I'm doing some preparation for the 72hr jam, trying to figure out how to make this piece of geometry I have in mind. There's going to be a control point on a roof, surrounded by angled windows of sorts. I've used the vertex tool to make a piece of the windows, but it's causing a problem in the Alt+P dialog, saying it's an invalid solid structure. Picture here: http://imgur.com/a/YzYhy Also, trying to clip the brush into smaller parts (to make window frames) causes some of the vertexes to move off grid. Any ideas what's causing the problem?