Sufyan: Typical of Quake II games when 3d models did not have skeletons for the sake of animation. If you think it looks bad in SiN then brace yourself for Kingpin!
HenitoKisou: This wobbly effect along with damage skins and soundtrack in both games are reasons alone to get them. ;-)
skip to 0:50, the moment that must have made every player go "Whoa, what's wrong with that characer model?" before realising that's how all characters and first person weapons are going to look. Even the motorcycle in the early part of the game is warping!
Anyways, I guess the reason this is happening in Quake, Quake II and games built on these engines without modification of the animation systems is because the vertices (in laymans terms, the corners of the polygons) are not weighted against an invisible skeleton. I never modded these old games but I would not be surprised to learn that the animators had to keyframe the vertices themselves to animate them. I have rigged hands with fingers on a couple of humanoid characters but even that must have been simple compared to animating stuff without skeletons.
