Hello to all Dual (and more ) extruder people.

Hello to all Dual (and more ) extruder people. I’m thinking of upgrading to Dual but I’m still not clear on the process in the software side. How do you cut an STL into multiple colors ? How do you feed these files to the slicer/printer ?

Slicer program can set the parameters.

Here’s a video by Adrian Bowyer that steps through the process for their tri-color Mendel:

The video is from their blog:
http://reprappro.com/reprappro-multi-colour-printing/

Slic3r reads .amf files and can create them from individual stls (that need to line up, of course). The specific process of splitting the model will depend on the CAD package you’re using, but basically, you’ll need each color/material in a different body and export each as an individual stls.
Slic3r can take a single stl and use different extruders for different parts of the print - specifically perimeters, infill and support material. It can either use different materials altogether, e.g. for water-soluble support material, or use a larger nozzle extruder for example for infill.