This is just a question, however I saw that there are two nearly same block: one of them is implemented in https://github.com/ros-navigation/navigation2/blob/main/nav2_smac_planner/src/smoother.cpp and other one is implemented in https://github.com/ros-navigation/navigation2/blob/main/nav2_smoother/include/nav2_smoother/smoother_utils.hpp

IMO, these are nearly same and sometimes a little much more confusing, for onw who doesnt know this stack very well. Somebody can run smoother twice blindly. I think We can remove this methods from smac because we can make a use of nav2_smoother package.

If you are interested, I can remove the unnecessary codes.