I was most of the time scavenging a wood nearby, and iv seen a hudge difference if i was using my vehicule or not; It was like every time i was using it, very soon i could see more animals nearby.
spawning can be somewhat in a large area, but often I don’t see anything after ±5 square (in the map) around where i make my base (so noise from car/ making stuff).
Maybe other guys could give you more detailed information about it, 'cuze it mostly what i noticed and maybe not exactly how it work.
Oh, and don’t forget to kill every dude you see, because game avoid spawn if there is too much guys around. And don’t be near town if you have set dynamic spawn of Z, or they will “eat” the slot of enemies.
