FMath::GetDotDistance

function Core Since 4.0

#include "Math/UnrealMathUtility.h"

Access: public Specifiers: static

Description

Computes the dot-distance of a direction vector relative to a coordinate system, returning the cosine of azimuth and sine of elevation. Returns true if the direction is in front of the AxisX plane.

Caveats & Gotchas

• OutDotDist.X is the dot of Direction with AxisX projected onto the AxisX/AxisZ plane, not a raw dot product. Its sign indicates left (-) vs right (+) of the reference forward axis, not front/back — front/back is the function's return value.
• All input vectors should be unit-length. Passing non-normalised vectors will produce incorrect angular distances without any assertion or error.

Signature

static CORE_API bool GetDotDistance(FVector2D &OutDotDist, const FVector &Direction, const FVector &AxisX, const FVector &AxisY, const FVector &AxisZ)

Parameters

Name	Type	Description	Default
OutDotDist	FVector2D&	Output: X = cos(Azimuth) relative to the AxisX/AxisZ plane; Y = sin(Elevation) relative to the AxisX/AxisY plane.	—
Direction	const FVector&	The direction toward the target.	—
AxisX	const FVector&	Forward axis of the reference coordinate system.	—
AxisY	const FVector&	Right axis of the reference coordinate system.	—
AxisZ	const FVector&	Up axis of the reference coordinate system.	—

Return Type

bool

Example

Check if an enemy is in front of and to the right of the camera C++

FVector CamFwd, CamRight, CamUp;
CameraComponent->GetForwardVector().ToDirectionAndLength(CamFwd, (float&)0);
CamRight = CameraComponent->GetRightVector();
CamUp    = CameraComponent->GetUpVector();

FVector2D DotDist;
bool bInFront = FMath::GetDotDistance(
    DotDist,
    (EnemyLocation - CameraComponent->GetComponentLocation()).GetSafeNormal(),
    CamFwd, CamRight, CamUp
);
if (bInFront && DotDist.X > 0.f)
{
    // Enemy is in front and to the right
}

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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