UBlueprintSpringMathLibrary::VelocitySpringDampVector2D

function Engine Blueprint Since 5.7

#include "Kismet/BlueprintSpringMathLibrary.h"

Access: public Specifiers: staticBlueprintCallable

Description

Damps InOutX towards TargetX using a target that follows a fixed linear velocity, giving control over interpolation speed via MaxSpeed while still producing smoothed motion. Useful for capped-speed UI or screen-space position tracking.

Caveats & Gotchas

• Marked UE_EXPERIMENTAL(5.7, "SpringMath is experimental") — behaviour and defaults may change in later engine versions.
• Requires three persistent in/out state variables (InOutX, InOutV, InOutVi); dropping or resetting InOutVi produces motion indistinguishable from CriticalSpringDampVector2D.

Signature

static void VelocitySpringDampVector2D(UPARAM(ref) FVector2D& InOutX, UPARAM(ref) FVector2D& InOutV, UPARAM(ref) FVector2D& InOutVi, const FVector2D& TargetX, float MaxSpeed, 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.	—
InOutVi	FVector2D&	The intermediate target velocity; must be persisted by the caller between calls.	—
TargetX	const FVector2D&	The target value of X to damp towards.	—
MaxSpeed	float	The desired speed to achieve while damping towards X.	—
DeltaTime	float	Timestep in seconds.	—
SmoothingTime	float	Smoothing time while damping towards X. A value of 0 gives a linear interpolation of X to TargetX.	0.2f

Return Type

void

Example

Move a UI cursor towards a target at a capped speed C++

FVector2D CursorPosition = FVector2D::ZeroVector;
FVector2D CursorVelocity = FVector2D::ZeroVector;
FVector2D CursorIntermediateVelocity = FVector2D::ZeroVector;

void UMyHUDWidget::NativeTick(const FGeometry& MyGeometry, float DeltaTime)
{
    UBlueprintSpringMathLibrary::VelocitySpringDampVector2D(CursorPosition, CursorVelocity, CursorIntermediateVelocity, TargetScreenPosition, /*MaxSpeed=*/800.f, DeltaTime, 0.2f);
}

Version History

Introduced in: 5.7

Version	Status	Notes
5.7	experimental	SpringMath is experimental.

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