https://www.splinedynamics.com/spline-combiner/

Spline Combiner is a 3dsMax plugin for simultaneous editing of multiple spline curves, wich lets you perform boolean operations between shapes, cut and break them into parts and control curve intersections.  Combine multiple independent shapes with boolean functions, like in a 2D vector software, using Union, Subtraction or Intersection methods.  Use the Shape Cutter tool to make cookie cuts on shapes and conveniently break them into smaller parts.  Automatically detect intersections between splines and add new vertices or place helpers. Find self intersections in single splines. Break lines at crossing points.