I have a couple levels that have elevated platforms that the enemies will go up and down as they pass. The initial issue I have is that when they are on their way back down the ramp, they dont fall as fast as the ramp goes down, they slowly glide down. If I apply Physics.gravity = new Vector3(); it works great when they go down the ramp, but now they are too heavy to go up the ramp. Is there a way to simulate gravity so they will butt against the floor at all times without giving them weight?
As syclamoth noted, objects in unity are sensitive to mass and volume, so if the scale of your game is built very small, the objects will act (in gravity) as very small objects do in real life (aka floating gently down). Try adjusting your characters mass. Often players and enemies won’t actually use real physics, but will use a sort of “sudo-simulated” physics that is easier to control and constrain. See the Unity FPS example project for reference. Hope this helps.
See this link http://forum.unity3d.com/threads/181705-GroundNPC?p=1241872#post1241872 . I hope this help