Hi PaQ - a bit of experimenting with a kind of "multi-planar" outline Extrude concept:



Still some things to clean up on it, but the idea is to make it recognize when a single closed curve is made up of multiple planar "chunks" and treat each of those chunks more like a planar face being shelled.

If I can iron out some of the details that could be one step to speed up this kind of box modeling process. There is some good possibility to add similar multi-planar single-outline processing to Offset and Planar I think.

- Michael