Mob aggro: how, exactly, does it work?

[GastlyGibus]

Something I've noticed for a long time but never really thought to ask about: how, exactly, does enemy aggro work in this game? Has anybody ever done a deep dive into the enemy's AI to see how it works? What makes them decide to attack, when to chase, when to run away?

It seems kind of simple at first glance. Enemy sees player, enemy attacks player. It's not always so simple, though. For example, if I jump right into an enemy's face, more often than not he'll instantly attack me. If I attack an enemy, they'll usually retaliate immediately. However, I've noticed that if you creep up close to an enemy, and stand just within his perception radius, he'll turn to face you, but will do nothing. He definitely sees me, he'll turn to follow my movements, but he won't attack, he won't chase, he'll just stare at me. We'll have an intense staring contest for a few seconds, until eventually he decides to attack me. What is he doing? Is he debating whether or not to attack me? Is he assessing the risk? Is he just petrified with fear and soiling himself right then and there?

 

Other things in that same vein seem odd to me as well. For example, why does pulling work? We're all familiar with this. Sometimes with a large group of enemies, you can snipe one of them, and that one enemy will come after you, but the rest of the group is completely oblivious and won't even move. Sometimes that pull will fail, and you'll get the entire group's attention. Sometimes you'll only attract part of the group, while the others remain unaware. What is the determining factor, if any, that causes the group to attack or not?

 

Teleporting enemies are also very strange. Sometimes they'll teleport away and then... just forget you exist. They return to a passive state and just calmly walk back to their spawn point. Freakshow who resurrect themselves will sometimes immediately bolt away and run without engaging, even when you attack them. There's a lot of oddities with enemy aggro and it's gotten me really curious to know if anybody has ever looked into this.

So tell me, how does enemy aggro work?

Edited August 5, 2023 by GastlyGibus

[Greycat]

There is (or was) an explanation - especially of taunting - somewhere, at least from live. I don't have a link right offhand...

 

While it doesn't just talk about aggro, there's always the Wiki's Taunt entry - https://homecoming.wiki/wiki/Taunt_(Status_Effect)  - to start with.

[Snarky]

Well.  You irritate a mob.  This is really easy for me, I have a knack.  Then that mob attacks you

[GastlyGibus]

1 hour ago, Greycat said:

There is (or was) an explanation - especially of taunting - somewhere, at least from live. I don't have a link right offhand...

 

While it doesn't just talk about aggro, there's always the Wiki's Taunt entry - https://homecoming.wiki/wiki/Taunt_(Status_Effect)  - to start with.

That's interesting. Thanks for the link. So it seems proximity is indeed a factor in aggro, though to what extent and how it works is still dubious. Sadly, the "aggro" hyperlink in that article only leads to a page giving a definition of the term, and nothing more. Would love to see a full breakdown of how aggro itself works.

Edited August 5, 2023 by GastlyGibus
edited to clarify

[Veracor]

Each critter maintains a list of enemy targets that it has non-zero threat to.  Threat is gained by vision, damage, directly taunting, or allies in the group fighting, and is lost overtime based on time and distance.  The threat loss from time is static, but the threat loss from distance is greater if the enemy target is far away, especially when out of line of sight.  Hence, enemies that teleport away are at risk of forgetting about the fight if no substantial debuffs or taunt were applied to them.  Note that there is a very low threat threshhold that must be passed before the critter will attack -- that's what you're observing when you run past a mob and they see you, but haven't built enough threat to begin attacking.  Staying in their vision increases that threat until they attack; if you're close, that threshhold will be reached almost instantly.

 

The actual "threat" list that the critter maintains works like a leaderboard when there are multiple enemy targets.  The critter initially picks the first person to generate threat with them, and anyone else that generates threat goes on the list below them.  If the person with the second-highest threat value becomes twice as much as the current person, the critter switches to them, and then the next second-highest threat must become twice that to cause another aggro switch (even if it's the first person trying to get aggro back).  The reason why this function exists is to stop an AV from rapidly flip-flopping between two tanks.  Lastly, if what would be the current target is already at their aggro cap, the critter will merely attack the next most-threatening target on the list until a space opens for the current target (with the Homecoming update, the critter may still throw a few attacks at the aggro-capped primary target, but will largely attack the next person on the list).

 

For building threat, the AT's scalar multiplies with damage, debuffs, and taunts being applied.  For damage this is straightforward: damage is multiplied, i.e. if a Tanker were to somehow not have their inherent of Gauntlet, the Tanker would be doing 4x as much threat to an AV as they are doing damage, since Tankers and Brutes have a threat scalar of 4.  For debuffs, this is not as well understood: the AI's interpretation of the threat caused by various debuffs is different -- for example, the AI thinks RechargeTime and Slows to be extremely threatening while it thinks Damage and Resistance debuffs are not very threatening.  It does appear that the duration of the debuffs also play a role in the threat that they cause.

