ParticleEmitter

Subclasses of this class are used in Emitter actors. The settings are pretty complex and require a fair amount of trial and error to get used to. Some examples can be found in our ParticleEmitter cookbook.

Properties

Acceleration Group

vector Acceleration

Vector which determins the acceleration of the particles in any of the three planes

Collision Group

This group controls the particles' collision behavior.

array<plane> CollisionPlanes

Can be used to specify planes in the Unreal world the particle will collide with. The planes will be used for collision when UseCollisionPlanes is True.

rangevector DampingFactorRange

Damping applied to the particle's velocity when it collides with something.

vector ExtentMultiplier

A multiplier for the particles' size for collision calculations.

range MaxCollisions

Maximum number of collisions before the particle is destroyed. This property will only be used when UseMaxCollisions is True.

int SpawnAmount

The number of sub-particles spawned when the particles collide with something.

rangevector SpawnedVelocityScaleRange

The velocity of the spawned sub-particles.

int SpawnFromOtherEmitter

The ParticleEmitter within the same Emitter actor used for the sub-particles.

bool UseCollision

Whether the particles should use collision.

bool UseCollisionPlanes

Whether the particles should collide with the CollisionPlanes.

bool UseMaxCollisions

Whether the particles should be destroyed when they reach their maximum number of collisons.

bool UseSpawnedVelocityScale

Whether to use SpawnedVelocityScaleRange for collision sub-particles.

Color Group

rangevector ColorMultiplierRange

Used to randomize the color of the particles. X corresponds to red, Y corresponds to Green and Y corresponds to blue.

array<ParticleColorScale> ColorScale

Used to change the color of a particle over time. You set both a color you want it to be, and the relative time at which you want it to be that color. It will fade from whatever color it is to the color you want it to be over the interval you specify. The time is relative, so 0.5 would be half the particles lifespan.

float ColorScaleRepeats

How many times to repeat the color scales. Example, if you have a color scale that changes it to black at 0.5 time(half its lifespan), with color repeats it will be black by the time its half way done living. With one repeat, it will be black at 1/4 of its lifespan, normal at 1/2, and black again at 3/4ths of its lifespan.

bool UseColorScale

Must be true for ColorScales and ColorScaleRepeats to have any effect on the particles.

Fading Group

bool FadeIn

If true, it will fade the particle in

float FadeInEndTime

If FadeIn is true, this is the time at which the particle will have completly faded in and is 100% visible. This is NOT relative. 0.5 is 1/2 a second, not 1/2 of the particles lifespan.

plane FadeInFactor

Specifies how much each component of the particle colors should be faded. 1 means start at 0 while e.g. 0.5 means start at half the normal value. X,Y,Z correspond to R,G,B and W corresponds to the alpha value.

bool FadeOut

If true, the particle will fade out.

plane FadeOutFactor

Specifies how much each component of the particle colors should be faded. 1 means end at 0 while e.g. 0.5 means end at half the normal value. X,Y,Z correspond to R,G,B and W corresponds to the alpha value.

float FadeOutStartTime

If Fadeout is true, this is the absolute time at which the particle will start fading out. Fading out overrules fading in, so if a particle is not yet faded in and starts fading out, it will start at full color values.

Force Group

bool UseActorForces

Whether the particles can be affected by Actor forces.
Note: Setting this to True can cause a huge performance hit and will only work when physics details are set high enough.

General Group

EParticleCoordinateSystem CoordinateSystem

Determines how the settings in the location section are calculated. See /Enums.

EParticleEffectAxis EffectAxis

int MaxParticles (const)

Maximum number of particles that this ParticleEmitter can have at a time.

bool ResetAfterChange

Determines if this emitter reset after a change has been made to its properties. It currently has no effect. (emitter resets no matter what if you make a change)

Local Group

bool AutoDestroy

Determines if this emitter will destroy itself once all particles are gone.

bool AutoReset

Determines if this emitter will reset itself after a specified amount of time.

range AutoResetTimeRange

The time delay for auto-resets.

bool Disabled

If true, this emitter wont emit anything. This is useful if you only want to test one of several ParticleEmitters in an Emitter actor or want to enable/disable them from code.

bool DisableFogging

Determines if particles are affected by distance fog.

string Name

A name for this ParticleEmitter

bool RespawnDeadParticles

Determines if dead particles (i.e. particles that have exceeded their lifespan or maximum collisions) should be respawned.

