The development of realistic computer-generated synthetic environments, also called distributed virtual environments , relies heavily upon computer-generated actors (CGAs) to provide accurate behaviors at reasonable cost so that the synthetic environments are useful, affordable, complex, and high fidelity. Unfortunately, the pace of synthetic environment development and the level of desired CGA performance continue to rise at a much faster rate than CGA capability improvements. This insatiable demand for realism in CGAs for synthetic environments arises from the growing understanding of the significant role that modeling and simulation can play in a variety of uses. These uses include training, analysis, procurement decisions, mission rehearsal, doctrine development, force-level and task-level training, information assurance, cyberwarfare, force structure analysis, sustainability analysis, life cycle costs analysis, material management, infrastructure analysis, and many other uses. In these and other uses of military synthetic environments, CGAs play a central role because they have the potential to increase the realism of the environment while also reducing the cost of operating the environment. The progress made in addressing the technical challenges that must be overcome to realize effective and realistic CGAs for military simulation environments and the technical areas that should be the focus of future work are the subject of this paper, which surveys the technologies and progress made in the construction and use of CGAs. In this, the third installment in the series of papers discussing CGAs, we conclude our discussion of CGA technologies by concluding the discussion of human behavior modeling for CGAs, and we present some suggested future research directions for CGA technologies.

The development of computer-generated synthetic environments, also called distributed virtual environments (DVEs), relies heavily upon computer-generated actors (CGAs) to provide accurate behaviors at reasonable cost so that the synthetic environments are useful, affordable, complex, and realistic. Unfortunately, the pace of synthetic environment development and the level of desired CGA performance continue to rise at a much faster rate than CGA capability improvements. This insatiable demand for realism in CGAs for synthetic environments arises from the growing understanding of the significant role that modeling and simulation can play in a variety of uses. These uses include training, analysis, procurement decisions, mission rehearsal, doctrine development, force-level and task-level training, information assurance, cyberwarfare, force structure analysis, sustainability analysis, life cycle costs analysis, material management, infrastructure analysis, and many other uses. In these and other uses of military synthetic environments, computergenerated actors play a central role because they have the potential to increase the realism of the environment while also reducing the cost of operating the environment. The progress made in addressing the technical challenges that must be overcome to realize effective and realistic CGAs for military simulation environments and the technical areas that should be the focus of future work are the subject of this series of papers, which surveys the technologies and progress made in the construction and use of CGAs. In this, the second installment of three papers in the series, we present a discussion of CGA software architectures and a discussion of approaches to human behavior modeling.

The development of computer-generated synthetic environments, also called distributed virtual environments , for military simulation relies heavily upon computer-generated actors (CGAs) to provide accurate behaviors at reasonable cost so that the synthetic environments are useful, affordable, complex, and realistic. Unfortunately, the pace of synthetic environment development and the level of desired CGA performance continue to rise at a much faster rate than CGA capability improvements. This insatiable demand for realism in CGAs for synthetic environments arises from the growing understanding of the significant role that modeling and simulation can play in a variety of venues. These uses include training, analysis, procurement decisions, mission rehearsal, doctrine development, force-level and task-level training, information assurance, cyberwarfare, force structure analysis, sustainability analysis, life cycle costs analysis, material management, infrastructure analysis, and many others. In these and other uses of military synthetic environments, computer-generated actors play a central role because they have the potential to increase the realism of the environment while also reducing the cost of operating the environment. The progress made in addressing the technical challenges that must be overcome to realize effective and realistic CGAs for military simulation environments and the technical areas that should be the focus of future work are the subject of this series of papers, which survey the technologies and progress made in the construction and use of CGAs. In this, the first installment in the series of three papers, we introduce the topic of computer-generated actors and issues related to their performance and fidelity and other background information for this research area as related to military simulation. We also discuss CGA reasoning system techniques and architectures.

A variety of challenges exist in the design of systems that can be used to host a wide variety of computer-generated actors (CGAs) that possess believable behaviors. The challenges arise in the areas of system architecture and design, knowledge-base design, decision-making mechanisms, and the distributed virtual environment (DVE) network interface. These challenges are especially significant if the DVE is to be used for training, because accurate training is essential to the ready application of training experience to real-world situations. The project described in this paper was undertaken to improve the quality of threat CGAs in DVEs utilized for aircrew training. In this paper, we describe the system and the reasons for its genesis. We present the system requirements, system architecture, component-wise decomposition of the system design, and structure of the major components of the decision mechanism. We conclude with a summary of our results to date and recommendations for further research.

The Air Force Institute of Technology Virtual Environments, 3-D Medical Imaging, and Computer Graphics Laboratory is investigating the 3-D computer graphics, user-interface design, networking protocol, and software architecture aspects of distributed virtual environments. In this paper we describe the research projects that are underway in the laboratory. These projects include the development of an aircraft simulator for a distributed virtual environment, projects for observing, analyzing, and understanding virtual environments, a space virtual environment, a project that incorporates “live” aircraft range data into a distributed virtual environment, a virtual environment application framework, and a project for use in a hospital emergency department. We also discuss the research equipment infrastructure in the laboratory, recent publications, and the educational services we provide.

The Distributed Simulation Internet (DSI) provides users access to large-scale, complex, active, unpredictable virtual environments. If users are to effectively use these environments, they will require support for understanding and acting in these environments. Support is necessary because humans have a time and space limited span of attention. The Satellite Modeler, Omniview true 3D, and Synthetic BattleBridge projects were undertaken to develop and investigate the interfaces and autonomous agents required to effectively support users of the Distributed Simulation Internet. The Satellite Modeler emulates the near-Earth space environment and portrays models of satellites moving in their correct orbits around the Earth. The motion of the satellites is broadcast to users of the DSI. The Satellite Modeler is intended to function as a training and operational aid for orbital analysts and to help them understand key spatial relationships for satellites in near-Earth orbit. The Omniview project was undertaken to provide interactive control and manipulation of a true 3D image and to thereby assist the user in understanding the activity within the DSI-hosted virtual environment. That project developed an interface that provides the Omniview user with the ease of use that a window, icon, mouse, and pointer GUI interface provides to users of 2D displays. The Synthetic BattleBridge is a system that, like the Omniview, portrays a DSI-hosted virtual environment but does not act in it. The Synthetic BattleBridge is designed to support users in making accurate and timely decisions by providing several different types of cognitive support for understanding and analyzing the activity in a battlespace. In this paper, we briefly describe each project and present some observations and conclusions we have drawn based on our experience with them.

As virtual environments grow in complexity, size, and scope users will be increasingly challenged in assessing the situation in them. This will occur because of the difficulty in determining where to focus attention and in assimilating and assessing the information as it floods in. One technique for providing this type of assistance is to provide the user with a first-person, immersive, synthetic environment observation post, an observatory, that permits unobtrusive observation of the environment without interfering with the activity in the environment. However, for large, complex synthetic environments this type of support is not sufficient because the mere portrayal of raw, unanalyzed data about the objects in the virtual space can overwhelm the user with information. To address this problem, which exists in both real and virtual environments, we are investigating the forms of situation awareness assistance needed by users of large-scale virtual environments and the ways in which a virtual environment can be used to improve situation awareness of real-world environments. A technique that we have developed is to allow a user to place analysis modules throughout the virtual environment. Each module provides summary information concerning the importance of the activity in its portion of the virtual environment to the user. Our prototype system, called the Sentinel, is embedded within a virtual environment observatory and provides situation awareness assistance for users within a large virtual environment.