StateTree Tools

Ready-made StateTree tools for Unreal Engine 5

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Play Montage

Plugin: StateTreeToolsCore Category: Animation

Plays an animation montage on a Skeletal Mesh Component and keeps the task running until the montage ends. Output delegate dispatchers fire for each montage lifecycle event — Completed, Interrupted, BlendOut, and BlendedIn — so downstream states or transitions can react to each phase.

Configuration

Actor (input)

Bind this to the actor whose Skeletal Mesh Component you want to animate. The component is resolved automatically based on the Setup.

Setup

Editor-only helper that stores the actor class and the name of the Skeletal Mesh Component to use. The actor class is auto-populated from the Actor binding; the component picker filters to USkeletalMeshComponent.

Montage To Play

The UAnimMontage asset to play.

Play Rate

Playback speed multiplier. Default is 1.0.

Start Position

Time offset in seconds at which playback begins within the montage. Default is 0.0.

Start Section

The montage section to jump to when playback starts. Leave as None to start from the beginning.

Stop All Montages

When enabled, all other montages playing on the same Anim Instance are stopped before this one starts. Default is true.

Stop Montage On Exit

When enabled the montage is stopped and blended out when the task exits (e.g. because a higher-priority transition fired). Default is true. When disabled the montage continues playing after the state exits.

Interruption Means Failure

When enabled the task completes with Failed status if the montage is interrupted. Default is false.

On Completed / On Completed Event

Fires when the montage plays through to its natural end. Bind the FStateTreeDelegateDispatcher output to other parts of the tree, or configure the OutputEventAction to dispatch a StateTree event automatically.

On Interrupted / On Interrupted Event

Fires when the montage is interrupted (for example by another montage). Configure the OutputEventAction to dispatch a StateTree event if needed.

On Blend Out / On Blend Out Event

Fires when the montage begins blending out. Configure the OutputEventAction to dispatch a StateTree event if needed.

On Blended In / On Blended In Event

Fires when the montage finishes blending in and is fully active. Configure the OutputEventAction to dispatch a StateTree event if needed.

Unreal Engine Version Notes

UE 5.6 and later

Task completes asynchronously the instant the montage ends — no per-frame tick is needed.
All four delegate dispatcher outputs (On Completed, On Interrupted, On Blend Out, On Blended In) fire at the exact moment each montage lifecycle event occurs.
All four OutputEventAction fields dispatch their configured StateTree events immediately when each callback fires.
Any StateTree compiled in UE 5.5 must be recompiled after upgrading to 5.6 for correct behaviour.

UE 5.5

Task completes via a per-frame tick that polls a shared completion flag. There is a one-frame delay between the montage ending and the task completing.
Any StateTree compiled in UE 5.6 must be recompiled after downgrading to 5.5 for correct behaviour.
Delegate dispatcher outputs (On Completed, On Interrupted, On Blend Out, On Blended In) appear in the details panel but are non-functional — FStateTreeDelegateDispatcher does not exist before UE 5.6 and these fields compile as no-op placeholders.
On Completed Event and On Interrupted Event still dispatch their configured StateTree events (fired from the tick).
On Blend Out Event and On Blended In Event do not fire on UE 5.5. These callbacks are not tracked in the 5.5 code path.

Error Handling

If the Actor is invalid, the Skeletal Mesh Component is not found, or the montage cannot be played, the task will fail. The task inherits Error Means Failure from FStateTreeTools_TaskCommon.

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