grafter is a software system that allows users to remix 3D printed machines. It does so by extracting mechanisms from existing machines in a semi-automatic fashion and using these as building bricks to create new machines with. This allows users to re-use the knowledge and engineering experience that went into modelling the original mechanisms and moreover saves the effort of tweaking and testing the mechanism until it works.

grafter does two things: guided by the user it extracts the relevant mechanisms and it allows the user to drag and drop them into other models to make a new machine. In the figure above, c shows the tricky part, every time parts with different colours (= different source models) touch, users would need to tweak the dimensions to make it work. d shows how grafter approaches this problem, looking at the red thing: it took the gears, the axles and the geometry that keeps these axles in place from the record player, it then cuts off the unnecessary geometry (the crank and turntable). It then splits the red axle and fuses it with the green axle at a place where no red geometry touches it any longer. The same happened in the red-blue region. 

Below are some models created using grafter, note how the color coding labels unique 3D models. Each mechanism only needs to be extracted once to then be re-used in various new configurations