[BUG] UBL with PROBE_MANUALLY can crash into the bed when "Mesh Edit" or "Fine Tune All" or "Fine Tune Closest" from LCD

[qurvento]

Bug Description

UBL with PROBE_MANUALLY crashes into the bed when running "Mesh Edit" or "Fine Tune All" or "Fine Tune Closest" from LCD. The printer tries twice to set Z=0 and crashes into the bed if current point's Z>0.

My Configurations

Creality Ender-3 v4.2.2
Marlin 2.0.7.1
AUTO_BED_LEVELING_UBL, PROBE_MANUALLY, LCD_BED_LEVELING, MESH_EDIT_MENU, UBL_MESH_EDIT_MOVES_Z
cfg.zip

Steps to Reproduce

1. Select "Motion/Unified Bed Leveling/Mesh Edit" or "Motion/Unified Bed Leveling/UBL Tools/Edit Mesh/Fine Tune All" or "Motion/Unified Bed Leveling/UBL Tools/Edit Mesh/Fine Tune Closest".

Expected behavior: moves to mesh point's Z plus paper width

Actual behavior: moves Z=0, back to Z_CLEARANCE_BETWEEN_PROBES and again to Z=0.

In unified_bed_leveling::fine_tune_mesh():
0 if 'H' option is missing. Could be set to MANUAL_PROBE_START_Z instead:

    #if ENABLED(UBL_MESH_EDIT_MOVES_Z)
        const float h_offset = parser.seenval('H') ? parser.value_linear_units() : 0;

Redundant Z move after moving to start position:

      do_blocking_move_to_xy_z(pos, Z_CLEARANCE_BETWEEN_PROBES);  // Move to the given XY with probe clearance
      TERN_(UBL_MESH_EDIT_MOVES_Z, do_blocking_move_to_z(h_offset));  // Move Z to the given 'H' offset

[boelle]

is this related to #19814 ?

[qurvento]

no

[sjasonsmith]

Don't be fooled by the "Merged" PR above, that was a similar issue that I thought might have shared a root cause with this. It is very similar, but in different code.

[sjasonsmith]

@qurvento I've posted a PR with your recommended changes. Can you look at it and verify that it works how you would expect?

[sjasonsmith]

Closing this as resolved, since we haven't heard back from @qurvento after the merged PR.

[github-actions]

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