Scale operator

The Scale operator allows you to control the size of particles.

Scale Rollout

  • Scale type: the particle scaling method to use.

Absolute: particle scales will be set to a user-defined absolute value.

Inherit previous: uses the current value of a particle’s scale as the starting point, prior to modifications.

Relative add: add a user-defined scale value to the current value of the particle’s scale.

Relative multiply: multiplies the current value of the particle’s scale by a user-defined vector.

Relative first: multiplies the value of the particle’s scale when it first entered the operator by a user-defined vector.

Scale by velocity: constructs a scale vector for each particle using its velocity as a multiplier along each axis. The multiplier is applied to the scale of the particle when it enters the event. Scale X/Y/Z values set to 0 will maintain the original scale of each particle.

Scale value

  • X/Y/Z %: the absolute values to use for the scale modification vector.

The effect of the absolute values on a particle’s scale depends on which scale type is selected.

Scale variation

  • X/Y/Z %: the amount of variation to apply along each axis of the intermediate scale values.

  • Uniform: the variation applied along each axis will be uniform, preventing proportion skewing.

Keyframe offset

  • Sync by: controls the method used to sync animated spinner values to particle event lifespans.


  • Value: the amount to interpolate particle scales from their previous value to the new value.

  • Variation %: the per-particle percentage of variation to apply.

In order to animate particles scaling towards a particular target scale, set the operator’s timing to “continuous” and set the interpolation value to something less than 1. Smaller interpolation values will result in slower interpolation speeds.


  • Seed: the seed value for all varied parameters.

Texmap Rollout

The texmap rollout allows you to control particle scales by sampling textures on nearby surfaces and multiplying scales by the resulting values. The darker the sampled texture value, the smaller the scale multiplier.

  • Multiply by texmap: controls whether texmap scaling will be enabled.

  • Texmap: the texture map to sample.

  • Surface offset as W: the distance from the particle to the closest surface will be used as the W coordinate in the UVW value which is used to sample the texture.

  • Object list: the list of objects whose surfaces will be sampled for UVW coordinates.

  • Sample: controls which sampler will be used for surface proximity tests.

  • Affect X/Y/Z: provides control over the amount of influence a texmap will have on each axis of the resulting scale vector.

Proximity Rollout

The proximity rollout allows you to control particle scales by measuring distances to nearby scene objects and their surfaces, and multiplying scales by the resulting values.

  • Multiply by proximity: controls whether proximity scaling will be enabled.

  • 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 affect of the proximity scale multiplier.

  • Object list: the scene objects used to calculate proximity multipliers.

  • Sample: controls which sampler will be used for surface proximity tests.