How to Modify STL for Dual Extrusion

[stevendm]

I have a dual extruder FF Creator Pro. There are precious few STLs on Thingiverse that take advantage of dual extrusion.

I there any way to take an existing STL file and edit it to use two colors? I know that it must be split into 2 files, one for each color and then put back together in Simpify3d. I am not talking about printing different layers in difference colors, I know how to do that. I am talking about taking a model, let's say a gnome and making the body brown and the eyes green.

Please point me in the right direction and I can take if from there.

Thanks

Steven