flexi-bot/docs/marlin/_gcode/G029-mbl.md

tag	title	brief	author	requires	group	related	codes	notes	parameters	examples
g029m1	Bed Leveling (Manual)	Measure Z heights in a grid, enable leveling compensation	thinkyhead	MESH_BED_LEVELING	calibration	M420 M421	G29	Requires the `MESH_BED_LEVELING` option in `Configuration.h`. Similar to `AUTO_BED_LEVELING_BILINEAR` with `PROBE_MANUALLY` but uses less SRAM. For automatic probe-based leveling enable one of the [`AUTO_BED_LEVELING_*`](/docs/configuration/configuration.html#bed-leveling) options instead. [`G28`](/docs/gcode/G028.html) disables bed leveling. Follow with `M420 S` to turn leveling on, or use `RESTORE_LEVELING_AFTER_G28` to automatically keep leveling on after [`G28`](/docs/gcode/G028.html).	tag optional values S false tag description 0 Produce a mesh report (see examples below). tag description 1 Start probing mesh points. tag description 2 Probe the next mesh point. tag description 3 Manually modify a single point with `X` `Y` `Z` parameters. (See also [`M421`](/docs/gcode/M421.html).) tag description 4 Set a global Z offset. Positive values are away from the bed; negative values are closer. tag description 5 Reset and disable mesh. tag optional description values I true **(Marlin 2.x)** With `S3`, the (0...n-1) X index of the mesh value to modify. tag type index int tag optional description values J true **(Marlin 2.x)** With `S3`, the (0...n-1) Y index of the mesh value to modify. tag type index int tag optional description values X true **(Marlin 1.x)** With `S3`, the (1...n) X count of the mesh value to modify. tag type count int tag optional description values Y true **(Marlin 1.x)** With `S3`, the (1...n) Y count of the mesh value to modify. tag type count int tag optional description values Z true With `S3`, the new mesh Z value. tag type linear float	pre code S0 mesh report: > G29 S0 Num X,Y: 3,3 Z offset: 0 Measured points: 0 1 2 0 +0.011 -0.020 -0.026 1 +0.017 +0.002 -0.019 2 +0.022 -0.030 -0.013 pre code **(Marlin 1.x)** Modify some mesh points and view the new mesh: > G29 S3 X3 Y3 Z0.042 > G29 S3 X2 Y2 Z-0.666 > G29 S0 Num X,Y: 3,3 Z offset: 0 Measured points: 0 1 2 0 +0.011 -0.020 -0.026 1 +0.017 -0.666 -0.019 2 +0.022 -0.030 +0.042 pre code **(Marlin 2.x)** Modify some mesh points and view the new mesh: > G29 S3 I2 J2 Z0.042 > G29 S3 I1 J1 Z-0.666 > G29 S0 3x3 mesh. Z offset: 0 Measured points: 0 1 2 0 +0.011 -0.020 -0.026 1 +0.017 -0.666 -0.019 2 +0.022 -0.030 +0.042

Mesh Bed Leveling (MBL) allows interactively measuring a Z height mesh without a bed probe. The only tool required is a piece of paper or a feeler gauge. MBL uses the mesh to compensate for variations in height across the bed.

Mesh Bed Leveling from the host:

1. Use G29 S0 to get the current status and mesh. If there’s an existing mesh, you can send M420 S1 to use it.
2. Use G29 S1 to move to the first point for Z adjustment.
3. Adjust Z so a piece of paper can just pass under the nozzle.
4. Use G29 S2 to save the Z value and move to the next point.
5. Repeat steps 3-4 until completed.
6. Use M500 to save the mesh to EEPROM, if desired.

Mesh Bed Leveling using an LCD controller: (Requires LCD_BED_LEVELING)

1. Select Level Bed then choose Level Bed (not Cancel) in the sub-menu.
2. Wait for Homing XYZ to complete.
3. When Click to Begin appears, press the controller button to move to the first point.
4. Use the controller wheel to adjust Z so that a piece of paper can just pass under the nozzle.
5. Press the controller button to save the Z value and move to the next point.
6. Repeat steps 4-5 until completed.
7. Use Control > Store memory to save the mesh to EEPROM, if desired.