UKismetMathLibrary::VSizeXYSquared

function Engine Blueprint Since 4.0

#include "Kismet/KismetMathLibrary.h"

Access: public Specifiers: staticUFUNCTIONBlueprintPure

Description

Returns the squared length of a 3D vector's XY components without a square root. The most efficient option for top-down magnitude comparisons.

Caveats & Gotchas

• Z is ignored. Combine with a separate Z check if you need to validate both horizontal and vertical constraints simultaneously.
• Result is length-squared in the XY plane — compare against Threshold * Threshold, not the raw threshold. Mixing squared and unsquared comparisons is a frequent source of subtle gameplay bugs.

Signature

static UE_INL_API double VSizeXYSquared(FVector A);

Parameters

Name	Type	Description	Default
A	FVector	The 3D vector whose squared XY-plane length to compute.	—

Return Type

double

Example

Check horizontal speed cap efficiently C++

double HorizSpeedSq = UKismetMathLibrary::VSizeXYSquared(CharacterMovement->Velocity);
if (HorizSpeedSq > MaxHorizSpeed * MaxHorizSpeed)
{
    // clamp horizontal velocity
}

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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