Selection painting by object

[YoyoBoy]

I'm trying to find a way to have an object paint a selection of verts on another dense object. Like Vol. Select can do, but I want it to leave a selection trail, and not just stay within the intersection of the objects. The next best thing would be to generate "wet maps" and use that to do the selection, but none of the scripts that I've been able to find that do that sort of thing are working for me in Max 2016 (like the Touch Texture Maker).

Thanks.

[YoyoBoy]

Oooh, this one looks like it might work, but it's sooooo sloooooowww.