Another way.
I also thought there was no need to act on all the faces. Here is a complex model. Skirt made with TIG's extrude-edges-by-vector-to-object EEbyVTO. Only problem I have trouble getting all the edges to go all the way to the face (I wonder if there's a lack of technique on my part). So I then pull the face up and intersect with model. (This method seems to choke on an even more complex model, but it might work.)
[image: IOEd_Screenshot2013-01-31at8.22.29PM.png]
[image: ktk5_Screenshot2013-01-31at8.25.03PM.png]
[image: HvC0_Screenshot2013-01-31at8.25.38PM.png]
[image: httg_Screenshot2013-01-31at8.26.47PM.png]