Inside of animation blueprint transition details, where are these events called too/how can I use them to call an event?

Development Programming & Scripting Blueprint
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Those Transition Start / End / Interrupt fields are not global Blueprint events you can call from anywhere — they are AnimBP transition events that fire inside the Animation Blueprint’s Event Graph.

:small_blue_diamond: Where are they called?

When you type a name into those fields (e.g. OnAimTransitionEnd), Unreal will:

  • Automatically generate an event in your Animation Blueprint → Event Graph

  • You can find it by right-clicking → Add Event → Animation → Transition Events

  • Or just search for the exact name you typed

These events are triggered by the state machine when:

  • Start → transition begins

  • End → transition fully finishes (this is what you want)

  • Interrupt → transition gets interrupted

They are queued and executed by the AnimBP when transitions occur (Epic Developer Community Forums)

:small_blue_diamond: Important limitation (this is where people get confused)

These events:

  • Only exist inside the AnimBP

  • Do NOT automatically fire in your Character BP or elsewhere

  • Are not “global gameplay events”

So if you want to use them outside → you must forward the event manually

:small_blue_diamond: How to actually use it (your use case)

You want:
:right_arrow: “When transition to Aiming is complete → show overlay UI”

Step-by-step:

  1. In your transition (Idle → Aiming):

    • Set Transition End = OnAimFinished

  2. In AnimBP → Event Graph:

    • Add event: OnAimFinished

  3. From that event, do one of these:

    • Call an interface (recommended)

    • Cast to your character and call a function

    • Set a variable (e.g. bIsFullyAiming = true)

  4. In your Character/UI:

    • React to that signal → show overlay

:small_blue_diamond: Better / alternative approaches (often preferred)

:white_check_mark: Option 1 — Use State Events (cleaner)

Instead of transitions, select the Aiming state itself and use:

  • On State Entered

  • On State Fully Blended

These are often more reliable for “state reached” logic.

:white_check_mark: Option 2 — Use Anim Notifies (for animation timing)

If you care about exact animation timing:

  • Add a Notify near the end of your aim animation

  • Trigger UI from that

:warning: But note: notifies at the very end can be skipped due to blending (Epic Developer Community Forums)

:white_check_mark: Option 3 — Use a bool (most common pattern)

  • Set bIsAiming

  • Transition based on it

  • When TimeRemaining < X → treat as “finished”

Simple and very stable.

:small_blue_diamond: TL;DR

  • Those fields create AnimBP-only events

  • You access them in the Animation Blueprint Event Graph

  • To use them elsewhere → forward the event manually

  • For your case, Transition End or State Entered is the right trigger