 

For the "taunt" effect in particular, the AT scalar is multiplied with the duration, which is effectively how threat is internally stored.  This is why a slotted Taunt (as in the power) from a Tanker is extremely sticky: when the Tanker uses this, they're effectively splatting a threat value of 80+ seconds on a target, which far exceeds the threat caused by, say, a Blaster's raw damage.  It should be noted that Tanker's Gauntlet and Brute's Punchvoke have their own unenhanceable taunt that all of their attacks apply (Tanker: 15 seconds AoE, Brute: 13.5 seconds ST), so even if the Tanker or Brute doesn't use Taunt, just their auras and attacks should be enough to hold aggro over a Blaster.  However, a low-damage Tanker or Brute that isn't using the power Taunt may get their aggro stolen by a Scrapper's damage, as Scrappers have the next highest threat scalar of 3, and especially if the Scrapper has their own taunt aura (such as Bio) or is applying slow debuffs (such as Ice).  The Scrapper may have enough juice to overcome the unenhanceable 15/13.5 second taunt that is being applied by the Tanker/Brute's attacks.

 

This page has a list of the different AT scalars that the mechanic of Threat gets multiplied by: https://homecoming.wiki/wiki/Threat

 

As to how exactly Threat stacks per target, I am uncertain.  It appears to decay faster the higher it has been stacked, but this is merely non-experimental observation.  It is entirely possible that it just doesn't stack and only uses the highest threat applied by a single instance (after regular decay).

Edited August 5, 2023 by Veracor

[carroto]

Mobs will commonly run when two conditions are met: They've taken damage (may require a certain % of their health bar), and one of their allies gets defeated.  Taunt seems to override this but I'm not sure exactly how they interact.  Sometimes the mobs will begin to run away and then turn around and come right back due to taunt, but other times they will just stand there without ever trying to flee.

 

I'm not 100% sure on this but I think I've observed that there are rank interactions with running too.  So if a minion is damaged and his boss ally gets defeated, he'll run for the hills.  Instead if a minion is defeated, his minion ally will return sooner if his boss is still in the fight.  I'd love to get confirmation on this somehow.

 

Mobs seem to also run if they are too heavily debuffed.  I don't remember which one but one of the Dark Miasma toggles can do this.

[Sanguinesun]

14 hours ago, GastlyGibus said:

Something I've noticed for a long time but never really thought to ask about: how, exactly, does enemy aggro work in this game? Has anybody ever done a deep dive into the enemy's AI to see how it works? What makes them decide to attack, when to chase, when to run away?

It seems kind of simple at first glance. Enemy sees player, enemy attacks player. It's not always so simple, though. For example, if I jump right into an enemy's face, more often than not he'll instantly attack me. If I attack an enemy, they'll usually retaliate immediately. However, I've noticed that if you creep up close to an enemy, and stand just within his perception radius, he'll turn to face you, but will do nothing. He definitely sees me, he'll turn to follow my movements, but he won't attack, he won't chase, he'll just stare at me. We'll have an intense staring contest for a few seconds, until eventually he decides to attack me. What is he doing? Is he debating whether or not to attack me? Is he assessing the risk? Is he just petrified with fear and soiling himself right then and there?

 

Other things in that same vein seem odd to me as well. For example, why does pulling work? We're all familiar with this. Sometimes with a large group of enemies, you can snipe one of them, and that one enemy will come after you, but the rest of the group is completely oblivious and won't even move. Sometimes that pull will fail, and you'll get the entire group's attention. Sometimes you'll only attract part of the group, while the others remain unaware. What is the determining factor, if any, that causes the group to attack or not?

 

Teleporting enemies are also very strange. Sometimes they'll teleport away and then... just forget you exist. They return to a passive state and just calmly walk back to their spawn point. Freakshow who resurrect themselves will sometimes immediately bolt away and run without engaging, even when you attack them. There's a lot of oddities with enemy aggro and it's gotten me really curious to know if anybody has ever looked into this.

So tell me, how does enemy aggro work?

 

The answer used to be more simple.  Since the evolution of the game whilst it was still live AND the tinkering around the HC devs have done to change aggro (and fleeing) rules, it isn't necessarily a clear cut easy explanation to give you and hence why there's been more than a few answers of things given to you thus far.  I highly recommend looking at last fall's aggro changes too as that's been the more recent one.

