Zombie AI Tweaks (Partial)

[SilentLight]

Having observed zombie behaviours, as well as the various combat tactics which seem... un-movie-like, I have a partial list of AI tweaks which I think might work to address gameplay mechanics, and introduce interesting dimensions of risk to gameplay.

 

Zombies Avoid Fire

 

I recognise PZ follows the trope of 'all zombies are braindead dumb', but I think it leads to behaviour that's too easy to cheese if they're too stupid, and they should have some 'basic survival instincts' to make them more challenging.

 

Having zombies avoid fire would mitigate tactics such as leading them into campfires, as well as going near other, already on-fire zombies, meaning a zombie horde won't naturally spread fire to other zombies. It has the added benefit of preventing a single zombie from stumbling through a fire and burning a player base down, and it mitigates campfire cheese as it would mean the zombies would path around the campfire, and not cluster around on-fire zombies.

 

On-fire Zombies "Panic"

 

This would simply be a random "drunken walk" (nothing too CPU intensive). So instead of constantly chasing the player, on fire zombies become confused and 'panic' (I mean, if their eyes have melted, their nose is full of soot and their ears are burnt to a crisp how can they navigate to the player anyway?). This would mean the on-fire zombies will "break away" from the zombie horde (thus reducing the odds of setting the other zombies on fire), and there's a real chance they could run off into forests and buildings to set them on fire during this "panic" state.

 

Accelerating Zombies

 

Zombies who have been pursuing a player for a while, instead of having a static, constant speed, will start to accelerate as their zombie adrenaline starts pumping. This means if a player tries to simply do a "brisk walk" to outwalk zombies in a straight line, it won't work and eventually the zombies will go from a shamble, to a walk, to a jog, to an all-out sprint. The acceleration decreases whenever zombies lose line-of-sight of the player, and resets back to zero if they get hit or shoved. Injured zombies cannot accelerate.

 

Climbers

 

Periodically, a spawned zombie will have the trait that they "like" to climb things (basically: if there's any sheet rope or rope it can climb in range, it will climb up it; this takes priority over everything except chasing the player). This is to make it so sheet ropes become a liability if left out as an "easy" way to avoid zombies.

 

50/50 Fence Mechanic

 

Zombies have a 50/50 chance to not cross a fence. Currently tactics for killing zombies involve back-and-forth vaulting over a (short) fence endlessly. In reality, zombies would not perfectly cross a fence every single time, and some zombies would get stuck on the other side. This would not only aid player escape (meaning every fence you cross is a 50/50 chance of losing zombies), but also would avoid this abnormal fighting tactic (as the end result would be zombies on both sides of the fence meaning you can't easily one shot crossing zombies).

 

Disabled Zombies

 

Some zombies will spawn with disabilities. Specifically, either a lack of hearing or a lack of vision (mutually exclusive). Lack of hearing means players cannot guarantee shouting or making noise will clear an area. Lack of vision means using line-of-sight to draw aggro won't work.

 

Noisy/Screamer Zombies

 

Some zombies on spawn will have the trait of being noisy/screamer zombies. They make noise the moment they spot the player, drawing other zombies in an area to the screamer zombie. This prevents players from easily 'picking off' zombies one-by-one.

 

Bite-less Zombies

 

Some zombies have the trait they cannot bite under any circumstances (implied: missing bottom jaw, missing teeth, broken neck, etc). This is to reduce the prevalence of bite events whilst still presenting threats (they can still lacerate or scratch), to make up for the introduction of smarter zombies. Zombies also have a probability of being turned into a biteless zombie via player attack with specific weapons (E.G. hammer), meaning the better you are at fighting (and not merely armour!), the lower your overall risk of being bitten.

 

Stealth Zombies

 

These zombies spawn in trees and other ideal hiding spots, however unlike normal zombies, they don't redistribute or form rally groups, so they're always in hiding, waiting to surprise a player. May also optionally ignore 'loud' sounds like shouting or idling cars and only attack the player when they're in range (so they can "ambush" players).

