Gcode flavours: Reprap vs. UltiGCode

Gcode has a certain layout and contains a different instruction set based on the machine it is written for. It is important to know how and why the machine handles certain gcode. This gcode flavour is used by the machines:

  • Ultimaker Original(+): Reprap (Marlin/Sprinter)
  • Ultimaker 2 (Go/Extended): UltiGCode
  • Ultimaker 2+ (Extended): UltiGCode

Ultimaker Original(+): Reprap (Marlin/Sprinter)

This is the first type of gcode used by the Ultimaker Original (+) series. It is meant to contain every single move the Ultimaker makes. This includes the Start/End-gcode and information like nozzle temperature and retraction settings.


The Start/End-gcode contains a few lines of code to make sure the machine starts and ends properly. It contains code to home the printhead and warm up the nozzle. The End-gcode contains proper information to cool down the machine and disable all stepper motors.

Material settings

The Reprap gcode flavour includes material settings. That means that the following parameters are included in the gcode:

  • Nozzle temperature
  • Bed temperature
  • Material flow
  • Fan speed
  • Filament Diameter

Ultimaker 2(+): UltiGCode

With the release of the Ultimaker 2, the UltiGCode was introduced. With the new firmware it is possible to slice a model in Cura and select different materials on the machine. This way, a single gcode can be printed with different materials.


The Start/End-gcode is not present anymore. The instructions are now programmed into the machine, before a print starts and when it ends.

Material settings

Material settings like nozzle and bed temperature are not present anymore. The settings are stored in the machine itself, and have to be set when a new type of filament is inserted.

Overview of Reprap vs. UltiGCode

The below overview shows which gcode flavour is user per machine. The material settings section views where the setting is located per machine.


* The flow is initially set in Cura, but it can be adjusted on the machine through the ‘tune’ menu.

**The fan speed has always been set by the gcode. But the Ultimaker 2 has the possibility to modify this speed by a percentage. With the Ultimaker 2+ this percentage is set to 100% for every material. The fan speed from the gcode is no longer affected by the machine setting.