The various states:
There are 3 states in the game:
- hidden: no enemy knows where you are
- located: enemies know where you are but don’t see you (for you it translates as a “ping” displayed on the ground)
- revealed: enemies see you and target your bodyparts
Perception & Stealth
Perception is the distance (in tiles) at which you “reveal” an enemy. Arthrons have 20, Scylla has 35, our soldiers have 35, … you can see the value if you check each unit’s “info” panel.
Some armors and perks modify perception, like the “double perception” head for tritons. I currently have a soldier with 59 perception (he can basically see the whole map).
Stealth on the other hand influences the enemy’s perception. It makes it smaller (positive stealth) or bigger (negative stealth).
If your soldier uses the Anvil-2 heavy armor (-50% stealth), an Arthron with perception 20 will “reveal” him at a distance of 30 tiles.
If your infiltrator is wearing the Styx infiltrator armor (+75% stealth), the same Arthron with perception 20 will “reveal” him at a distance of 5 tiles.
How it works out
An enemy can’t shoot at you if you are not “revealed”. So as long as your infiltrator remains far enough from enemies, they won’t return fire when you shoot at them (although they now “located” you) and overwatch won’t trigger because they don’t see you.
I do shoot at tritons when they are “located” and not “revealed”, but the AI doesn’t do it against your soldiers.
So now, when you play, you have to do some math.
What’s the distance in tiles that I can get without getting revealed ?
distance = "enemy perception" x (1 - "soldier stealth" / 100)
You can’t know for sure if you are “hidden”, “located” or “revealed”. Except for infiltrators, if you see that their bonus 25% stealth has disappeared, you are “revealed”.
Oh, and I guess there is still the bug that dead enemies hear you so you are located if within 5 tiles of a dead enemy (mist sentinels for instance).