Look
At (all)
This option allows you to select an object and force it to constantly
look at another selected object, in all viewports simultaneously.
Using:
1. Select
an object.
2. Click
on the Look At (all) Button on the top toolbar or (Tools/Object
Tools).
3. Click on the object that you want the first object to look at. The first object will spin around so as to look at the selected object. When the object is moved it will always look at the other object. When the object being looked at moves the first object looking will move and rotate accordingly on its own so as to always look at the object. This will occur in all of the viewports simultaneously.