UBlueprintSpringMathLibrary::VelocitySpringDampFloat

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. Use this instead of CriticalSpringDampFloat when you need to cap the approach speed explicitly.

Caveats & Gotchas

• Marked UE_EXPERIMENTAL(5.7, "SpringMath is experimental") — behaviour and defaults may change in later engine versions.
• Takes three persistent in/out state variables (InOutX, InOutV, InOutVi) rather than two — omitting InOutVi or re-zeroing it every tick breaks the velocity tracking that distinguishes this from the plain critical spring.
• A SmoothingTime of 0 produces a linear interpolation from X to TargetX capped at MaxSpeed, not a snap — this differs from the critical-spring functions where 0 means an instant snap.

Signature

static void VelocitySpringDampFloat(UPARAM(ref) float& InOutX, UPARAM(ref) float& InOutV, UPARAM(ref) float& InOutVi, float TargetX, float MaxSpeed, float DeltaTime, float SmoothingTime = 0.2f);

Parameters

Name	Type	Description	Default
InOutX	float&	The value to be damped; updated in place each call.	—
InOutV	float&	The velocity of the damped value; must be persisted by the caller between calls.	—
InOutVi	float&	The intermediate target velocity; must be persisted by the caller between calls.	—
TargetX	float	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

Damp a value with a capped approach speed C++

float Value = 0.f, Velocity = 0.f, IntermediateVelocity = 0.f;

void AMyActor::Tick(float DeltaTime)
{
    Super::Tick(DeltaTime);
    UBlueprintSpringMathLibrary::VelocitySpringDampFloat(Value, Velocity, IntermediateVelocity, TargetValue, /*MaxSpeed=*/50.f, DeltaTime, 0.25f);
}

Version History

Introduced in: 5.7

Version	Status	Notes
5.7	experimental	SpringMath is experimental.

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