Quick Way to Extrude Line to Make Ledges? I'm not sure how to explain with words so hopefully the images can do it justice, but is there an easy way to essentially duplicate vertices/lines such that the new set will remain attached to faces one side while the original set remains attached to the other side?
Ah ha! Apparently it's called Rip-Fill. Simply select the desired vertices/edges and press Alt+V. And it seems you can pick which side moves by which side the mouse started on when you press Alt+V. Amazing.