I find that I can set Required Bank for an event in editor. But what is this used for? I put all events and audio into one bank called FirstSoundBank for example. All included events are imported into Unreal using Wwise picker. After that, I generate sound data but get an error read that "Error: File missing or invalid:C:\Users\Username\AppData\Local\Temp\CookUAkAudioEvent15E2DA944F83F18F292A4DAE8EFD66A9.txt." Then I set the requrieed bank to FirstSoundBank in any event(even new event that created in unreal editor and does not exist in wwise!), generate again and is successful. So what is this used for?
Another question is that when Sound Bank get loaded in unreal. In the example above, I don't load sound bank anywhere, but it still works. I find that there is one property called Autoload in SoundBank. So when does it get loaded and when does it get unloaded? I made several experiments but none matches my expectation and even does not make sense to me!
Still the example above. Two events called A and B are included with their audio in FirstSoundBank. None of their required bank is set. Autoload of FirstSoundBank is set to true. Then, I create a new event called C in unreal editor(no such event in wwise editor). The required bank of C is set to FirstSoundBank(otherwise will fail to generate SoundBank). None reference to C exists in unreal. But A and B can still be posted successfully. That means FirstSoundBank is loaded. But why? by whom? where? when?