Copy Marlin auto leveling
Least squares. Is it that hard? When we buy expensive borosilicate glass expecting it to be flat and it isn't 3 points is a total and complete waste of time. Useless. Frustrating. Aggravating. Leads people to vent their frustration on your forums at you. Yes every imbecile out there knows 3 points determine a plane. And sure iii can measure 3 points of an exactly precise flat surface and expect a reasonable approximation. Add a .1mm glitch in the surface across the thing, it's good enough to print on, but worthless for 3 points t auto leveling. WORTHLESS! stoo assuming ideal and live in reality.