Please note that ExternalSim is no longer directly supported and no future enhancements are planned for this feature.

The capabilities found in the SimObject API can be considered the second iteration of ExternalSim and is the recommended path forward for external simulation development and integration.

The ExternalSim capabilities of Prepar3D give developers to ability create their own external simulations that can be ran inside of Prepar3D. An example ExternalSim project is included with the Prepar3D SDK. The example shows how to create a simple East/West/North/South object movement simulation that is used to control the 'Externally Simulated Flyable Object (E.S.F.O.)' vehicle. To experiment with the E.S.F.O., copy the entire ESFO folder:

SimConnect Samples\ExternalSim\ESFO

to Prepar3D's miscellaneous SimObjects folder:

The vehicle will be selectable from the Select Aircraft/Vehicle user interface, under Prepar3D, as the ExternalSim E.S.F.O..

The E.S.F.O. can be moved East/West though the aileron controls, North/South though the elevation controls, and the elevation is controlled though the throttle.

When creating external simulations, the object's configuration file should specify the following information, per variation:

Configuration Data
ExternalSimID The GUID that is referenced in the ExternalSim dll.
ExternalSimData Specific data related to the ExternalSim. (Optional)
ExternalSimModule The location of the ExternalSim dll. (Optional)

Additionally, inside the sim.cfg file, under General, the category should be ExternalSim.

NOTE: If ExternalSims are not appearing in your aircraft selection screen, confirm that the object is inside the ..\SimObjects\Misc folder and that your Prepar3D.cfg has ExternalSim listed under Main in the User Objects setting variable.

Specific implementation details are described in the SimConnect documentation. For more information on the External SimObject container, please read the Sample SimObject Container using an External Sim article.