Figure 4.23 - Empty object
How can an Empty help us with an Array? At the Array options, you have
a field called Object Offset. Use the Empty as the Object Offset.
We can use any object from the scene in Blender as the Object Offset,
which controls distance, rotation, and scaling. The Empty is convenient
for offering an invisible reference object. It won't appear in a render.
For instance, if you have an existing Array and add an Empty to the
Object Offset field, it will immediately control your Array. If you rotate and
move the Empty, it creates a unique shape using the Array (Figure 4.24).