Core Particle System Nodes

The following are the default nodes when you make a base particle system.

This node holds the collection of core nodes a particle system consists of. A subgraph is a scope that can contain nodes. Each subgraph can be scheduled and evaluated in a different way.

Omnigraph offers push pull and dirty pull evaluation. An action graph evaluator. In the future more evaluations will come online.

A complex effect may be assembled from multiple particle systems.

Emitter Node

The emitter injects new particles into the system. Its UI is divided into several sections: Emitter, Emission Cycle, Spawn, Display, Orientation, Collision and Source Primitive sections.

Emitter

This group of parameters control the Emitter basics.

Emitter	Description
Active	Toggle: Controls whether the Emitter Node is Active or Inactive.
Emit from Volume or Surface	Toggle: When enabled, particles will be emitted throughout the volume of the Emitter Source Prim. When disabled, particles will be emitted from the surface of the Emitter Source Prims.
Random Seed	Changing this value changes the particles emitted randomly.
Emit From Particles	When enables, particles can be emitted from particles.

Emitter Spawn Rate

This group controls how you want the particle to spawn. Burst, looping.

Spawn Rate	Description
Spawn Rate Per Second	Emission rate number of particles per second.
Spawn Rate Per distance	Emission rate, in particles per unit of distance. Emission active when source moves.

Emitter Emission Cycle

This group of parameters control the Emitter Node’s method of spawning. The particle system is looping or bursting.

Emission Cycle	Description
Activate Cycle Emission	Toggle: When Enabled, emission will be made active and inactive in cycles with period specified by the Cycle Emission. Enable this toggle to use Burst Spawn Count. The active portion is specified by Cycle Emission Start and Cycle Emission End.
Loop Cycle	Toggle: When Activate Burst Emission is on and this is enabled, the cycle runs repeatedly. When Activate Burst Emission is on and this is disabled, the cycle only runs once.
Cycle Duration	When Activate Cycle Emission is on, this is the cycle time period in seconds.
Cycle Emission Start	This is a value from 0 to 1 indicating where in the cycle emission starts. This only applies when Activate Cycle Emission is on. If this value is 0, the emission will start at the beginning of the cycle, regardless of cycle duration. Example: If cycle duration is 7 seconds, and this value is 0.5, emission will start 3.5 seconds after the beginning of each cycle. Example: If cycle duration is 4 seconds, and this value is 0.5, emission will start 2 seconds after the beginning of each cycle.
Cycle Emission End	This is a value from 0 to 1 indicating where in the cycle emission ends. This only applies when Activate Cycle Emission is on. If this value is 1, the emission will stop at the end of the cycle, regardless of cycle duration. Example: If cycle duration is 7 seconds, and this value is 0.5, emission will end 3.5 seconds after the beginning of each cycle. Example: If cycle duration is 4 seconds, and this value is 0.5, emission will end 2 seconds after the beginning of each cycle.
Burst Spawn Count	Number of particles to emit at time zero or at the beginning of the Emission in each cycle. Activate Cycle Emission must be enabled.

Emitter Lifespan

This group allows you to change the lifespan of the particle in seconds.

Lifespan	Description
Lifespan	Lifetime of the particles in seconds
Lifespan Random	Randomly change the lifetime to the particle per spawn.

Emitter Direction, Speed and Mass

This group of parameters control the particle’s behavior on spawn.

Direction, Speed and Mass	Description
Emit Along Axis	Uses the Emitter Source toi push particles along the X axis. Rotate the Emitter Source to change the push direction. Emit Along Axis averages with Emit Away From Center Speed influences the particle’s speed.
Emit Away From Center	Pushed particles out from the Emitter Source Shape normals. The shape of the Emitter Source influences the direction of the push. Emit Away from Center averages with Emit Along Axis. Speed influences the particle outward push.
Random Direction	Push particles in a random X,Y,Z direction per spawn.
Add Source Velocity	When this is non-zero, this portion of the velocity of an emission source is added to the particles emitted from it. The higher positive or negative value, the more velocity applied respectively. If zero no velocity is applied.
Speed	The outward movement of the particle per Spawn See Emit Along Axis and Emit Away From Center.
Speed Random	Randomly change the Speed of the particle per spawn.
Mass	“Weight” of the particle.

Emitter Display

This group of parameters control the particle’s visualization. This works with the Translucent Material.

