This project was designed to look at how large detailed simulations conducted to support federal policy and preparedness could be better communicated and quality checked through the use of Virtual Reality. The goal was to take the underlying population data which is synthesized from myriad datasets and the results of our simulations and create a compelling visualization that allows the dynamics of the simulation to be appreciated in both its detail and scale, while allowing the user to validate the verify the behavior of the simulation embedded in this data. The test case was originally intended to be infectious disease, however, we pivoted to a catastrophic disaster due to a pressing need for the quality assurance part of the project for a follow-on study. Specifically, this disaster was an improvised nuclear attack in downtown Washington DC. More details of this study are reported in the literature (1,2) , in brief we model the behavior of over 700K individual agents in the affected area. They are imbued with full agency, choosing where to go, what to do, and when to do it, based on local information about their health, family status, and others around them. They communicate and move around the DC area while being impacted the condition of their surroundings and are exposed to radioactive fallout. The resulting interface allows the user to see the health state and movement patterns of the individuals and provide a very useful means to verify and appreciate the complexity of this simulation.

3D Visualization and Simulation of Infectious Disease Spread
In the image above, we see the general tools in the foreground for manipulating the timestep of the simulation. The yellow glow on the horizon is ground zero. We also see the map on the floor “darkened” representing that this during non-daylight hours in the simulation, which is one of the cues that can change the agent’s behaviors.
3D Visualization and Simulation of Infectious Disease Spread
In this screen shot, we see many red X’s, representing agents who are deceased, in the vicinity of ground zero. The green triangles represent agents that are on the move, and the hexagons represent agents that are momentarily paused for several timesteps. This glyphs are sized based on the number of agents it represents (captures the scale while not having 300 glyphs all right on top of each other). Additionally, one can note that some of these glyphs are green (full health), orange (injury or degraded health), or red (deceased). Capturing this level of information density while maintaining a “larger” overview was a primary design goal.
3D Visualization and Simulation of Infectious Disease Spread
This screenshot shows the legend which is anchored just north of where all the agents are in Washington DC and thus is accessible to the user at any given time to aid in interpreting what they are viewing. Additionally, the time step, time of day, and time since detonation are also displayed which (with the aid of the time of day lighting) allows the user to stay oriented along the timescale.
3D Visualization and Simulation of Infectious Disease Spread
This screenshot proves a good perspective on the from ground zero to the evacuation points which are place well outside the population of intense analysis. How, when, and who moves to these evacuation routes is a primary outcome of these studies, as we explore what policies and increase survivability and minimize the total time spent in the radioactive disaster zone in the heart of DC.
3D Visualization and Simulation of Infectious Disease Spread
This screenshot shows an initial prototype for a “controller” linked display. The colored lines shows the counts of individuals in the various states of mobility. The yellow corresponds to the temporarily stopped individuals and one can see a large number of them slowly decline over time as more and more people move and evacuate. The blue line are those who are moving, the red are the deceased which grows quickly after the blast and then more gradually in the hours following. The green line are those who are permanently stopped and they gradually decline as many of them are grievously injured and eventually succumb to their injuries and die.Overall, this project was a success and has generated a tool that will be quite useful as we continue to conduct experiments using this simulation platform. The current implementation allows reasonably rapid extraction of the key data from the simulation results and packages it into a format readable by the Unity engine and creates the environment as illustrated above.

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