In the Walkthru-CFAST Project we are attempting to realize some of these advantages for the benefit of fire safety in architectural environments. This work is based on a project to integrate the National Institute of Standards and Technology's (NIST) Consolidated Model of Fire and Smoke Transport (CFAST) [1] into the Berkeley Architectural Walkthrough (Walkthru) [2] system. CFAST currently provides the world's most accurate simulation of the impact of fire and its byproducts on a building environment. Integrated into the Walkthru, it provides real-time, intuitive, realistic and scientific visualization of building conditions in a fire hazard situation from the perspective of a person walking through a burning building. The viewer can observe the natural visual effects of flame and smoke in fire hazard conditions; alternatively, scientific visualization techniques allow the user to ``observe'' the concentrations of toxic compounds such as carbon monoxide and hydrogen cyanide in the air, as well as the temperatures of the atmosphere, walls, and floor. Warning and suppression systems such as smoke detectors and sprinkler heads can be observed in action to help determine the effectiveness of those systems. This technology will be used to improve fire safety by helping engineers and architects evaluate a building's potential safety and survivability through performance-based standards (i.e. how well the building protects its occupants from the fire). With more development, it could also be used to help train personnel in firefighting techniques and rescue operations by presenting them with practice situations that are too risky to be simulated in the real world.
While the combination of virtual reality and environmental simulation constitutes a framework for very powerful tools, it also raises many implementation challenges. Among these challenges are interaction with the virtual world, setting up and dynamically changing simulation conditions from within the virtual world to a simulator, designing ``visualization-oriented'' simulators, transporting simulation results to the visualizer, integrating the simulator's results with the virtual environment, and visualizing those results in a way that is useful to the user; either descriptively, in the case of scientific visualization applications, or realistically, in the case of training or entertainment applications. These problems are compounded by an additional desire to distribute both the virtual environment and the simulation over multiple computers -- potentially connected by high-latency, low-bandwidth networks such as the Internet -- when attempting to simulate and visualize large buildings with hundreds of rooms.
In a paper accepted to SIGGRAPH'97 [3], we present an approach to the problem of distributed simulation-visualization data management that is optimized for densely occluded polyhedral environments (i.e. buildings) based on the Walkthru and CFAST programs. Walkthru has already addressed some of the problems of distributed visualization and of the interaction between the user and the virtual world [4]. We show that the basic virtual environment structure used in the Walkthru, a spatial subdivision of the world into densely occluded cells with connecting portals, can be put to good use for simulation data management. In addition to optimizing the visualization task, it is also useful for optimizing bandwidth requirements between a visualizer and simulator, both for the purpose of communicating scenario information to the simulator and communicating simulated states back to the visualizer. Using this structure, we can optimize bandwidth requirements for arbitrarily large visualizations and simulations, and relieve the visualization and simulation designers of the complexity of the data management problem. The solution is easily extensible to multiple distributed visualizers and simulators operating on one virtual world. It also suggests an important attribute of future simulation design for simulation developers who wish to make ``virtual reality-oriented'' real-time simulators: the ability to ``concentrate'' simulation efforts on areas of the environment of immediate interest to the observer, denoted by those areas which are currently being observed in real-time.
[1] R. Peacock et al. "CFAST, the Consolidated Model of Fire Growth and Smoke Transport," NIST Technical Note 1299, U.S. Dept. of Commerce, Feb. 1993.
[2] T. Funkhouser, C. Sequin, and S.Teller, "Management of Large Amounts of Data on Interactive Building Walkthroughs," Proc. Symp. on Interactive 3D Graphics, Boston, Mar.. 1992.
[3] R. Bukowski and C. Sequin, "Interactive Simulation of Fire in Virtual Building Environments," to appear in Proc. of SIGGRAPH'97, Los Angeles, Aug. 1997.
[4] R. Bukowski and C. Sequin, "Object Associations: A Simple and Practical Approach to Virtual 3D Manipulation," Proc. Symp. on Interactive 3D Graphics, Monterey, Apr. 1995.
<-- Back to Soda Hall Home Page
<-- Back to GRAPHICS Projects Page