UBlueprintSpringMathLibrary::SpringCharacterUpdate

function Engine Blueprint Since 5.7

#include "Kismet/BlueprintSpringMathLibrary.h"

Access: public Specifiers: staticBlueprintCallable

Description

Advances a character's position toward a target velocity using a damped spring, smoothing out sudden velocity changes rather than snapping to them instantly. Intended as a lightweight alternative to a full movement component for simple custom motion.

Caveats & Gotchas

• Marked UE_EXPERIMENTAL(5.7, "SpringMath is experimental") — behaviour and defaults may change in later engine versions.
• InOutVelocity and InOutAcceleration are caller-owned state that must persist between calls (e.g. as member variables) — passing fresh zeroed locals every tick defeats the spring and produces jittery motion.
• Unlike VelocitySpringCharacterUpdate, this function has no maximum acceleration clamp, so a large TargetVelocity change combined with a short SmoothingTime can produce very high instantaneous acceleration.

Signature

static void SpringCharacterUpdate(UPARAM(ref) FVector& InOutPosition, UPARAM(ref) FVector& InOutVelocity, UPARAM(ref) FVector& InOutAcceleration, const FVector& TargetVelocity, float DeltaTime, float SmoothingTime = 0.2f);

Parameters

Name	Type	Description	Default
InOutPosition	FVector&	The position of the character; updated in place each call.	—
InOutVelocity	FVector&	The velocity of the character. Must be stored and persisted by the caller between calls, usually starting at zero.	—
InOutAcceleration	FVector&	The acceleration of the character. Must be stored and persisted by the caller between calls, usually starting at zero.	—
TargetVelocity	const FVector&	The target velocity of the character.	—
DeltaTime	float	The delta time to tick the character.	—
SmoothingTime	float	The time over which to smooth velocity; it takes roughly this long for the character to reach the target velocity.	0.2f

Return Type

void

Example

Advance a character position with a damped spring C++

FVector Position = GetActorLocation();
FVector Velocity = FVector::ZeroVector;
FVector Acceleration = FVector::ZeroVector;

void AMyCharacter::Tick(float DeltaTime)
{
    Super::Tick(DeltaTime);
    UBlueprintSpringMathLibrary::SpringCharacterUpdate(Position, Velocity, Acceleration, DesiredVelocity, DeltaTime, 0.25f);
    SetActorLocation(Position);
}

Version History

Introduced in: 5.7

Version	Status	Notes
5.7	experimental	SpringMath is experimental.

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