Spread operator

The Spread operator allows you to directly move particles in various directions, by adjusting their position instead of applying forces.


Coordinates

  • Particle/World space: controls which coordinate system the spread values will be calculated within.

  • Relative to particle scale: when in particle space mode, the spread values will be transformed relative to the particle’s scale.

When “relative to particle scale” is enabled, the scale of each axis of the particle’s transform will act as a multiplier on the resulting spread vector. So if you offset a particle 1 unit along the z-axis, and the particle has a scale of [5,10,20], the particle will be moved 20 units up along the direction of its transform’s z-axis in world space, even though in local particle space it will have only moved 1 unit along that axis.

Position Offsets

  • X/Y/Z: allows you to move particles along a world-aligned axis by a precise value.

Random Spread

  • X/Y/Z: the overall distance to move particles, in random directions.

  • ± X/Y/Z: controls the amount of variation to apply to the initial X/Y/Z distances.

Velocity

  • Affect velocity direction: controls whether the direction between a particle’s old position and its new position will affect the direction of its velocity vector.

Interpolation

  • Normal interpolation: linearly interpolates the current value towards the target value.

  • Full interpolation on entry: linearly interpolates the particle's current value towards the target value, unless the particle's event age is 0 - then the particle's current value will be set to the target value.

  • Full interpolation at time of birth: linearly interpolates the particle's current value towards the target value, unless the particle's age is 0 - then the particle's current value will be set to the target value.

  • Curve interpolation (static): uses a curve to interpolate the particle's current value towards the value assigned to the particle when the particle first entered the event.

  • Curve interpolation (dynamic): uses a curve to interpolate the particle's current value towards the target value.

  • Duration: the number of frames over which the curve interpolation will be performed.

  • Value: the amount to linearly interpolate values each frame.

  • Variation %: the amount of variation to apply to the interpolation value.

Noise Spread

The noise settings allow you to offset the way in which particle positions are moved.

  • Noise mode: controls which noise algorithm will be used.

  • Noise texmap: the texmap that will be used by the noise texmap mode(s).

  • Noise preview: a preview image showing a 2D representation of the selected noise mode.

  • Strength: the strength of the noise (a multiplier on the default noise range of [-1, 1]).

  • Frequency: the speed at which the noise will evolve over time.

  • Scale: the scale multiplier for position values sent through the noise algorithm. Smaller values create larger noise patterns.

  • Roughness: controls the amount of extra detail applicable noise modes will generate.

  • Lacunarity: controls the scale of successive noise octaves for applicable noise modes.

  • Iterations/Octaves: controls the number of overlapping noise patterns that applicable noise modes will generate.

  • Phase: provides manual control over the evolution of the noise over time.

Uniqueness

  • Seed: the seed value for all varied parameters.

  • Seed by time: the seed value will be incremented with the current time in ticks.