Computer Graphics and Interaction

Multi-user VR systems are mostly aimed at social interaction, whereas exploitation of shared virtual environments for educational purposes has been largely ignored. We introduce the notion of tutor-based systems and consider the main differences between a tutor-based multi-user system and a social interaction system. In the proposed approach, one of the users is the tutor while the others represent auditors. This paper focuses on possible means for expressing a tutor's role including special auditor's operating modes supported by the mechanism of net-routes. Theoretical considerations have been tested on the DILEWA experimental system

Recently, two algorithms improving the real-time simulation of ar- ticulated models in virtual environments have been published: 1) fast collision detection for linear blend skinning and 2) spherical blend skinning. Both linear and spherical blending solve the skin- ning problem of a skeletally controlled 3D model (e.g., an avatar), but only spherical blending avoids artifacts such as the candy- wrapper.

Not all participants in a collaborative virtual environment (CVE) need to be informed of every other participant's activities. The technique used for filtering irrelevant messages is known as interest management, which has to minimize network traffic and to reduce the burden of clients. However, considering the CVE shared state maintenance, interest management is nothing else than a disruption of the

While the textual chat is a highly popular tool for various kinds of social interactions, its extension to the visual three-dimensional domain remains almost untouched and without practical utilization yet. This paper discusses advantages and disadvantages of spatial virtual environment when used as a platform for connecting people and serving for social and cultural interaction. The differences between textual chat

The paper presents various issues dealing with presentation of cultural heritage objects in a virtual space. While the reconstruction techniques are mentioned just briefly, the attention is paid to the visualization approaches for wide audience, ie techniques targeted ...

The paper analyses requirements on virtual urban scenes presented on the web. Basic principles and methods for data preparation and processing are introduced. Several useful and practical approaches are shown on examples taken from one real implementation of a virtual city - the Virtual Old Prague project. The paper explains why complex virtual cities are still missing on the web and shows ways how to extend already existing web sites by three-dimensional urban objects.