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No visible reason why this particular rail is getting attacked. Just stand still for almost 4 minutes and rail near Copper Ore 1 gets eaten.

I dont know. But isnt it normal that biters may attack rails? (in vanilla?)

It's extremely rare for them to attack rails like this. They target turrets, pollution sources, that sort of thing. Only after that's done do they go on a rampage through things like rails, so as long as your turrets hold out your rails will always be safe. They'll also attack things that block movement, but rails don't qualify.

They used to skip to the rampage if they were attacking the player but the player got out of range, but that behaviour was removed.

Biters clear out an area when they try to make a new base. Maybe he is doing that?

Imo this is not a bug, but looking at previous classifications, it seems there is no consensus among devs either.
FYI: This is reproducible wo mods as well. A group of biters is accumulating south of the horizontal rail line and then walking in direction to the copper mine, they stop left to the vertical track and attack/destroy some of it until they stop on their own.

Loewchen wrote:Imo this is not a bug, but looking at previous classifications, it seems there is no consensus among devs either.

Either way the behaviour should be consistent. Attack rails all the time or none of the time.

Please don't make them attack rails all the time, it would be impossible to have outposts.

Rhamphoryncus wrote:

Loewchen wrote:Imo this is not a bug, but looking at previous classifications, it seems there is no consensus among devs either.

Either way the behaviour should be consistent. Attack rails all the time or none of the time.

I don't think it needs to be consistent. The devs have been trying to make the aliens to be organic. It isn't bad, or is even good, if they perform unpredicted actions.
Or you can think of this: aliens are not your friends and they know what you are doing. They know you built the rails, and the rails will eventually cause pollution. They have planned to destroy the rails for long time. You just witness this happens.

The biter attacked entities in the chunk with the highest pollution in its vicinity. In your case, that chunk happened to only contain rails – so it attacked rails.

Usually, this isn't what you'd expect to happen. Chunks that are the local maximum of pollution usually are those where some heavy polluting activity takes place – so when biters decide to attack those local maxima, they usually attack heavy polluters. But, in your case, your mining outpost had filled its buffers and stopped mining a while before the biter went on to attack. The pollution had started dissipating – faster in chunks with more trees, slower in chunks with fewer trees. So, after a while, the chunk with least amount of foliage became the local maximum, even though there was no pollution being produced on it. And that's when the biter decided to attack the local maximum.

So, you could say the real cause of this bug is that you didn't send a train to your outpost soon enough, and the mining operation shut down.

Technically this is indeed not a bug, as attacking the local maximum is exactly what we intended. But we decided to change it anyway, so that biters will now only attack chunks that contain entities that can actually produce any pollution – i.e. not just rails.

So, fixed in 0.14.15.

Oxyd wrote:The biter attacked entities in the chunk with the highest pollution in its vicinity. In your case, that chunk happened to only contain rails – so it attacked rails.

Usually, this isn't what you'd expect to happen. Chunks that are the local maximum of pollution usually are those where some heavy polluting activity takes place – so when biters decide to attack those local maxima, they usually attack heavy polluters. But, in your case, your mining outpost had filled its buffers and stopped mining a while before the biter went on to attack. The pollution had started dissipating – faster in chunks with more trees, slower in chunks with fewer trees. So, after a while, the chunk with least amount of foliage became the local maximum, even though there was no pollution being produced on it. And that's when the biter decided to attack the local maximum.

So, you could say the real cause of this bug is that you didn't send a train to your outpost soon enough, and the mining operation shut down.

Technically this is indeed not a bug, as attacking the local maximum is exactly what we intended. But we decided to change it anyway, so that biters will now only attack chunks that contain entities that can actually produce any pollution – i.e. not just rails.

So, fixed in 0.14.15.

Oxyd: if i understand correctly, with this implementation if a chunk only has walls, big eletric poles and rails, bitters will not attack?

