Handler Reference

ElysImpact ships with 30 built-in handlers organized into 9 categories. Every handler inherits the shared base properties documented at the bottom of this page.

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Base Handler Properties

All handlers expose the following properties in their Details panel.

Activation

Property	Type	Default	Description
bEnabled	bool	true	Master on/off toggle for this handler instance.
ExecutionChance	float (0–100)	100	Probability (%) that this handler fires each time the asset plays. Use < 100 for randomized variety.

Timing

Property	Type	Default	Description
StartDelay	float (≥0)	0	Seconds to wait after session start before this handler fires. Use to stagger simultaneous effects.

Intensity

Property	Type	Default	Description
IntensityScale	float (≥0)	1.0	Per-handler multiplier stacked on top of session CombinedIntensity.
IntensityRandomRange	float (≥0)	0	±random variation added to IntensityScale each play.
IntensityOverLifetime	UCurveFloat*	null	Optional curve (X=NormalizedTime, Y=multiplier) that modulates intensity across the handler's duration.

Performance

Property	Type	Default	Description
MaxPlayDistance	float (≥0)	0	Maximum camera distance to play. 0 = always play.
LODDistanceFade	float (≥0)	500	Distance at which intensity fades toward zero (must be ≤ MaxPlayDistance).

Conditions

Property	Type	Description
TargetTagRequirement	FGameplayTagQuery	Tags that must be present on the target actor for this handler to fire.
SourceTagRequirement	FGameplayTagQuery	Tags that must be present on the source actor for this handler to fire.

Music Sync

Property	Type	Default	Description
bQuantizeToBeat	bool	false	When true, defers execution to the next ElysMusicEngine beat tick. Falls back to immediate execution if ElysMusicEngine is absent.
BeatDivision	ERP_EBeatDivision	Quarter	Beat subdivision used for quantization.

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Audio

SoundEffect

Plays a USoundBase (Cue, Wave, or MetaSound) at the target's location.

Property	Type	Default	Description
Sound	USoundBase*	null	Primary sound to play.
RandomSounds	TArray<USoundBase*>	empty	Pool of sounds for anti-repetition. When non-empty, a random entry is chosen instead of Sound.
VolumeMultiplier	float (0–4)	1.0	Volume scale.
PitchMultiplier	float (0.1–4)	1.0	Pitch scale.
PitchVariation	float (0–0.5)	0	±random pitch variation applied each play.
bIs2D	bool	false	When true, plays as a non-spatial 2D sound.
Attenuation	USoundAttenuation*	null	Optional custom attenuation settings.

Tip: Fill RandomSounds with multiple impact variants to avoid the "machine gun" repetition effect automatically.

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ControllerRumble

Sends force feedback to the player controller associated with the target actor.

Property	Type	Default	Description
ForceFeedbackEffect	UForceFeedbackEffect*	null	FFE asset to play. Recommended — assign this for full per-motor control.
LeftMotor	float (0–1)	0.5	Low-frequency motor intensity (fallback when no FFE assigned).
RightMotor	float (0–1)	0.8	High-frequency motor intensity (fallback).
Duration	float (≥0.01)	0.2	Rumble duration in seconds.
PlayerIndex	int (≥0)	0	Target player index.

Note: Assign a UForceFeedbackEffect asset for best results. The manual motor fallback logs a warning and requires an FFE asset to function in UE 5.6.

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Camera

CameraShake

Triggers a UCameraShakeBase subclass on the local player camera.

Property	Type	Default	Description
ShakeClass	TSubclassOf<UCameraShakeBase>	null	The shake blueprint or class to play.
Amplitude	float (≥0)	1.0	Scale applied to the handler's resolved intensity, then passed as the shake's inner scale.
bAttenuateWithRadius	bool	false	When true, shake amplitude fades by distance from the target.
AttenuationRadius	float (≥0)	1000	Radius over which attenuation applies. Visible only when bAttenuateWithRadius is enabled.

