falloff map for distribution-alternative?

[super gnu]

You can't use falloff, because it's "render based" map.
The only way I can think of, is using gradient ramp, and try making gradient to be more white  on the center of the cylinder can, and go gradient to black on edges. You can use planar mapping for that.
You need to create gradient ramp something like this:
https://photoshopcafe.com/wp-content/upl...der001.jpg

That above approach is, if your camera don't move around the can... if it moves... well, not sure how to achieve that.
Maybe render falloff, that you will use as a mask in some composite app.

seems the key would be to render the falloff map..  

good suggestion

thanks...