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 EA³ is presented and evaluated. EA³ is based on an existing IM algorithm, called A³ which uses euclidean distance to discover entities of interest. A³ was improved by utilizing a ray visibility algorithm, which helps to filter out traffic originating from entities behind obstacles. The evaluation of EA³ and A³ was conducted using an extensible networked virtual environment called real tend. The results show that, when either EA³ or A³ is used, the overall network throughput can be lowered significantly. In a city-like test scene, the drop was approximately 50 per cent with A³ and 62 per cent with EA³ compared to the situation when no IM algorithm was used. In terms of CPU load EA³ is slightly heavier to use when there is a lot of open space inside the virtual environment.