Method to specify the Solidify thickness based on another surface I have a set of concentric spheres of varying radii, each a different color (material). I would like to use the SOLIDIFY modifier, and add a thickness to each such that it fills in the distance between the larger sphere and the smaller sphere. 

I plan to put this in a script, so I have tried to build an algorithm based on their radii (and the difference of), but something's not working out. A visual example may help. Below is a 1-D model from the outside of the largest sphere (left) the center of the concentric spheres "(center)":

Crrnt:
1.......2...3......4.....5......(center)

Ideal:
1111111 2222 3333333 444444 5555555 (center)
You could add a driver to the Thickness value.



In this example, I've used the property dimension.x (it corresponds to the diameter).

If you need the value to change only at certain steps, you can set the interpolation mode to constant:


When you duplicate the sphere (alt +d), the driver will automatically update and it will mantain the reference to the proper diameter.

NOTE:
Remember to apply the scale transformation after scaling, otherwise the Thickness value will scale too.