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Components Reference

Document Summary: A description of the various components utilized in the Unreal Engine.

Document Changelog: Created by Andrew Scheidecker. Updated by Scott Sherman.

PrimitiveComponent

primitive.jpg

Collision Property Description Default
BlockRigidBody If True, the component will block Rigid Bodies. False
RBChannel Indicates what type of object this should be considered for rigid body collision. RBCC_Default
RBCollideWithChannels Types of objects that this physics objects will collide with. None
Lighting Property Description Default
bAcceptsDynamicLights Whether the primitive is affected by dynamic lights. True
bAcceptsLights Whether the primitive is affected by any light. False
bAllowAmbientOcclusion Controls whether ambient occlusion should be allowed on or from this primitive, only has an effect on movable primitives. Note that setting this flag to FALSE will negatively impact performance. True
bCastDynamicShadow Whether the primitive should cast a dynamic shadow. True
bCastHiddenShadow Whether the primitive should cast a shadow when HiddenGame is true. False
bForceDirectLightMap If True, forces all static lights to use lightmaps for this primitive, regardless of the light's UseDirectLightMap property. False
bUsePrecomputedShadows Whether the primitive should use shadowmaps (static shadows). False
CastShadow Whether to cast any shadows or not. False
LightingChannels Lighting channels controls light/primitive interaction. Interaction is only allowed if at least one channel is shared. None
Physics Property Description Default
bFluidDrain Whether this object should act as a 'drain' for fluid, and destroy fluid particles when they contact it. False
bFluidTwoWay Whether fluid interaction with this object should be 'two-way' - that is, force should be applied to both fluid and object. False
bIgnoreRadialForce Will ignore radial forces applied to this component. False
bIgnoreRadialImpulse Will ignore radial impulses applied to this component. False
bNotifyRigidBodyCollision Whether the OnRigidBodyCollision function should be called for physics collisions involving this PrimitiveComponent. False
bUseEffectScene Whether to run physics for this object in a separate 'effect' scene that contains no world geometry, but is ticked after PostAsyncWork (but before the final component updating). False
bUseHardwareScene Whether this should be placed in a hardware scene. False
PhysMaterialOverride Allows you to override the PhysicalMaterial to use for this PrimitiveComponent. None
PrimitiveComponent Property Description Default
AbsoluteRotation If True, the Rotation will be in world units (as opposed to relative to the Actor). False
AbsoluteScale If True, the Scale will be in world units (as opposed to relative to the Actor). False
AbsoluteTranslation If True, the Translation offset will be in world coordinates (as opposed to relative to the Actor). False
bIgnoreHiddenActorsMembership (Hack to allow the primitive to be rendered even if the parent actor is part of the camera's HiddenActors array.) False
Rotation Sets the rotation offset of the component. (Pitch 0, Roll 0, Yaw 0)
Scale Sets the uniform scale of the component. 1.0
Scale3D Sets the scale of the component per axis. (1, 1, 1)
Translation Sets the position offset of the component. (0, 0, 0)
Rendering Property Description Default
bAcceptsDecals Whether the primitive will accept any decals. False
bAcceptsDecalsDuringGameplay Whether the primitive will accept decals that are spawned during gameplay. Treated as False if bAcceptDecals is False. True
bAllowApproximateOcclusion If True, this primitive will not need exact occlusion information. False
bForceMipStreaming If True, forces all the primitive's textures to be fully loaded (with all mips) whenever its level is loaded. False
bOnlyOwnerSee If True, this primitive will only be visible when the view actor is the component's owner (directly or indirectly). False
bOwnerNoSee If True, this primitive will be invisible when the view actor is the component's owner (directly or indirectly). False
bUseAsOccluder Whether this primitive should be used to occlusion cull other primitives. False
CullDistance The distance where this primitive should be culled. 0 is treated as 'unlimited'. The distance calculation uses the center of the primitive's bounding sphere. 0.0
DepthPriorityGroup Which scene depth priority group to draw the primitive in. SDPG_World
HiddenEditor Whether this primitive should be hidden in the editor. False
HiddenGame Whether this primitive should be hidden in the game. False
MotionBlurScale Adjusts how blurry this primitive will be when it's motion blurred. 0.0 turns off motion blur for this primitive. 1.0

StaticMeshComponent

Extends upon PrimitiveComponent.

