UBlueprintSpringMathLibrary::VelocitySpringDampVector

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. Commonly used for a follow-camera or AI positioning that should not exceed a maximum approach speed.

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 CriticalSpringDampVector rather than the intended capped-speed behaviour.
• MaxSpeed is a hard cap on approach speed, not a target cruising speed — small SmoothingTime values combined with a low MaxSpeed can make the value appear to move at a constant speed rather than easing in and out.

Signature

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

Parameters

Name	Type	Description	Default
InOutX	FVector&	The value to be damped; updated in place each call.	—
InOutV	FVector&	The velocity of the damped value; must be persisted by the caller between calls.	—
InOutVi	FVector&	The intermediate target velocity; must be persisted by the caller between calls.	—
TargetX	const FVector&	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 follow point at a capped maximum speed C++

FVector FollowPosition = GetActorLocation();
FVector FollowVelocity = FVector::ZeroVector;
FVector FollowIntermediateVelocity = FVector::ZeroVector;

void AFollower::Tick(float DeltaTime)
{
    Super::Tick(DeltaTime);
    UBlueprintSpringMathLibrary::VelocitySpringDampVector(FollowPosition, FollowVelocity, FollowIntermediateVelocity, TargetActor->GetActorLocation(), /*MaxSpeed=*/600.f, DeltaTime, 0.3f);
    SetActorLocation(FollowPosition);
}

Version History

Introduced in: 5.7

Version	Status	Notes
5.7	experimental	SpringMath is experimental.

Feedback

Was this helpful?