The Spawn operator spawns new particles from existing particles.
Spawns child particles the first time a particle enters the operator
Spawns child particles at a rate per time step.
Spawns child particles at a rate per frame over time.
Spawns child particles at a rate per second over time.
The rate per frame can be calculated as (rate / framerate).
Simulate substeps: controls whether particle positions will be interpolated along their velocity by a random value, to simulate substep spawning.
Spawns child particles along the trajectories of their parents, at defined spatial increments.
If a parent particle travels a distance greater than the step size value over a particular step of the simulation, the distance traveled will be properly subdivided such that child particles will be spawned at equal distance intervals.
Spawns child particles at the vertex locations of a parent particle’s shape mesh.
Spawns child particles inside voxels within the overall volume of a parent particle’s shape mesh.
Voxel size: the size of individual voxels, in which particles will be spawned.
Accuracy: controls the accuracy of the raycaster used to compute information about whether a particle is inside or outside of a shape mesh’s volume.
If a parent particle’s shape mesh is not closed, or is self-intersecting, increasing the accuracy value can improve results and reduce artifacts.
Spawns child particles if their parent was marked by a Collision operator as having colliding with a surface at the end of the previous time step.
Spawns child particles at contact reports reported by the PhysX solver located on a parent particle’s PhysX hull.
By filtering desired simulation groups, you can control which types of PhysX contacts will spawn particles.
Spawn %: the percentage of parent particles that will spawn child particles.
Offspring: the number of child particles a particular parent particle will spawn, per time step.
Relative to property: controls whether offspring counts will be relative to a particle property.
Property: the property type which the offspring counts will be relative to.
*Threshold: the target threshold that particle property will be compared to, when assigning offspring counts.
Exponent: the exponent that particle property ratios will be raised to. Larger exponent values will increase the offspring count disparity between large and small property values.
Invert: controls whether the resulting property ratio will be inverted.
Mark spawned particles: when enabled, newly spawned particles will have the specified value assigned to their specified custom data float channel.
Channel: the channel to assign the custom float property value.
Value: the custom float property value.
By marking spawned particles, you can also filter them out from spawning particles themselves using operator filters. This allows you to easily avoid exponential generation of new particles without having to move spawned particles to another event.
Parent particle position: spawned particles will be located at the position of their parent.
Parent shape surface: spawned particles will be located at a random position on their parent particle’s shape surface.
Mat ID enabled: controls whether particles will only be spawned on faces with a specific material ID.
Mat ID: the specific material ID of faces particles will be spawned on.
Offset: the distance from the parent particle’s shape surface, along its face normals, to offset spawned particles.
Align to Surface: controls whether particles will be aligned to the surface of their parent.
Inherited %: controls how much velocity child particles will inherit from their parent.
Divergence: controls how much child particle velocity vectors will diverge from that of their parent.
Noise amount: controls the amount of noise variation that will be applied to child particle velocity vectors.
Noise scale: controls the scale of the noise variation applied to child particle velocity vectors.
Inherited %: controls how much spin child particles will inherit from their parent.
Divergence: controls how much child particle spin vectors will diverge from that of their parent.
Inherited %: controls how much scale child particles will inherit from their parent.
Min volume: parent particles with a shape mesh volume below this value will not spawn children.
Min velocity: parent particles with a velocity magnitude below this value will not spawn children.
Min impulse: parent particles with PhysX contacts whose impulse is below this threshold will not spawn children.
Per particle: limits the total number of children that an individual particle can spawn, per time step.
Total: limits the total number of children that can be spawned, per time step.