====== Understanding the gcode Z offset ======
...currently a work in progress...\\
{{ :shopping.png?100 |}}
{{tag>articles z_offset}}

=== Good Further Reading ===

  * Ellis's Print Tuning Guide on [[https://ellis3dp.com/Print-Tuning-Guide/articles/first_layer_squish.html|First Layer "Squish"]]

==== Related wholly to non-tangential squish ====

=== General concepts of squish and non-tangential shape ===

(wip)

Generally speaking an otherwise uninfluenced extrusion from the nozzle will have a circular cross section. If an extruded line is placed next to another extruded line which each have a circular cross section they only tangentially connect. It will also only tangentially connect with the plate resulting in very poor adherence. A more rectangular cross section is desirable for maximal surface area connection. By adjusting the layer height very slightly we can control this shape and it will become more "stadium" shapped, (==), flat on the top and bottom and rounded on the sides. 

If we don't have good surface area connection in the extrusion lines the print will also be very weak and fall part on the layers. 

=== Squish will be different for different layer heights ===

=== Squish will be different for different filaments ===

  *  Material
  *  type
  *  brand
  *  color
  *  Build plates

=== What does good squish look like? ===
  *  Examples (click to enlarge)
     * {{:9tbrmczrjfdqftu3tcgbnc-1200-80.png?400|}}
     * {{::image.png?400|}}

==== Setting the gcode offset value ====

=== Klipper commands ===
The gcode z offset is set with the ''SET_GCODE_OFFSET'' klipper command and you should read its documentation, at https://www.klipper3d.org/G-Codes.html#set_gcode_offset
All other methods of changing the value just equate to this command. You can set it to a absolute value like
<code>
SET_GCODE_OFFSET Z=0.075
</code>
or adjust it relative to its current value like 
<code>
SET_GCODE_OFFSET Z_ADJUST=0.3
</code>

=== Fluidd GUI ===

[[Fluidd]] provides easy to use controls and displays the current value, live. 

{{ :fluid_z-offset_settings.jpg |}}

=== Why not by Screen ===

Workflows using the [[Screen]] can be problematic as proper attention needs to be considered for how this value may be being changed by other controls. It is not displayed live and the value shown can be stale. This can result in issues when it send incremental value changes. Saving it in the Screen's workflows can also trigger changes to other values unintentionally. It's better and easier to change the value in the console or in the [[Fluidd]] GUI. 


=== Slicer settings===


== Printer settings ==

You can set the gcode z offset as part of the printer configuration. 

{{ :orca_slicer_z-offset_settings.jpg?400 }}

== As a filament setting (change filament gcode)==

{{ :orca_slicer_filament_z-offset_setting.jpg?400 }}

===== Setting and calibrating the gcode z offset =====

Follow the procedure described in [[how_should_i_set_the_z_offset_to_adjust_nozzle_height|How should I set the z offset]].

=== Can this be realistically calibrated using the paper method? ===

No. 

At best the paper method will asymptotically approach the thickness of the paper being used. Yet this is an arbitrary value nearly in the ball park of what a typical z offset might be. The z offset we're seeking is filament dependent and will vary by the filament being used. We're seeking a correct affect on the shape of the extrusion's cross section, a "smush", and that can't be defined by some arbitrary height. 

The same logic applies to using [[why_not_feeler_gauges|feeler gauges]].

===== Related Topics =====

=== Is the CC setting the z offset or setting the probe z offset? ===

(...work in progress...)

The Elegoo Centauri Carbon has sensors to "set the z offset", yet it's realistically setting the probe offset. Prints will oftern stil require a z offset adjustment which can be set in the slicer. 
==== Z Probe calibration -- the other Z Offset ====

(...work in progress...)
==== How the Probe and GCODE Z Offset Relate ====

(...work in progress...)