Hi Rudl, where is the Rhino tutorial that you're following?

MoI does not currently have as good of a way to sort of suck down a curve that is bending around in 3D on to a surface as Rhino does, so if the tutorial is relying on kind of warping the curve around the object and then using it to trim the object that might not work as well in MoI. Instead in MoI I'd recommend using cuts by planar curves directly.

I'll see if I can give you a recommendation, but it could help if you could post a link to the tutorial so I could see what it was trying to do.

- Michael