When you isolate a polygroup in ZBrush, you can then work with it independently. After isolating one or more polygroups, for example, you might want to delete those that are hidden, which you could then do with Tool > Geometry > Modify Topology > Del Hidden.
First, you’ll want to be in Draw Polyframe mode, so that you can see all all the polygroups. You can toggle this mode with SHIFT + F as shown below.
Hold CTRL + SHIFT and click on a given polygroup to isolate it, hiding all the others.
Hold CTRL + SHIFT and click on an empty place in the canvas to return all polygroups to view.
If the Select Rect brush is your active brush, you can SHIFT + CLICK and drag a rectangle on an empty place in the canvas to invert the visible polygroups.
Selecting more than one polygroup
Here’s the procedure for selecting more than one polygroup as described in the ZBrush documentation for polygroups:
- Press CTRL + SHIFT and click on the mesh where one group is
- Invert that selection: press CTRL + SHIFT then click and drag outside of the mesh
- Press CTRL + SHIFT and click on the other groups you want to select
- Invert this selection: press CTRL + SHIFT then click and drag outside the model