Occlusion Based Message Dissemination Method in Networked Virtual Environments

Virtual spaces that host hundreds or even thousands of users create enormous amounts of traffic, which usually is broadcasted to the entire environment and congests the network medium very quickly. In this paper, a novel interest management (IM) algorithm called EA
³
is presented and evaluated. EA
³
is based on an existing IM algorithm, called A
³
which uses euclidean distance to discover entities of interest. A
³
was improved by utilizing a ray visibility algorithm, which helps to filter out traffic originating from entities behind obstacles. The evaluation of EA
³
and A
³
was conducted using an extensible networked virtual environment called real tend. The results show that, when either EA
³
or A
³
is used, the overall network throughput can be lowered significantly. In a city-like test scene, the drop was approximately 50 per cent with A
³
and 62 per cent with EA
³
compared to the situation when no IM algorithm was used. In terms of CPU load EA
³
is slightly heavier to use when there is a lot of open space inside the virtual environment.