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CameraFOVPulse

Briefly expands or contracts the player camera's FOV, then eases back.

Property	Type	Default	Description
FOVOffset	float	15.0	Degrees added to the current FOV at peak. Negative values contract the FOV.
Duration	float (≥0.01)	0.3	Time in seconds for the full in–out cycle.
Curve	UCurveFloat*	null	Optional override curve (X=[0,1], Y=FOV multiplier).

This handler requires per-frame ticking. It restores the original FOV on completion.

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Gameplay

ChainResponse

Triggers another UERP_ImpactResponseAsset from within a handler, enabling composable response trees.

Property	Type	Default	Description
Asset	UERP_ImpactResponseAsset*	null	The response asset to trigger.
IntensityOverride	float (≥0)	0	Intensity for the chained asset. 0 = inherit current intensity.
ExtraDelay	float (≥0)	0	Additional delay (stacks on top of this handler's own StartDelay).

Use case: A "HeavyHit" asset can chain to a "ScreenFlash" asset and a "TimeDilation" asset via separate ChainResponse handlers, keeping each asset focused and reusable.

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DebugLog

Prints context information to the screen and/or log. Remove or disable in shipping builds.

Property	Type	Default	Description
Message	FString	"ElysImpact: Debug"	Custom message prefix.
bPrintToScreen	bool	true	Print to viewport.
ScreenDuration	float (≥0.1)	3.0	On-screen display duration in seconds.
ScreenColor	FLinearColor	teal	Color for the on-screen message.
bPrintToLog	bool	true	Print to output log.
bIncludeContext	bool	true	Append Target, Intensity, DI, and EventTag to the message.

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SetActive

Enables, disables, or toggles visibility/collision/tick on the target actor's root component or actor.

Enum ERP_ESetActiveMode	Description
Enable	Force-enables the selected flags.
Disable	Force-disables the selected flags.
Toggle	Flips the current state.

Property	Type	Default	Description
Mode	ERP_ESetActiveMode	Toggle	Enable / Disable / Toggle.
bAffectVisibility	bool	true	Toggle SetActorHiddenInGame.
bAffectCollision	bool	false	Toggle SetActorEnableCollision.
bAffectTick	bool	false	Toggle SetActorTickEnabled.
RestoreAfter	float (≥0)	0	Seconds before reverting to the prior state. 0 = never restore.

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SpawnActor

Spawns an actor class at the target's location (with optional relative offset).

Property	Type	Default	Description
ActorClass	TSubclassOf<AActor>	null	Class to spawn.
LocationOffset	FVector	zero	Position offset from the target root.
RotationOffset	FRotator	zero	Rotation offset.
bRelativeOffset	bool	true	Interpret offsets relative to the target's transform.
bAttachToTarget	bool	false	Attach the spawned actor to the target.
LifeSpan	float (≥0)	0	Auto-destroy after N seconds. 0 = never destroy automatically.

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TriggerGameplayEvent

Dispatches a Gameplay Ability System event to the target or source actor.

Property	Type	Default	Description
EventTag	FGameplayTag	none	GAS event tag (e.g., GameplayEvent.Hit.Stagger).
Magnitude	float (≥0)	0	Event magnitude. When > 0, overrides Context.Magnitude.
bSendToSource	bool	false	Send the event to the source actor instead of the target.

Requires the target actor to have an AbilitySystemComponent.

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Movement

Impulse

Applies a physics impulse to the target's root primitive component (or LaunchCharacter for pawns).

Enum ERP_EImpulseDirection	Description
AwayFromSource	Direction from source to target.
AlongNormal	Uses Context.ImpactNormal.
WorldUp	Straight up (+Z).
Custom	Uses CustomDirection.

