A group object stores a set of links to geometry points. You can store a complex point selection to a group. Applying modifications later to the defined set of points becomes easier: you can modify the group instead of modifying the points directly.

You can also use the group for selecting and deselecting the points afterwards; the control bar shows the required tools as soon as you select a group object.

A group can refer to points of a single object or to multiple objects.

A group object for controlling the upper edge of a wine glass