FVector::IsNearlyZero

function Core Since unknown

#include "Math/Vector.h"

Access: public Specifiers: const

Description

Returns true if all three components are within Tolerance of zero. Useful for checking if a velocity or direction vector has become negligible.

Signature

bool IsNearlyZero(T Tolerance = UE_KINDA_SMALL_NUMBER) const

Parameters

Name	Type	Description	Default
Tolerance	float	Maximum absolute value for each component to be considered nearly zero. Defaults to UE_KINDA_SMALL_NUMBER (1e-4).	UE_KINDA_SMALL_NUMBER

Return Type

bool

Caveats & Gotchas

• Tests each component independently against Tolerance — a vector with one large component and two near-zero components will return false.
• The default tolerance UE_KINDA_SMALL_NUMBER (1e-4) is more lenient than FMath::IsNearlyZero's default. This is intentional for typical vector usage in gameplay.
• For pure zero checks (no tolerance), use IsZero() instead — it performs an exact equality test.

Example

Guard direction use after interp C++

FVector Velocity = GetCharacterMovement()->Velocity;
if (!Velocity.IsNearlyZero())
{
	FVector FacingDir = Velocity.GetSafeNormal();
	SetActorRotation(FacingDir.Rotation());
}

Version History

Introduced in: unknown

Version	Status	Notes
5.6	stable	—

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