I’m assuming this simulator is something like one of those airplane simulators where the seat moves with the actions on screen? Or, even if it’s not that complex, you have a computer running a program that takes input from the player and then outputs it to the screen. Like a game.
My best advice, although this should be clear (given I’m understanding your situation correctly), is to add the FMOD API to this ‘game’ the computer is using. When I say API, I mean what you get in the Unity/Unreal integration, which is FMOD 5 if I’m not mistaken.
Instead of a plugin, which doesn’t even sound like a plugin -more of an output from the app/game-, you should try and port FMOD 5 into this program. If the app is running on C# then, theoretically, you just need the Unity Integration and change where FMOD looks to find the dll’s and banks, then change it to be specific to your app (copy and paste the Unity integration code). If it’s not built on C# then you’ll have to go to the much more effective route of downloading the programmer’s API which shows you how FMOD is built.
You would then need to write that into your game and you then have FMOD; just build an FMOD project with all your audio and logic built in and you’re good to go.
But if you really really really want to build a plugin then it’s all laid out for you in the programmer’s API and documentation. In short -and from what I can understand of it- FMOD uses dll’s for their plugins. Have a look at the fmod_distance_filter.dll which is built into FMOD (it’s in a folder called ‘Plugins’ last I checked); to get it in game, copy the dll into a folder that I can’t remember and add the plugin name to FMOD Settings. That’s it.
For the actual building of the plugin then I’m not sure as I haven’t delved that deep yet. Although, if you want to do any of this then you’re going to need a good grasp of coding and I’d suggest working on something a little less complex to learn that.
But best of luck! Maybe doing this will make you a pro by the end of it!