UBlueprintSpringMathLibrary::CriticalSpringDampRotator

function Engine Blueprint Since 5.7

#include "Kismet/BlueprintSpringMathLibrary.h"

Access: public Specifiers: staticBlueprintCallable

Description

Interpolates InOutRotation towards TargetRotation using the motion of a critically damped spring, storing the resulting angular velocity back into InOutAngularVelocity. Convenience overload of CriticalSpringDampQuat for Rotator-based workflows.

Caveats & Gotchas

• Marked UE_EXPERIMENTAL(5.7, "SpringMath is experimental") — behaviour and defaults may change in later engine versions.
• Internally converts to and from FQuat, so it is subject to the same gimbal-related quirks as any FRotator-based interpolation near the pitch singularity; prefer CriticalSpringDampQuat directly if you are already working in quaternion space.
• InOutRotation and InOutAngularVelocity must be persisted by the caller between calls, not re-initialized each tick.

Signature

static void CriticalSpringDampRotator(UPARAM(ref) FRotator& InOutRotation, UPARAM(ref) FVector& InOutAngularVelocity, const FRotator& TargetRotation, float DeltaTime, float SmoothingTime = 0.2f);

Parameters

Name	Type	Description	Default
InOutRotation	FRotator&	The rotation to be damped; updated in place each call.	—
InOutAngularVelocity	FVector&	The angular velocity in deg/s; must be persisted by the caller between calls.	—
TargetRotation	const FRotator&	The goal rotation to damp towards.	—
DeltaTime	float	Timestep in seconds.	—
SmoothingTime	float	Smoothing time for the spring. Larger values give more damped behaviour; 0 snaps InOutRotation to TargetRotation.	0.2f

Return Type

void

Example

Smooth a Blueprint-friendly Rotator towards a target C++

FRotator SmoothedRotation = GetActorRotation();
FVector RotationalVelocity = FVector::ZeroVector;

void AMyActor::Tick(float DeltaTime)
{
    Super::Tick(DeltaTime);
    UBlueprintSpringMathLibrary::CriticalSpringDampRotator(SmoothedRotation, RotationalVelocity, TargetRotator, DeltaTime, 0.2f);
    SetActorRotation(SmoothedRotation);
}

Version History

Introduced in: 5.7

Version	Status	Notes
5.7	experimental	SpringMath is experimental.

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