By default, this trigger will operate when a player runs into it, but altering the properties can change this. The above options tell Unreal how the trigger is operated, but you can also tell it who or what can act on it. This is the default setting and the trigger can only be activated by the player. Any pawn, such as the player, A Skaarj, or even a rabbit can set this trigger off. This broadens it even further.
Any class can activate it.
The trigger will only activate when a projectile hits it. These triggers creates an area which other pawns are scared of and so will avoid. In this trigger you can tell the elevator mover to move directly to any one of its keyframes. This is a very useful trigger. This is very useful for puzzles.