is there a way to close and extrusion like this. ?

thanks mike

look this post http://moi3d.com/forum/messages.php?webtag=MOI&msg=1021.1 :)
if you don't arrive to cut the cap's lines in 2 parts re ask it here ;)

If that has a simple profile from the top view, I would probably try to get half of that curve projected down flat on to the top plane and then extrude that up, and then trim the vertical extrusion. If you want to post the .3dm file I can show you some more details.

- Michael

Normally the way that I would approach building something like that would be to actually draw just 2 2D profiles, and then the curve that you show there will be created by the intersection between the 2 extrusions rather than starting by modeling that curve directly.

So for example with these 2 profiles, one from the Front view and one from the Top view:



Select one of them, then run Construct / Boolean / Isect, then select the other one and push Done (or right-click in a viewport). That will do an automatic extrude + intersect each volume to produce this:



- Michael