These 3 great plugins are ideal for working with spline shapes in 3ds Max. Either for Architectural Visualization, 3D logo design or spline modeling in general.
Spline Cleaner is an advanced batch processing tool for cleaning, repairing and managing spline curves in Autodesk 3ds Max.
Spline Combiner is a 3dsMax script 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.
SubSpline is an Advanced Subobject Selector & Material IDs Editor for spline shapes in 3dsMax.