Creates a new, empty UV set
on the current object. You can then create the UVs in the set using
one of the mapping/projection methods. This feature is also available
for use from the Polygons menu in the UV
Texture Editor.
You can choose to share this UV set (every instance
has the UV set), Per Instance Shared (all selected
instances share the new UV set), or Per Instance Unshared (all
selected instances get a unique UV set).