There are five bed leveling systems supported by the Marlin firmware.
/**
* Choose one of the options below to enable G29 Bed Leveling. The parameters
* and behavior of G29 will change depending on your selection.
*
* If using a Probe for Z Homing, enable Z_SAFE_HOMING also!
*
* - AUTO_BED_LEVELING_3POINT
* Probe 3 arbitrary points on the bed (that aren't collinear)
* You specify the XY coordinates of all 3 points.
* The result is a single tilted plane. Best for a flat bed.
*
* - AUTO_BED_LEVELING_LINEAR
* Probe several points in a grid.
* You specify the rectangle and the density of sample points.
* The result is a single tilted plane. Best for a flat bed.
*
* - AUTO_BED_LEVELING_BILINEAR
* Probe several points in a grid.
* You specify the rectangle and the density of sample points.
* The result is a mesh, best for large or uneven beds.
*
* - AUTO_BED_LEVELING_UBL (Unified Bed Leveling)
* A comprehensive bed leveling system combining the features and benefits
* of other systems. UBL also includes integrated Mesh Generation, Mesh
* Validation and Mesh Editing systems. Currently, UBL is only checked out
* for Cartesian Printers. That said, it was primarily designed to correct
* poor quality Delta Printers. If you feel adventurous and have a Delta,
* please post an issue if something doesn't work correctly. Initially,
* you will need to set a reduced bed size so you have a rectangular area
* to test on.
*
* - MESH_BED_LEVELING
* Probe a grid manually
* The result is a mesh, suitable for large or uneven beds. (See BILINEAR.)
* For machines without a probe, Mesh Bed Leveling provides a method to perform
* leveling in steps so you can manually adjust the Z height at each grid-point.
* With an LCD controller the process is guided step-by-step.
*/
//#define AUTO_BED_LEVELING_3POINT
//#define AUTO_BED_LEVELING_LINEAR
//#define AUTO_BED_LEVELING_BILINEAR
//#define AUTO_BED_LEVELING_UBL
//#define MESH_BED_LEVELING
/**
* Choose one of the options below to enable G29 Bed Leveling. The parameters
* and behavior of G29 will change depending on your selection.
*
* If using a Probe for Z Homing, enable Z_SAFE_HOMING also!
*
* - AUTO_BED_LEVELING_3POINT
* Probe 3 arbitrary points on the bed (that aren't collinear)
* You specify the XY coordinates of all 3 points.
* The result is a single tilted plane. Best for a flat bed.
*
* - AUTO_BED_LEVELING_LINEAR
* Probe several points in a grid.
* You specify the rectangle and the density of sample points.
* The result is a single tilted plane. Best for a flat bed.
*
* - AUTO_BED_LEVELING_BILINEAR
* Probe several points in a grid.
* You specify the rectangle and the density of sample points.
* The result is a mesh, best for large or uneven beds.
*
* - AUTO_BED_LEVELING_UBL (Unified Bed Leveling)
* A comprehensive bed leveling system combining the features and benefits
* of other systems. UBL also includes integrated Mesh Generation, Mesh
* Validation and Mesh Editing systems. Currently, UBL is only checked out
* for Cartesian Printers. That said, it was primarily designed to correct
* poor quality Delta Printers. If you feel adventurous and have a Delta,
* please post an issue if something doesn't work correctly. Initially,
* you will need to set a reduced bed size so you have a rectangular area
* to test on.
*
* - MESH_BED_LEVELING
* Probe a grid manually
* The result is a mesh, suitable for large or uneven beds. (See BILINEAR.)
* For machines without a probe, Mesh Bed Leveling provides a method to perform
* leveling in steps so you can manually adjust the Z height at each grid-point.
* With an LCD controller the process is guided step-by-step.
*/
//#define AUTO_BED_LEVELING_3POINT
//#define AUTO_BED_LEVELING_LINEAR
//#define AUTO_BED_LEVELING_BILINEAR
//#define AUTO_BED_LEVELING_UBL
//#define MESH_BED_LEVELING