staticmesh.jpg

AdvancedLighting Property Description Default
bUseSubDivisions If True, use subdivisions instead of just the triangle vertices for static vertex lighting. True
MaxSubDivisions Maximum number of subdivisions. 8
MinSubDivisions Minimum number of subdivisions, needs to be at least 2. 2
SubDivisionStepSize Subdivision step size for static vertex lighting. 16
Rendering Property Description Default
Materials The assigned StaticMesh will have its own Materials assigned to it, but if you wish to change them, you can add fields to this array and then assign the selected Material in the generic browser, with the Use button. Empty
StaticMeshComponent Property Description Default
bIgnoreInstanceForTextureStreaming Ignore this instance of this static mesh when calculating texture streaming information. This can be useful when doing things like applying character textures to static geometry, to avoid them using distance-based streaming. False
bOverrideLightMapResolution Whether to override the lightmap resolution defined in the static mesh. True
OverriddenLightMapResolution Lightmap resolution to use if bOverrideLightMapResolution is True. 0
StaticMesh The assigned StaticMesh. None
WireframeColor Color to use when drawing the StaticMesh in wireframe. Blue-Green

Different default properties:

Collision Property Default
BlockRigidBody True
Lighting Property Default
bAcceptsLights True
bUsePrecomputedShadows True
CastShadow True
Rendering Property Default
bAcceptsDecals True
bUseAsOccluder True

SkeletalMeshComponent

With this component you can place a SkeletalMesh into your level. Note that this is not a pawn that you can assign AI Scripts to but more like a statue in the level in the shape of a SkeletalMesh.

skeletalmesh.gif

Property Description Default
SkeletalMesh Here you can assign a SkeletalMesh None
Animations This feature has not yet been documented. None
PhysicsAsset This feature has not yet been documented. None
Attachments This feature has not yet been documented. None
Materials The assigned SkeletalMesh will have its own Materials assigned to it, but if you wish to change them, you can add fields to this array and then assign the selected Material in the Generic Browser, with the Use button. None

ArrowComponent

This Component is used for showing the direction of an Actor (such as in a SpotLight Actor). Here are all of the fields alterable under the ArrowComponent tab:

arrow.gif

Property Description Default
ArrowColor Sets the color of the arrow (color picker available) Red
ArrowSize the factor by which the length of the neck of the arrow is multiplied. (1 = 48 units long, 2 = 96 units long, 10 = 480 units long) 1.0

AudioComponent

This Component defines additional per instance properties for a playing sound. Most of the properties (delay, looping, attenuation, etc.) are stored in the sound cue.

Property Description Default
Sound The name of the sound file assigned to this actor None
InstanceParameters Used to pass information into the SoundNodeWaveParam sound node Empty
PitchMultiplier Used to play a sound at a higher or lower frequency 1.0
PriorityMultiplier Used to prioritise sounds; the higher the value, the less likely the sound will be dropped 1.0
SoundCue The sound cue to be played None
VolumeMultiplier Used to make sounds quieter or louder; 0.0 is completely silent, 1.0 is full volume. 1.0

CylinderComponent

This Component creates a non-visible in game cylinder that can be used to detect collisions between other Actors. In order to activate the blocking aspect of this component, you must set the proper settings under the main collision tab in the Actors properties (not the seemingly relevant fields within the Components tab pictured below).

cylinder.gif

Property Description Default
CollisionHeight This value is half of the total height of the collision cylinder 22.0  
CollisionRadius This is the radius of the collision cylinder 22.0

DynamicLightEnvironmentComponent

DynamicLightEnvironmentComponent samples the static lights affecting the actor, and creates a fixed number of lights to represent it.

See LightEnvironments for more information on using DynamicLightEnvironmentComponent.

Property Description Default
bEnabled Changes whether the actor will use the DynamicLightEnvironmentComponent, or normal lighting. True
LightVisibilityRefreshTime The seconds that the actor's static shadowing will be cached between updates. 0.2
InvisibleUpdateTime The seconds between light environment updates when the actor isn't visible. 2.0
EnvironmentTransitionTime The seconds it takes to crossfade between light environment changes. 0.3
MinTimeBetweenFullUpdates The minimum number of seconds between light environment updates. 0.15
AmbientShadowColor The color of the environment's ambient shadow-only light. R=0.15 G=0.15 B=0.15
AmbientShadowSourceDirection The direction of the environment's ambient shadow-only light. X=0 Y=0 Z=1

HeightFogComponent

See HeightFog.

LineBatchComponent

This is an internal component that speeds up line drawing. It cannot be editted. Nothing to see here.

ParticleSystemComponent

The ParticleSystemComponent represents an instance of a particle system. Typically, it is found under the properties of an AEmitter actor that has been placed in a level.

