Mesh Bed Leveling
Most beds aren't perfectly flat, but software measurement and compensation can account for an imperfect bed with Mesh Bed Leveling. This process collects a series of height points along a grid pattern overlayed on your bed and then saves a heightmap of the collected points. When the machine is operating, it applies a linear interpolation between heights such that XY movement also causes some small corrective movement in Z.
In a single-extruder setup, mesh bed compensation is usually defined where the ZProbe has some XY offset from the extruder tip. Since Jubilee can change tools, we will instead collect the height map assuming a "virtual tool" that is directly on top of the ZProbe. In other words, we assume no offset during the point collection process. When we calculate tool offsets per-tool later, we will measure the offset from the virtual tool (aka: the ZProbe) and apply them there.
Ensure that all tools are put away and that all axes are homed. Then unapply any existing Mesh offset with
M561
From here, define the grid dimensions and number of points with
M557 X10:290 Y10:290 P6
The above command tells the machine to probe 36 pts (6 x 6) within the square formed by corner coordinates (10, 10) and (290, 290). We do not recommend increasing the square size. However, you can increase the number of points per axis if you like. The process will simply take longer with marginal gains.
Next execute the probing with
G29
When the process completes, a window with a heightmap should pop up that looks something like this:
After inspecting and closing the window, the settings will be saved to the SD card, but you must still tell the machine to apply the mesh bed compensation. The best place to do this is in the homez.g file. At the very beginning of the file, add
M561
and at the very end of the file, add
G29 S1
Doing so cancels existing offsets before running the 3-point bed leveling process and then applies them as soon as the 3-point leveling process is finished.