Hi Gunter,

> Thanks very much Max. I can't seem to get it right though..

For n-sided to work, you need to make sure to select surface edges and not the original generator curves. If your original curves are right in the same location as the surface edges you need to select, then hide the curves so they won't get in the way of selecting edges.

So you want to have an extrusion like this with a set of edges selected like this (again, the key thing is these are _edges_ selected here, not the original generator curve objects):



Then when you run Construct > NSided you will get this kind of result:



Those will have some angularity right in the immediate neighborhood of the sharp corner but it gets nice and smooth as it travels a little ways away from it.

- Michael