ball group command


ball group s <keyword ...> <range>

Primary keywords:

add    remove    slot

Specify ball group names. Use of the group logic is described in the description of Groups in the General Components section. By default s is assigned to the group slot Default. Use the add keyword to assign the group name to the next available slot and the remove keyword to remove s from all slots.


Assign s to the next available slot.


Remove s from all slots.

slot s2

Assign the group s to slot s2. By default, slot Default is used.

Usage Examples

Create a group of balls named top_grip whose centroids’ \(y\)-position lies between 0.049 and 0.05.

ball group 'top_grip' range position-y 0.049 0.05

from “tension.dat” in Rock Testing

Create a group of balls named inclusions whose centroids lie within the circle centered at -1.0 -3.0 with a radius of 0.5.

ball group 'inclusions' range circle center -1.0 -3.0 rad 0.5

from “inclusions.dat” in Inclusions in a Matrix

Create a group of balls named BackLeft whose centroids’ \(x\)-position is given by the inline FISH formula.

ball group 'BackLeft'   range position-x [lbx-0.05\*dx]     0.0       ...

from “BlenderBalls.dat” in Ribbon Blender