I have a blob. It likes to go through holes. It goes through one aperture. It moves up, splits, goes into two apertures, comes back together and leaves through another aperture. I want to loft one ring, then fork into two rings, then come back together at one ring, forming a continuous, single loft. Simple problem? It could easily be done with polygons by separating the faces, but I want mah NURBS!
Its best done with Meshes as they do not have this topological constraint. Kangaroo is a system which does allow dynamic relaxation on meshes (among other things). This topology can be easily achieved with box modelling and then smoothing / subdivision with Weaverbird.
Yeah, not sure how to post rhino files. Just think of it as a ring, another ring above it, then two rings, one going left and one going right. I guess the question is less grasshopper and more rhino modeling, and fixing the tangents.