Autodesk have annexed Exotic Matter's Naiad. Here's a demo of the final version of standalone Naiad.
Houdini Engine for Autodesk Maya
SideFX have released Houdini Engine for Maya, with 3ds Max and Unreal versions coming soon.
Labyrinth for 3ds Max
Labyrinth is a spline plugin for 3ds Max which allows users to create splines on any given object in 3ds Max.