This is a mirroring tool across X and Y axis for 3ds Max 2016 using MCG. It works fine with tris and quads but creates an edge visibility problem to faces larger than quads. I also attach the flipNormals compound that I use for further research. I 'll keep updating but if someone finds a solution before I do please note.
--0.2 update: weld vertices across mirroring
--0.3 update: code optimisation and solve welding problem