What Is the Meaning of G-Code Flavor in 3D Printing?

If you’ve ever navigated to the Machine Settings section of Cura, whether it’s to correct the dimensions that your 3D printer supports or to modify the Start G-code section, you have most likely noticed the G-code flavor dropdown menu, with a good chance that it’s set to the Marlin option by default due to the popularity of Creality (Ender series in particular) and Prusa 3D printers.

In this article, we will explain the meaning of the term “G-code flavor” that you can come across on various slicer software, take you through the process of finding the G-code flavor that your 3D printer uses, and take a look at how you can quickly change the G-code flavor setting in Cura if it becomes necessary.

What Is the Meaning of G-Code Flavor in 3D Printing?

While G-code is a programming language shared across different firmware, the way that each firmware interprets a particular G-code command can be different based on how the firmware is coded, effectively meaning that G-code commands don’t always have to be universal even though they mostly are.

As this creates a scenario where it becomes necessary for the slicer software you’re using to know which firmware your 3D printer is running to avoid creating a G-code file with incompatible or incorrect G-code commands that your firmware may not recognize at all, require a different syntax for, or even have distinct functionality than intended, the set of G-code commands that any particular firmware supports is considered to be a separate G-code flavor, which makes it possible to make a distinction between firmware with various G-code command sets and adjust things accordingly.

For instance, while the M226 G-code command in Marlin Firmware triggers the Wait for Pin State action, running the M226 on RepRapFirmware will result in a G-code Initiated Pause instead, which is an example of two firmware behaving entirely differently even when the G-code command you’re sending is exactly the same, as the developers of each firmware decided to give the M226 G-code command a different functionality.

So, in a case where you configure your slicer to use the RepRapFirmware G-code flavor, even though your 3D printer is running Marlin Firmware, and tell the slicer to pause the print at some point for a filament change, the G-code file will end up having the M226 G-code command that will prompt your 3D printer to incorrectly run the Wait for Pin State action, rather than the M0 G-code command, which would be correctly initiating a pause on a 3D printer that runs Marlin Firmware.

Similarly, if G-code flavors didn’t exist at all, the slicer would technically have no way of determining whether it should insert M226, M0, or any of the other pause commands that different firmware support, such as @pause for Repetier, which would effectively lead to a scenario where it becomes impossible to create a G-code file that contains the correct G-code commands for any firmware.

Finding Out Which G-Code Flavor Your 3D Printer Uses

Considering not having your slicer set to the correct G-code flavor can easily create a scenario where your 3D printer won’t be able to interpret some of the G-code commands contained within correctly, as we have discussed earlier, which can even lead to print failure in some cases, finding out which G-code flavor your 3D printer uses is a vital part of configuring your slicer correctly for a successful print.

If you haven’t made any modifications to the firmware of your 3D printer, the quickest and most reliable way to ensure that you’re using the correct G-code flavor for your 3D printer is to add your 3D printer correctly on Cura, as Cura can select the right G-code flavor automatically for every 3D printer by default due to this information already being saved in it.

On the other hand, if you have changed the firmware on your 3D printer, which means that there’s a possibility for the G-code flavor to be different than the default (causing Cura’s pick to be wrong), you should look at the name of the firmware instead, as the name of the G-code flavor will almost always be identical to the name of the firmware, such as Marlin G-code flavor for Marlin Firmware, Repetier G-code flavor for Repetier-Firmware, and RepRap G-code flavor for RepRapFirmware.

Finally, if you’re using Klipper, the G-code flavor you should be using is Marlin (Smoothieware also works according to the official documentation), which is something worth mentioning as there are many Klipper users who ask this question due to Klipper not having its own G-code flavor setting in Cura.

Changing the G-Code Flavor Setting in Cura

To change the G-code flavor setting in Cura, you will need to start by clicking the tab on the top-left corner, where your printer’s name is, and click the Manage Printers button on the dropdown menu that appears.

cura printer selection


Next, verify that the correct 3D printer is selected on the left pane, and click the Machine Settings button afterward, as the modification you will be doing to the G-code flavor setting will only affect the 3D printer that’s currently active.

If the Machine Settings button doesn’t show up, click the three stacked lines icon on the top-right corner first, and click Activate.

cura printers menu


Finally, click the G-code flavor dropdown menu (right above the Start G-Code section), pick the correct G-code flavor for your 3D printer, and close the Machine Settings window, which will cause the changes to take effect automatically.

cura machine settings gcode flavor


Conclusion

While slicer software should usually set the G-code flavor correctly based on the model of the printer you’ve added, it’s still a good idea to double-check this setting and ensure that there are no problems, especially if your 3D printer seems to be displaying erratic behavior in some cases for no apparent reason.

As the G-code flavor names are usually named after firmware, such as Marlin or Repetier, or the brand of the 3D printer in cases where it comes with its own custom firmware, such as Ultimaker or MakerBot, finding out which G-code flavor your 3D printer uses, and correcting the G-code flavor setting should be a breeze in most cases.