Well shoot, we can code it without G31 theoretically I think. G31 just makes life easier on us by automatically storing the coordinates in a file upon contact, then retract and incrementally jog by say 0.001, move in a pattern by same amount until contact, write to file, retract and repeat unto ~= contact while moving across a user defined coordinate plane. How did Mr. Barker do his probing video on youtube with Mach4? Bet you he just coded a script for execution or maybe that's why we only see a short video clip...I'm near done with code for auto tool setting without using G31. Well that's my intent anyways. I know tool setting is just one point. But if you succeed in accurately reproducing that coordinate over so many instances then all is needed is just to expand the code for top of material across your table to produce a file. Then...import it to Solidworks or Rhino 5 for conversion, alterations, toolpath and back to Mach for production. I know, it's sounds easy but it's not.