Effective remote modeling in large-scale distributed simulation and visualization environments

Abstract

A Distributed Interactive Simulation provides the illusion of a single, coherent virtual world to a group of users located at different machines connected by a network. Users expect to see a consistent world view, to interact closely with one another and with other simulation entities in the virtual world, and to be shielded from the application's distributed nature. Networked virtual environments are used for multiplayer video games, military and industrial training, and collaborative engineering. Network bandwidth, network latency, and host processing power limit the achievable size and detail of future simulations. This thesis describes network protocols and algorithms to support remote modeling, allowing a host to model and render remote entities in large-scale distributed simulations. These techniques require fewer network resources and support more entity types than previous approaches. The Position History-Based Dead Reckoning (PHBDR) protocol provides accurate remote position modeling and minimizes dependencies on network performance and entity representation. PHBDR is a foundation for three protocols: (1) Axis Point Protocol: Models entity orientation by tracking the position of points in the entity's local coordinate system. (2) Multiple-Detail Channels: Protocol architecture for modeling entity structural change at different levels of detail depending on locally available computational and network resources. (3) Projection Aggregation Entities: Protocol for bundling information from entities dynamically grouped by their type and location. This thesis shows that a simple, efficient protocol can provide smooth, accurate remote position modeling and that it can be applied recursively to support entity orientation, structure, and aggregation at multiple levels of detail; these protocols offer performance and costs that are competitive with more complex and application-specific approaches, while providing simpler analyses of behavior by exploiting this recursive structure. In support of this claim, this thesis shows that: (1) PHBDR is a simple, efficient protocol that provides smooth and accurate remote modeling for a broad range of entities and explicitly recognizes network latency. (2) PHBDR is still smooth and accurate when used to model entity orientation, entity structure at multiple levels of detail, and entity aggregations. (3) The recursive protocol structuring provides better network performance and reduced software complexity when compared with the application-specific approaches deployed in previous systems.