How to extrude a circular shape out of an object I have some problems extruding a circle that I projected onto another object. The setup looks the following. 

The circle mash was projected onto the object using the "shrinkwrap" modifier. Now I want to extrude it upwards to get an object that sits on top of the underlying structure. The same worked with a plane, as you can see on the right side of the picture. But with a circle, I have no N-Gon that I can extrude. Is it just not possible or how would a workaround look like?
Thanks for your help!
Add a circle, use Knife Project tool and extrude the result. I always do and it works well every time. Or, if you insist on using Shrink Wrap, add a circle and right after select filling, e.g. N-gon, in the Add Circle panel to the left