Doing Grass By Rounded Platform- Do You Use Polygon Editing Or ????

Novica

I decided to try something more complicated, so I'm bumping grass up against a round platform base. I tried getting the grass inserted UNDER the platform, then rotating the grass so those tips would be down (as yards aren't always flat and rolling/uneven parts make it interesting) but I'd like to know how to edit out that part of the square piece of turf and make a rounded cut to just end where the platform starts.

D-formers or the polygon editing tool come to mind (which I've never used.) So need some step by step help here?
(Leaving for a few hours, not ignoring you. Will check back in.) Thanks in advance- I don't recall seeing this addressed before, if so, just a link would be appreciated (IF it tells how to do it.) This would be handy for others to know as well.
Cathie

Novica

I just finished a test render for lighting and here's the sliver showing the grass and platform.

Novica

Here's how to use that polygon editing tool, in case anyone's interested. And I guess no one knows how to do the grass thing, so I'll figure it out.
http://www.daz3d.com/forums/discussion/28138/P375/#451083