10 réponses à ce sujet

[Lynx7725]

Can we get a Dev clarification on enemy detection algorithms?

Basically, I would like to get to get to know the bones that enemy detection works off. Right now, we know there's a visual element and a non-visual element. Just how this affect gameplay though, is unknown.

EDIT: Some updated info from this thread.

====================

Visual:

• Enemy reacts to the players sufficiently "realistically" that it appears the system traces LOS from all enemy to each player and react accordingly.
  
• There appears to be a "front visibility" arc which each enemy unit has. Detection appears higher in this front visibility, as a player can sneak up on an enemy from the rear.
  
• There may be a visual distance limit after which detection does not work, but this is not proven.

====================

Non-Visual:

• Enemies also always roughly know where the player is; this is a necessity, otherwise I suspect the mooks would spawn and just idle at the spawn point. The "wall hack" is needed for the mooks to be "encouraged" to work out a path to get to the player.  That's also why you see stupid behavior sometimes, like shooting at a wall or clustering in a corner (on White, especially). Sometimes, this can be exploited.
  
  

  Brenon Holmes wrote...
  There are some instances when enemies will cheat, for example if there's only one player left alive (or only one player at all) they will periodically peek behind the curtain to get an idea about where the player is...

  
  
• Side note: Player turrets and drones are especially prone to this stupidity, IMO observing Turret and Drone behaviors give some insights into detection algorithms (assuming they use the same algo, which is code efficiency).
  
• It is also known that the enemy can react to sneaky gits from behind; the implication is that there has to be some sort of non-visual detection algorithm.
  
• It is observed that AI tracks visibility arcs from the players, and AI would have different behaviour in and out of visibility arcs.
  
• It is unknown whether the AI observe and back trace tracer fire. This is particularly important for snipers.
  
• It is unknown whether the AI is drawn to weapons fire and explosions.
  
• It is unknown how cover/ concealment affects detection.

====================

Tracking

• It is now known that AI -- likely each enemy -- tracks a player's position (meaning, they keep tabs on each of the 4 player individually).
  
  

  Brenon Holmes wrote...
  
  A bunch of the Geth AIs (Hunter, Pyro) move to the player's location - generally this will bring them within hearing distance if you don't vacate the area they were moving to.

  
  
• Under specific circumstances, the AI would cheat and load your current position. This is necessity. Otherwise the AI would not be very intelligent.
  
  

  Brenon Holmes wrote...
  If you're soloing (or everyone is dead except you), you're in a bit of a tough situation since they'll be peeking relatively often. Your best bet in that situation is to stay mobile. If you're specced for duration on your cloak, use it before you get to cover or whatever position you want to fire from so that they think your last position was out in the open. When you shoot, they'll know where you are again so you need to pick up and move again... etc.
  
  If you're just playing normally most of the above applies, if you need to pass by an enemy - storm past it and keep running for a bit. Make sure you clear the immediate vicinity of an enemy, otherwise they'll know where you are (AI hearing).

====================

Guesswork:

• Non-visual detection is likely to work on a distance based algorithm, with factors such as player running/ firing or making noise being factors that would up detection count.
  
  

  Brenon Holmes wrote...
  There is a sound model, so certain things cause sound that the AIs can hear - footsteps, powers, gunfire, death... etc.
  
  Footstep sounds only travel 3m though, if I recall correctly. So if you were to run past an enemy, they'd probably hear you - but they still wouldn't know exactly where you were once you passed outside of footstep range.
  
  [Edit]
  Just went and looked at the data - footstep hearing distance is somewhat variable from 3-6m depending on the enemy type.
  

  
  
  
• However, if detection algorithms are worked such that weapons fire and running noise would "weigh" one Player above the others, this can create a possible tactic where a "Feint/ Decoy" character can deliberately make noise to draw fire. This is somewhat pausible already, as during objective waves it is possible for a lone teammate to draw off enough enemies to make life easier for the rest.
  
• Note that after reviewing what is said by Brenon Holmes, I personally believe that the system works on a broadcast method; When the player takes an action, the action is broadcasted and any enemy that is within detectable range updates their tracking of you. Different actions likely has different weightage; gunfire should weigh more, running less, so there can be an element of stealth in this game... except the AI cheats.
  
