PC Stairs, barbed wire, and zombie pathing.

[ktr]

I'm more curious if anyone else has had the same/similar experience.

So, we built out a tower with a 'zombie run' on one side. The run is just a winding corridor that ends with a door, armed with dart traps and barbed wire. The run itself does have steel walls. The rest of the base had a two layer steel wall. However, the zombies refused by in large to go to the run unless they were already coming from that general direction.

Slightly befuddled, because we had tested this build before and it worked, I added another layer of steel to the rest of the base. And yet the zombies kept attacking this ONE spot. In fact, they'd spawn on the opposite side of the base, go right past the zombie run and then attack that spot. We figured out that it was where the stairs leading up to the next floor is. While I get that distance wise, the path they wanted to take was shorter, it seemed strange that three layers of steel read as easier that a relatively open path that wasn't that much longer.

Especially, when we had stairs in our test build.

After more finagling, it seemed like the barbed wire might be the culprit. Though our plan is to get another screamer, make her mad and see what they do before we want to say 'yeah, that was it'. I'm fairly certain that we had the barbed wire in the test build too.

Still, though, I would expect them to want to go through relatively weak barbed wire instead of steel.

Now we have no stairs and just nerd pole up from the basement which is a less than satisfactory solution for us.

edit: spelling

 

[OldManBrian]

Personally I think they should ignore traps, spikes, and barbed wire. Otherwise what's the point of using them, they'll just always path around them?

 

[RestInPieces]

Personally I think they should ignore traps, spikes, and barbed wire. Otherwise what's the point of using them, they'll just always path around them?

Exactly. This must have been a oversight in the first place. I believe they will definitely change that in the future.

 

[ktr]

I'm okay with the traps having some weight in the calculations depending on block size maybe? For example, I'd think dart traps would have weight more or less comparable to their durability. A turret though would have far less because it can be moved around easier. The ones I go back and forth on are the spike traps and the barbed wire. I do think their weight calculations should be low, if they exist at all.

 

[meganoth]

Is your corridor high enough, i,e. three blocks or more? If you have traps on the floor the zombies might ignore that block for calculations and count the ceiling blocks as something they have to work through. This seemed to be a problem at least in 17.0.

 

[Umbrella]

Hi, I have 2 remarks

1) Wires matter, but I noticed this from different perspectives:

(i) When trying to prevent zombies from climbing (on each other) onto the wall of a toothless (some toothie-like box base, where the top-to-ceiling faces are 1 block full, 1.5 empty, and 0.5 full), putting ladders either face up on the 3rd block, or bottom on the 4th will prevent zombies from climbing, but won't prevent them from jumping (which is needed to reduce block damages to viable levels). When I use barbed wire instead of ladders, the 3rd block up position prevent them from jumping, not the 4th.

(ii) Now when the wire is vertical, such as a horizontal segment [wall, wire left, wire right, wall], Zs will go in between walls. Moreover, the wire acts as a defense to the wall that they would otherwise have broken.

My guess is that they see the block as empty, but try to avoid the trap by not jumping in (i) or staying in the middle in (ii). Maybe it is accounted for when computing how many block to break, but ignored when computing a free path.

2) Elevation-first matters. It seems zombie favor the vertical distance over the horizontal one (you can see this by comparing zombie breaking a wall of box base on ground, but taking the long path when the box is elevated). You have to exploit this. If you put the stairs further from you / closer to where you want them to go, this will incite them to take the path. I have no idea of the precise numbers though.

What you should do is give them a ladder or stairs right after the traps, or/while making your stairs not a path (put a jump somewhere before elevation, eg a ladder on 3rd block : you can jump grab it, but Z don't see a path).

Also, maybe building full walls allows them to dig diagonnally into it, giving them the incentive of height. Maybe a wall with the 2nd bock empty will interest them less (but might let dog through) ?

A few questions:

A) Where are players standing ? At what elevation ?

B) What length are the 2 paths ?

C) How did you position the wire (including faces) ? Did they have at least a free 1-block wide path on the long road ?

 

[ktr]

Is your corridor high enough, i,e. three blocks or more? If you have traps on the floor the zombies might ignore that block for calculations and count the ceiling blocks as something they have to work through. This seemed to be a problem at least in 17.0.

