It reminds me of x-splines. The only implementation I've seen of them is in Xfig. Each control node has a slider that lets you smoothly change between approxima

It reminds me of x-splines. The only implementation I've seen of them is in Xfig. Each control node has a slider that lets you smoothly change between approximating the node, exactly smoothly interpolating through the node, or sharply (i.e. with a corner) interpolate through the node. It was one of the first papers I ever read: https://static.aminer.org/pdf/PDF/000/593/089/x_splines_a_spline_model_designed_for_the_end_user.pdf https://static.aminer.org/pdf/PDF/000/593/089/x_splines_a_sp...