• In particular, Tactical Cloak can be seen as a detection de-buff, but not a total "null detection" power. It's powerful, but not perfect, particularly if the player cloaked in visual or is moving fast. (Shooting does not matter as it would immediately decloak).
  
• Specific to Tact Cloak:
  

  Brenon Holmes wrote...
  Enemies remember where you were - if you've just cloaked they'll keep spraying that area. If you clear the area immediately after you cloak (or are cloaking while moving) you shouldn't get hit by gunfire. 
  
  Conversely, if you cloak while remaining still and under fire, you'll have to wait for them to retarget... which could take up to a couple seconds in the worst cases.

• Suspicion is that there is no "aggro" mechanics, just a weighted "detected" mechanism, in which the easiest detected Player is attacked preferentially.

====================

Would appreciate if the Devs can share some insights, so that we can come up with interesting tactics to better our game.

Modifié par Lynx7725, 23 juillet 2012 - 05:41 .

[Brenon Holmes]

Lynx7725 wrote...

Can we get a Dev clarification on enemy detection algorithms?

<snip>

I'll go over a few of the systems and hopefully that will answer some of your questions? :happy:

Perception (Sight / Hearing)

Vision works within a cone and has a set radius. Outside of that cone and radius, they can't see. Enemies will periodically do LOS tests from their 'eyes' to the player, abiding by the peripheral vision cone and sight radius values.

There is some small amount of sharing, if a couple enemies are near each other they can pass information to each other (though this data isn't as good as them having seen the player for themselves). So if a Geth Trooper is standing next to a Prime, he can tell the Prime when he sees you. Then the Prime sort of knows where you are.

Hearing works within a radius but isn't as strong a type of perception as vision - it gives them a rough idea about where a player is. All sorts of things the player does trigger sound events... walking, firing your gun, using a power, dying... etc. You also generate sound when you fire past an enemy (they hear the sound of your shot flying past their head). From that they can get a general idea about where the shot came from.

Different types of sound make different amounts of noise...

Targetting is based on a whole mess of factors - there is no "aggro" system. Enemies will evaluate all the possible targets periodically (every second or so) and select the best one, if a different target is better (if they think they'd have a better chance of killing the other target), they'll often switch... though they do like to keep their current target if they're fairly close in terms of value.

Example Target Weight Factors:
* Range
* Stealth
* Old Target
* Player vs Henchman
* Perception
* "Good" firing arcs
* etc.

[Brenon Holmes]

Drayce333 wrote...

OK but can you tell us why submission net says it does massive damage to armored targets but it doesn't in reality?

That doesn't really seem like it has anything to do with the topic... so... not really, sorry.

ProfGast wrote...

Thanks for the info! I've always been curious on how the target evaluation is done (I'm often at the wrong end of the AI's targetting despite being farther away, in cover, etc etc.) I guess I'm good at staying in good firing arcs?

Odds are if you feel like you have good lines of fire on the enemy, they're thinking the same thing about you... unless you have a nice elevation advantage. You could also be getting dumped on by any infiltrator friends... less visible targets for them means more enemies targetting you. :happy:

mrwizeguy wrote...

Thanks again Mr Holmes.

Do they take into account objectives or only player position ?

Just player position.

OneTrueShot wrote...

Would you be able to clarify on this a little more? So very often I feel like I'm targetted based on rank or being the highest scorer. Are these two factors?

 

Nope - current score, rank, level, class... none of those are weighted at all. I did have a cheat in for a while that looked up a co-worker's name and targetted him specifically... but that was just during development - it's not live. :innocent:

Angel Beats wrote...

I have one question: Is score being taken into account?

Brenon I read that there is no aggro system, but by god it sure feels like it a little. xD I feel like I pull the enemies attention away from my teammates way too much. Heh.

Distance does play a rather large role - so if you're in melee range you're more likely to be considered a threat. If you run up with your Paladin and shield smash a guy, he's probably going to spin around and try to feed you his claw.

Lynx7725 wrote...

I guess that's why they have to cheat. Some spawn points are "hidden", no direct LOS. This I "know" is because player LOS into a spawn point will "diminish" the probability of spawning, so spawn point design has to cater for that. Without peeking, the units would just... stay put? 

