this is my 1st post. Im working on a project where i basically want to take an image that has three colours, separate the colours and then create an STL file of each colour regions. 

I want to use the modelbuilder library (  http://forum.processing.org/topic/announcing-first-release-of-modelbuilder-library) to create and export the STL. but im not sure how to create the mesh? i basically want the mesh to look like the colour region but have depth as if it was cut out of a metal plate.

Does anyone know of a simple way or to point me in the right direction. I can easily separate the colours, but am finding it hard to get started on the STL/mesh.

Any help would be appreciated