Location Group

This sets the sets the dimensions of the emitter domain: the place where particles will spawn (though they may m,ove out of this afterwards).

int AddLocationFromOtherEmitter

You can specify another ParticleEmitter's index within the Emitter actor's Emitters array to spawn particles relative to that other emitter's particle locations.

range SphereRadiusRange

Used when StartLocationShape is Sphere. Particles will spawn any distance between the min and max from the center of the emitter. If both max and min are the same, particles will spawn all along the outside of a sphere with this radius.

vector StartLocationOffset

Offset from the origin of the ParticleEmitter's coordinate system. The type of coordinate system is selected under General → CoordinateSystem.

rangevector StartLocationPolarRange

Used when StartLocationShape is Polar. StartLocationPolarRange specifies spherical polar coordinates.

X

Presumably angle in the YZ plane, but just this and radius (i.e. 0 for both Y) just makes a line.

Y

Angle in the XZ plane. Set this to ( 0, 65536 ) and suitable radius for a disc shape.

Z

The radius.

rangevector StartLocationRange

Used when StartLocationShape is Box. See DM-Oceanic for a good example: for a line of bubbles, just set one co-ordinate, eg X: -64, 64. For a plane surface of bubbles, set two. The rotation of the enclosing Emitter actor orients this domain.

EParticleStartLocationShape StartLocationShape

Sets the shape. This determines which of the above numeric properties is used. See /Enums.

Mass Group

range StartMassRange

MeshSpawning Group

vector MeshNormal

range MeshNormalThresholdRange

rangevector MeshScaleRange

This determines the size scale of an emitted mesh. It takes each axis independantly, so setting a good range can result in a lot of different shapes on the same mesh.

EParticleMeshSpawning MeshSpawning

StaticMesh MeshSpawningStaticMesh

bool SpawnOnlyInDirectionOfNormal

bool UniformMeshScale

If this is true, the settings in meshscalerange are no longer used for each axis independantly. Instead, the mesh will be scaled along all axis using the x values.

bool UniformVelocityScale

bool UseColorFromMesh

bool VelocityFromMesh

rangevector VelocityScaleRange

Rendering Group

bool AcceptsProjectors

int AlphaRef

bool AlphaTest

bool ZTest

bool ZWrite

Revolution Group

Revolution moves all particles around a central point or area. This might be useful for vortex-like particle effects.

rangevector RevolutionCenterOffsetRange

The range of where the center of revolution for this particle will be

array<ParticleRevolutionScale> RevolutionScale

float RevolutionScaleRepeats

rangevector RevolutionsPerSecondRange

Determines how many times the particle will orbit the center per second, it takes each axis independantly.

bool UseRevolution

If true, the particles will orbit a center point.

bool UseRevolutionScale

Whether the RevolutionScale settings should be used.

Rotation

Rotation rotates the particle itself around its center.

bool DampRotation

Whether collision should affect a particle's rotation.

rangevector RotationDampingFactorRange

How collision affects the particle's rotation.

vector RotationNormal

The normal used when UseRotationFrom is set to PTRS_Normal.

rotator RotationOffset

vector SpinCCWorCW

The chance that particles will spin clockwise. 0 will make all particles spin counterclockwise, 0.7 will give a 70% chance that particles spin clockwise and a 30% chance for spinning counterclockwise.

bool SpinParticles

Whether particles should spin.

rangevector SpinsPerSecondRange

The range that determines how fast the particles will spin. X, Y and Z correspond to Pitch, Yaw and Roll.

rangevector StartSpinRange

Specifies the initial rotation of the particles. Again, X, Y and Z correspond to Pitch, Yaw and Roll.

EParticleRotationSource UseRotationFrom

What to base the rotation on. See /Enums.

Size

array<ParticleTimeScale> SizeScale

float SizeScaleRepeats

rangevector StartSizeRange

bool UniformSize

bool UseRegularSizeScale

bool UseSizeScale

Skeletalmesh

range RelativeBoneIndexRange

Actor SkeletalMeshActor

vector SkeletalScale

ESkelLocationUpdate UseSkeletalLocationAs

Sound

EParticleCollisionSound CollisionSound

range CollisionSoundIndex

range CollisionSoundProbability

array<ParticleSound> Sounds

EParticleCollisionSound SpawningSound

range SpawningSoundIndex

range SpawningSoundProbability

Spawning

bool AutomaticInitialSpawning

float InitialParticlesPerSecond

float ParticlesPerSecond

Texture

bool BlendBetweenSubdivisions

EParticleDrawStyle DrawStyle

int SubdivisionEnd

array<float> SubdivisionScale

int SubdivisionStart

Texture Texture

int TextureUSubdivisions

int TextureVSubdivisions

bool UseRandomSubdivision

bool UseSubdivisionScale

Tick

float MinSquaredVelocity

float SecondsBeforeInactive

Time

range InitialDelayRange

Determines how long before this emitter will become active

range InitialTimeRange

range LifetimeRange

Determines the lifespan of the particles that this emitter emits.

