Emitter nodes spawn particles that can be manipulated in a particles system. Any Emitters need to be connected to a Particle Root node, and they will only spawn particles within that particle system unless modified appropriately.
Every emitter has a “Max Particle Count” attribute which, depending on the value of the Respawn Enabled parameter, defines either: the maximum number of particles from that emitter that may be alive at any one time if Respawn Enabled is ticked; or the total number of particles that may be emitted from this emitter if Respawn Enabled is not ticked. However the total number of particles in the system is defined by the Particle Root Node and there may be multiple emitters competing for those particles, so it may be impossible to fully satisfy the value set by “Max Particle Count”. Emission occurs per frame in node order and depends on the Emission Rate attribute, so it is possible for an emitter that is evaluated first to consume all of the particles in the system and leave none left for the other emitters.
Every emitter has a set of common properties defining the rate at which particles are emitted and their life time.
|Emitter Active||Change whether the emitter is on or off.|
|Randomness||How much randomness is added in the particles movement.|
|Life||Control how low long each particle exists for.|
|Life Randomness||Control the randomness for the life of each particle.|
|Emission Rate||What percentage of the particles are emitted from the emitter per second.|
|Max Particle Count||Set a maximum particle count for the emitter.|
|Respawn Enabled||Toggle whether a particle can respawn.|
|Shader||Ability to over-ride internal shader. See writing custom shaders.|
Emitters have an input named “Colour Control Nodes” that allows a Colour Ramp node to be connected which can control the colour of emitted particles via a gradient or colour palette. The Colour Selection Mode attribute determines the way in which colours are selected by the emitter from the palette.
|Colour Selection Mode|| Choose how the input colour affects the particles.
|Colour Selection Parameters||A number used to select the colour output.|
Every emitter node has a set of properties that define its material. The material allows some control over how particles are rendered on a per emitter basis such as their size and colour.
|Colour||RGB colour of particles.|
|Diffuse||Control how much the light is scattered from the surface of the object.|
|Emissiveness||Control how much light is emitted by the particle.|
|Life Colour Affecter Weight||Controls how much the result of any Life Colour Shading nodes are blended with the particle’s colour.|
|Particle Scale||Scale the size of the particle.|
|Dof Amount||How much depth of field effects the particles material.|
|Density||The density, for use in some simulations.|
|Temperature||The temperature, for thermal dynamics simulations.|
|Cooling Rate||The cooling rate, for thermal dynamics simulations.|
|Density Decay||Control the rate of decay in the density.|
|Fade In Time||What percentage through the particles life span the particle fades in.|
|Fade Out Time||What percentage through the particles life span the particle fades out.|
|Image Emitter||Mesh Emitter||Primitive Emitter||SDF Emitter||Screen Emitter|
|Trail Emitter||Video Feature Emitter|