Hi Felix, For the question part to me, you have described exactly what to do!!! I would model the medallion on the pillar the way you describe. The only reason to use Zsurf or BobArt, is if you are needing some kind of "Very organic" type of look or surface... Like a tree limb "WITH BARK".

Your model is nice. Yes, it should read "SOLID" if the surfaces were well formed and joined properly... If it reads joined surfaces, then those gaps most likely exist.. For me, the fastest way to learn MoI is the 3 tutorials that come with the help file... Michael covers many aspects, even basic NURBS modeling is learned from these.. They are very nice to watch. Short, concise and packed full.. Not painful like other video tutes.