Adrian has been working on printing in multicolours and multi-materials.
We designed our Mendel to be able to accommodate three hot ends on the X carriage meaning that three different colours could be used for each print.
Here are the results:
RepRapPro Multi-material Printing from Adrian Bowyer on Vimeo.
We use two controllers on the Mendel - one master and one slave to drive all of the heads and motors. We have integrated the driving of this with our version of Marlin (Dev branch on our Github
We also want to get the user interface really easy to work with, so we have set things up so that you can build multicolour objects interactively on a 3D image of the build bed from easily defined mutually interlocking parts from a CAD system such as OpenSCAD.
The hardware is all working and we are currently putting together a Beta release package as there are a couple of tweaks needed still in the software.