UKismetMathLibrary::Matrix_InverseTransformVector

function Engine Blueprint Since 4.0

#include "Kismet/KismetMathLibrary.h"

Access: public Specifiers: staticBlueprintPure

Description

Transforms a direction vector by the inverse of the matrix without applying translation. Converts a world-space direction into the local space of the matrix. The header notes that for normals with non-uniform scale you should use TransformByUsingAdjointT instead.

Caveats & Gotchas

• This is not correct for transforming surface normals under non-uniform scaling. Normals must be transformed by the transpose of the inverse (adjoint), not the plain inverse. Use TransformByUsingAdjointT on FMatrix directly for that case.
• Like Matrix_InverseTransformPosition, this recomputes the inverse every call. Cache the inverse matrix if transforming many vectors.

Signature

static UE_INL_API FVector Matrix_InverseTransformVector(const FMatrix& M, FVector V)

Parameters

Name	Type	Description	Default
M	const FMatrix&	The transform matrix to invert before applying.	—
V	FVector	The world-space direction vector to transform into local space.	—

Return Type

FVector

Example

Convert a world-space impact normal into local space C++

FMatrix WorldToLocal = Actor->GetActorTransform().ToMatrixWithScale();
// OK for direction vectors that aren't surface normals
FVector LocalDir = UKismetMathLibrary::Matrix_InverseTransformVector(WorldToLocal, HitResult.ImpactNormal);

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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