Download  Spline Editor FREE Unity. 

Spline editor extension will help you easily create and maintain splines in your project.

Features:
♥ Spline loops;
♥ Spline branches;
♥ Save in play mode;
♥ Runtime editor;
♥ ZTest (on/off);
♥ Spline follow script;
♥ Spline smoothing;
♥ Spline Twisting;
♥ Spline control point modes;
♥ Spline control points editing (snap mode);
♥ Append/Prepend curves;
♥ Full editor Undo/Redo support;