Tool:Polygroups Subpalette
From ZBrush Info
This subpalette allows different groups of polygons to be displayed in different colors, to make working with regions of a model easier. It consists of controls that assign polygons to groups depending on certain criteria.
In addition to visually delimiting separate areas of a model, polygroups also allow visibility operations to easily show or hide groups.
Auto Groups: Puts polygons into groups so that group borders correspond to abrupt changes in mesh topography (shape).
Uv Groups: Assigns groups based on externally defined UV coordinates. Polygons will be assigned groups corresponding to the textures to which they map.
Group Visible: Assigns all visible polygons to a single group. This is used to assign a custom group to the visible polygons of a partially hidden mesh, to facilitate further manipulation.
