Once that is done we need to adjust the Soft Selection of the new Vol. Select modifier to expand its selection area. Again, these adjustments should be made according to the scene's needs (Fig.07).

Fig. 07
Now it's clear why we chose Addition (Add) for the selection method in Vol. Select. Otherwise, the selection wouldn't add the second into the first, so the effect would not work. Notice that now we have two different levels of subdivision. The first level is closer to the center and has two subdivisions: the first modifier MeshSmooth plus the second.
Now we can repeat this process as many times as necessary until we've created the level of subdivision that we need (Fig.08).

Fig. 08
Now try to select the controller (the sphere) and move it over the Plane to see how the subdivision appears (Fig.09 – 10).

Fig. 09

Fig. 10
To complete the tool we'll make a link from controller to our camera. But first of all, leave the controller next to the camera (Fig.11).

Fig. 11
After, set the scene we'll link (here I'm using the tool Select and Link) to the controller, always following the camera (Fig.12).

Fig. 12
Another really important detail that should not be forgotten is entering our controller's properties and disabling the option that makes it renderable. This way, it won't show on the render and it won't influence our scene (Fig.13).

Fig. 13