SO I have a part that is essentially a tube with compound curves. While one end is open it does have a large flange so I made that the print surface.
However, Cura either wants to close both ends off completely or not at all. Here you can see the original drawing, note that you can see all the way through.
When I get it into Cura - in Ghost view you can see the flange at the bottom
So with Bottom and top >0 I get a solid closure over both open ends even though the drawing has no top at all or solid bottom
Ok fair enough, set top and bottom to 0 so now when I show the layers I do not get the flange that IS in the drawing. So, I either get a roof that can not be printed and a solid layer on the bottom where it should be just a flange OR I get a no flange at all on the bottom.
So what dumb noob mistake am I making!