A useful tool for 3ds Max that lets users easily deal with with Smoothing Groups.

PolySmoother is a useful tool for 3ds Max that lets users easily deal with with Smoothing Groups. It will help you visualize and manage the Smoothing Groups in a quick and easy way. 

The tool allows users to set hard and soft edges, select edges by convexity, copy, paste, modify and optimize Smoothing Groups, as well as convert them from and to UV mapping, among many other features. 

PolySmoother supports several 3ds Max versions (2014-2018). You can learn more and get the tool for $45 here.