Writing a program to recognize a body part and then track objects (like snapchat)?

Question

Programming

Good afternoon. In programming, unfortunately, not a pro yet. Mostly in the 3D area.
I want to create a program that determines where the body / arms / legs are separately and later, when choosing an object (in the program), this object could be put on that part of the body where it was indicated in the program.
For example - recognizes feet - select shoes (in the program) - shoes on the foot. But it happens in real time.
Where should you start studying? What to study? Or you can modify the source codes or so.

Answer 1

1. Recognition of a body part.
2. Revealing the parameters of the model of a given part of the body (width, height, angles, etc.).
3. Based on p2, you can build a model skeleton (some characteristic points).
4. These points must be marked on the models of objects.
5. Then the matter is simple: we rotate the 3D model according to the characteristic points p4 and determine which parts of the 3D model are visible and which are obstructed by a part of the body.