It looks like a fun tool!

But it is actually pretty hard to do completely blobby stuff like this with NURBS surfaces.

One part of the definition of a NURBS surface is that it is organized like a 2D grid, with a U and V direction. When stuff is going in all directions at once like this type of blobby stuff, it is hard to calculate a UV grid for NURB-ifying it.

That's why this type of meta-ball type technique generates polygon mesh output only, it is easier to fill in the surface skin of it by having just little triangles all over the place without needing any additional UV type organization. The mechanism usually used is called "marching cubes", which basically fills in just one little slice of the blob at a time by basically intersecting it with a voxel cube grid. The "little bit at a time" apporach just does not lend itself well to NURBS calculation.

Even though MoI is kind of shooting for a sketching type feel, there is kind of an accuracy vibe stressed in MoI as well. It's kind of a different thing than a cartoon blobby type sketch...

- Michael