bed levelling calibration parametric concentric squares

This is a bed levelling helper, you can customise the bed size, line width and spacing using the scad file. As the lines are tightly packed it gives you more opportunities to make adjustments and see the result as it prints. You can also use it to asses how flat your print bed actually is over the entire surface. Using a bed levelling print seems to give better results than using a shim on its own (you should do that before attempting the print anyway).