That's sort of a different thing, we just don't really want players to see enemies spawn usually... since it looks bad to see guys appear out of thin air. :happy:

When they spawn, they do get seeded with some initial perception data though (they cheat). This lets them know where everyone is at spawn time so they have a rough idea about where to go to find enemies.

So, detection is weighed.. hmm. I also take it on faith that AI units share "hearing" info: "Hey Bob, I hear a rat scampering around below. Go check it out?"

Hearing data was shared at one point... I don't know that it is anymore, since it wasn't that useful for the AIs.

Thus it's more accurate to describe Tactical Cloak as a detection debuff power? Some options there for new powers really. I see now how decoy can work, simply by forcing itself to be higher on the priority list. 

 

Sort of, TC also has some other effects in the power itself that helps manipulate how enemies react to it. I believe it can force enemies to re-evaluate if any are currently targetting you. That's probably a good way of looking at it though.

(and that's correct about Decoy, they're effectively weighted a lot higher)

Modifié par Brenon Holmes, 27 juillet 2012 - 06:18 .

[Brenon Holmes]

 

ka243 wrote...

Im curious as to why banshees totally ignore decoys. Is the target priority messed up on them? This seems to be the case with brutes too. However brutes are interested in combat drones. Banshees seem to ignore those too. Maybe its a bug.

I always take shock on my decoys. Will enemies be more attracted to a shocking decoy than a non shocking one?

Certain enemies can't actually fight some of the player pets, mostly because the player pets don't have any proper collision... so melee attacks don't really work properly against them. Those types of enemies generally just ignore them (currently there are some bugs with that bit of code).

ProfGast wrote...

Thanks for the snappy responses again Brenon. A couple of random related questions: does Cerberus smoke block any LOS for anyone except human players? Or do all factions have Thermal Goggles?

Are certain classes/races easier to see/have higher sighting weights? (Krogan, Batarian, Turian)

 

Smoke blocks enemy vision, just like it does for the player. Bigger player meshes would be *slightly* easier to see under certain circumstances... but not really in any noticeable way.

Dorryn wrote...

If enemies can only see in a cone in front of them, why is it that when I throw a biotic at an enemy who's turning his back on me, half the time they'll dodge it?

 

That's a separate mechanic that really doesn't have anything to do with perception really - enemies just have the ability to dodge projectiles, there are % chances for that to trigger and various cooldowns.

An easy way to deal with them is either to shoot at them to trigger an evade, then immediately throw your power as they can't evade anymore (on cooldown). Or you can get the AoE evolutions on your powers and if you arc them down you'll hit even though they dodge (AoE tags them). Or just back to back powers if you have really short CDs.

DarkSpooky wrote...

Mr. Holmes, how does this account for the enemies being able to notice you shadow striking them, IE turning around before you actually hit them and then attacking you?

I'm not really sure about that one, but if I had to guess - when you "teleport" you probably make a footstep noise at the new location which they would hear and possibly react to (especially if they were already targetting you).

AbhijitSM wrote...

What about geth rocket troopers detection. Theirs seems to be the most ridiculous in the game . They start firing at you as soon as they spawn maybe or start firing rockets when they are behind a wall when they have not even see you or also when a player is behind them at a good distance (say 15 feet) out of their sight but they seem to just turn around & fire in some milliseconds.

Is this working intentionally or just a glitch ??

 

There are some problems with rocket fire for the geth yes, but those mostly have to do with in-cover fire delays vs out of cover fire delays (sometimes they're able to double-rocket). The behaviour you're describing sounds like what most enemies should be able to do (though reaction times are different based on difficulty usually) - it's probably just more noticeable since it's a big ass rocket flying at your head? :happy:

Hypertion wrote...

enemys include if a player is is cover as part of how they determine what is a easier target right? from my observations this also is part of what allows a Decoy to be effective, if all players are in cover then the decoy is also the easiest target. ive noticed that players in cover are often less likley to be targeted than one that is exposed and standing, but it could be just chance so i thought i would try to ask.

 

Yep, though the decoy also has other mechanics to encourage enemies to target it as well. :happy:

Modifié par Brenon Holmes, 27 juillet 2012 - 07:05 .

