How does morphing programs actually work ?

[arteqt]

Hey, i am thinking about writing an open-source 32-bit morpher, since there are no updates on the current ones ,however i did not get into model editing/swapping since tbc and early wotlk and need some guidelines.

So, here is the deal. i really dont know anything about how does morphing programs work. Seems like they only change the player's models into other things, which means its not the old-fashioned dbc+hex model swapping. So what is it ?

I am not expecting any lecturing under this topic, all i want from you is directing me to topics that i need to check out. Any help, anything to start with would be great. Thanks in advance.