UKismetMathLibrary::Vector4_Size
#include "Kismet/KismetMathLibrary.h"
Access: public
Specifiers: staticUFUNCTIONBlueprintPure
Description
Returns the Euclidean length (magnitude) of a FVector4 including all four components: sqrt(X²+Y²+Z²+W²).
Caveats & Gotchas
- • All four components contribute including W. If your Vector4 holds a 3D direction with W=0, this is equivalent to Vector4_Size3 and either can be used. But if W is non-zero (e.g., a quaternion or homogeneous point), the result is the full 4D length which is rarely the intended spatial length.
- • Involves a square root — avoid calling in tight loops where Vector4_SizeSquared suffices (e.g., comparing magnitudes: compare squared values instead).
Signature
static UE_INL_API double Vector4_Size(const FVector4& A)Parameters
| Name | Type | Description | Default |
|---|---|---|---|
| A | const FVector4& | The vector whose magnitude is calculated. | — |
Return Type
double Example
Check whether a 4D vector is unit-length C++
FVector4 Q(0.0, 0.0, 0.7071, 0.7071); // quaternion-like
double Len = UKismetMathLibrary::Vector4_Size(Q);
bool bIsUnit = FMath::IsNearlyEqual(Len, 1.0, 1e-4);Version History
Introduced in: 4.0
| Version | Status | Notes |
|---|---|---|
| 5.6 | stable | — |
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