Trigger

bool ResetOnTrigger

float SpawnOnTriggerPPS

range SpawnOnTriggerRange

bool TriggerDisabled

Velocity

int AddVelocityFromOtherEmitter

rangevector AddVelocityMultiplierRange

EParticleVelocityDirection GetVelocityDirectionFrom

vector MaxAbsVelocity

range StartVelocityRadialRange

rangevector StartVelocityRange

bool UseVelocityScale

rangevector VelocityLossRange

array<ParticleVelocityScale> VelocityScale

float VelocityScaleRepeats

Warmup

float RelativeWarmupTime

float WarmupTicksPerSecond

Other Properties

These properties aren't visible in UnrealEd. All of them are transient, i.e. their value won't be saved when saving a game. Some of these properties represent scary internal stuff and probably shouldn't be touched.

int ActiveParticles

Currently active particles

bool AllParticlesDead

Whether all particles have died.

int BoneIndex

box BoundingBox

color Color

vector ColorMultiplier

int CurrentCollisionSoundIndex

int CurrentMeshSpawningIndex

int CurrentSpawningSoundIndex

int CurrentSpawnOnTrigger

int DeferredParticles

int Flags

vector GlobalOffset

int HitCount

bool Inactive

float InactiveTime

float InitialDelay

bool Initialized

int KillPending

float Mass

int MaxActiveParticles

float MaxLifetime

float MaxSizeScale

array<vector> MeshVertsAndNormals

vector OldLocation

vector OldMeshLocation

int OtherIndex

Emitter Owner

The Emitter actor this ParticleEmitter belongs to.

int ParticleIndex

Index into circular list of particles

array<Particle> Particles

Contains the data of all active particles. See /Structs for details about the Particle data type.

float PPSFraction

Used to keep track of fractional PPTick

int PS2Data

bool RealDisableFogging

vector RealExtentMultiplier

vector RealMeshNormal

vector RevolutionCenter

vector RevolutionsMultiplier

vector RevolutionsPerSecond

vector Size

vector SpinsPerSecond

vector StartLocation

vector StartSize

vector StartSpin

int Subdivision

float Time

float TimeTillReset

vector Velocity

vector VelocityMultiplier

bool WarmedUp

Enums

See /Enums.

Structs

See /Structs.

Methods

SpawnParticle (int Amount) [native]

Spawns a specified amount of particles.

Trigger ( ) [native]

Performs the action specified in the Trigger property group. This function is called by the parent Emitter actor's Trigger function.

Known Subclasses

•  BeamEmitter
•  MeshEmitter
•  SparkEmitter
• SpriteEmitter
• TrailEmitter? (abstract)

Related Topics

• ParticleEmitter Cookbook
•  EmittersReference
•  EmittersExamples

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Category Class (UT2003)

Foxpaw: TrailEmitters don't seem to work, even when you move them around. I couldn't find any combination of settings that produced a visible output. I think that they are a work in progress.

Wormbo: With a new class MyTrailEmitter extends TrailEmitter; and these Emitter properties I got a nice effect:

    Begin Object Class=MyTrailEmitter Name=MyTrailEmitter0
        Acceleration=(Z=-300.000000)
        StartSizeRange=(X=(Min=10.0,Max=10.0),Y=(Min=10.0,Max=10.0),Z=(Min=10.0,Max=10.0))
        StartVelocityRange=(X=(Min=-200.0),Y=(Min=-200.0,Max=200.0),Z=(Max=200.0))
        Name="MyTrailEmitter0"
    End Object
    Emitters(0)=MyTrailEmitter'myLevel.MyTrailEmitter0'

Foxpaw: Ah, I see. I was thinking that they worked differently, that if you moved the emitter it should leave a "trail" of particles behind. I see now that they operate very much like SparkEmitters, only with sprites instead of sparks.