Automatic UV

This function attempt to apply an optimized UV mapping based on the object to prevent parts of the UV mesh from overlapping, which is quickly the case with more complicated objects. In addition, depending on the parameters set, groups of UV polygons are arranged at a fixed distance from each other and with maximum utilization of the texture area. You can also use this tool with an active polygon selection if you just like to unwrap a part of your object.
Just keep in mind that Seam Selections and Pins are ignored by this tool.