Yeah, the total wall height is five blocks. There is a one block high floor (a ramp leads onto it) and iron bars up top. The interior clearance space is three blocks high. (I wanted four, but we had a *tiny* building miscalculation.

 

[ktr]

Hi, I have 2 remarks
1) Wires matter, but I noticed this from different perspectives:

(i) When trying to prevent zombies from climbing (on each other) onto the wall of a toothless (some toothie-like box base, where the top-to-ceiling faces are 1 block full, 1.5 empty, and 0.5 full), putting ladders either face up on the 3rd block, or bottom on the 4th will prevent zombies from climbing, but won't prevent them from jumping (which is needed to reduce block damages to viable levels). When I use barbed wire instead of ladders, the 3rd block up position prevent them from jumping, not the 4th. So here they see the block as full, and ladder as empty (obviously, this makes sense if they have to climb ladder)

(ii) Now when the wire is vertical, such as a horizontal segment [wall, wire left, wire right, wall], Zs will go in between walls. So here, the wire is seen as empty (or maybe its hp is low enough, but it wasnt the case in (i)). Moreover, the wire acts as a defense to the wall that they would otherwise have broken.

2) Elevation-first matters. It seems zombie favor the vertical distance over the horizontal one (you can see this by comparing zombie breaking a wall of box base on ground, but taking the long path when the box is elevated). You have to exploit this. If you put the stairs further from you / closer to where you want them to go, this will incite them to take the path. I have no idea of the precise numbers though.

What you should do is give them a ladder or stairs right after the traps, or/while making your stairs not a path (put a jump somewhere before elevation, eg a ladder on 3rd block : you can jump grab it, but Z don't see a path).

A few questions:

A) Where are players standing ? At what elevation ?

B) What length are the 2 paths ?

C) How did you position the wire (including faces) ? Did they have at least a free 1-block wide path on the long road ?

Hue, interesting, so we may need to reposition how the barbed wire faces. I feel like I should have thought of that.

Answers

A.) We stand on top of the run and shoot down through iron bars - so four to five blocks (at least) higher than the zombies. There's one person that likes to perch on the 3rd floor of the tower which is probably another 15 ish blocks up

B.) The place they were hitting is exactly 3 blocks from the base of the (former) stairs. The zombie run adds about another 40 -ish blocks and a single iron door to get to the same spot at the stairs.

C.) We had the barbed wire across the open corridor (one block) so maybe that was the big issue.

 

[Umbrella]

we may need to reposition how the barbed wire faces.

That's more of a guess, to explain what I observed in (i-ii). Again they do go into [wall, wire left, wire right, wall].

and a single iron door

I guess you should leave it open.

The zombie run adds about another 40 -ish blocks

That's a long path. From ths xmls, the base length is 20 (25 when running), but then this interferes with blocks to break. I could give example of what's enough or not, but my point is that it actually depends on how far an elevation is available on the path.I would not be surprised if they prefer to break through 3 steels to gain 4 elevations right away, instead of taking 40 more blocks without elevation.

If they don't see an elevation shortcut, they'll be less tempted. You should try this:

give them a ladder or stairs right after the traps, or/while making your stairs not an elevating path for them

or that (not tested)

Maybe a wall with the 2nd bock empty will interest them less

 

[Umbrella]

Now we have no stairs and just nerd pole up from the basement which is a less than satisfactory solution for us.

Put a ladder starting on the 3rd block high. You can jump to it, Zs cant (just don't put it at an accumulation point where they climb on each other)

Maybe a wall with the 2nd bock empty will interest them less

Actually, they would still gain the 1st elevation. Maybe 1st block empty is better (not tested)

 

[ktr]

Put a ladder starting on the 3rd block high. You can jump to it, Zs cant (just don't put it at an accumulation point where they climb on each other)

Actually, they would still gain the 1st elevation. Maybe 1st block empty is better (not tested)

Thanks for this and the other suggestions! We'll see what we can do with them.

