Slow operator

The Slow operator allows you to dampen particle forces. It should be used instead of a Drag spacewarp to slow particles down within a flow.

The Slow operator should usually be placed above any other operators that apply forces to particles within an event. Since operators are evaluated in order, this will dampen forces when the next time step is evaluated, without damping forces added to particles in the current time step.


Velocity

  • X/Y/Z: the amount to dampen particle velocities, per axis.
Variation: the per-particle amount of variation to apply.
Only Affect:
  • Values greater than zero: a velocity value along a particular axis will only be dampened if it is above zero.

  • Values less than zero: a velocity value along a particular axis will only be dampened if it is below zero.

  • All values: all velocities values will be dampened.

Sometimes you might only want to dampen particle velocities in a certain direction. For example, you might want to dampen particle velocities as particles move upwards, but not as they move downwards with gravity (to prevent unwanted bouncing). Use the appropriate “only affect” type to precisely control which values will be dampened.

Spin

  • X/Y/Z: the amount to dampen particle spin, per axis.
Variation: the per-particle amount of variation to apply.

Influence

  • Relative to mass: the amount of damping applied will be relative to a particle’s mass.

Timestep

  • Slow on subframes:: controls whether to apply damping to particles on subframes. Turning this on will affect how quickly particles will be slowed, if simulation time steps are set to smaller than 1 frame.

Objects

  • Slow by surface proximity: controls whether the affect of the operator will be relative to a particle’s proximity to nearby objects.

  • Slow if inside volume: controls whether the proximity effect will be applied to particles inside a surface.

  • Object list: the list of input objects whose proximity will be tested.

Proximity influence

The proximity influence extends outwards from the surface of nearby obstacles.

  • Distance: particles within this distance will be fully affected.

  • Falloff: the effect on particles beyond the base distance, but within this falloff distance, will diminish according to the inverse-square law.


  • Invert inverts the effect of proximity slowing.

Uniqueness

  • Seed: the seed value for all varied parameters.