I want to edit a bspline curve/surface by dragging, adding or removing the control points. I've searched lots of materials, and there are no more information about adding or removing control points. There are lots of knots inserting and removing algorithms and APIs, but knots' operations are not intuitive. I remember some CAD software have the ability to add or remove control points rationally.
Does anybody have any idea? Any suggestion or paper reference is welcome. Thanks in advance.