 

Dozy Zombie Mechanic

 

If a player opens a door in a house to a room that contains a zombie (indoor zombies only!), and that zombie was not alerted to the player's presence before hand, the zombie will be in a dozy state and will not 'instantly' chase. This both rewards stealth and gives noobs a chance to react (E.G. by shutting the door again if unarmed) to their first zombie encounter.

 

 

 

[EnigmaGrey]

Almost none of this fits Project Zomboid. :/

 

50/50 fences? Sure, maybe.

 

Zombies already differ in physical state. We are not going to L4D it.

 

Discount the human characteristics from Romero zombies and focus on Brook's stuff to get a better idea of why we've landed on what we did.

[RichardSwett]

 

7 hours ago, EnigmaGrey said:

50/50 fences? Sure, maybe.

 

Updating the AI to act a bit smarter around fences would add a really fun way to weigh risk versus reward around fences and windows. 

 

If the player is within a certain small radius to where the zombie may vault over that window or fence, then the zombie will go for a grab over the fence and attempt to bite the player. Similar to the scene in Shaun of the Dead where the guy gets grabbed through the window of the bar and ripped to shreds. This would still fit the mindlessness of Brook's zombies.

 

Gameplay wise, this would balance the instakill cheese over windows and fences where players are just waiting with their backs against the fence/window for zombies to vault over. Instead this would make it a matter of timing/skill to keep distance to not get grabbed before the zombie vaults and not getting tripped when the zombie lunges after the vault. High risk, high reward for the instakill. 

 

I think that this would be a welcomed change given the new updates to breakable chain link fences and could be linked in to the WIP in regards to updated zombie fence AI. 

[SilentLight]

On 4/23/2024 at 10:49 AM, EnigmaGrey said:

Almost none of this fits Project Zomboid. :/

 

That's okay, it's why they're suggestions. We can always adjust the ideas or ignore them.

 

Zombies already differ in physical state. We are not going to L4D it.

 

I'm not suggesting visually distinctive zombies, but behaviourally different, and they're intended to address what I think is player cheese, they're not meant to be specialised classes. So the climber zombie is still a standard zombie - it's just one capable of climbing ropes. In theory, you could give a climbing trait to all zombies, but I feel like it would result in swarmed ropes.

 

On 4/23/2024 at 10:49 AM, EnigmaGrey said:

Discount the human characteristics from Romero zombies and focus on Brook's stuff to get a better idea of why we've landed on what we did.

 

Does that include Brook's work in World War Z, which follows on from his survival guide? Perhaps I have misremembered, but weren't zombies capable of 'stack-climbing' (they could climb on each other unintentionally to scale even tall walls)? I don't know the proper term for it.

 

Perhaps my rope climbing suggestion is maybe too sophisticated for a mindless zombie, although I tried to keep the suggestion functionally simple from a coding standpoint. You could have the zombies mindlessly stack up on each other, which would be Brooks consistent? But I imagine that would be coding hell to implement.

 

I'll rethink the fire suggestions if it is pure mindlessness zombies. Perhaps the zombies could extinguish the campfire flames as they walk over it instead? It would still mean the cheese is partially viable, but if you had a low ignition rate, it would be more likely the campfire would get extinguished (by treading/disruption/oxygen removal from sheer quantities of zombies).

 

On 4/23/2024 at 6:48 PM, RichardSwett said:

then the zombie will go for a grab over the fence and attempt to bite the player. Similar to the scene in Shaun of the Dead where the guy gets grabbed through the window of the bar and ripped to shreds.

 

I like this suggestion as a variant to the 50/50 mechanic, and it is what I thought would have happened if I had my back turned to an open window with a zombie behind it when I first started playing. Also seen in Resident Evil (whilst yes, I know they're a games series, it was also turned into movies).

 

 

[getstoopid]

I like the idea of the trampled campfire (zrampled... had a typo in first and wanted to share as I found it hilarious). It's realistic and a balanced counter for this tactic.

The rope climbers are way too much for my taste, even the stacking is somewhat meh... but would maybe depend on its implementation and how it looks in the end.

Edited April 27 by getstoopid

[SilentLight]

12 hours ago, getstoopid said:

I like the idea of the trampled campfire (zrampled... had a typo in first and wanted to share as I found it hilarious). It's realistic and a balanced counter for this tactic.

