Hi David, I'm not really sure what to tell you - it's difficult to control things in the way you're trying to do here with basically trying to reverse engineer how the shape has to be in order to generate the cut you want from the other direction.

Usually with NURBS things are not done in this way, usually there is more of a focus on profiles generating the main shape instead of focusing on the cuts to try and generate the main shape from.

I guess when you don't get the right form from the other direction of your cuts, the deviation there is giving you some information about how you need to manipulate the main shape in order to bring it closer to what you want. So then you probably have to edit the curve at the bottom to make a more tapered shape or something that will come closer to what you want.

I think for your case here it's something like your shape needs to be a lot less sphere like, the widest point needs to be more near the back and it has to taper in a ways at least that's what it seems like...

But it's not very easy to define a shape in this particular way that you're trying to do here...


If you don't really know what shape you want but instead want to derive that shape by incrementally pushing things around, that whole method of point tweaking is more suited for a sub-d or displacement brush sculpting program rather than a NURBS program. The NURBS toolset is more oriented around the concept of you knowing a bit more directly what the base shape should be formed like.

- Michael