PSysComp.jpg

Property Description Default
bAutoActivate Indicates whether the particle system will activate automatically at level start. TRUE
bResetonDetach Indicates the particle system should reset when detached from the scene. FALSE
InstanceParameters An array of parameters sets specifically for this instance of the particle system. EMPTY
SecondsBeforeInactive The number of seconds the system should wait while not being rendered before de-activating itself. 0.0 for PSysComp default, 1.0 for AEmitter usage
Template The UParticleSystem to use as the template for the component. EMPTY

Light Components

For more information about lighting visit LightingReference, ShadowingReference and MasteringUnrealIntroToLighting.

Common Light Properties

Properties that are common for all lights.

commonlight.jpg

Property Description Default
bCastCompositeShadow If True the light will contribute to the composite shadow for primitives which use a composite light environment. True
bEnabled Whether the light is enabled or not. True
bForceDynamicLight If True the light will be dynamic - producing dynamic stencil shadows and not using pre-calculated lighting in lightmaps or shadowmaps. False
bOnlyAffectSameAndSpecifiedLevels Whether to only affect primitives that are in the same level or in one of the explitly specified levels. False
Brightness This determines the brightness of the light. 1.0
bUseVolumes Whether to use the inclusion and exclusion volumes. False
CastDynamicShadows Whether the light should produce shadows from primitives that can cast dynamic shadows. True
CastShadows Whether the CastDynamicShadows and CastStaticShadows properties are used or not. True
CastStaticShadows Whether the light should produce shadows from primitives that can cast static shadows. True
ExlusionVolumes If bUseVolumes is True, primitives who touch one or more of these volumes will not be affected by the light, overriding the InclusionVolumes. Empty
Function Optional light function to project from the light. None
Function -> Scale The size of the light function in light space, where Z points out from the light and X and Y make up the perpendicular (texture) plane. (1024,1024,1024)
Function -> SourceMaterial The material to use for the light function projection. This is a requred field, and the material must have bUsedAsLightFunction set to True. Only the Emmissive output is used from the material. Empty
InclusionVolumes If bUseVolumes is True, primitives must touch one or more of these volumes to be affected by the light. Empty
LightAffectsClassification This property is for organizational purposes. With this, you can look at an existing light and understand the purpose of it. It's also useful for searches. For instance, you can search for all lights that affects dynamic objects and then show which ones are not explicitly set to Dynamic Affecting. LAC_DYNAMIC_AND_STATIC_AFFECTING
LightColor The color of the light (color picker available) White
LightingChannels The light will only affect primitives where there is an overlap between their lighting channels. See also LightingChannels BSP/Static/Dynamic/CompositeDynamic
LightShadowMode Type of shadowing used. Note that LightShadow_Normal requires the shadow receiver to be dynamically lit to show any shadows. See also ModulatedShadows. LightShadow_Normal
MaxShadowResolution Maximum resolution of the shadow buffer. If 0, it will use the value specified in BaseEngine.ini. A projected shadow will fade out as it approaches the minimum resolution. 0
MinShadowResolution Miniimum resolution of the shadow buffer. If 0, it will use the value specified in BaseEngine.ini. 0
ModShadowColor Shadow color, if LightShadowMode is set to LightShadow_Modulate. Black
OtherLevelsToAffect The set of other levels to affect if bOnlyAffectSameAndSpecifiedLevels is True. Empty
ShadowProjectionTechnique Specifies which technique to use to filter projected shadows. See also ShadowBufferFilteringOptions. ShadowProjTech_Default
UseDirectLightMap If True, the light will be precalculated into lightmaps for static geometry. False

DirectionalLightComponent

Additional properties for a DirectionalLightComponent. See also LightingReference: DirectionalLight.

directionallight.jpg

Property Description Default
TraceDistance Maximum distance between two objects in order to produce a shadow. 100000.0

PointLightComponent

Additional properties for a PointLightComponent. See also LightingReference: PointLight.

pointlight.jpg

Property Description Default
FalloffExponent How fast the light intensity falls off. Higher values make the light fade out quicker. 2.0
Radius Maximum radius of the light, at which point the light drops off to complete darkness. 1024.0
ShadowFalloffExponent Works as FalloffExponent, but for modulated shadows. 2.0
Translation With this property, the light can be moved away from the actor's position. (0, 0, 0)

Different default properties:

Property Default
bCastCompositeShadow False
CastDynamicShadows False
LightAffectsClassification LAC_STATIC_AFFECTING
UseDirectLightMap True
LightingChannels BSP/Static/CompositeDynamic

