I recorded this video, sorry that without a sound. 3ds max Flow Connect https://youtu.be/ag5yY0kPIcg and Set Flow, this tool works same like Flow Connect but not create geometry, but work with existing geometry. https://youtu.be/WYHpPo9njLk sorry for my english
The issue of whether Blender add-ons(or any other GPL work) constitute a derivative work is not as clear-cut as you make it out to be. Some argue that dynamically linked libraries are okay, as long as they don't contain source code from the original work. Some would say it doesn't even matter, and that things like plugins…
It's just how max users describe the feature of spilt normals, but agree max has a terrible work flow for this, they way maya handles it is way better. Once it is implemented in blender though than we can worry about the best work flow for this feature.