[Brenon Holmes]

mrwizeguy wrote...


Excuse me in am being dumb or something here and a bit of topic...

But does this line confirm there are stealth changes in the game ? because i cant recall seeing anyof these posted.



On topic thanks for the direct answear Mr Holmes.

No... the things I'm referring to there were modified before ship. Any hotfixes/balance modifications are posted in Eric's notes... and I believe the policy for patches is similar (though in a different place?). :happy:

Modifié par Brenon Holmes, 27 juillet 2012 - 07:12 .

[Brenon Holmes]

Mozts wrote...

I have to say: This thread is awesome.

I know there was already a answer about a class and levels, but what about races? Do enemies target a big slow Krogan the same way they target a ninja-like Drell?

They do, but they're more likely to hit the Krogan (since he's bigger and slower). Enemies have a bit of aim lag, so if you're moving perpendicular to the direction of fire, you're a less likely to get hit... especially if you're moving extremely quickly.

Modifié par Brenon Holmes, 27 juillet 2012 - 07:13 .

[Brenon Holmes]

mrwizeguy wrote...

Since you brought this up , i would like to ask a few more things.

Let me clear a few things first. We know that enemy has a shooting delay ( for example geth hunter has 0.25sec ) is this the "aim lag" you are talking about or is it another factor?

So , my question here is , if you run past the ememy behind him , is there a turning speed value calculated or regardles the angle you will be shot at a .25s rate?

I find that the enemy has no "sensitivity" turning speed values set and has amazing speeds at lock,turn,shoot.

(Different factor)

There's a couple things there - enemies have a sort of fire point. A position in space that they aim at for their shots, as you move that point lags a bit behind you (it sort of simulates what might happen to a real person trying to keep a bead on a target).

They also have accuracy computations that affect the spread of their shots, these are affected by things like:
* If they've just turned
* Is the target moving
* are they moving
* did they just notice the target
* etc.

Lynx7725 wrote...

Can I check if activating Objectives (in this case the capping objective, but hacking also does this) increases detection by enemy? There is a sound component and there is a visual effect...

I believe there's a "sound" that enemies can hear when you activate something.

Dorryn wrote...

Still, allowing enemies to dodge powers coming at them from behind seems an awful lot like cheating to me. I mean there is that issue but you have to add the fact that they have lightning-quick reflexes : they can dodge a rank 6 throw at 1200 newtons cast only 2 meters from them. I can accept that from the geth (they do think at the speed of light after all) but from the others? That's over(s)kill.

Well, they still have to obey certain laws... a dodge doesn't mean they automatically dodge the power. If you run up to a Trooper and fire off a power, he'll try to dodge... but still probably get hit by the power anyways... since it takes him a bit of time to clear the space that your power would pass through. :happy:

dr_random wrote...

Only the Prime seems to have superior spotting power. It is said a drone can spot cloaked players. 
How far can it spot? Yesterday I resorted to just missile the last Prime on Gold as it always seemed to know where I was, regardless of distance (Rio: Central complex:Prime, Crates right in front of LZ: N7Shadow)

Well, the Prime may have been peeking at your actual location - depending on the situation. If you were alone, or the only player left it's possible that he was peeking to see where your actual location was... so he could function at least a little... instead of sitting on his hands. :happy:

ka243 wrote...

Thank you for the reply!  I suspected something was wrong with this.  I work as a software tester in my real life.  Just to clarify: which part do you consider to be a bug? That banshees ignore decoys or that decoys are immune to melee or both?  As the decoy is a projection and not a physical thing it makes sense to me that they should be immune to melee type attacks.

It's a bug that the Banshees target them... they're flagged to ignore certain types of player pets, but they don't always.

neurovore wrote...

But I wasn't satisfied with it myself. Could there not have been an "explore behavior" for right after spawning? ie. the enemy simply starts exploring the battlefield, until first contact, after which the gunfire would draw the others in, possibly causing some flanking to occur. Sure, most of the time there's already gunfire going on when the enemy is spawning. But in order to encourage flanking, randomly choose a few midlevel units (hunters, pyros, centurions, brutes, anything semi-durable and reasonably fast) to explore for 10-15 seconds and then get drawn towards gunfire, unless they run into a "first contact" before that. Dunno. Just hyperbole, like I said. No effect on this game, but perhaps in the future.

