by mh » Mon Mar 21, 2011 7:26 pm
It depends on what you want to happen after the head is shot off.
If you want the enemy to just stagger around a bit and then fall over, then you could add some more frames to each model - some of the damage frames might be good to duplicate, and obviously you'll need to do the dead frames too - and move the head vertexes to somewhere they won't be seen, like inside the body. You'll need to do this manually for each and every MDL file as the Quake models don't contain any headless frames.
Then you need to add locational damage to the engine because the Quake engine doesn't have locational damage. This will need per-poly hit detection - another thing that the Quake engine doesn't have. Without this there is no way of detecting whether or not an enemy has been hit in the head.
Then you need to test it, bug fix it, and make sure that it plays nice with other mods and maps.
If this sounds like too much work (and it is) then just download the patch you were given and study how it was done in the patch, which can be a useful way of learning how to do things for yourself.