A Toolkit for Developing Multi-User, Distributed Virtual Environments

Abstract

This paper reviews the design and operation of the VR Toolkit developed at IBM Research. Ease of use was emphasized both for the application builder and the toolkit extender. The system supports distributed processing, the building of multi-user shared environments, as well as a variety of specialized I/O devices such as gloves, 3-D position sensors, sound generation, speech recognition, and 3-D graphics displays, under an open and extensible architecture. Virtual world environments are created using a mixed object-oriented and event based paradigm for defining system behavior. Basic units, called modules, represent entities in the world such as objects, operations, functions or users. Modules communicate with each other by producing and consuming events, and are defined at a high-level using rules written in C++ that determine how events are handled. The VR Toolkit, designed to be run on one or more workstations, includes a development environment consisting of C++ class libraries for module construction, interprocess communication, device support, and hierarchical object-oriented graphics. The run-time environment includes an X Window System based control panel for dynamically constructing worlds from a collection of modules, allocating processes among hosts, editing modules, and monitoring operation, and a library of ready to use modules for various devices and common operations