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Introduction & Concepts

This chapter introduces SimGe and the core ideas you need before building object models and federations. If you would rather dive in, jump to the Quick Start.

What is SimGe?

SimGe (Simulation Generator) is a Windows desktop application for designing High Level Architecture (HLA) distributed simulations and generating their code. With SimGe you can:

  • Author and edit object models (FOM/SOM) with a full table-based editor.
  • Compose models from reusable modules and visualize their dependencies.
  • Design the federation architecture — which applications participate and how they connect to the RTI.
  • Import and export standard HLA model files (FED / FDD / DIF).
  • Generate code for federate applications, targeting the modern IEEE 1516-2025 / Fora workflow.

SimGe is a free academic research tool aimed at federation designers — the simulation developers who plan and build HLA federations.

HLA in brief

The High Level Architecture (HLA) is a standard for building distributed simulations out of independent programs that interoperate at run time:

Term Meaning
Federate A single participating simulation/application.
Federation A set of federates working together toward a common run.
RTI (Run-Time Infrastructure) The middleware that connects federates and routes data.
FOM (Federation Object Model) The shared data contract for a whole federation — the object classes, interaction classes, and data types everyone agrees on.
SOM (Simulation Object Model) The slice of objects/interactions a single federate can publish or subscribe to.
MOM (Management Object Model) The standard, built-in objects/interactions used to manage and monitor a federation.

These models are all expressed with the HLA Object Model Template (OMT) — the common tabular structure (object classes, interactions, attributes, parameters, data types, dimensions, and more) that SimGe edits in the Object Model Editor (OME).

Modular FOM

SimGe represents object models as composable modules rather than one monolithic file. Each module is a self-contained .sfom (metadata) + .xml (content) pair, and modules combine to form the complete model.

  • Module roles — Standalone (no dependencies), Dependency (used by others), Composed From (built by combining modules), and Standard (read-only system modules such as the MIM/MOM).
  • Dependencies — a module can build on others; SimGe tracks these links and shows them in the dependency graph.
  • Composition & merge — when you export or generate code, SimGe merges the composed modules into a single, standard-compliant FOM suitable for the RTI.

Modularity lets you reuse standard distributions (e.g. RPR-FOM, NETN) and keep your own additions in separate, focused modules. See Modular FOM Concepts for the full picture.

Supported HLA standards

SimGe understands three standard generations:

  • HLA 1.3 — legacy support (import/export of .fed).
  • IEEE 1516-2010 — widely used production standard.
  • IEEE 1516-2025 — the newest standard and the focus of SimGe's active code-generation path (via the Fora protocol client).

When you import an older model, SimGe can upgrade it to IEEE 1516-2025 so you work in a single, modern representation.

How the pieces fit together

A typical SimGe workflow moves through these stages:

  1. Create or open a project — a project (.fap file) holds your models, federation design, and settings. See Creating a Project.
  2. Build the object model — add modules and edit them in the OME, or import an existing FED/FDD.
  3. Validate and analyze — check the model with validation, the dashboard, and metrics & reports.
  4. Design the federation — define federate applications and their RTI connections in FAME.
  5. Generate code — produce federate code with the Code Generator.

Key terms at a glance

Term Short definition
OMT Object Model Template — the tabular structure of an HLA model.
FOM / SOM / MOM Federation / Simulation / Management Object Model.
Module A reusable, self-contained part of an object model (.sfom + .xml).
FAP Federation Architecture Project — SimGe's native project file (.fap).
OME Object Model Editor — where you edit module contents.
FAME Federation Architecture Modeling Environment — where you design the federation.
FED / FDD / DIF Standard HLA model file formats SimGe imports and exports.
Fora The IEEE 1516-2025 RTI client targeted by code generation.

A fuller Glossary is provided in the appendix.

Next: Quick Start: Your First Project