When I watch my Shapeoko 3 XXL run some MeshCAM NC files, I observe quite a few times when the cutter moves up and back down without changing X or Y. It would seem that the up move could be eliminated (maybe the down move goes to a lower Z). A fairly simple post processor should be able to recognize up-and-down Z moves, without X or Y moves in between, and eliminate them.
Has anyone worked on such an optimization (which could work on all gCode files).
Jon