And drones being able to crowd control Banshees due to glitches... This annoys me a fair bit. People are clamoring for difficulty, but instead of asking for AI-crippling issues to be fixed, they want a new difficulty level.

Well, I think you could look at this one of several ways:

* If we did have an explore behaviour - they'd explore for a short duration (as you point out), then have contact with the player force and start to fight... from that point on, you'd basically have what you have now for all intents and purposes.

The issue being that we would have had to make additional behaviours (patrol? search?), plus ambient behaviours... (if the players are all cloaked... the enemies need to look somewhat intelligent while sitting around doing basically nothing). The feature set for the AI starts to get a bit out of hand when you start including all these additional behaviours that don't necessarily support the primary gameplay... :happy:

* We don't really have stealth gameplay across all classes... so while it might be pretty interesting for one of six classes, it isn't really something that everyone could benefit from easily.

* Narratively, you're being inserted into a hostile space... I think it's fairly reasonable to assume that they know you're coming.

Modifié par Brenon Holmes, 28 juillet 2012 - 08:09 .

[Brenon Holmes]

 [quote]M A F I A wrote...

Since in here we got nice devs who actually answers questions I am gonna take advantage of that and ask a few things about AI behaviour which always made me curious.

1) Different weapons shoots have different sound intensity for instance a Geth SMG doesn't make as much sound as the loud bang of the Claymore. Does the AI hear more/better louder weapons as logic dictates or they are all alike to the AI and they hear all weapons the same way?
[/quote]

Different levels of AI sound didn't really make any kind of noticeable difference for the player... so all guns make the same amount of sound for the AIs. The only difference is how sensitive their hearing is.

[quote]
2) Tactical Cloak doesn't render you completely invisible (à la Predator) since a human can see another human cloaked if he has a trained eye or if he stands very close to it, my question is can the AI see cloacked players if they are close enough or ar they completely invisible to the AI? (Experience tells me they can kinda see you even while cloacked, less but they see you).
[/quote]

Nope. If you stand perfectly still and don't do anything... an AI passing by can't see you at all.

[quote]
3) In a game like Diablo 3 certain enemies are coded to target the lowest/highest HP player, does this mechanic exists in ME3 as well?
[/quote]

Nope.

[quote]
4) Special Effects such as Fury's Black Aura or Justicar's Barrier do they make you MORE visible to the AI or these things do not affect the AI at all?
[/quote]

Nope, cosmetic elements don't affect which targets they'll focus on. :happy:

[quote]Sabina261187 wrote...

I've got several good answers to my questions about the AI's gameplay in this thread, thank you for that Holmes..  

There is a few things I still can't figure out though.. When aiming at a nemesis with a sniper on gold/platinum, I always wonder, even though cloaked, and out of sight for a long time, and having new position, the second your cross hit's her head, she starts running is she was already a headless chicken, how can that be possible, do we cause a red light to strike her as well as she does to us?[/quote]

The Nemesis will react to being flanked - which is what it sounds like is happening in your description. She does't know you're aiming at her - but it's possible that another player has moved into position to flank her... that makes her scared... and she runs away.

[quote]
And also, I have noticed a new wall-hack-kinda ability, wich i don't know if it's a glitch or bug, or actual intentional to make it harder; on Glacier Platinum especially, the Banshee's can "teleport" through walls from the science lab and down to the extraction zone, even though you're running around a corner and become out of sight.. And even though other enemies are a lot closer and you're cloaked behind her she "moonwalk-teleports" backwards? And is there a sound difference to the enemies hearing-tracking if you're running contra walking?[/quote]

Once the Banshee starts teleporting towards you - she'll continue to do so along the path she originally planned, regardless of whether you cloak or not. Walking will generate the same noise as running - but it generate the footstep events less frequently.

[quote]
And final questions, since me and my buddies have been talking about it, and I like to think that way; does your decoy attract more attention when it's colored in awful Tutti-Frutti colors than if it was in total camuflage-color and then, does the enemy spot you more after destroying your decoy, because you just "teached" them to go after "you" as a decoy? Could be awesome if that is true... Thanks in advance! [/quote]

hehe, nope... sorry.

