UBlueprintSpringMathLibrary::CriticalSpringDampVector2D

function Engine Blueprint Since 5.7

#include "Kismet/BlueprintSpringMathLibrary.h"

Access: public Specifiers: staticBlueprintCallable

Description

Interpolates InOutX towards TargetX using the motion of a critically damped spring, storing the resulting velocity back into InOutV. Commonly used to smooth 2D UI positions or screen-space coordinates.

Caveats & Gotchas

• Marked UE_EXPERIMENTAL(5.7, "SpringMath is experimental") — behaviour and defaults may change in later engine versions.
• InOutX and InOutV must be persisted by the caller between calls; each axis is damped independently.

Signature

static void CriticalSpringDampVector2D(UPARAM(ref) FVector2D& InOutX, UPARAM(ref) FVector2D& InOutV, const FVector2D& TargetX, float DeltaTime, float SmoothingTime = 0.2f);

Parameters

Name	Type	Description	Default
InOutX	FVector2D&	The value to be damped; updated in place each call.	—
InOutV	FVector2D&	The velocity of the damped value; must be persisted by the caller between calls.	—
TargetX	const FVector2D&	The goal value to damp towards.	—
DeltaTime	float	Timestep in seconds.	—
SmoothingTime	float	Smoothing time for the spring. Larger values give more damped behaviour; 0 snaps InOutX to TargetX.	0.2f

Return Type

void

Example

Smooth a widget's screen position towards a target C++

FVector2D WidgetPosition = FVector2D::ZeroVector;
FVector2D WidgetVelocity = FVector2D::ZeroVector;

void UMyHUDWidget::NativeTick(const FGeometry& MyGeometry, float DeltaTime)
{
    UBlueprintSpringMathLibrary::CriticalSpringDampVector2D(WidgetPosition, WidgetVelocity, TargetScreenPosition, DeltaTime, 0.2f);
    SetPositionInViewport(WidgetPosition);
}

Version History

Introduced in: 5.7

Version	Status	Notes
5.7	experimental	SpringMath is experimental.

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