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Emitter Module Size

This module allows the size of emitted particles to change over time.

  • Size over lifetime - Allows the particles to change their size over lifetime.
    • Uses a standard Distribution Property UI, which allows you to set a curve, for example, to tightly control the size over the particle or emitter’s lifetime, or to randomize it.
  • Size By Speed - Allows you to set the particle’s size based on the current velocity of the particle.
    • Velocity Range - The velocity of the particle is scaled by this value, to result in the final strength of the effect.
    • For example, if the particle is travelling at 5 units per frame, and the Velocity Range is set to 10.0, this would mean that the final effect will be at 0.5 strength, as the particle is travelling at half the speed of its range. The smaller this number, the more of an effect differences in velocity will make to the particle size.
    • If this is set to 0, the raw velocity of the particle itself will be used without any scale.
    • Scale Factor - Allows you to set a bound for the minimum and maximum scale of particles based on their velocity.
      • Uses a standard Distribution Property UI.
      • The final computation of the size of a particle is essentially the ratio of the particle’s current velocity over the Velocity Range value, linearly interpolated between the min and max size given by this scale factor.
      • If a curve is used for the Scale Factor, the resulting size is sampled directly from the curve.

The particle’s base scale is multiplied by this value - particles that are big to start with, will remain big compared to ones that started small, for example.

  • Size Scale
    • Identical to Size over lifetime.
    • Allows you to have two curves affecting size.