 

[RipClaw]

Could it be that you tested the building in 17.1? The AI has been changed and this leads to results like yours. My solution is a trench around the base that is at least 3 blocks deep and 2 blocks wide with an exit where you want the zombies.

The zombies usually avoid the trench and therefore go through the desired entrance.

 

[ktr]

Could it be that you still tested the building in 17.1? The AI has been changed and this leads to results like yours. My solution is a trench around the base that is at least 3 blocks deep with an exit where you want the zombies.

It was probably a 17.1 build. When you say exit, do you mean such as a incline up that would lead them into the zombie run?

 

[RipClaw]

It was probably a 17.1 build. When you say exit, do you mean such as a incline up that would lead them into the zombie run?

Yes. A ramp so that the zombies can leave the trench.

 

[ktr]

Perfect. Thank you!

 

[Kattla]

Personally I think they should ignore traps, spikes, and barbed wire. Otherwise what's the point of using them, they'll just always path around them?

Oh, i hope spikes stay as they are, at least that zombies will see them as blocks or halfblocks.

IE: A wall 2 block tall, or 1 block tall with a block deep trench.

Spikes placed in front of that.

Zombies will see it as a stair/path, but fail the last jump.

The spike gets destroyed, and the zombies move on to the next

spike.

Works until all spikes are destroyed, and with a risk of zombies jumping

atop of each other.

Unless zomething changed in the last experimental builds.

 

[Umbrella]

The zombies usually avoid the trench and therefore go through the desired entrance.

I haven't tested that in particular, but it shows how much a sudden -3 elevation is underweighted in the path calculation. I usually end up putting my base on pillars, but maybe a trench is just enough, at least when you don't path-break them.

Oh, i hope spikes stay as they are, at least that zombies will see them as blocks or halfblocks.

Yeah that's great. But the thing is that the pathing algorithm introduces a few subtleties with the barb wire (contrary to the barb fence wire you are using). I don't think it boils down to simply "full" or "not full" block (see my points (i) vs (ii) in my previous answers). Maybe because these are traps, the behavior also depend on frame true collision, and hence face orientation.

@ktr : you use barb wire right, not barb fence wire ?

 

[meganoth]

A.) We stand on top of the run and shoot down through iron bars - so four to five blocks (at least) higher than the zombies. There's one person that likes to perch on the 3rd floor of the tower which is probably another 15 ish blocks up

B.) The place they were hitting is exactly 3 blocks from the base of the (former) stairs. The zombie run adds about another 40 -ish blocks and a single iron door to get to the same spot at the stairs.

C.) We had the barbed wire across the open corridor (one block) so maybe that was the big issue.

In our base we start combat at ground level so the zombies have a short clear path to us. Only when or if they nearly reached us do we go up to the first floor. We also have two entrance corridors on opposite sides so that their maximum path to calculate is cut by half. And it works.

40 blocks sound like a lot. I think Fataal once mentioned the block distance where the pathfinding algorithm stops looking further for a path and that might have been 40 (?).

 

[ktr]

@ktr : you use barb wire right, not barb fence wire ?

yes, just the wire.

In our base we start combat at ground level so the zombies have a short clear path to us. Only when or if they nearly reached us do we go up to the first floor. We also have two entrance corridors on opposite sides so that their maximum path to calculate is cut by half. And it works.
40 blocks sound like a lot. I think Fataal once mentioned the block distance where the pathfinding algorithm stops looking further for a path and that might have been 40 (?).

The area dimensions are smaller than 40 blocks (i think 13x10 but I might be misremembering) and the path is winding, instead of straight since I figured there was a limit to how far out they'd 'search' for a path. But yeah, it might be too long.

 

[Auner]

Zombie block damage is so high that anything “winding” is liable to be ignored (unless you’re very experienced or lucky). Making the run a two-wide straight hallway, 2 block thick walls, no more than 10 long, with barb wire on both walls facing inwards, and a ramp leading to the second floor... that has worked every time for me. I can then stand on the bars and shoot them as they funnel in, with the bonus of cops almost never spitting vomit. Then just have traps for the stairs to clean up missed Z’s, but pathing is really really finicky now and Z’s sometimes go into destruction mode simply because another zombie has blocked them momentarily...