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  3. USpringArmComponent

USpringArmComponent

This component tries to maintain its children at a fixed distance from the parent, but will retract the children if there is a collision, and spring back when there is no collision.

API > API/Runtime > API/Runtime/Engine

This component tries to maintain its children at a fixed distance from the parent, but will retract the children if there is a collision, and spring back when there is no collision.

Example: Use as a 'camera boom' or 'selfie stick' to keep the follow camera for a player from colliding into the world.

   
Name USpringArmComponent
Type class
Header File /Engine/Source/Runtime/Engine/Classes/GameFramework/SpringArmComponent.h
Include Path #include "GameFramework/SpringArmComponent.h"

Syntax

UCLASS (ClassGroup=Camera, Meta=(BlueprintSpawnableComponent), HideCategories=(Mobility),  
       MinimalAPI)  
class USpringArmComponent : public USceneComponent

Inheritance Hierarchy

Implements Interfaces

Constructors

Name Remarks Include Path Unreal Specifiers

USpringArmComponent ( const FObjectInitializer& ObjectInitializer
)

   GameFramework/SpringArmComponent.h  

Constants

Name Type Remarks Include Path
SocketName const FName The name of the socket at the end of the spring arm (looking back towards the spring arm origin) GameFramework/SpringArmComponent.h

Variables

Public

Name Type Remarks Include Path Unreal Specifiers
bClampToMaxPhysicsDeltaTime uint32 If true AND the view target is simulating using physics then use the same max timestep cap as the physics system. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Lag
bDoCollisionTest uint32 If true, do a collision test using ProbeChannel and ProbeSize to prevent camera clipping into level. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=CameraCollision
bDrawDebugLagMarkers uint32 If true and camera location lag is enabled, draws markers at the camera target (in green) and the lagged position (in yellow). GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Lag
bEnableCameraLag uint32 If true, camera lags behind target position to smooth its movement. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Lag
bEnableCameraRotationLag uint32 If true, camera lags behind target rotation to smooth its movement. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Lag
bInheritPitch uint32 Should we inherit pitch from parent component. Does nothing if using Absolute Rotation. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=CameraSettings
bInheritRoll uint32 Should we inherit roll from parent component. Does nothing if using Absolute Rotation. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=CameraSettings
bInheritYaw uint32 Should we inherit yaw from parent component. Does nothing if using Absolute Rotation. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=CameraSettings
bIsCameraFixed bool Temporary variables when applying Collision Test displacement to notify if its being applied and by how much GameFramework/SpringArmComponent.h  
bUseCameraLagSubstepping uint32 If bUseCameraLagSubstepping is true, sub-step camera damping so that it handles fluctuating frame rates well (though this comes at a cost). GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Lag
  • AdvancedDisplay
bUsePawnControlRotation uint32 If this component is placed on a pawn, should it use the view/control rotation of the pawn where possible? When disabled, the component will revert to using the stored RelativeRotation of the component. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=CameraSettings
CameraLagMaxDistance float Max distance the camera target may lag behind the current location. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Lag
  • Meta=(editcondition="bEnableCameraLag", ClampMin="0.0", UIMin="0.0")
CameraLagMaxTimeStep float Max time step used when sub-stepping camera lag. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Lag
  • AdvancedDisplay
  • Meta=(editcondition="bUseCameraLagSubstepping", ClampMin="0.005", ClampMax="0.5", UIMin="0.005", UIMax="0.5")
CameraLagSpeed float If bEnableCameraLag is true, controls how quickly camera reaches target position. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Lag
  • Meta=(editcondition="bEnableCameraLag", ClampMin="0.0", ClampMax="1000.0", UIMin="0.0", UIMax="1000.0")
CameraRotationLagSpeed float If bEnableCameraRotationLag is true, controls how quickly camera reaches target position. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Lag
  • Meta=(editcondition="bEnableCameraRotationLag", ClampMin="0.0", ClampMax="1000.0", UIMin="0.0", UIMax="1000.0")
PreviousArmOrigin FVector   GameFramework/SpringArmComponent.h  
PreviousDesiredLoc FVector Temporary variables when using camera lag, to record previous camera position GameFramework/SpringArmComponent.h  
PreviousDesiredRot FRotator Temporary variable for lagging camera rotation, for previous rotation GameFramework/SpringArmComponent.h  
ProbeChannel TEnumAsByte< ECollisionChannel > Collision channel of the query probe (defaults to ECC_Camera) GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=CameraCollision
  • Meta=(editcondition="bDoCollisionTest")
ProbeSize float How big should the query probe sphere be (in unreal units) GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=CameraCollision
  • Meta=(editcondition="bDoCollisionTest")
SocketOffset FVector Offset at end of spring arm; use this instead of the relative offset of the attached component to ensure the line trace works as desired GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Camera
TargetArmLength float Natural length of the spring arm when there are no collisions GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Camera
TargetOffset FVector Offset at start of spring, applied in world space. GameFramework/SpringArmComponent.h
  • EditAnywhere
  • BlueprintReadWrite
  • Category=Camera
UnfixedCameraPosition FVector   GameFramework/SpringArmComponent.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

