Cura not using Relative Extrusion

[Sporech 1]

Hi,

 

With Cura, I am trying to use relative extrusion. I have found the setting and it was already ticked. I made sure to slice my model with the setting enabled, yet looking at the GCode, it's using absolute extrusion?

 

(Extruder argument clearly counting up)

 

Does anyone know if this is a bug?

 

Thank you

[obewan 37]

Remove the M82 from the printers start code in printer management

[Sporech 1]

Hi,

 

Sorry for the delay, my printer's start code doesn't contain a M82 instruction. Cura seems to be ignoring the relative extrusion setting, are there any other settings that could be overriding it?

 

Thank you

[GregValiant 1,354]

You have ticked the setting "Relative Extrusion" in the "Special Modes" section?  Cura should be adding an M83 right after your start gcode.

[Sporech 1]

On 12/30/2021 at 9:27 PM, GregValiant said:

You have ticked the setting "Relative Extrusion" in the "Special Modes" section?  Cura should be adding an M83 right after your start gcode.

Yes, relative extrusion is enabled under special modes, but it is being ignored.

[GregValiant 1,354]

With your model loaded and Cura set up ready to slice, use the "File | Save Project" command and post the 3mf file here.  I would assume it's a setting somewhere and it should show up in a project file.

[Sporech 1]

Sure, do take a look 

UM3_test_cube.3mf

[GregValiant 1,354]

"This setting has been hidden by the active machine and will not be visible."

So it's an Ultimaker printer thing rather than a Cura thing.  It's called out in the base "ultimaker.def.json" definition files as an override.

 

"relative_extrusion":
        {
            "value": false,
            "enabled": false

 

[Sporech 1]

Excellent! Thank you so much for finding that. Where are the machine JSON files saved?

[GregValiant 1,354]

In Windows they are in "...Program Files\Ultimaker Cura 4.x.x\resources\definitions".

I'm not very familiar with the UM line of printers but I would assume they put that in because Relative extrusion isn't quite as accurate as Absolute extrusion.  I'm not sure why that is but it may have to do with the way the numbers are rounded during the calculations.