3d solid subtraction problem

[orla91]

hello to all I have to create a very simple solid for extrusion so I designed in 2d my shape and then I planned to extrude it but this is not feasible, i.e. a non-cable cylinder comes out. then I thought to get it by subtraction but it doesn't work (or I can't) so I tried to extrude the shape with surfaces but I can't close the figure (img1). I have to get img2!! Help me please, I'm at first with 3d autocad and I have to make it (revit doesn't seem very suitable for such a form)

 

[MarcoBi]

first extrude the outer polyline, then the inner one and subtract between solid 1 and solid 2.

 

[orla91]

does not make me extrude as solid the inner part but automatically extrude it as surface (despite me put solid mode)

 

[Tristan]

Are you sure the polyline is really closed? ?