-- It solves the problem with flipped faces (problem that can't be fixed just with resetXform) that happens by using the default mirror tool on objects that are in a container.
-- It mirrors along the pivot point of the topmost container (in the chosen axis). If there is no container then it mirrors along the first object in the selection.
-- Flip UVs, mirrors the UVs of all selected objects to compensate for the mirrored objects.
-- Copy Materials, makes an identical COPY of the same material as the original counterpart of each mirrored object.
Installation: Just drag and drop the script into the 3ds max viewport. Then go to Customize > Customize Interface > category: waRp Tools > waRp Mirror
It was only tested in 3ds Max 2013
It was meant to be used in combination with my other scripts, but it will work as a standalone script. (It calls the RemoveTurbo script.)
If you like all of the scripts that are in the tutorial you can download them by clicking the warp_tools_bundle.rar in the attachment