Amapi sucks!! I hate it. The symbols in it make no sense at all. I barely make any model with it. I would put your head in toilet if you convicted Eovia to put Amapi in Carrara. Spline and Vertex is the most basic modeling but it lacked some small things. Spline Modeling needs xyz coordinate planes with bezier curves on all dimensions on each sections. Vertex Modeling needs better nurbs controls and able to control the curves parameters on each regions on a model. Symmetery mouse pointers like ZBrush or Germni. Other idea for Vertex Modeling is add XYZ breazer curve controls in it like Spline Modeling. Create separate GIs on background and backdrop. Accessible to SDK seems fine to me but it need more definations how to use references.