SkyLightComponent

Additional properties for a SkyLightComponent. See also LightingReference: Skylight.

skylight.jpg

Property Description Default
LowerBrightness Controls the brightness of the lower hemisphere of the skylight. 0.0
LowerColor Light color for the lower hemisphere of the skylight. White

Different default properties:

Property Default
CastShadows False
LightAffectsClassification LAC_USER_SELECTED

SpotLightComponent

Additional properties for a SpotLightComponent. See also LightingReference: SpotLight.

spotlight.jpg

Property Description Default
FalloffExponent How fast the light intensity falls off. Higher values make the light fade out quicker. 2.0
InnerConeAngle Determines how large the inner cone is (in degrees). The light within the inner cone has full brightness. 0.0
OuterConeAngle Determines how large the outer cone is (in degrees). The light within the outer cone falls off gradually. 44.0
Radius Maximum radius of the light, at which point the light drops off to complete darkness. 1024.0
ShadowFalloffExponent Works as FalloffExponent, but for modulated shadows. 2.0
Translation With this property, the light can be moved away from the actor's position. (0, 0, 0)

Different default properties:

Property Default
bCastCompositeShadow False
CastDynamicShadows False
LightAffectsClassification LAC_STATIC_AFFECTING
UseDirectLightMap True
LightingChannels BSP/Static/CompositeDynamic

SceneCaptureComponent

All SceneCaptureComponent types have a set of common properties that can be modified.

Property Description Default
TextureTarget Render-to-texture resource for the resulting scene capture. Note that the scene capture won't render anything unless it has an assigned target texture. None
bEnablePostProcess Toggles the post processing step that is applied to the scene False
bEnableFog Toggles any height fog rendering False
ClearColor The background clear color for the texture target Color(0,0,0)
ViewMode Enumerates the differnet view and lighting configurations SceneCapView_LitNoShadows
SceneLOD Sets the maximum Level of Detail (LOD) setting for all geometry in the scene (Currently not implemented)
FrameRate Sets the FPS (Frames per Second) rate to capture the scene 30 Hz
PostProcess Post process chain to be used by the capture None

The available modes are:

Mode Description
SceneCapView_Lit Default rendering mode for UE3 scenes with dynamic shadows and lighting
SceneCapView_Unlit No shadows or lighting passes are used when rendering the scene
SceneCapView_LitNoShadows Same as the default lit rendering mode but without dynamic shadows
SceneCapView_Wire All geometry in the scene is rendered using wireframe mode

SceneCapture2DComponent

This component handles rendering 2D captures.

Property Description Default
Common SceneCaptureComponent properties
FieldOfView The horizontal field of view used to calculate the view projection 80 deg
NearPlane The screen aligned view distance that represents the near clip plane 20
FarPlane The screen aligned view distance that represents the far clip plane 500
bUpdateMatrices If this flag is set to false then the view and projection matrices are not automatically updated, and they can be set manually True

SceneCaptureCubeMapComponent

This component handles rendering the six capture passes for each face of a cube map render target texture.

Property Description Default
Common SceneCaptureComponent properties
NearPlane The screen aligned view distance that represents the near clip plane 20
FarPlane The screen aligned view distance that represents the far clip plane 500

SceneCaptureReflectComponent (Dynamic Reflections)

This component handles rendering the scene using a mirror plane to flip the current view and to clip all the geometry that is behind the plane.

Property Description Default
Common SceneCaptureComponent properties
ScaleFOV not used 0

SceneCapturePortalComponent

This component renders the scene as if it was viewed through a portal at another location.

Property Description Default
Common SceneCaptureComponent properties
ViewDestination The actor at the view location for this portal None
ScaleFOV not used 0

SpriteComponent

This Component creates an icon at the center of the placed Actor that always faces the camera. It is mainly used in the editor and is not normally found as an edittable property.

Property Description Default
Sprite Here you can set what texture will be displayed (a texture -not a material, must be used) Texture2D'EngineResources.S_Actor'
bIsScreenSizeScaled Whether to scale with the screen size, or leave the same dimensions as the screen changes size false
ScreenSize The sprite has the size of this fraction of the screen size in each dimension 0.1

WindDirectionalSourceComponent

This feature has not yet been documented.

winddirection.gif

Property Description Default
Strength   1.0
Phase   0.0
Frequency   1.0

WindPointSourceComponent

This feature has not yet been documented.

windpoint.gif

Property Description Default
Strength   1.0
Phase   0.0
Frequency   1.0
Radius   1.0
Duration   0.0