Property	Type	Default	Description
Force	float (≥0)	500	Impulse magnitude (units/s² equivalent).
UpwardForce	float (≥0)	0	Additional upward force component.
DirectionMode	ERP_EImpulseDirection	AwayFromSource	Direction calculation mode.
CustomDirection	FVector	up	Used when DirectionMode is Custom.
bUseLaunchCharacter	bool	true	Use ACharacter::LaunchCharacter on character targets.
bOverrideVelocity	bool	false	Override current velocity instead of adding to it.

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Attract

Smoothly moves the target actor toward the source or impact point.

Enum ERP_EAttractTargetMode	Description
UseSource	Move toward the source actor's location.
UseImpactPoint	Move toward Context.ImpactPoint.

Property	Type	Default	Description
TargetMode	ERP_EAttractTargetMode	UseSource	What to move toward.
Speed	float (≥0)	300	Movement speed (cm/s).
Duration	float (≥0)	0.5	Max time to attract for.
StopRadius	float (≥0)	50	Stop when within this distance.

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Bounce

Applies a squash-and-stretch bounce simulation that decays over multiple cycles.

Property	Type	Default	Description
SquashAmount	float (≥0)	0.3	Peak squash scale along the primary axis.
StretchAmount	float (≥0)	0.4	Peak stretch scale along the primary axis.
BounceCount	int (≥1)	3	Number of bounce cycles before settling.
Damping	float (≥0.01)	0.7	Multiplier applied to each successive bounce amplitude.
Axis	FVector	up	Axis along which the bounce occurs.

Duration is automatic based on BounceCount and Damping.

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Oscillate

Translates the target back and forth along an axis using a sine wave.

Property	Type	Default	Description
Direction	FVector	up	World-space oscillation axis.
Distance	float (≥0)	20	Peak displacement in cm.
CycleTime	float (≥0.01)	1.0	Duration of one full oscillation cycle.
Duration	float (≥0)	3.0	Total oscillation time.
bRandomizePhase	bool	false	Start at a random point in the cycle.

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Spin

Continuously rotates the target around an axis for a set duration.

Property	Type	Default	Description
Axis	FVector	up	World-space rotation axis.
DegreesPerSecond	float	360	Rotation speed.
Duration	float (≥0)	1.0	How long to spin.
bRestoreOnComplete	bool	false	Snap back to original rotation when done.

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Particles

ParticleEffect

Spawns a Niagara particle system at or attached to the target.

Enum ERP_EParticleAttachment	Description
Attached	Attached to the target mesh at SocketName.
AtImpactPoint	Spawned at Context.ImpactPoint (detached).
AtActorRoot	Spawned at the target's root transform (detached).

Property	Type	Default	Description
NiagaraSystem	UNiagaraSystem*	null	The Niagara system asset to spawn.
AttachmentRule	ERP_EParticleAttachment	AtImpactPoint	Where to spawn or attach.
SocketName	FName	None	Socket or bone name for Attached mode.
LocationOffset	FVector	zero	Position offset.
RotationOffset	FRotator	zero	Rotation offset.
Scale	FVector	one	Scale applied to the system instance.
bAutoDestroy	bool	true	Destroy the component when the effect completes.

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Post-Process

Post-process handlers modify the scene's post-process volume. They require a blendable or a UPostProcessComponent on the camera or player pawn.

BloomPulse

Briefly increases the scene's bloom intensity, then eases back.

Property	Type	Default	Description
BloomIntensity	float (≥0)	5.0	Peak bloom multiplier.
Duration	float (≥0.01)	0.25	Full pulse duration in seconds.
Curve	UCurveFloat*	null	Optional intensity-over-time curve.

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ChromaticAberration

Adds chromatic aberration (lens distortion) for a brief moment.

Property	Type	Default	Description
Intensity	float (0–5)	2.0	Peak aberration strength.
Duration	float (≥0.01)	0.2	Duration in seconds.
Curve	UCurveFloat*	null	Optional intensity-over-time curve.

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ColorGrade

Temporarily shifts saturation, contrast, brightness, and tint.

