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MAK Legion — The Scalability Framework for STE

One significant accomplishment stemming from MAK's US Army STE CSE OTA efforts is the MAK Legion Scalability and Interoperability Framework, which was selected to enable scaling to millions of entities in a distributed simulation. (STE CSE OTA stands for Synthetic Training Environment, Common Synthetic Environment, Other Transactional Authority.) The CSE Integrated Product Team (IPT), consisting of multiple government agencies, contractors, and other COTS tool vendors, evaluated several scalability and communication frameworks. In July 2020, MAK Legion was selected considering capability, performance, price, and data rights.

What is MAK Legion?
MAK has implemented Legion, which is a scalability and interoperability communications framework that uses a Data Oriented Design for exchanging entity state and events between simulation applications — virtual simulators, constructive simulations, game engines, and other tools that go into a simulation system. Legion is designed for both cloud and local deployment on multiple platforms.

Legion consists of:
  • Legion Data Store Library – enables optimized multi-threaded simulation applications.
  • Legion Network Library – efficiently passes updates and events between applications.
  • Legion Entity Server – maintains and serves authoritative state based on client interest.

Key accomplishments on MAK Legion from the STE CSE OTA:
  • 3.8 million cloud-hosted entities were initially generated by a "clutter client" and used to demonstrate Legion's data storage and networking prototype to the integrated STE team.
  • Legion was increasingly tested using VR-Forces to generate 2 million pattern-of-life entities.
  • Integrations were made to share entities and interactions with VR-Forces, VR-Vantage, BISim's VBS4, 4C's Exonaut, and the US Army's OneSAF.
  • Engagements were demonstrated between VBS4 and VR-Forces (e.g. VR-Forces dropping a bomb on terrain, causing damage to trees and entities, as well as craters in the terrain skin in both VR-Forces and VBS4).
  • Ownership transfer was demonstrated between VBS4 and VR-Forces: VBS4 Player took ownership of an entity that was previously VR-Forces controlled and vice versa.
  • 4C integrated Exonaut with Legion so that entities published by VR-Forces or other simulations were available in the Training Management Tool (TMT).
  • Hundreds of instances of VR-Forces were deployed to the cloud (AWS) along with the Legion Server, to support scenarios with millions of entities.
  • A simple web interface was built to start and stop virtual machines on demand, and to launch and configure Sim Engines.
  • A Legion monitor was developed that connects to the cloud-based Legion Server and provides diagnostic information, performance stats, and simple visual monitors of all entities.

How Legion has impacted the MAK ONE products
Continuing well beyond the prototype successfully developed under the STE CSE OTA, MAK has productized Legion and begun integrating it into the MAK ONE suite of modular simulation and interoperability products.

  • Consistent with MAK's 30-year history of openness, MAK continues to prove interoperability by integrating with the Unreal and Unity game engines.
  • The MAK Data Logger is being extended to record and playback Legion exercises.
  • A Legion broker is being developed to support interoperability between Legion, DIS, HLA, and other simulation protocols with VR-Exchange brokers.

Computer Generated Forces (CGF)
  • Achieving simulations in the millions requires more than a data storage and network communication mechanism. CGF applications must simulate millions of entities.
  • VR-Forces 5.0 simulation engine is a multi-threaded, scalable version of VR-Forces capable of simulating millions of entities.
  • This high-performance version of VR-Forces takes advantage of multi-core computing architectures to simulate ten thousand entities on a standard gaming PC. This version scales-up nicely by adding more core processors to individual machines. It scales-out by deploying multiple instances on local machines or a cloud platform.
  • Interest management and multithreaded updates take advantage of the Legion Scalability Framework.
  • Capabilities that benefit users regardless of networking protocol used — Legion, DIS, or HLA.

First Person Simulators
  • Applications that simulate a single entity must be tailored to thrive in simulations with millions of entities.
  • VR-Vantage and VR-Engage were extended to use Legion's interest management to specify which of the millions of entities are relevant to visualize and interact with.
  • The performance of the VR-Vantage render engine was increased to render 2-3K or more entities in the field-of-view at 60Hz.

Why MAK?
MAK has a 30-year history of developing simulation interoperability standards with proven longevity. We do things that are revolutionary in an evolutionary way making things as compatible as possible. This Legion effort stands on, and leverages, all the good work that's been done over the past 25 years on DIS, HLA, RPR FOM, and some other elements worked on by SISO and other organizations. We're reusing many of the same enumerations, data types, coordinate systems, and concepts like dead reckoning, but exchanging that data in a more efficient, scalable, and cloud-friendly way. 

Looking forward...
MAK is beginning the SISO standardization process by forming a Study Group at the Spring 2021 Simulation Interoperability Workshop. We are continuing to support integrations of Legion with game engines, simulators, and simulation systems around the world. With Legion and MAK's modular approach to interoperability, we expect Legion to open the door to massive simulations capable of simulating all the military assets in a world populated with millions of civilian patterns-of-life entities. 

MAK Legion is Made in America by our software development team in Cambridge, Massachusetts and Orlando, Florida. Contact us at This email address is being protected from spambots. You need JavaScript enabled to view it..

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