Kaleidospace
This group adds 3D symmetry to the particle grid.
Mirror Mode
Defines the symmetry axes. Choose Horizontal, Vertical, or both.

Off | Horizontal
Vertical | H+V

Behaviour
Defines the symmetry operation. Mirror and Remove works like a regular kaleidospace where half of the image (volume in this case) is mirrored and the other half is not visible (since it is replaced by the reflection). Mirror Everything works so that particles are mirrored both ways so that nothing is discarded:

Mirror and remove | Mirror everything

Center XY, Z
Defines the symmetry center.