Property	Type	Default	Description
Saturation	float (0–2)	0.0	Target saturation. 0 = fully desaturated (dramatic hit flash).
Contrast	float (0–3)	1.0	Target contrast.
Brightness	float (0–3)	1.0	Target brightness.
Tint	FLinearColor	white	Color tint overlaid on the scene.
Duration	float (≥0.01)	0.5	Duration in seconds.

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DepthBlur

Applies depth-of-field blur, simulating a momentary focus loss.

Property	Type	Default	Description
FocalDistance	float (≥0)	200	Distance (cm) at which the scene is in focus.
NearBlurSize	float (≥0)	4.0	Blur kernel size for objects closer than focal distance.
FarBlurSize	float (≥0)	4.0	Blur kernel size for objects further than focal distance.
Duration	float (≥0.01)	0.3	Duration in seconds.

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Time

TimeDilation

Slows or accelerates time — either globally or per-actor.

Enum ERP_ETimeDilationScope	Description
Actor	Dilates only the target actor's tick rate.
Global	Calls SetGlobalTimeDilation, affecting the entire world.

Property	Type	Default	Description
TargetScale	float (0.05–10)	0.3	Time scale factor. 0.3 = 30% speed (slow motion).
Duration	float (≥0.01)	0.2	Duration in seconds before restoring.
Scope	ERP_ETimeDilationScope	Actor	Actor-local or global dilation.
Curve	UCurveFloat*	null	Optional dilation-over-time curve.
bRestoreOnComplete	bool	true	Restore normal time scale when done.

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Transform

ScalePunch

Briefly punches the target's scale and springs back, giving hits a satisfying "pop".

Enum ERP_EScalePunchMode	Description
Uniform	Scales all axes equally.
PerAxis	Scales each axis from PunchScale independently.

Property	Type	Default	Description
Mode	ERP_EScalePunchMode	Uniform	Uniform or per-axis punch.
PunchScale	FVector	(0.25, 0.25, 0.25)	Peak scale offset added to the base scale.
Duration	float (≥0.01)	0.3	Full punch-and-return cycle time.
Curve	UCurveFloat*	null	Optional punch multiplier curve.

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Jiggle

Spring-simulation jiggle on position, rotation, or scale that naturally decays.

Enum ERP_EJiggleMode	Description
Position	Jiggle in world position.
Rotation	Jiggle in rotation (Euler angles).
Scale	Jiggle in local scale.

Property	Type	Default	Description
Mode	ERP_EJiggleMode	Scale	Which transform component to jiggle.
Amplitude	FVector	(0.15, 0.05, 0.05)	Peak displacement per axis.
Frequency	float (≥0.1)	10.0	Oscillation frequency (Hz).
Damping	float (≥0.01)	0.5	Decay rate. Higher = settles faster.
bRandomizeDirection	bool	false	Randomize initial jiggle direction each play.
SettleThreshold	float	0.005	Stop ticking once displacement drops below this.

Duration is automatic (indefinite until settled).

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SquashAndStretch

Applies a spring-damped squash-and-stretch deformation along a primary axis, with optional volume preservation.

Property	Type	Default	Description
Amplitude	float (≥0)	0.3	Initial stretch amplitude.
Frequency	float (≥0.1)	8.0	Oscillation frequency (Hz).
Damping	float (0.01–5)	0.6	1.0 = critically damped (no oscillation).
PrimaryAxis	FVector	up	The stretch axis (usually the actor's up vector).
bPreserveVolume	bool	true	Scale perpendicular axes inversely to maintain volume.
SettleThreshold	float	0.005	Stop when deformation drops below this.

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LookAt

Rotates the target actor to face the source or impact point.

Enum ERP_ELookAtMode	Description
Instant	Snap to the target rotation immediately.
Lerp	Smoothly interpolate over LerpDuration seconds.

