Stealth Mechanic Clarifications

[Tryble]

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EDIT: As of 1.5, the Rogue's been reworked. Information here is likely no longer useful!





I'm not 100% certain on how stealth works. I'll collect various bits of information here.

Here's how npcs currently work (if I've read the code right):

If they don't have a target (or a 10% chance if they do), they set their target to the closest hostile in their field of view (out to their sight range, usually 10, but blocked by walls), regardless of stealth/invisibility/etc.

When an npc loses sight of their target (from walking behind a wall, stealth, or whatever), they try to guess its position. They have a radius X that goes up by 1 each turn, starting from 1 on the first turn they fail to see you (Or 3 if they've never seen you before). They pick a random position within X spaces of your true position, and average that with whatever their last guess was. That's where they treat you as being.


Here's what I don't like about it:

• NPCs always know you're there if you enter their field of view, even if you have 9999 stealth. It starts out slightly inaccurate, but they are still alerted to your presence.
• They can divine your location if you teleport halfway across the map.
• The averaging doesn't work for large jumps. If I make a jump they'll target the space roughly halfway between for a turn, which doesn't make much sense.

So, there are two states an enemy can be in where Stealth is concerned: Alerted or Aware, based on whether they succeeded a detection check this turn.

• Alerted but exact position unknown: Enemy failed detection check, but is aware that you're nearby and will approach you for attacks. But as they don't know your exact position, they may attack or cast at incorrect squares. Enemy physical attacks suffer the 2/3 blindfighting miss chance check. Shadowstrike succeeds on these enemies.
• Aware: You are completely visible to this enemy, and they will attack your exact location directly. Shadowstrike fails.

As far as Stealth goes, it is almost incapable of actually hiding your presence from enemies as detailed by graswandir above. Enemies automagically detect you as soon as you're in LOS, but will mistake your exact location if they fail detection rolls, granting you the blindfight bonus and possible misaimed arrows/spells from casters. You can see the same behavior from enemies when you flee out of LOS quickly enough (with some form of very quick movement) and stay out of sight, and watch the enemy behavior with Track/Clairvoyance/Arcane Eye. They meander around attacking/casting on seemingly random tiles, having mistaken your location quite badly. If you can perform a short range jump without breaking stealth, enemies will probably be way off in their location guess in the same fashion.

The point of obtaining an ultra-high Stealth score is to ensure that they enemies remain uncertain of your location as much as possible, as well as ensuring Shadowstrikes can land. It will not reliably protect you. Enemies that can't see you do suffer a 2/3 miss chance separate from Defense checks, and spells can outright miss if they target the wrong tile, but that leaves a reasonable chance that attacks will come in completely unhindered, and a couple of those in a row is gonna spell trouble for you.


Questions:

• How is Stealth vs Detection checks done? It doesn't appear to be the same as Saves/Accuracy. Enemies with 15 Detection can detect a 45 Stealth power rogue even at long range pretty often.
• What happens if one enemy is alerted to your presence, but another enemy is aware? Will they communicate your exact location, or is the first enemy swinging blindly?
• If you mouseover an enemy that has 'caught sight' of you, under Target, it says Target:Character name, looking <direction>, or Target:Character, looking at you. I can't tell what this means, exactly.

If anyone knows better and can correct me, I'll edit the OP for those souls desperately googling for answers in the future.

[grayswandir]

Melee prompts an extra stealth check.
There is no "Unaware" state. They move immediately to "previously spotted" as soon as you move within LoS.
Being unable to see your enemy, for whatever reason, gives you a flat 2/3 miss chance for melee/archery. Unless they're illuminated - then you can hit them just fine, even if you're blinded.

[cctobias]

Also keep in mind that ranged weapons have a fall off on crit as range gets higher HOWEVER spells do not and channel staff is a spell. So you can channel staff from range 8 with full crit benefits PLUS the extra stealth HIPS modifier range gives.

[Tryble]

There is no "Unaware" state. They move immediately to "previously spotted" as soon as you move within LoS.

There was a post two years ago here (and another here) that claim that enemies that haven't passed a detection check simply don't react to you at all. The current version of Stealth's tooltip also says "If successful (re-checked each turn), enemies will not know exactly where you are, or may not notice you at all."

Has there been a change, or is there something I'm misinterpreting?
No matter how high your Stealth is, enemies always act as if alerted and will converge on you if you have open LOS to them?

If you mouseover an enemy that has 'caught sight' of you, under Target, it says Target:Character name, looking <direction>, or Target:Character, looking at you. I can't tell what this means as far as further detection checks or enemy movement goes.

The relevant section of code is in NPC.lua, starting at line 413. If I'm reading this correctly, an alerted enemy doesn't know exactly where the player is, but we're given a hint on what square they ARE observing. It's a square offset from the player, so if the target says "Looking North", then this means the enemy is targeting the square just above, from the player's view...I think.
If that's right, it gives us a chance to predict where they're going to throw the next turn's attack?



Apologies if I'm being weird about all this, I'm just trying to understand exactly how this mechanic works.

[grayswandir]

Here's an earlier post of mine:

Here's how npcs currently work (if I've read the code right):

If they don't have a target (or a 10% chance if they do), they set their target to the closest hostile in their field of view (out to their sight range, usually 10, but blocked by walls), regardless of stealth/invisibility/etc.

