Hi I cheated in doing this, in fact I used subdivision surfaces, I made this choice because I would have to do many curves and many lofts with Moi3D, but that's one of the methods, it's a challenging model and you have to use several commands, but simple to do and there are several approaches you can use, however I hope that this sample attached below in the Zip file can help you find a personal solution with Moi3D.