Cant paint foliage on mesh

I am trying to paint grass on a a rock model of mine, I have used the foliage tool many times, but not since the most recent updates to it. Right now the tool isnt even responding I try to paint in my scene on just some basic rocks, and the tool doesnt even show a size reticle. Was thier a new change that changes how you paint? Also is it possible to paint in my blueprint, things are dynamically spawned in our world and I would like to paint in that objects blueprint as its not static.