Ok, maybe you will reply now, how can I do this:
I want to make a trigger to open the chute, it must open at 20 meters high.
So I need a trigger that checks if the player is at 20 meter and then he must activate the action from the action menu called Open Chute
Keep in mind that the guaranteed safe parachuting altitude is 75 meters. Having the player *attempt* to open his chute manually at 20 meters will almost guarantee death because the player will probably react too slowly. Even if he reacts in time, the chute doesn't have enough time to open, so he'll die anyway.
If you bother to have a trigger detect if he is 20 meters (or any altitude, for that matter), you might as well just have the trigger automatically open his chute. That's my thought, at least.
In any event, to answer your question, in the trigger's Condition field, put the following code:
(getPos player1) select 2 <= 20Your post isn't too clear about why you need to detect the altitude with a trigger, but I assume you meant to say that he can *only* open his chute when he is 20 meters or lower in altitude (again, guaranteed death).
If this is the case, then instead of using a trigger, in your script run by the Open Chute action, have it check if the player is <= 20 meters, and if not, then exit. That would work much better.