@Forest. Sorry to take so long to get back with you. I originally started using CamBam on a Harbor Freight milling machine that I converted to CNC. The MPCNC is way more fun though! I’m not sure that I always use a post-processor. I only used one when I added a laser and I needed a post-processor to turn the laser on and off. I had to define the laser pin in the Marlin firmware too in order for all of this to work. The only other thing is to change the syntax for gcode comments so that it will work with Marlin firmware too. I am attaching my Laser PP in case you want to see both how I turn the laser on/off and the revised gcode comment syntax.