The Pack UVs tool can automate the process of organizing UV data to fit into the 0 to 1 UV space. The command includes options for Pack, Stretch and Orient as well as a Gaps percentage setting. You can think of this command as an automated puzzle solver. With the default settings the command will move, scale and rotate each UV island until they all fit within the 0 to 1 UV grid as if solving a complex jigsaw puzzle.
The various toggle options include Pack, Stretch and Orient. Pack enables basic positional transforms of UV islands, Stretch enables the UV data to be scaled and Orient enables rotation of the islands.