When an npc loses sight of their target (from walking behind a wall, stealth, or whatever), they try to guess its position. They have a radius X that goes up by 1 each turn, starting from 1 on the first turn they fail to see you (Or 3 if they've never seen you before). They pick a random position within X spaces of your true position, and average that with whatever their last guess was. That's where they treat you as being.

I didn't go deep into target passing, but it seems pretty good to me when I look at it. You can't pass your target if you can't see your target currently.

It might be slightly out of date, but I don't think there's been any major revisions since.

[Tryble]

Okay, I've edited the OP. Stealth is weird, man.
I can see why so many players hate the current Stealth system, if even the tooltip implies you should be able to walk around completely unnoticed but the enemies automagically home in on your area no matter what. On the plus side, any kind of high speed movement should be able to throw enemies off a bit.



Here's another strange thing. While messing around with stealth on low level enemies, I noticed some enemies bump-attacking themselves when they've seriously mistaken my position. I've seen this happen twice, once in a corridor and once out in the open.

[Micbran]

Mages will also just throw random spells at where they think you are. Stealth is pretty much your only defense for rogue. Use it wisely!

[cctobias]

Okay, I've edited the OP. Stealth is weird, man.
I can see why so many players hate the current Stealth system, if even the tooltip implies you should be able to walk around completely unnoticed but the enemies automagically home in on your area no matter what. On the plus side, any kind of high speed movement should be able to throw enemies off a bit.



Here's another strange thing. While messing around with stealth on low level enemies, I noticed some enemies bump-attacking themselves when they've seriously mistaken my position. I've seen this happen twice, once in a corridor and once out in the open.

I don't hate stealth. But it does give people that completely wrong and backwards impression.

Yes so basically stealth is a fairly major offensive gain (more so on lower difficulties due to equipment differences) and only a modest defensive gain. The main benefit of stealth is the free and increased crits. As a secondary benefit you get some "mistargeting" this should in no way be relied upon as a defense but sometimes does help some. As far being able to "sneak by stuff" no don't even bother. HOWEVER stealth does have an effect of obviously making things "lose track" of you faster when you run awayand lose LOS.

The mistargetting in conjunction with the scoudrel tree's mistargetting does start to be a half-way decent defense. But in general, no matter what your stealth rating or current status you will get hit a lot and thing will actively try to attack you. They will sometimes miss or hit other things.

Think of stealth mainly as offensive with a very very modest defensive benefit you should absolutely not rely on in anyway, except possibly for better running away. For normal difficulty, if you can stay in stealth reliably (requires equipment for melee), it is a very strong offensive buff that essentially doubles your damage.

[Winddbourne]

Weird and interesting. As I'm understanding this thread stealth thus becomes a very late bloomer.

* For the first three levels it is only giving a minor defensive benefit.

* For levels 4-9 it is giving one automatic critical strike with a bonus ranking from ~+14-71% extra critical damage; not quite doubling your damage like a block would and not even being able to reliably reactivate after a few turns.

* From levels 8-12 you get an increasing chance to re-enter stealth ONCE a fight.

* At levels 12-16 you get a chance to stay in stealth after taking an action based on your stealth value. Initially this is 4% of your stealth value, but at five points of investment it becomes 189% of your normal stealth score matched against their detection power.

That means at level nineteen or so you can get the benefit of a "nearly" eternal "block" ability after investing 20 points and really putting your emphasis on the cunning side of the tree. This is postponed if you invest in other skills to make it worthwhile. You probably do want points in lethality both so you can use all that cunning, and for another 25% critical damage. You also probably want to be using attack skills that already give you up to 300% damage improvement with little point investment.

Realistically this becomes a valuable offensive tool around level thirty. But it comes at the cost of a lot of point investment and defense. You can't wear heavy armor, and it seems (I'm not sure) like you should avoid the fungus tree or other trees that revolve around constant skill usage to minimize random stealth checks that could take you out of sneak while approaching a fight.

So if I'm understanding this right it is like psi-blades. If you are going to play with it you had better plan from the start to build your character entirely around it. If you are just putting in a few points it's not going to be worth it. That first big hit against an enemy you could have killed instantly anyway is wasted and you are probably surrounded by other enemies. Meanwhile a big boss isn't likely to die from that first blow and may also have minions surrounding it.

I'm not the sort who looks at the code, and I may be misunderstanding so if I'm off here please explain how and why. Thanks.

[ster]

stealth never becomes good i'm afraid, especially not with the tradeoff that your character instantly dies if a sawbutcher looks at you funny

[voltteccer]

Realistically this becomes a valuable offensive tool around level thirty.

Stealth comes online as a valuable weapon at level 13, when you have invested a minimum of 5/1/1/2 in the category, becoming more effective as you approach 5/5/1/5 (the third talent is not really worth investment).

You must plan your character around stealth from the start because it locks you out of heavy armor, and heavy armor is incredibly powerful.

Stealth is bad because you are forced to gimp your defenses to use it, and defense>>>>offense.

[Effigy]

It's actually very strong for ranged characters, but that mainly applies to Adventurers. Being able to get 100% crit chance and some bonus crit multi from one category and ~16 class points is quite powerful. You give up heavy armor, but it's not really needed for ranged characters if you have other defensive tools.

[ster]

guess what you can make adventurers that are completely unkillable on madness or deal 150k+ a turn
meanwhile stealth is bad it's like 80 crit mod for the massive tradeoff of using light armor and like 15 class points

[sajberhippien]

So, in regards to the info being outdated with 1.5, does anyone know how/what has changed?