Event triggered by another event with probability


I am trying to figure out how to get a multi-instrument event to trigger another multi-instrument event. The first event has a loop brace around it to keep triggering the one shots. However, it has probability on it so it’s not always playing. Is there away to have the second event get triggered by the first but only when the first is actually playing? Appreciate any help. Thanks

I’m afraid I don’t fully understand what you’re asking. What behavior are you trying to achieve?

When you say “multi-instrument event,” do you mean a multi instrument, or an event containing one or more multi instruments?

A multi instrument can trigger any instrument in its playlist, so adding a multi instrument to a multi instrument’s playlist is one way of making a multi instrument trigger another multi instrument.

Similarly, an event can trigger another event by means of an event instrument or command instrument.

Thanks for helping. I’ll try and explain what I’m trying to achieve in a clearer way. I have 2 separate events. Each contain 1 audio track. In both events, each of those audio tracks have a multi instrument loaded up with 4-5 one-shots. I want one of the events to trigger the other. Is this possible?

Let me explain an in game scenario. I’m building up an environment in Unreal and I am placing a bird call emitter (event 1). This event’s multi-instrument has probability set around 40%. My second event is another bird. I want this bird to respond to the call of the first one but only when the first one plays. Is there a way to set this up in Fmod? Maybe the current way that I’m trying to go about is wrong and you can shed some light on how it can be done.

There are two common ways to trigger an event from another event.

The first is to use an event instrument. This is an instrument that creates and plays an instance of another event, and routes its output into the track that contains the event instrument. You can create an event instrument for an existing event by dragging the existing event onto a track or playlist in another event.

The second is to use a command instrument. Command instruments create new instances of events. These event instances inherit the 3D attributes of the events that create them at the time of creation, and do not more thereafter.

In either case, you could potentially get the behavior you want by adding a sequential multi instrument to your bird call event, and putting your existing multi instrument inside the playlist of the new multi instrument. Then, add an event instrument or command instrument to the playlist, such that it plays after the first instrument. All you need to do then is set the probability of the top-level multi insturment to 40%, and the probability of the multi insturment in the referenced event the same way, and you will have an event that randomly plays a birdcall, and then only if the birdcall plays, randomly plays another birdcall.

This seems like a good way to get an event to trigger another, but if I want different spacial qualities for the bird call and response then this wouldn’t do the trick, correct? For example, if I wanted to place a bird call in a specific area and have the response at another specific location, then using event instances within the same event doesn’t seem to achieve this. I was reading up on the transceiver effect and I think this is how I would achieve it, but I wanted to make sure I’m not making things unnecessarily complicated.

You’re right that the methods I described couldn’t be used to trigger an event with different 3D attributes to the triggering event.

A transceiver effect could potentially work, but because every sending transceiver effect instance with a given channel sends its signal to every receiving transceiver effect set to that channel, there is no practical way to make the signal sent from a specific event instance be received by a specific event instance, effectively inhibiting multiple simultaneous instances of either event.

As such, if you want to have multiple instances of either event in your game world, it may be simpler to control the probability of both events triggering from your game’s code, rather than trying to build the behavior into those events.