UAnimInstance::CalculateDirection

function Engine Blueprint Since 4.0

#include "Animation/AnimInstance.h"

Access: public Specifiers: UFUNCTIONBlueprintCallableENGINE_API

Description

Computes the angle in degrees (–180 to 180) between a velocity vector and a base rotation, projected onto the horizontal plane. Commonly used in locomotion blend spaces to drive directional movement animations (strafing, backpedaling).

Caveats & Gotchas

• Returns 0.0 when the velocity vector is near-zero length, which can cause blend spaces to snap to the forward idle pose. Guard against this by checking velocity magnitude before calling.
• The calculation is 2D only — it projects onto the XY plane and ignores the Z component. Characters moving on steep slopes or flying will get inaccurate direction values unless you zero out the Z velocity first.

Signature

UFUNCTION(BlueprintCallable, Category="Animation", meta=(BlueprintThreadSafe))
ENGINE_API float CalculateDirection(const FVector& Velocity, const FRotator& BaseRotation) const;

Parameters

Name	Type	Description	Default
Velocity	const FVector&	The velocity vector to compute the direction from, typically the character's movement velocity.	—
BaseRotation	const FRotator&	The reference rotation to measure the direction against, typically the character's actor rotation or control rotation.	—

Return Type

float

Example

Drive a locomotion blend space direction variable C++

void UMyAnimInstance::NativeUpdateAnimation(float DeltaSeconds)
{
	Super::NativeUpdateAnimation(DeltaSeconds);
	if (APawn* Pawn = TryGetPawnOwner())
	{
		FVector Velocity = Pawn->GetVelocity();
		FRotator Rotation = Pawn->GetActorRotation();
		Direction = CalculateDirection(Velocity, Rotation);
		Speed = Velocity.Size();
	}
}

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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