virtual FRotator GetDesiredRotation()

 Returns the desired rotation for the spring arm, before the rotation constraints such as bInheritPitch etc are enforced. GameFramework/SpringArmComponent.h  

FRotator GetTargetRotation ()

 Get the target rotation we inherit, used as the base target for the boom rotation. GameFramework/SpringArmComponent.h
  • BlueprintCallable
  • Category=SpringArm

FVector GetUnfixedCameraPosition()

 Get the position where the camera should be without applying the Collision Test displacement GameFramework/SpringArmComponent.h
  • BlueprintCallable
  • Category=CameraCollision

bool IsCollisionFixApplied()

 Is the Collision Test displacement being applied? GameFramework/SpringArmComponent.h
  • BlueprintCallable
  • Category=CameraCollision

Overridden from USceneComponent

Name Remarks Include Path Unreal Specifiers

virtual FTransform GetSocketTransform ( FName InSocketName,
ERelativeTransformSpace TransformSpace
) const

 Get world-space socket transform. GameFramework/SpringArmComponent.h  

virtual bool HasAnySockets()

 Returns true if this component has any sockets GameFramework/SpringArmComponent.h  

virtual void QuerySupportedSockets ( TArray< FComponentSocketDescription >& OutSockets
) const

 Get a list of sockets this component contains GameFramework/SpringArmComponent.h  

Overridden from UActorComponent

Name Remarks Include Path Unreal Specifiers

virtual void ApplyWorldOffset ( const FVector& InOffset,
bool bWorldShift
)

 Called by owner actor on position shifting Component should update all relevant data structures to reflect new actor location GameFramework/SpringArmComponent.h  

virtual void OnRegister()

 Called when a component is registered, after Scene is set, but before CreateRenderState_Concurrent or OnCreatePhysicsState are called. GameFramework/SpringArmComponent.h  

virtual void TickComponent ( float DeltaTime,
enum ELevelTick TickType,
FActorComponentTickFunction* ThisTickFunction
)

 Function called every frame on this ActorComponent. GameFramework/SpringArmComponent.h  

Overridden from UObject

Name Remarks Include Path Unreal Specifiers

virtual void PostLoad()

   GameFramework/SpringArmComponent.h  

Protected

Name Remarks Include Path Unreal Specifiers

virtual FVector BlendLocations ( const FVector& DesiredArmLocation,
const FVector& TraceHitLocation,
bool bHitSomething,
float DeltaTime
)

 This function allows subclasses to blend the trace hit location with the desired arm location; by default it returns bHitSomething ? TraceHitLocation : DesiredArmLocation GameFramework/SpringArmComponent.h  

virtual void UpdateDesiredArmLocation ( bool bDoTrace,
bool bDoLocationLag,
bool bDoRotationLag,
float DeltaTime
)

 Updates the desired arm location, calling BlendLocations to do the actual blending if a trace is done GameFramework/SpringArmComponent.h  

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