[quote]xXHAVOCXx wrote...

So will these detection bugs (turrets attacking cloaked players, detection while teleporting, double geth rockets, decoys) be patched in the near future?
[/quote]

I'm not sure that those are necessarily bugs... turrets use the same systems as other enemies. So if you cloak, they'll continue to fire at the location they think you were at.

By "detection while teleporting", I assume you're referring to the Shadow? It's not really clear what's going on there yet - so I can't really say what's happening (just my earlier guess). :happy:

We're always fixing issues, but there's a fairly big list of SP and MP issues that are addressed with each patch and only so much time to do each one in... so I can't really make any promises beyond bringing up the issues you've mentioned.

[quote]
Also to mention about detections after using a medic gel where enemies immediately start attacking you before you even got up. Especially for phantoms and geth turrets, it kinda feel like being spawn camped when you're the last one alive...[/quote]

I am kind of curious... what would you expect them to do in that case? You do currently have 100% immunity to damage until you regain control...

[quote].458 wrote...

Question for Brenon...
I've noticed that almost every time I line up a long distance head shot of an enemy under cover, for say a nemesis, and some others as well, that they move very quickly after. It's like they know they've been lined up. This is consistent, and I'm pretty fast at this, I try to line up before zooming and fire and zoom simultaneously. Do some of the enemy have a perception to dodge scoped in head shots?
[/quote]

Nope, they're on a semi-random timer and move around a bit periodically to keep things interesting.

[quote]
One reason I like armor piercing is that lining up a head shot on someone COMPLETELY behind cover never seems to cause them to run. Seems they do not know to run if they are under the misconception that they are in a safe spot (with good AP there is no safe spot if you can be seen).
[/quote]

They will actually remember that they got shot in the cover and let others know that it's not a great place to hang out... but if they can't see you they can't really figure out what would be a better place to hang out - so that's probably what you're seeing. :happy:

[quote]realgundam wrote...

Is it possible to get out the aim lag timing? so we know what kind of +mov speed to aim for.

[/quote]

Ah... it's something like 4 meters a second or something like that. Fast enough to catch up to a player moving at full run speed (not storm speed). (I can't remember off the top of my head, sorry)

Modifié par Brenon Holmes, 28 juillet 2012 - 08:27 .

[Brenon Holmes]

 

Xerorei wrote...

Pretty much every enemy is acutally cheating shadow strike and pre-viewing the supposedly hidden and lethal strike, I get lucky sometimes and get one but realistically speaking they more often than not detect me before I've even completed the power.

I'm not really sure about the specifics of the power, I haven't really looked at it (not at work right now either, so can't really peek at it)... but I'd guess it's either one of two things. Either you're making noise when you teleport behind them and the enemy hears it... or you're not actually "cloaked" at the new location when you do the strike.

I'd really have to debug it to know what's going on for real.

What exactly does the algorithim take into effect when searching random matches, I always end up with people from Eastern Europe or Asia, I'm talking Estonia, Russia, Thailand, Signapore, Lateriva, etc, and I'm living in Memphis, Tennessee.

Heh... that I couldn't say... I don't know much about the matchmaking systems. :happy:

soldo9149 wrote...

Thanks for answering all these questions Brenon Holmes.

No problem! I'm always up for some nice civil discussion.... plus the stuff I'm working on now is starting to wind down, so I have a bit more time to chat... or sleep... 

Modifié par Brenon Holmes, 28 juillet 2012 - 08:33 .

[Brenon Holmes]

reioni wrote...

Ok this post has answered most of my questions about when Decoy fails it's mostly due to someone drawing the enemy's attention away from the decoy but you're saying there are certain enemies it's NOT supposed to agro.  Does this include a decoy with shock traited to help draw the attention?  Or is it shock that's causing the bug to happen and drawing their attention?  Also, are banshees the only ones that are supposed to ignore the decoys (because it seems like when a well place/use decoy is ignored it's by an elite [atlas, prime, etc])?  The description on the skill itself doesnt specify that certain targets will ignore it.  It just says "Distract opponents with this decoy".  I had always thought there was just a chance that the elites might "see through" the deception of the decoy.

