That is a wonderful solution, thank you Eric!
I am facing a similar problem, but in mine, I want the wall to be visible, and show some trimwork along the bottom, very much like this sample image. I downloaded this sample from Chief Architect so that I could open it up and see how it was done and cannot for the life of me determine what they did! It is definitely an attic wall, but how did they set that perfect arc and trim it out?: