UE4 Particle system Basic properties for self-study

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One of the most effective ways to achieve stunning effects in a game is to use a particle system. The current UE4 version is 4.8.1. The UE4 has a very powerful modular particle system editor called Cascade. Like the universal particle system design, the UE4 particle system produces particles from the emitter and achieves different effects by setting the properties of the emitter and the particles. In a single particle system, UE4 can add multiple transmitters at the same time, which can be combined to achieve a very flashy effect. In the editor, the emitter is evaluated from left to right, while the module's order of operations is from top to bottom. The UE4 particle system supports LOD at the same time to effectively control the amount of particles consumed in the scene. Particles in the system can also receive light, as long as the material is used to set. There is a problem with the Blit label on the LOD in the current document, which can be referred to Answerhub. As with other UE4 parts, most of the properties are very easy to understand. However, it is necessary to pass the document over and over again to know what features are available in the system and which are not.

Particle System Class
The properties of the particle system itself, click on the empty space without the emitter will appear.
Particle System
System Update Mode
The updating mode of particle system is divided into real-time and fixed two kinds, which are usually used in real time.
Update Time_fps
Step setting in fixed-time mode.
Warmup time
Warm-up time. The time the particle system should initially be in, usually used for environmental effects such as fog, to ensure that the particle system is in full state at the beginning of the game. Will consume a certain amount of computation.
Warmup Tick Rate
System Preheat step. The lower the numerical accuracy, the higher the value, the lower the computational consumption. 0 represents the default stride size.
Orient Zaxis toward Camera
Locks the z axis of the particle to the camera.
Seconds before Inactive
When the particle system is no longer being rendered, after how long it takes to stop the operation, 0 means no stop.
Thumbnail
Content browser thumbnail with attributes, there is nothing particularly noteworthy about the place.
Lod
LOD-related properties of the particle system.
LOD Distance Check Time
The time interval for checking the distance of the particle system, which only works when the Lod method is set to Automatic, is used to automatically toggle LOD display.
LOD Method
How Lod is switched. Automatic is determined automatically by the distance, Directset is adjusted by the code, activateautomatic to the code when the system is initialized.
LOD Distances
The distance range of the LOD level is set, and each value represents the maximum distance of the current level.
LOD Settings
As described at the beginning, this property does not currently make sense because the current lit property appears to be unavailable.
Bounds
The boundary box body, which is controlled by the switch, determines that the particle system is no longer calculated when the particle is not in the field of view to reduce system consumption.
Clicking Set fixed boundary directly on the toolbar above will automatically generate one, and then you can manually fine-tune it in the properties.
Image
Delay
Delay, setting the time at which the particle system delays activation after calling Activatesystem.
Delay
The time of the delay.
Delay Low
The lower limit of the delay time, requires the following range switch to start.
Use Delay Range
The delay range switch. The delay after opening will be random between [delay low ~ delay].
Macro UV
Chinese name is unknown. The UV mapping coordinates are used to tile a map on all particles.
Macrouvposition
Determines the center of the entire UV tile.
Macrouvradius
Determines the radius of the UV tile.
Occlusion
Covered.
Occlusion Bounds Method
The way the boundary is obscured. None is to not enable masking, particle bounds is a boundary defined by the particle system, and custom bounds is a customized masking boundary.
Custom occlusion Bounds
Customize boundaries, and you can see previews in viewports when you adjust them.
Materials
Named Materia Slots
A material parameter slot that can be exposed to external blueprints.

Particle Emitter Class
The properties of the emitter.
Particle
Emitter Name
Emitter Name
Initial Allocation Count
When this value is not 0 o'clock, the emitter will use this value as the number of initialized particles emitted.
Quality level Spawn
Displays the quality setting scale, which determines the scale at which the system's video settings are low, to reduce system consumption.
Detail Mode
The transmitter's display accuracy, the transmitter will not work when the system's display accuracy is below this setting.
Disabled lods Keep Emitter Alive
The emitter remains in the active state when the LOD is in a forbidden state.
Cascade
The display settings in the editor.
Emitter Render Mode
The render mode of the emitter. Normal is rendered normally, point is near display, cross is the intersection line, Lights only is light, none is not displayed.
Emitter Editor Color
The color of the emitter in the editor.
Collapsed
Whether to expand the display emitter.

Particle Module Class
The base class of the particle module, which provides some common properties.
Cascade
3DDraw Mode
If you open it, the corresponding secondary rendering information is displayed.
Module Editor Color
The color of the module in the editor.

Typedata Modules
The type of emitter. When added, it is the default type and can be modified by adding type data.
Image
There are five types that can be added to achieve different types of particle effects.
In addition to Typedata, there are many other modules. As control of the particle emitter is added to the particle emitter to achieve different particle effects.

