Distributed Virtual Walkthrough

In a distributed walkthrough system, a geometry database server maintains a huge collection of virtual objects and their positions in the virtual environment. Human viewers utilizing database clients connected to the server through networks may view the objects by walking through the virtual environment. To model a large and complex environment, the database is often very large.

Several approaches have been proposed to distribute objects from the server to the clients in distributed virtual reality applications. Most existing systems, such as DIVE, SIMNET, and VLNET, transmit the whole geometry database to the clients before the walkthrough starts. To use the systems in an Internet environment, either the size of the geometry database needs to be small or the viewer has to wait for a long pre-loading time before starting the walkthrough. Another approach to distribute the objects in the geometry database is to send them on demand to the clients during the walkthrough. This approach employs a standard client-server architecture, in which a central server maintains the geometry database of the virtual environment and distributes data to clients when requested. Both approaches, however, require the models of the visible objects to be completely transmitted before the corresponding images can be rendered. This might result in uneven frame rates in a congested network such as the Internet and will cause a jittered walkthrough. It also limits the scene complexity that the system can handle.

In this project, we are developing a distributed walkthrough system for use in an internet environment. This system has two major features:

We have just completed the implementation of the prototype system. However, there are still a lot of fine tuning needed in order to get the best performance.


Last updated on 9th October, 2004.