Hi Rob, no unfortunately there is no way to produce an accurate offset of a NURBS curve purely by transforming control vertices.

For other kinds of transformations like Translation, Rotation, Scaling, those are all things that can be achieved just by moving the control points of a curve to a new location.

But offset is a way different kind of transformation than those, a lot of things can potentially shift in the shape of a curve when it is offset.

So instead of doing a "control point transform", Offset instead needs to go through a kind of incremental fitting process to produce the offset curve. Currently the geometry library that I am using does a rather heavy fitting process which is oriented mostly towards producing an accurate result and not towards making a result with a small number of control points.

Anyway, that is the explanation for what you are seeing there.

This is something that I do want to tune up in the future, but it is not an easy thing to mess with right now unfortunately.

- Michael