For me, the tricky part about this was modeling the locket. I am by no means a stranger to 3D modeling; It is just that my skills are a little rusty. After teaching myself 3DS Max when I was 15, and then spending two full years of college doing 3D animation in Maya, I left the world of virtual 3D forms and did not look back. Over the years, all of the trauma was carefully purged from my head while I spent my time making real things. If I had known ten years ago that by making virtual things, you would some day be able to press a button and get a real thing in return, I may not have been so quick to flash my memory. Anyhow, while I may have been quite good at 3D modeling 10 years ago, I am currently in the process of relearning a lot of the skills. Fortunately, it is coming back rather quickly.
I am including two different sets of files. The first set is the 3-part locket in STL format for people without 3DS Max and who just want to figure this out on their own. The second set is the 3DS Max file that is set up such that it will be easy to import and insert your face into the locket. The following instructions will show you how to use the 3DS Max file to complete and export your own custom locket.
Step 1: Iterations
Step 2: Catch Yourself
Download 123D Catch, load in your image sequence, and compute the photo scene.
If all goes well, you should have a 3D model of yourself. If not, start over from the beginning with no images.
Select and delete any weird bits that are protruding from yourself.
Finally, export it as a .obj file.
Step 3: Lift the Lid
Step 4: Import
Select the model and click on the modifier tab. Choose "Cap Holes" from the modifier list.
Scale and reposition it such that it sits nicely in the bottom part of the locket.
Step 5: Close the Lid
Make sure that the 3D model of your face does not touch the underside of the top part of the locket. If it does, it will not close properly, and you should reposition/scale your face such that it can fit.
Step 6: Boolean
Select "Subtract (A - B)" and click "Pick Operand B."
Click on the large box.
If all goes well, you should be left with a bust of your head that fits perfectly within the locket.
Step 7: Rotate the Lid
The hinge attached to top of the lid will no longer be aligned with the hinge's pin.
Move the lid until the hinge is centered upon the pin. Basically, the rungs from the top part of the hinge should be aligned with rungs of the bottom part of the hinge.
Step 8: Attach
Edit mesh should already be in the modifier stack. Make sure it is selected.
Click on the "attach" button and then click on the face. It should change the locket to be the same color as the face.
Step 9: Export
Select each part of the locket individually and export it as an STL.
Step 10: Fix the STLs
Open each STL one by one and go through the following process:
1) Click on the red plus.
2) Click "automatic repair" at the bottom
3) Select the standard repair option
4) Click "Apply Repair"
5) It will ask if you want to "Remove old part?" Click "yes"
6) Finally, go to "Part --> Export Part --> as STL"
7) If there are further problems, it will ask you to fix them. If prompted, click the button to repair fixes, wait for the green check, and click Export.