I don't really want to go into the specifics of how the bug is reproduced... but basically certain enemies (bosses and  some melee only enemies) are supposed to ignore some player pets entirely. As if they weren't there... so speccing it differently wouldn't affect that.

Shadow Strike -  I had a wierd bug where i came around a corner a good distrance from a Non-leaping Banshee, far enough away I wasnt worried about magnet hands and to get some distance from her I Cloaked and then used Shadow Strike on a target farther behind her.  As I was using my space magic to fly though the air with shadow strike, when i whooshed past her, before i had landed at my target, good ol' magnet hands McBanshee grabbed me mid air.  Shouldnt I have had less weight because I was cloaked?  How does your system justify that one?

It depends on how Shadow strike works - again I'm not really sure about the specifics. If you teleport, that doesn't really make any sense to have occurred... if you physically move across the intervening space, it makes a bit more sense - either you aren't actually "cloaked" as far as the game is concerned, or she heard you as you were moving past. Again though, I'd have to look at the code to get a better idea.

Fury (and I think these questions work for slayer as well be I dont have one) - 2 questions about this one. 

When you dodge through a wall how does that effect your threat wieght?  I do realize you are now out of their LOS but they dont really see where you've gone from there (did you go left, right or straight) are they going to "cheat" and see what direction you ran off in before you are in their LOS again?

Nope, they'll get pretty confused. The teleport doesn't have any directionality for the AI... so from their perspective, if you go through the wall - it's basically like you just vanished. If they can see where you end up, they'll react normally (as if you'd just moved laterally incredibly quickly).

Second question.... those Banshee Magnet hands...I've poofed through a wall away from a banshee and she has somehow managed to teleport just her hands through the wall and pull me right back in to the room.  The time between my poof and my surpise reapperance thanks to Magnet Hands McBanshee I thought would have been sufficient to account for server lag.   I guess this would go back to my first question on the fury/slayer and ask is the threat just the same even though you're now out of the line of site and she bugged and grabbed me or was this just a very wierd server lag thing?

I've mentioned it in a couple other threads, but there are some bugs with the Banshee sync kill - mostly related to how long it takes her to turn. Essentially there can be a 1-2 second delay after she decides to kill you (while she's turning to face you) in worst cases... after that delay you're going to get synced. Throw in a bit of latency and the problem is a bit worse. There's a fix in a future patch that will makes that particular issue better.

haisho wrote...

Interesting question: does suppressive fire force the AI into a defensive position, or will they move as they normally would?

 

Sort of - when in cover they don't like to shoot when they're under fire. So if you spray at them, they'll keep their heads down until you stop for a bit. :happy:

.458 wrote...

I also want to thank Brenon for his replies. Feedback is incredibly nice to have.

I was just thinking, because of replies above, it might be nice to have a new attachment to weapons: A supressor to eliminate enough noise to become even harder to find. That's a big part of the real world sniper. Also for people who don't lose their hearing. Hmm, one more thing...since walking makes noise, and so do weapons, it would be fun to have gear for quiet walking, and suppressor for weapons. Detection is a huge part of the game.

 

That's an interesting idea, I can poke Eric and the guys about it.

NewStrings wrote...

I know I'm going back a bit here, but this is a frustrating issue. When you say that we have 100% immunity until we regain control, you're talking AI time. If I go down beside a Phantom (I know, my fault for dying, but still), the Phantom camps my corpse even though there are three other people alive on the map. And if I medi-gel she hits me within a hundredth of a second of regaining control and I'm insta-killed at worst, or dead again at best. It's all very well having immunity until you regain control but if you can't do anything (e.g. escape, shoot, fire a power) before getting killed again then it's pointless. 

 

Well, technically she should be ignoring you now... since dead people aren't really valid targets. I know what you mean though as I've definitely experienced that myself. I'm not exactly sure what she (and some other enemies) is/are doing. We can add that to the list of things to look into.

Hypertion wrote...

hey, why are Rocket Troopers seemingly able to fire several Rockets back to back at random? also how is it that Hunters can still Fire while preforming the stunned animation, while knocked to the ground, or held in stasis?

