UTSAF: A Simulation Bridge between OneSAF and the Unreal Game Engine

1. UTSAF: A Simulation Bridge between OneSAF and the Unreal Game Engine* J. Manojlovich, P. Prasithsangaree, J. Chen, and M. Lewis

2. Agenda Introduction and Motivation Some Background Challenges in Bridging Distributed Simulation Our Proposed UTSAF Architecture Snapshots from our testbed Conclusions

3. Background Modular Semi-Automated Force (ModSAF) and OneSAF SIMNET, DIS and PDU Unreal Tournament (UT) Game Engine RETSINA

4. ModSAF Military simulation environment Provide a platform within which all services (Army, Air Force, Navy, etc.) could expand the synthetic battle space Provide an architecture to support a community of SAF developers who would expand the battle space through the integration of individual code modules

6. ModSAF Communication IP multicast ModSAF uses the Distributed Interactive Simulation protocol (DIS, IEEE1278 1993). Protocol Data Unit is basic packet of information There are roughly 100 different classes of PDU, but generally only the Entity State PDU is interesting for simulation purposes

7. Distributed Interactive Simulation The purpose of DIS is to create and maintain an interactive virtual environment for the following purposes: Training Replace and supplement field training Testing Planning Standard for communicating a �ground truth� database among hosts

8. Distributed Interactive Simulation (cont.) Basic unit of DIS is the �entity� These are typically vehicles in the simulation, such as tanks, trucks, aircraft, or missiles DIS also specifies how to transmit terrain information, and electromagnetic emissions like radio and radar

9. What is Unreal Tournament? UT is a multiplayer video game Produced by Epic games (http://www.epicgames.com) Runs on Windows, Linux, Macintosh, PlayStation, and Xbox http://www.unrealtournament2003.com

11. Why Use UT? By using UT as a base, we can avoid needless reinventing while benefiting from a proven development platform UT is designed for programming, and many tools and resources are available to assist outside developers UT runs well on commodity hardware and software, such as Windows and Linux

12. Why Use UT? (cont.) UT has numerous user interface enhancements over ModSAF Three dimensional, instead of two Ability to attach view to entity Much easier to dynamically change the field of view in UT Can use other projects that are built on UT

13. Problems When the virtual simulators are not exactly the same, it gets harder to pass entity information between these simulators UT was not designed for full external control, so the built-in functionality must be overridden many times

14. Attribute Transfer Between Virtual Domains What is absolutely necessary? Entity identification Position in virtual world Coordinate systems What else is useful? Entity velocity, appearance, orientation

15. Entity Conversion Naturally one would like to know what each object looks like in the original virtual environment, so that the corresponding objects in the other environment resemble them Appearance includes such things like color and texture

16. Entity Conversion (cont.) ModSAF does not have 3D models for the entities in the simulations For UTSAF, we had to both acquire from public sources, and create from scratch, our 3D models 3D Studio Max Milkshape3D

17. Terrain Conversion Once you have the entities moved into the other simulator, you naturally want the static portions of the simulation as well Walls, floors, ground, sky� Two approaches Convert what's in the original simulation Create new terrains from scratch, hand tune to look like original simulation

18. Terrain Conversion (cont.) We chose to convert the ModSAF terrains directly to the Unreal format Multi-step conversion pipeline ModSAF ? OpenFlight ? 3D Studio ? Unreal TerraVista DART NuGraf 3ds2unr Unreal levels are restricted in size, so ModSAF terrains are converted piecemeal

19. UTSAF Testbed Roughly tell what are in our testbed environments. I�m not sure that we should put the CAVE theater, but I think it makes the slide look cool!Roughly tell what are in our testbed environments. I�m not sure that we should put the CAVE theater, but I think it makes the slide look cool!

20. RETSINA Agent Architecture Reusable Environment for Task-Structured Intelligent Networked Agents http://www.cs.cmu.edu/~softagents Multi-agent system (MAS) that supports communities of heterogeneous agents Implements distributed infrastructural services that facilitate the interactions between agents, as opposed to managing them

21. RETSINA in Multi-Agent Environments Roughly explain the Multi-agent architecture Roughly explain the Multi-agent architecture

22. Why use Agents? We�ve found agents to be effective �glue� for tying together disparate proprietary software that cannot be linked by conventional means Allows for loose coupling of different pieces of software, and sharing of information among software that normally cannot do so

23. Problems with Agents Communication lag Network lag Operating system latency Architecture complexity The more components in a system the more susceptible it is to failure Agent programming being more loosely coupled than other types, is more immune to this type of failure however

24. Unreal Tournament Agents The most important of the remaining agents are the ones that talk to UT Since this currently is a one way street, these are not referred to as brokers, but they will eventually become them These agents listen for the DIS information from the broker, and pass the updated entity information to UT

25. Gamebots Network Extension

26. Gamebots Shot

27. UTSAF Architecture - Explain each component in detail. - Also state that which component is doing the jobs of bridging as explained in previous slides.- Explain each component in detail. - Also state that which component is doing the jobs of bridging as explained in previous slides.

28. SAF Broker Agent

29. Gamebots Agent

30. A BioChem Depot in ModSAF

31. A BioChem Depot in UTSAF

32. A Typical UTSAF Screenshot

33. Communication Lag There is a tremendous amount of packets that come out of ModSAF If the broker cannot keep up with the traffic, a gap in communication will develop between what ModSAF is sending, and what the broker is telling the UT agents

34. User Disorientation When ModSAF environments are large, people can easily get lost and disoriented Common problem: Where is north? There is a need for a world-centered frame of reference of the entire virtual environment An overall map, for example

35. Future Work We are currently investigating the effects of network packet filtering Preliminary results suggest that filtering out even 80% of incoming packets has little noticeable effect on the simulation We are working to expand the size of ModSAF terrain represented Our major focus for UTSAF currently is to represent uninhabited aerial vehicles (UAVs) in realistic 3D