Multicolour printing with desktop FDM(Fused Deposition Modelling) 3D printers is a relatively new advancement. It stands to reason then that there's still a lot of confusion on how to prepare 3D models to be printed on these machines. It also doesn't help that each manufacturer has taken a different approach as to how to feed these different colour filaments in to the printers nozzle. If you are using a Bambu Labs printer you're likely familiar with the AMS(Automatic Material System). If you are using the Flashforge system then it is the IFS(Intelligent Filament System) which is doing the job of feeding through each different colour of filament.
Fortunately regardless of hardware setup the software handles the colour printing preparation more or less the same. You will have to use an advanced slicer such as Orca Slicer or Bambu studio depending on what printer you have. Older slicers such as Flashprint or Cura are not up to the task. Let's take a look at the steps necessary to prepare a model and print it out in 4 colours.
STEP 1:
Create your design using 4 colors (or 8 / 12 / 16 colors if you have multiple AMS units)
Click ‘Finish’ when you are happy with your design.
STEP 2:
Open the Teacher Dashboard -> Class Management -> Classes and find the design.
Use the 3 dot menu to "Download 3D Files”:
STEP 3:
Go to "My 3D Files"
Use the download icon to download the design in OBJ file format.
Note: STL’s don’t include the colour information only geometry.
STEP 4:
Import the multicolour OBJ into Orca Slicer or Bambu Studio and the colour information will be automatically imported and will attempt to map the colours of the model to the filaments you have loaded on your machine.
If you imported an STL or a model with only a single colour you would need to 're-paint' the design in Orca! a tedious process. Fortunately with OBJ you don't have to.
With an OBJ import you will be given the opportunity to 'assign' colors from the design to the filament you have loaded:
STEP 5:
You can now prepare the file for printing as normal!
STEP 6:
The colours shown in the slicer will not directly relate to your filament colours unless there is smart filament updating mechanism, such as in the BambuLabs AMS. You will need to buy the physical filament which looks closest to the colour you wish to achieve in the print. If you decide you want to change the colours of the model later, you won't need to slice again. Most multicolour 3D printers will give you the option to reassign colours.
