Can't Implement Interface when Function has no Output

Development Programming & Scripting Blueprint
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1

I am using Unreal Engine 4.10.4 (Binary, not self-compiled) on a Windows 10 machine.

Whenever I make a function in a Blueprint Interface that does not have an output pin, it has the unusual side-effect of making me unable to implement the function. My example:

I made an interface called I_Pickup and in that interface I made two functions

  • SetPhysicsState(boolean) : void
  • SetCollisionState(boolean) : void

None of these two have any outputs as you can see. When I then go to implement those two methods in my Soda_Can_BP Blueprint I cannot see the functions in the interfaces section of the Blueprint. Adding outputs (any output) to those two functions make them visible.

Another effect of this is that if you then go into the Interface and remove the output pins after you implemented them in your blueprint that implements that interface, the Interface functions work normally in your blueprint.

2

Hello,

I have attempted to reproduce your issue, but did not see the same behavior. Could you please provide the steps that you are following to reproduce the issue in a clean project?

Thank you

3

Hello,

I am marking this topic as resolved for tracking purposes, as we have not heard from you in a few days. If this issue persists, feel free to respond to this thread. For any new issues, please create a new Answerhub topic.

Have a great day

4

I am having this problem too. To reproduce:

  1. Create an interface named MyInterface.

  2. Create a function inside MyInterface named OnCollected, then some inputs, and a boolean output named IsValid.

  3. Create an actor blueprint, named MyActor.

  4. Add MyInterface to implement list of MyActor.

  5. Implement OnCollected function with something inside MyActor.

  6. Compile. You will see that it gives this error: Pin named IsValid doesn’t match any parameters of function OnCollected

5

Hello,

I’ve followed the steps you’ve provided and have not been able to reproduce the issue. How are you implementing the function in your blueprint? That could be what is causing the issue as I am not experiencing it on my end. Could you provide a screenshot of the implementation?

6

Hello,

I am marking this topic as resolved for tracking purposes, as we have not heard from you in a few days. If this issue persists, please feel free to respond to this thread. For any new issues, please create a new Answerhub topic.

Have a great day