Display	Description
Particle Size	Change the size of the particle or mesh in X,Y,Z.
Random Particle Size	Randomly change the size of the particle or mesh in X,Y,Z per spawn.
Indexed Object	Object index is valid if you have multiple sources to output. The number corresponds with the order you imported your sources.
Random Indexed Object	Randomly pick an Object Index source in a range per spawn.
Generate Color and Opacity	Toggle: If enabled the particle will generate color and opacity. This allows the particle to be colored with vertex colors and opacity to be influenced by a float.
Color	Sets a vertex color per particle spawn. You must have Generate Color and Opacity enabled above and Enable Vertex Colors enabled in your Translucent Material
Random Color	Sets a random vertex color to the particle per spawn. You must have Generate Color and Opacity enabled above and Enable Vertex Colors enabled in your Translucent Material.
Opacity	Controls how transparent your particle renders. You must have Generate Color and Opacity enabled above and Enable Opacity enabled in your Translucent Material If your translucent Particle isn’t displaying correctly, toggle Enable Fractional Cutout Opacity in RTX Settings, Ray Tracing.
Random Opacity	Randomly change the particle Opacity per particle spawn. You must have Generate Color and Opacity enabled above and Enable Opacity enabled in your Translucent Material If your translucent Particle isn’t displaying correctly, toggle Enable Fractional Cutout Opacity in RTX Settings, Ray Tracing.

Emitter Orientation

This group of parameters control the particle’s orientation.

Controlling Orientation If you want a particle or shape to be in a specific orientation, disable Face Active Camera and Orient With Active Camera in the Geometry Replicator or Point Instancer. Aim Inherits Velocity in Solver also can influence Orientation.

Orientation	Description
Rotation	Rotate the particle in X Y Z in degrees.
Random Rotation	Randomly rotate the particle in X, Y, Z along a degree range per spawn.
Aim	Aim points the particle in a specific direction in x,y,z.
Random Aim	Aim the particle in a random direction per spawn.
Up	Change the ‘top’ value of the particle in x, Y, Z.
Random Up	Randomly change the ‘top’ value of the particle on spawn.

Emitter Emit From Particles

This group allows you to alter the trail of the emitter. You must have the particles as a source for your trail emissions for these parameters to function. This group allows you to inherit the following parameters from the particle system source emitter.

Emit From Particles	Description
Random Position	Multiplier: Randomize source particle positions.
Velocity	Multiplier: Inherit Velocity when emitting from particles.
Mass	Multiplier: Inherit Mass when emitting from particles.
Scale	Multiplier: Inherit Scale when emitting from particles.
Radius	Multiplier: Inherit Radius when emitting from particles.
Color	Multiplier: Inherit Color when emitting from particles.
Opacity	Multiplier: Inherit Opacity when emitting from particles.

Emitter Collision

This group of parameters control the particle’s collision shape.

Collision	Description
Radius Influences Scale	Toggle: If enabled the Radius of the collision multiplies the Size of the particle. You must have Scale Inherit Collision Radius toggled in the Solver.
Collision Radius	The radius of the particle collision in the world.
Self Collision Radius	The radius of the particle collision with other particles.
Random Radius	Randomly set a collision radius in a range.

Emitter Source Primitive

This group allows you to add source primitives to your emitter.

Source Primitive	Description
Primitive	This field shows where your source geometry primitive is located in the stage/layer.
Add Target(s)	This button allows you to add source primitives to the emitter.

Solver Node

The solver node implements numerical integration of the underlying particles data at each simulation step.

Solver

Solver Parameter	Description
Active	Toggle: Controls whether the Node is Active or Inactive.

Solver Status

Status Parameter	Description
Current Particle Count	Displays the active count of particles in real time

Solver Particle Spawn

Particle Spawn Parameter	Description
Aim Inherits Velocity	Aim parameters inherit the velocity of the particle.
Maximum Particle Count	The Maximum amount of particles to spawn per cycle. -1 is no maximum.

Solver Evaluation Mode

Evaluation Mode Parameter	Description
Playback Evaluation	Toggle: Simulate in runtime or animation playback mode.
Playback Start Frame	The start frame of the simulation in animation playback mode.
Playback End Frame	The end frame of the simulation in animation playback mode. -1 is no end frame.

State prim

The State prim is automatically created by the Solver when a particle system is createdusing the menu method. It has no user-facing functionality.

Euler Angles to Quaternions Node

This node converts rotations from Euler angles to quaternions.

Euler Angles to Quaternions

Euler Angles to Quaternion Parameter	Description
Rotation order	the order of rotation

Merge Particle Node

The Merge Particles node combines multiple particle systems.

Merge Particles

Merge Particles Parameter	Description
Active	Toggle: Is the Merge Particles Node active?
Max Count	What is the maximum count of particles to spawn per cycle -1 means to spawn particles based on spawn rate

Merge Particles Relationships

Merge Particles Relationships	Description
inputs:particles	Add Targets: Allows you to add particle relationships

Simulation Space Node

The Simulation Space Node allows you to attach a particle to the local space of an object. The particle system is locked into that object’s position, rotation, and scale.

Simulation Space

Simulation Space	Description
Active	Toggle: Is the Simulation Space Node active?

Simulation Space Use

Use	Description
Position	Toggle: Is the position currently active?
Rotation	Toggle: Is the rotation currently active?
Scale	Toggle: Is the scale currently active?