I've been hoping for a method to be able to apply full colour to objects, or at the very least, solid colours that can't be bought in the chosen material (such as copper coloured polycarbonate). I was thinking that because the SecSavr is 5 axis and could technically have 1 tool for each of CYMKW and still have tools left over for the actual print, a feature I call "Auto PaintShop" could be implemented.

Sounds like Hackaday thinks so too: https://hackaday.com/2016/11/16/direct-to-object-3d-printing/

Solutions I have also thought of in the past:

• Airbrush
  • Paint could get in unideal places, such as the build plate. A sacrificial shield could be printed to prevent this.
• Acrylic pens
  • They are only usable for single colour filling.