 

To give the players something back, I think they should be allowed to dig vertical holes with a shovel, which zombies (and maybe players?) can fall into, allowing them to intentionally set up booby traps that aren't overkill.

 

The rope climbers are way too much for my taste, even the stacking is somewhat meh... but would maybe depend on its implementation and how it looks in the end.

 

Understanding these zombies have to be really, really dumb will make the whole 'hiding on the second floor of a floaty rope tower' difficult to counteract.

 

I was going to alternatively suggest having them having a chance of intentionally destroying the rope, even when the player isn't present, however I feel that's incredibly harsh, where-as a climber would be a manageable but persistent threat and nuisance.

 

Limited Durability Sheet Ropes?

 

Alternatively, it could be made so sheet ropes have limited durability. I get their purpose is to be used for escape (per Brooks' survival guide), but in reality cloth would not make for a durable climbing unit and it would rip (the more weight being carried up, the more it will tear). So maybe it should only be viable for a couple of uses - enough to make an impromptu escape with, but not so durable it becomes a de facto climbing ladder.

 

A rope might be more durable, but a single nail is going to struggle to withstand the repeated climbing/weight shifts, and either the rope is going to fray or the nail will dislodge (maybe a rope gives 10 uses compared to a sheet rope's 2?). If accessibility is intended, then perhaps a dedicated, more durable rope ladder could become an option, requiring multiple ropes (not sheet!) and multiple nails.

 

This would actually give an incentive to upgrade from a makeshift 'rope' made out of clothes to a properly made rope.

 

You could then make a highly durable metal ladder as the 'final form'.

 

 

I am curious though - how mindless are these zombies? Is there any flexibility to this rule, E.G. they can (somehow) open doors or open windows? Or any particular non-mindless task they're allowed to perform that doesn't violate the restriction?

[getstoopid]

Zombies damage/dedtroy the ropes already afaik... and players building floating safehouses aren't interested in a challenging game so they'll always find a way to exploit the mechanics

[KerikPlay123]

Yep, if the zombies are on fire, as in case with humans IRL, their eyes won't be functional anymore, and they might not even hear well anymore due to literally "melting" and turning into ash, it's kinda dumb to see this unlogical situations when there's a burning horde following you so simply, ignoring the fact that their eyes and stuff might've already melted 100 times during the time period when they all were burning.

 

More clever zombies can be a sandbox option. Rn the only REALLY DANGEROUS option to enable there is: "sprinters", all the rest physical abilities (toughness, strength, for example) are just making the gameplay a little bit harder, but not actually hard if you'll play logically and use actual planning and brain to be stealthy there.

 

Well, you can also make them open doors right now, or navigate around objects better w/ navigation options, but it'd still be better to have more zombie AI variety-related options to choose from  in sandbox mode (as mentioned here: avoiding fire, climbers, ect.)

 

 

"Disabled zombies" and "bite-less zombies" also DO make sence, at least we won't have zombies so much predictable anymroe in terms if they will likely bite you or not, and if they suddenly will otusmart you, or if luck would be on your side. It fits to any zombie game if you really do consider it to be more in-depth realistic

 

Some previous survivor would deal serious injuries to some zombie but not kill it and for example decapitate its limb or even jaw as a result of the fight, and then you meet this rare zombie, and it can't either bite you (if its jaw is missing), or deal some other sort of damage (depending on wich limbs are decapitated))

 

Zombies with gear on them like welding masks and motorcycle  helmet should NOT be able to bite players, it makes complete sence and is way more realistic, obviously. But you still can get any other type of wound except bites from such zombies, as they still might have arms to to that, even though their mouth is basically blocked by some physical object (helmet, mask)

 

 

The more variety - the better, more realistic, and less predictable gameplay in other cases

 

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Also, it could all be just a sandbox option, wich can be enabled or disabled by the players only in sandbox mode. Want climbing zombies? want disabled ones, or those avoiding some danger like fire? Launch sandbox mode and enable, or disable these behaviour options there, again, the more opportunities in sandbox mode - the better.

Edited Thursday at 12:09 PM by KerikPlay123