Can I scale an object based on the relative distance to another object? I have a series of empties (let's call them scale_empties) that scale separate portions of a mesh. I would like to use a separate "master_empty" (or other object) to travel over the scale_empties and, as it does, scale the underlying scale_empties based on how close the master_empty is... Sorta like this...

Start position:



As the master_empty travels, it scales the scale_empties:



Anyway... the goal is to allow one or more master objects to travel along a series and scale as they go....  Possible?
Driver Based Approach

Image below shows driver added to x scale of Empty.002.  The driver variable var is of Distance type and returns the distance between itself (Empty.002) and the master empty (Empty.001).  

The expression 4 - var if var &lt; 2 else 1 is set up such that if the empties are within 2 bu of each other the scale value is (4 - var) and if outside that range the scale is 1.  Change the numbers to suit.

Use the interface to copy this driver and paste into other scale fields.

When pasting into other empties scale fields, change the target of non master empty to match.