A Large Scale Distributed Virtual Environment Architecture

Abstract

Virtual Environment (VE) is a simulation application that is widely used for the development of computer generated synthetic environments. A Distributed VE (DVE) allows many users to access a VE concurrently from different locations. Most current DVEs are still using simulator-centric architecture that views VE operations as a set of homogenous simulators, each aggregating data structure and all the actors operating on the data structure. This architecture limits the number of users involved in the DVE. It reduces users' experiences because the area of VE is restricted. Also, when the number of objects increases, the VE runs more slowly. Although other architectures such as Distributed Scene Graph and Sirikata, have become available, the simulator still manages many objects in the simulation. It also restricts the number of objects and users involved in the VE. This paper proposes a new architecture to enable large scale distributed virtual environment. A simulator separation method is developed based on objects consisting of one process for one object (1P1O). The 1P1O architecture has a core component that comprises several simulators. In order to maintain the object, each simulator has two engines: physics engine and scripts engine. To maintain the consistency of the simulation, we introduce Universe that stores all objects state generated by simulators. Universe is responsible to store the state updates and disseminate them to interested simulators. There are two aspects used to evaluate the scalability of the 1P1O model, i.e. the number of objects and the number of concurrent users involved. Parameters such as CPU usages and memory allocation are used to analyze and evaluate the performance of the model. Experiments are conducted with varying number of objects and users. Compared with current architecture, the 1P1O model scalability and performance are better than current existing models in P2P network. The experiment results also comply with the mathematical model of the simulator and universe.