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Krakatoa Repopulate Particles Tag

Last edited on May 7, 2014


The Krakatoa Repopulate Particles Tag can be used to increase the particle count of any Krakatoa particle source. It generates a cloud of new particles based on the various data channels of the source particles.


To add a Krakatoa Repopulate Particles Tag, select a Krakatoa particle source object, right-click it and select (New Tag) > Krakatoa Tags > Krakatoa Repopulate Particles.

User Interface


Enable Particle Repopulation checkbox

  • Checked by default.
  • When unchecked, the tag will be ignored and no repopulation will be performed at render time or in the viewports (if viewport preview is enabled)

Fill Radius spinner and slider

  • Defines the influence radius of each particle.
  • Default is 1 cm.
  • This value controls the range within which new particles will be seeded around the original particle.
  • It also defines the voxel spacing of the grid used for repopulation calculations.

Subdivision spinner and slider

  • Defines the number of voxel subdivisions.
  • Default is 0 (no subdivisions)
  • When set to higher values, will subdivide the voxel grid accordingly, producing finer distribution and more particles.
  • A value of 1 produces 2x2x2=8 subdivisions, a value of 2 produces 3x3x3=27 subdivisions and so on.
  • Normally, 5 particles are created in each subdivision, but this can be changed using the following control:

Number Of Particles Per Subdivision spinner and slider

  • Defines the number of particles in every Subdivision (voxel and its sub-voxels according to the Subdivisions value avove).
  • Default is 5.

Density Falloff Start spinner and slider

  • Defines the start of the Density Falloff relative to the radius distance from the particle.
  • Defaults to 0.
  • Tha falloff is generally linear, but when the Start is set to 0, no falloff will be calculated.
  • When the start is set to 1.0, the complete distance from the particle to the edge of the radius will contain the linear falloff.
  • When the value is set to 0.5, the inner half of the radius will be populated with constant Density, the outer half will perform the linear falloff.

Random Seed spinner

  • Defines the random seed for the distribution of the new particles.
  • Default is 42.
  • This value can be used to change the random pattern when particles are moving through the repopulation grid. In particular, you can animate (keyframe) this value over time to produce a changing random pattern to make the repopulated particles look like a noisy foam, otherwise it will appear as if the source particles are revealing a static pattern in space.

Enable in Viewport checkbox

  • Default is unchecked.
  • When checked, the viewport will preview the repopulated particles (could be very slow!)


See Also

Introduction > Particle Repopulation