I’ve said it’s impossible for arms, hands and guns. I maintain it. For the simple reasons that first persons hand would look goofy seen from someone else’s view (http://www.youtube.com/watch?v=-jBKKV2V8eU) and would make too heavy models for a 3rd person view. It’s not only impractical, it would make for a bad optimization too.
I’ve talked about legs that could have been the same between 1st and 3rd person model. That’s all. And even for that, IF it’s the case, it was possible back then because games didn’t looked as polished as now, and having feet sliding on the ground wasn’t strange.
As I’ve said, it’s not the case in L4D. Legs again, when someone else turn, his legs are following the movement, feet are sliding. When if you look at your feet, they’re more or less quite immobile on the ground, till you’ve turn too much and then they move. And I’m quite sure it’s the same for other recent games.