Navigation Techniques in an Astronomical Observatory Context: Implementation and Evaluation in a Software Platform

International audience3D Virtual Environments (3DVE) come up as a good solution to transmit knowledge in a museum exhibit. In such contexts, providing easy to learn and to use interaction techniques which facilitate the handling inside a 3DVE is crucial to maximize the knowledge transfer. We took the opportunity to design and implement a software platform for explaining the behavior of the Telescope Bernard-Lyot to museum visitors on top of the Pic du Midi. Beyond the popularization of a complex scientific equipment, this platform constitutes an open software environment to easily plug different 3D interaction techniques. Recently, popular use of a smartphones as personal handled computer lets us envision the use of a mobile device as an interaction support with these 3DVE. Accordingly, we design and propose how to use the smartphone as a tangible object to navigate inside a 3DVE. In order to prove the interest in the use of smartphones, we compare our solution with available solutions: keyboard-mouse and 3D mouse. User experiments confirmed our hypothesis and particularly emphasizes that visitors find our solution more attractive and stimulating. Finally, we illustrate the benefits of our software framework by plugging alternative interaction techniques for supporting selection and manipulation task in 3D

Intelligent autonomous agents in HLA virtual environments

Many simulations of virtual environments involve realistically behaving autonomous agents to give users as much interaction capabilities as possible. In this kind of simulations, interoperable architectures such as the High Level Architecture enable us to create complex and lively environments from simple simulations of different kinds of entities. However, making simulations collaborate requires to give existing agents the ability to interact with the newly integrated ones. Such a task generally consists in redefining existing behaviours completely. Hence, making several even interoperable simulations collaborate, implies long and demanding developments while interoperability tries to prevent them. Such drawbacks are mainly due to the fact that most behavioural models are based on nite state machines and expert systems for which designers have to describe exhaustively all agents'behaviour. Classifier systems enable designers to describe agents' behaviours through goals ("what to do") instead of transitions or set of rules ("how to do it"). Then, agents learn how to reach those objectives using evolutionary learning algorithms. Such a modeling is more suited for the development of interoperable simulations. Indeed, adding new simulated agents only requires to add new goals to the existing ones. This paper presents the distributed driving simulation we built using interoperable subsimulations. At first, it presents how classier systems make agents' behaviour easily evolutional in the context of interoperable simulations. Then, it shows how interoperability enables us to share the management of autonomous entities between several computers in a distributed way

Evolution d'entités virtuelles coopératives par système de classifieurs

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