For a while I've wanted to do this, but I was hesitant to make a mold of my face. it seemed like it would be a big mess. After playing around with 123D Catch I thought, "this will work!". Now we don't have to mess around making a mold of our face, but we can do it digitally with entirely free software.
This flow of this project is as follows:
Pictures -> 123D Catch -> .obj file -> 3D modeling software -> editted .stl file
-> Freemill -> g-code -> Notepad -> CNC Router - > Foam negative mold
-> Plaster Positive mold -> Plastic vacuum forming -> Painting -> Awesomeness.
So as you can see there is a lot to this. We are going to duct tape a lot of software together and get this to work. Lets do it!
Step 1: 123D Catch - Making the Model of Your Face
123D Catch prefers that the lighting is even and it requires that nothing moves. We took a series of photos around ourselves in order to resolve our faces. Angular spacing of 5 to 10 degrees is best. 20 or 30 pictures worked here. You'll have to experiment as things like hair and beards will affect the model.
Simply load the pictures into 123D Catch and generate the model. They are loaded into the cloud to do its work.
Once you have a model that looks like it is going to work (this might take a few tries), you'll want to generate a high res version of it and then export that as an .obj file. Don't worry about all the extra stuff, just make sure that the face looks ok.
Now that we have the 3D file we can work on modifying it in order to remove the extra parts and smooth out any bumps. We will use some other free software to accomplish this.