 

Just as one example of how its complicated perhaps:

 

Pulling- depends on the AT doing the pulling, depends on the power used to do the pulling with, depends on other powers that may have mitigations from players to that effort by the person pulling or from the team itself, depends on the Mob the pull was initiatited(ie their scripted response) on and the fail result actions too etc etc etc etc etc.  Basically lots of variables that either people just make a basic note of or they just dont bother caring too much about and just deal with the results one way or another.  

 

 

 

 

[Snarky]

1 minute ago, Sanguinesun said:

 

The answer used to be more simple.  Since the evolution of the game whilst it was still live AND the tinkering around the HC devs have done to change aggro (and fleeing) rules, it isn't necessarily a clear cut easy explanation to give you and hence why there's been more than a few answers of things given to you thus far.  I highly recommend looking at last fall's aggro changes too as that's been the more recent one.

 

Just as one example of how its complicated perhaps:

 

Pulling- depends on the AT doing the pulling, depends on the power used to do the pulling with, depends on other powers that may have mitigations from players to that effort by the person pulling or from the team itself, depends on the Mob the pull was initiatited(ie their scripted response) on and the fail result actions too etc etc etc etc etc.  Basically lots of variables that either people just make a basic note of or they just dont bother caring too much about and just deal with the results one way or another.  

 

 

 

 

Yeah, i used to pretend I understood agro.  With the latest changes?  Nope.  

[Sanguinesun]

8 minutes ago, Snarky said:

Yeah, i used to pretend I understood agro.  With the latest changes?  Nope.  

 

In a faux Matrix's Morpheus voice, "What if I told you that one of the worst pieces of advice a live dev gave to a community run game set of devs was to always keep your player base 'guessing'?"

 

 

Or maybe... there is no spoon....

😎

Edited August 5, 2023 by Sanguinesun

[Herotu]

On 8/5/2023 at 10:15 PM, Sanguinesun said:

 

In a faux Matrix's Morpheus voice, "What if I told you that one of the worst pieces of advice a live dev gave to a community run game set of devs was to always keep your player base 'guessing'?"

 

 

Or maybe... there is no spoon....

😎

I think it's good to be unpredictable. 

 

Predictable = boring.

 

If you want boring, I know a spreadsheet I can put you in touch with ...

[GM Crumpet]

It always amuses me when you snipe someone from a distance and they fall over but their friend doesn't react.

"So we going out for drinks after the shift Barry?".....

"Well I dunno, the missus is a bit frazzled with the new baby and everything. I might just go straight h... uuurgh...." <falls over dead>

"Sounds like a plan Barry. Barry? Oh he must have wandered off." ...........totally fails to notice Barry's lifeless body directly in front of him

[Bionic_Flea]

4 minutes ago, GM Crumpet said:

It always amuses me when you snipe someone from a distance and they fall over but their friend doesn't react.

 

I discovered yesterday that if you are reeeeeally far away -- so far that you have a targeting reticle but you can't see the NPC -- and snipe from that distance, the sniped dead NPC doesn't fall over until you enter visual range.  Something about a tree falling in the woods comes to mind.

[Snarky]

36 minutes ago, Bionic_Flea said:

 

I discovered yesterday that if you are reeeeeally far away -- so far that you have a targeting reticle but you can't see the NPC -- and snipe from that distance, the sniped dead NPC doesn't fall over until you enter visual range.  Something about a tree falling in the woods comes to mind.

game has a long history of people standing while being dead.  look at me....

[Bionic_Flea]

He wasn't undead.  He was dead dead, but forgot.

[srmalloy]

1 hour ago, GM Crumpet said:

It always amuses me when you snipe someone from a distance and they fall over but their friend doesn't react.

What I've found is that repetition seems to be key — snipe a mob out of a spawn with Boost Range running, so you're 240+ feet away, and the spawn will usually just stand there. Snipe a second one down, and they'll aggro on you. Back on Live, my AR/EM Blaster would hover up near Imperious while waiting for an ITF to fill out and snipe the mobs in the courtyard over on the north side of the valley. The first shot was always "Huh. Fred fell down"; the second would have the survivors pissed off and charging the platform.

[Sanguinesun]

8 hours ago, Bionic_Flea said:

He wasn't undead.  He was dead dead, but forgot.

 

 *Ryan Renolds voice*:  "He was just resting... some people just sleep on their feet..."

[Scarlet Shocker]

On 8/5/2023 at 7:24 AM, Snarky said:

Well.  You irritate a mob.  This is really easy for me, I have a knack.  Then that mob attacks you

 

This is Snarky's forum modus operandi, as well as in game 🤣

[Scarlet Shocker]

On 8/7/2023 at 2:19 PM, Bionic_Flea said:

He wasn't undead.  He was dead dead, but forgot.

 

Norwegian blue by any chance?