If primitive groups are defined by the input, this SOP defines "groupings" of metaballs - lists of one or more groups containing metaballs. All of the metaballs in a grouping are merged in the standard way, while separate groupings are not merged in to the same surface. This allows users to specify how metaballs are to be merged. In particular, metaballs in the same grouping are merged by taking the sum of their weights, while separate metaball groupings are merged by taking the maximum of the weights of metaballs in the separate groupings.
Number of Metaball Groupings
Specifies the number of metaball groupings to be defined by this SOP. The number of groups can be adjusted using either the numeric field or the 'More', 'Less' and 'Clear' buttons.
A unique field with this name is generated for each metaball grouping added by the Number of Metaball Groupings parameter. This field specifies the primitive groups to be included in a particular grouping. Multiple group names in this field should be separated by spaces.