Required Module
Some basic properties of the particle emitter are set in this module. This module is required and cannot be deleted manually.
Emitter
Emitter-related properties.
Emitter Materia
The material used by the particles emitted by the particle emitter.
Emitter Origin
The launch point of the particle emitter.
Emitter Rotation
The initial rotation of the emitted particles.
Screen Alignment
The orientation of the particle relative to the camera.
Facingcameraposition particle rotation toward camera position (ignoring camera selection)
Square faces the camera and uses the x-axis for unified scaling
Rectangle for cameras, non-unified zoom
Velocity moves toward the camera and the particle's own direction, running non-uniform scaling
Away from center deviation from centre direction
Typespecific using definitions in Typedata (only mesh types are available)

 Use Local Space

Whether to use local space or to use the parent node's coordinate transformation.
Kill on Deactivate
Whether to destroy particles when inactive.
Kill on completed
Whether to destroy itself when execution is complete.
Sort Mode
Sort mode.
Psortmode_none not sorted
Psortmode_viewprojdepth sorting based on view map depth
Psortmode_distancetoview based on particle-to-camera distance sorting
Psortmode_age_oldestfirst particle survival time sorting, oldest priority
Psortmode_age_newestfirst particle survival time sorting, oldest priority

Use Legacy Emitter time
Whether to use traditional launch timings. Traditional launch timings use emitterduration and secondssincecreation to calculate the transmitter time, which may be problematic in a cyclic or time-varying particle system. When not in use, a new method is used, which is calculated using Deltatime.
Orbit Module affects Velocity Align
When turned on, the effects of the surround module are applied to particles on the speed screen alignment (screens alignment:velocity).
Duration
Time interval, the interval before the emitter starts looping.
Emitter Duration
The interval of time before the transmitter enters the loop is 0 without circulation.
Emitter Duration Low
Transmitter interval low value, need the following switch to open only valid.
Emitter Duration Use Range
Interval time range switch. When open, the interval will be random between [Emitter duration~emitter Duration Low].
Duration Recalc each Loop
The interval is recalculated every time the loop is completed
Emitter Loops
The number of transmitter cycles is 0 and the cycle is permanent.
Delay
Emitter Delay
Delay time. Unlike Duartion, the transmitter is not emitting particles during delay.
Emitter Delay Low
Delay time low value, need the following switch to open only valid.
Emitter Delay Use Range
The delay range switch. The delay after opening will be random between [Emitter delay~emitter delay low].
Delay First Loop only
Delay only before the first cycle
Sub UV
Sub UV properties are for sub UV modules, which can be found here: SUBUV module properties and applications.
Interpolation Method
Interpolation method.
None does not apply SUBUV feature
Linear (linear) transitions linearly in sub-image order, but not with the next image
Linear_blend (linear _ blending) is a linear transition in sub-image order, blended with the next image
Random (random) Next sub-image is randomly extracted, but not mixed with the next image
Random_blend (Random _ Mix) The next sub-image is randomly extracted and blended with the next image

Sub Images Horizontal
Number of sub-images on the x-axis of the map.
Sub Images Vertical
The number of sub-images on the map y-axis.
Scale UV
The scale of the UV scale.
Random Image Chagnes
The number of transformations in a random image during the life cycle of a particle.
Macro UV
Similar to the macro UV properties of particle systems.
Rendering
Use Max Draw Count
Whether to use maximum draw times limit
Max Draw Count
Limit value for maximum number of draws
Uvflipping Mode
UV Flip mode for all particles.
Flip UV Flip UV
Flip Uonly flipping U
Flip Vonly Flipping V
Random Flip UV randomly flipped Uvs
Random flip uonly randomly flips u
Random Flip vonly randomly flips V
Random Flip UV Independen randomly flipped UVS (UV Independent)

Normals
Emitter Normals Mode
Calculation mode of emitter Normals
enm_camerafacing default mode, normals are generated by cameras facing the geometry
Enm_spherical a sphere centered on the Normals Sphere Center to generate normals
The enm_cylindrical generates normals by passing through the normal Sphere center and a cylindrical body in the direction of Normalscylinderdirection.

Normals Sphere Center
The parameters that are used in normal generation depending on the options.
Normals Cylinder Direction
The parameters that are used in normal generation depending on the options.
Materias
Named Materia Overrides
Specifies the material slot name to replace the material used by the emitter. The material in the slot can be set by the blueprint.

Spawn
This is also a required module that cannot be deleted. Used to set how particles are emitted.
Spawn
Rate
The number of particles produced per second.
Rate scale
Emission rate scaling factor.
Apply Global Spawn Rate Scale
If this switch is turned on, then the emitter's scaling factor will be affected by R in the global setting. Emitterspawnratescale numerical effects.
Process Spawn Rate
The rate setting is not processed until it is opened, and when there are multiple spawn in the emitter, any of these options will cause rate not to be processed.
Burst
Outbreak. Forces a certain amount of particles to be emitted within a given time.
Particle Burst Method
The way the particles explode.

Instant immediately
intepolated interpolation
Burst List
A list of particle burst parameters for specifying time and particle outbreaks. There are three properties for array elements.

Count number of particles exploded
Count low breaks the number of particle lower bounds, which is no effect when 1
Point in time of outbreak

The scaling factor for the

Burst scale
outbreak.
Process Burst List
is not processed until the Burst list is opened, and any spawn module in the emitter does not open this switch, causing the Burst list to not be processed. The editor properties that are common to
Cascade
.
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At this point, the main properties of the particle System section are collated. But there are a lot of modules and particle types that are not being studied, and the basic parameter meanings are useless in the case of just knowing the meaning. So we decided to study the particle system from a practical point of view.