The rocket issue has to do with in-cover fire delays vs. out of cover fire delays. They work through different systems, so if a Rocket Trooper transitions from in-cover to out of cover rapidly he can sometimes get off two shots with his rocket since they're tracked with separate timers. Other enemies can do this as well, but it's no-where near as noticeable.

With Hunters, I'm not really sure - I don't know that I've seen that particular issue. If I had to guess though, I suspect it would have something to do with the mechanics of the Geth Shotgun and it being a charge weapon. Most likely the shot will just go off if their shot was cancelled in mid-shot.

DnVill wrote...

Really informative responses thanks.

Though I have a question that might be slightly off-topic.

The Geth Primes curving plasma shots, are they considered a bug or a feature?

I find it kinda silly that these shots seem to track you. I know this applies to the GPS as well which makes it really effective.

 

It's intentional - certain projectile shots have seeking on them. Banshee, Geth Rocket, Atlas Rocket, Ravager Shot, Geth Prime, Geth Prime Rocket Drone. The amount varies a bit, when we didn't have it on them Geth Primes were pretty trivial... and that (the seeking) felt better than cranking up the speed on the projectiles. :happy:

Modifié par Brenon Holmes, 28 juillet 2012 - 10:41 .

[Brenon Holmes]

Pifase wrote...

Very interesting discussion indeed  

I would love to hear more about enemy's AI:
- pathfinding
- tactical intelligence, how many infantry tactical manuals you had to read etc.

The AIs use standard Unreal pathfinding, path nodes that define what you could think of as train rails all over the level. The AIs can evaluate if a particular section of the path is dangerous (exposed to enemy fire, people died there recently... etc) and incorporate that into the path they'd like to take when closing with the player.

Well... there's a difference between actual intelligence and perceived intelligence. It's actually pretty easy to make an AI that can be murderous and beat the crap out of the player - since they generally have a lot more information about the simulation than the player does... however that's not usually very fun.

We focused more on behaviours and abilities that could easily be understood - and thus easily dealt with by players. The interesting part was when those behaviours were then combined... all in all I think we're relatively happy with the result. :happy:

- use of cover, it varies in all enemy factions. Is there somekind of damage treshold when to cover? 
- Do enemies react player formations? 4x lone wolfs vs. very tight group formation? Is there a difference?
- Have developers ever been suprised by the players? For example do we perform poorly in some situations or very well on others? 

There are thresholds on when to stop leaning out of cover, yes. The enemies will *seem* to react to players spreading out :happy:. That mostly has to do with targetting algorithms and pathfinding though.

.458 wrote...

It's probably outside the scope of this thread, but I would find it very interesting to know if the devs talk about more complex AI behavior on bigger/newer maps/scenarios...something that would be more challenging to the brain even without more buffed enemy.

 

A little, but large scale AI changes aren't really in the cards... it took us a long time to develop the systems that we have now - it'd take a fair chunk of time to work out something new. :happy:

.458 wrote...

This thread makes me wonder something very arcane...if the use of a power or biotic makes noise, does that mean that the very act of an infiltrator going into tactical cloak can be heard and attract the bad guys?

 

Ah... I think it might actually. Heh, I never really thought about that... but yeah. I guess if you were undetected behind an enemy a small ways away and you cloaked - they might hear that. 

YIRAWK wrote...

How do enemy turrets and drones targeting system work? I notice that they can shoot cloaked enemies from a long distance away without seeing them cloak and without being in footstep range. Is this the mentioned peeking or do they have a special targeting system?

They should work in the same way as the regular AIs... if you cloak out of LOS and walk across out into the street they shouldn't be able to see you. If they do, perhaps there's a bug there... it's not something I've noticed personally though.

It is possible that you could be detected by a nearby enemy, and that makes its way back to the Turret somehow.

Razerath wrote...

I tried looking to see if you already said it but what is the average distance in which an enemy can "hear" you run, shoot, get an objective, cloak etc...?

 

Ah, it varies from enemy to enemy... but something like 3-6 meters maybe? It'll also depend on the type of sound being made. Footsteps are relatively quiet... guns are quite loud - so some sounds can be heard a small ways past the normal distance.

Modifié par Brenon Holmes, 28 juillet 2012 - 11:02 .