UKismetMathLibrary::Atan2

function Engine Blueprint Since 4.0

#include "Kismet/KismetMathLibrary.h"

Access: public Specifiers: staticUFUNCTIONBlueprintPure

Description

Returns the full-circle arc tangent of Y/X in radians, correctly handling all four quadrants. The result is in the range (-π, π].

Caveats & Gotchas

• Parameter order is Atan2(Y, X) — swapping them gives the complementary angle, a subtle bug that is hard to spot at runtime.
• When both Y and X are zero the result is 0 by convention, but this case often indicates a degenerate direction vector that should be guarded against upstream.

Signature

static UE_INL_API double Atan2(double Y, double X);

Parameters

Name	Type	Description	Default
Y	double	The Y component (numerator).	—
X	double	The X component (denominator).	—

Return Type

double

Example

Yaw angle of a 2D direction C++

FVector Dir = (TargetLocation - MyLocation).GetSafeNormal();
double YawRad = UKismetMathLibrary::Atan2(Dir.Y, Dir.X);
double YawDeg = UKismetMathLibrary::RadiansToDegrees(YawRad);

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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