Property	Type	Default	Description
Mode	ERP_ELookAtMode	Instant	Instant or smoothly lerped.
LerpDuration	float (≥0.01)	0.2	Duration for smooth rotation. Visible only in Lerp mode.
bLockPitch	bool	false	Keep pitch unchanged (only rotate yaw).
bLockRoll	bool	true	Keep roll unchanged.
bLookAtSource	bool	true	Look at the source actor. When false, looks at ImpactPoint.

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Visual

MaterialFlash

Briefly applies an overlay material to the target's mesh, then removes it.

Property	Type	Default	Description
OverlayMaterial	UMaterialInterface*	null	Material applied via SetOverlayMaterial.
Duration	float (≥0.01)	0.15	How long the overlay stays on.

Create a simple emissive or solid-color material for a classic "damage flash" effect.

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RimHighlight

Applies a rim/Fresnel material overlay to make the target glow from the edges.

Property	Type	Default	Description
RimMaterial	UMaterialInterface*	null	Fresnel rim overlay material.
Color	FLinearColor	gold	Multiplied with the material's color parameter.
Duration	float (≥0)	0.4	How long the rim effect lasts.
bPulse	bool	false	Oscillate the rim intensity over the duration.

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AfterImage

Spawns translucent ghost copies of the target at fixed intervals, creating a motion trail.

Property	Type	Default	Description
GhostCount	int (≥1)	3	Number of ghost copies to spawn.
SpawnInterval	float (≥0)	0.05	Seconds between ghost spawns.
GhostLifetime	float (≥0.01)	0.3	How long each ghost persists before fading.
Opacity	float (0–1)	0.5	Ghost transparency.
GhostMaterial	UMaterialInterface*	null	Optional override material for ghosts (e.g., a translucent emissive).

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VisibilityBlink

Blinks the target's visibility on and off a fixed number of times.

Property	Type	Default	Description
Duration	float (≥0)	1.0	Total blink duration.
BlinkCount	int (≥1)	4	Number of blink cycles.
bAccelerateOverTime	bool	false	Increase blink frequency over the duration.
bRestoreOnComplete	bool	true	Ensure visibility is restored when done.

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VisibilityFlicker

Randomizes the target's visibility at irregular intervals for an organic flicker effect.

Property	Type	Default	Description
MinInterval	float (≥0.01)	0.03	Minimum time between visibility flips (seconds).
MaxInterval	float (≥0.01)	0.12	Maximum time between visibility flips.
MinVisibleChance	float (0–1)	0.4	Minimum probability of being visible at each flip.
Duration	float (≥0)	1.0	Total flicker duration.

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ScreenFade

Fades the player's screen in, out, or flashes it to a solid color.

Enum ERP_EScreenFadeType	Description
FadeIn	Fade from solid color back to the game view.
FadeOut	Fade to a solid color.
Flash	Fade out then immediately back in (single flash).

Property	Type	Default	Description
FadeType	ERP_EScreenFadeType	Flash	The fade mode.
Color	FLinearColor	black	The solid color to fade to/from.
Duration	float (≥0.01)	0.3	Total fade duration.
bHoldOnComplete	bool	false	Hold the fade state at completion (manual restoration needed).

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Handler Count Summary

Category	Count	Handlers
Audio	2	SoundEffect, ControllerRumble
Camera	2	CameraShake, CameraFOVPulse
Gameplay	5	ChainResponse, DebugLog, SetActive, SpawnActor, TriggerGameplayEvent
Movement	5	Impulse, Attract, Bounce, Oscillate, Spin
Particles	1	ParticleEffect
Post-Process	4	BloomPulse, ChromaticAberration, ColorGrade, DepthBlur
Time	1	TimeDilation
Transform	4	ScalePunch, Jiggle, SquashAndStretch, LookAt
Visual	6	MaterialFlash, RimHighlight, AfterImage, VisibilityBlink, VisibilityFlicker, ScreenFade
Total	30