MCG FootPrint allows interactive footprints between two objects to be created in 3ds Max.
WeightPro for 3ds Max
WeightPro is a 3ds Max plugin for automatic, fast and smooth Skin modifier weighting, regardless of mesh topology.
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.