[naasking]

> the simplest is just mixing filaments, like one mixes paint. The article doesn't spell out the reason it doesn't work, I am curious as to why.

Plastic flow is laminar, where colour mixing requires turbulence. If you make a turbulent nozzle, it's basically impossible to print reliably with it (the pressure used to push filament out of the nozzle is mostly absorbed/redirect into turbulence).

[MayeulC]

Thank you for the clear & concise answer. A rotating nozzle and/or alternating colors might work then, but that would be a relatively complex engineering project.