If you define a function in an interface that has 0 outputs, it will not show up in the blueprints that implement the interface, and thus you have to create a dummy output even if you don’t need it.
C++ equivalent of eg. void MyFunc().
Adding inputs doesn’t change anything.
BellyInterface:
BigBelly blueprint:
Jiggle does not show up in the BigBelly blueprint.
So you have to create a dummy output to implement it:
Furthermore, if you after adding the dummy output and having implemented the now functioning function, remove the output and recompile, all hell breaks lose in the BigBelly:
Calling the unimplemented functions is not a problem however (No point, though, since there’s nothing to call them on):