UKismetMathLibrary::Quat_FindBetweenNormals

function Engine Blueprint Since 4.15

#include "Kismet/KismetMathLibrary.h"

Access: public Specifiers: staticBlueprintPure

Description

Generates the shortest quaternion rotation between two unit-length vectors. Faster than Quat_FindBetweenVectors because it skips internal normalization.

Caveats & Gotchas

• Both input vectors must be unit-length; passing non-normalized vectors will produce incorrect rotations without any error or assert in shipping builds.
• The antiparallel case (dot product == -1) still produces an arbitrary perpendicular rotation. If you need a deterministic fallback for opposite normals, pick a fallback axis explicitly.

Signature

static UE_INL_API FQuat Quat_FindBetweenNormals(FVector StartNormal, FVector EndNormal);

Parameters

Name	Type	Description	Default
StartNormal	FVector	Unit-length vector the rotation starts from.	—
EndNormal	FVector	Unit-length vector the rotation ends at.	—

Return Type

FQuat

Example

Align a mesh normal to a surface hit normal C++

// MeshUp is already unit-length (e.g. actor Up vector)
FVector MeshUp = GetActorUpVector();
FVector SurfaceNormal = HitResult.Normal; // normals from line traces are already unit
FQuat AlignRot = UKismetMathLibrary::Quat_FindBetweenNormals(MeshUp, SurfaceNormal);
SetActorRotation((AlignRot * GetActorQuat()).Rotator());

Version History

Introduced in: 4.15

Version	Status	Notes
5.6	stable	—

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