FredHp wrote:

Oxyd wrote:The biter attacked entities in the chunk with the highest pollution in its vicinity. In your case, that chunk happened to only contain rails – so it attacked rails.

Usually, this isn't what you'd expect to happen. Chunks that are the local maximum of pollution usually are those where some heavy polluting activity takes place – so when biters decide to attack those local maxima, they usually attack heavy polluters. But, in your case, your mining outpost had filled its buffers and stopped mining a while before the biter went on to attack. The pollution had started dissipating – faster in chunks with more trees, slower in chunks with fewer trees. So, after a while, the chunk with least amount of foliage became the local maximum, even though there was no pollution being produced on it. And that's when the biter decided to attack the local maximum.

So, you could say the real cause of this bug is that you didn't send a train to your outpost soon enough, and the mining operation shut down.

Technically this is indeed not a bug, as attacking the local maximum is exactly what we intended. But we decided to change it anyway, so that biters will now only attack chunks that contain entities that can actually produce any pollution – i.e. not just rails.

So, fixed in 0.14.15.

Oxyd: if i understand correctly, with this implementation if a chunk only has walls, big eletric poles and rails, bitters will not attack?

imo they will still attack walls, if they block their movement. but they will not attack electric poles, if they lonely in chunk.

I think it means that they will only attack non-polluting entities if they are in their way, which means that they might attack an electric pole if it is in a forest or if they are in a big group and one of the middle biters can't pass left or right of it.
Now I'm wondering though: can biters attack rocks?

TheUnknown007 wrote:I think it means that they will only attack non-polluting entities if they are in their way, which means that they might attack an electric pole if it is in a forest or if they are in a big group and one of the middle biters can't pass left or right of it.
Now I'm wondering though: can biters attack rocks?

that indeed might be true.
also rock is not as hard as metal so why not?

but since they don't attack trees (or at least i have not seen them), probly will not attack them. i suspect they will not attack things, that are not enemy force. and rocks should be neutral. that's also why spawn blackbox as neutral force. even if you die in mid of bitter nest, you still can pickup your stuff (if you dare )

Biters do attack trees, you can see that if they try to chase you through a dense forest (they can't find a path and try to clear one by attacking the trees)

FredHp wrote:

Oxyd wrote:The biter attacked entities in the chunk with the highest pollution in its vicinity. In your case, that chunk happened to only contain rails – so it attacked rails.

Usually, this isn't what you'd expect to happen. Chunks that are the local maximum of pollution usually are those where some heavy polluting activity takes place – so when biters decide to attack those local maxima, they usually attack heavy polluters. But, in your case, your mining outpost had filled its buffers and stopped mining a while before the biter went on to attack. The pollution had started dissipating – faster in chunks with more trees, slower in chunks with fewer trees. So, after a while, the chunk with least amount of foliage became the local maximum, even though there was no pollution being produced on it. And that's when the biter decided to attack the local maximum.

So, you could say the real cause of this bug is that you didn't send a train to your outpost soon enough, and the mining operation shut down.

Technically this is indeed not a bug, as attacking the local maximum is exactly what we intended. But we decided to change it anyway, so that biters will now only attack chunks that contain entities that can actually produce any pollution – i.e. not just rails.

So, fixed in 0.14.15.

Oxyd: if i understand correctly, with this implementation if a chunk only has walls, big eletric poles and rails, bitters will not attack?

They will not choose it for attack when going to attack your base. They can still attack poles and walls for other reasons, such as when they get stuck or when it's necessary to reach their target. And yes, they'll attack trees and rocks as well.

TheUnknown007 wrote:Biters do attack trees, you can see that if they try to chase you through a dense forest (they can't find a path and try to clear one by attacking the trees)

my forests are not dense enough, or maybe they are not that "dense", to let bitters destroy them trees

but i usually setup wall perimeter around base anyway, so what happens behind them walls ... might have not seen.

since we got confirmation from devs, there is no question here anyways