UeD Tutorials By Rachel Cordone

Advanced xEmitters and xEmitter Properties

In this tutorial I am going to cover the properties of emitters and show you how to make various effects with them. Feel free to skip the first section if you are only trying to make one effect in particular.

There are 4 groups in the xEmitter’s properties that we need to go into to fully understand how to use them. Here is a pic highlighting what I will be covering here:


The two properties under Display that we are concerned about are Skins and Style.

Skins – Tells the emitter what texture to use for it’s particles. Textures specifically made for xEmitters are in the EmitterTextures and EmitterTextures2 packages, although you can try other textures for unique effects or special purposes.

Style – Sets the texture’s properties. Here is an example using a lense flare type texture:

Texture Examples

<- None, Normal, Particle

<- Masked

<- Translucent

<- Modulated

<- Alpha, AlphaZ

<- Additive

<- Subtractive

Modulated may look like Normal, but it’s similar to Translucent. The whiter the part of the texture, the more it shows through. For most applications you will want to use Translucent.


bSuspendWhenNotVisible – This turns off the emitter when you are not looking at any of the particles. Keeping this set to True lowers the resources needed to play the level.

mChildName – Assigns a Tag to particles produced by this emitter.

mDelayRange – Sets a time delay range between each set of particles produced.

mLifeRange – Particles die out at a random time between these two values.

mMaxParticles – The maximum number of particles that this xEmitter will have onscreen simultaneously. If this number is reached the emitter will wait until one dies out before producing another.

mParticleType – Sets the type of particle produced by this xEmitter.

Particle Types

Particle Types

Particle Types

Particle Types





mRegen – If set to true, the emitter will regenerate particles as they die out.

mRegenOffTime – Sets the range for the time that the emitter is Off (does not produce particles).

mRegenOnTime – Sets the range for the time that the emitter is On (produces particles).

mRegenRange – Sets the range for number of particles per second that the emitter produces.

mSpawningType – ST_Sphere – Particles travel in a straight line that can be adjusted with movement properties.
                           ST_Line – Particles appear along a straight line path and do not move.
                           ST_Explode – Particles shoot out in random directions.
                           ST_ExplodeRing – Particles shoot out in a ring pattern from the emitter.


mAirResistance – Sets the acceleration rate for the particles. A positive number will cause them to slow down, a negative number causes them to speed up.

DirDev – Direction Deviation. Set this to create random variations in the particle’s direction along the XYZ axis.

mMassRange – Causes the particles to be affected by gravity. Negative numbers cause them to be repelled.

mPosDev – Particles start at a random position along the axis between this radius.

mPosRelative – Setting this true makes the PosDev relative to the emitter’s direction instead of the XYZ axis.

mSpeedRange – Sets the particle’s speed range.

mSpinRange – Sets the spin rate for the particles.

Advanced xEmitters and xEmitter Properties Page 2


mAttenFunc – ATF_LerpInOut – Produces a slow fade in to full brightness.
                          ATF_ExInOut – Fades the particle in then out or double fades, based on the mAtten properties.
                          ATF_SmoothStep – Fades the particle in then out based on the mAtten settings.
                          ATF_Pulse – Produces a fade in and out, unadjusted.
                          ATF_Random – Particles jump to random brightness levels.
                          ATF_None – Particles are constantly at full brightness.

mAttenKa – Sets the fade in value for the particles (0-1).

mAttenKb – Sets the fade out or second fade value of the particles.

mAttenuate – Set to false is the same as ATF_None.

mColor Range – Sets the range of colors for the particles (random color between the two).

mGrowthRate – Setting this positive makes the particles grow larger over their lifetime. Negative values make themshrink.

mLifeColorMap – The color of the particle will follow the texture input:

mNumTileColumns – Set this to the number of columns in the Skin texture used.

mNumTileRows – Set this to the number of rows in the Skin texture used.

Important: ONLY set these values as a whole number greater than 0, otherwise it will crash the editor.
The game selects random tiles to display each time a particle is generated, to make effects like fire and water more realistic.

mRandOrient – Particles start at a random rotation.

mSizeRange – Particles start at a random size between these two values.

Example uses of xEmitters

Random Card Chucker




Water Stream



Thanks for reading and trying this one out.  I hope you enjoyed and learned something new.  I will have many more as we delve more into the wonderful world of Unreal Editor!