# Roll, Pitch, Yaw rotations - Strange Behavior

**URL:** <https://forums.unrealengine.com/t/roll-pitch-yaw-rotations-strange-behavior/286938>\
**Category:** Programming & Scripting\
**Tags:** unreal-engine\
**Created:** [June 28, 2014, 11:41am UTC](https://forums.unrealengine.com/t/roll-pitch-yaw-rotations-strange-behavior/286938 "2014-06-28T11:41:03Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![dbrizov](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@dbrizov](https://forums.unrealengine.com/u/dbrizov)\
**Post date:** [June 28, 2014, 11:41am UTC](https://forums.unrealengine.com/t/roll-pitch-yaw-rotations-strange-behavior/286938/1 "2014-06-28T11:41:03Z")

</div>

Hi guys, I am rotating an object and I found a strange behavior. I manually set the rotation of the object in the scene so that the **Local Coord System** of the object is not equal to the **World Coord System**. When I rotate the object around the **Roll(X) and Pitch(Y)** axes, the rotation is performed around the **Local X and Y** axes of the object. However, when I rotate the object around the **Yaw(Z)** axis, the rotation is performed around the **World Z axis**. Is this a correct behavior or I am not using the **SerActorRotation(FRotator NewRotation)** method correctly?

Here is the code:

```
// Pickup.h

UCLASS()
class APickup : public AActor
{
	GENERATED_UCLASS_BODY()

public:
	/** The root component of the pickup object */
	UPROPERTY(VisibleDefaultsOnly, BlueprintReadOnly, Category = "Components")
	TSubobjectPtr<USceneComponent> SceneComponent;

	/** The static mesh of the pickup object */
	UPROPERTY(VisibleDefaultsOnly, BlueprintReadOnly, Category = "Components")
	TSubobjectPtr<UStaticMeshComponent> PickupMesh;

	/** The rotation rate of the pickup object in degrees/second for each axis of the FRotator */
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Rotation")
	FRotator RotationRate;

	virtual void Tick(float DeltaTime) override;
};

// Pickup.cpp

APickup::APickup(const FPostConstructInitializeProperties& PCIP)
	: Super(PCIP)
{
	this->PrimaryActorTick.bCanEverTick = true;

	this->SceneComponent = PCIP.CreateDefaultSubobject<USceneComponent>(this, TEXT("SceneComponent"));
	this->RootComponent = this->SceneComponent;

	this->PickupMesh = PCIP.CreateDefaultSubobject<UStaticMeshComponent>(this, TEXT("PickupMesh"));
	this->PickupMesh->AttachTo(this->RootComponent);

	this->RotationRate = FRotator(180.0f, 0.0f, 0.0f);
}

void APickup::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

	this->SetActorRotation(this->GetActorRotation() + (this->RotationRate * DeltaTime));
}

```

---

<div class="post-metadata">

**Author:** ![AnxGotta](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@AnxGotta](https://forums.unrealengine.com/u/AnxGotta)\
**Post date:** [June 28, 2014, 1:32pm UTC](https://forums.unrealengine.com/t/roll-pitch-yaw-rotations-strange-behavior/286938/2 "2014-06-28T13:32:34Z")

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First off, the docs say `SetActorRotation`(**[link](https://docs.unrealengine.com/latest/INT/API/Runtime/Engine/GameFramework/AActor/SetActorRotation/index.html)**):

```
bool AActor::SetActorRotation(FRotator NewRotation)
{
    if (RootComponent)
    {
        return RootComponent->MoveComponent( FVector::ZeroVector, NewRotation, true );
    }
 
    return false;
}

```

So if we look at `MoveComponent`, the docs say (**[link](https://docs.unrealengine.com/latest/INT/API/Runtime/Engine/Components/USceneComponent/MoveComponent/index.html)**):

```
NewRotation Parameter ==> The new desired rotation in world space.

```

So this function you are using sets the new rotation relative to world space coordinates.

Here are two suggestions for what you are trying to do:

Use `AddActorLocalRotation` (**[link](https://docs.unrealengine.com/latest/INT/API/Runtime/Engine/GameFramework/AActor/AddActorLocalRotation/index.html)**).

```
void APickup::Tick(float DeltaTime)
{
    Super::Tick(DeltaTime);

    this->AddActorLocalRotation(this->RotationRate * DeltaTime, false);

}

```

Hopefully this fixes the problem for you =)

**Edit:** I initially had two functions to choose from for modifying local rotation… I haven’t tested one so I removed it from the answer. The remaining one should work fine as I currently use it this way.

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<div class="post-metadata">

**Author:** ![dbrizov](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@dbrizov](https://forums.unrealengine.com/u/dbrizov)\
**Post date:** [June 28, 2014, 3:23pm UTC](https://forums.unrealengine.com/t/roll-pitch-yaw-rotations-strange-behavior/286938/3 "2014-06-28T15:23:05Z")

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Thank you very much mate, very useful answer. I guess I need to spend some more time exploring the docs.

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<div class="post-metadata">

**Author:** ![AnxGotta](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@AnxGotta](https://forums.unrealengine.com/u/AnxGotta)\
**Post date:** [June 28, 2014, 4:03pm UTC](https://forums.unrealengine.com/t/roll-pitch-yaw-rotations-strange-behavior/286938/4 "2014-06-28T16:03:49Z")

</div>

The class hierarchy in UE is pretty big and can become overwhelming quickly. The reason I made the answer like this is so you can use the same logic to help you (and others) debug future problems that are similar in nature =)

I’m glad the solution worked for you as I had a very similar problem in the past =D