Biter-ness (Basics questions)

[Porter65]

Hey,

I would like to understand better the basic dynamic of population generation for the autochtone population on the planet.

Literally, biters are generated from thin (polluted) air, right? As each as a cost in pollution. But they are also definitively generated without pollution, so how it works, this generation over time?

Culling the herd. When I pass around a biter base, and I kill a hundred or so pursuing me, does it achieves anything? It will raise slightly evolution, but are losses a real loss to the base? Or will they be compensated, because of generation over time?

Is evolution speed logarithmic ?
I fear the worse soon, i.e. facing Behemoths while not prepared for them. Clearing 'only' 12 bases and Evolution is already at 0.4. Does it means that clearing 20 more is evolution 1? That would be terrible, as I play on a Death World and they are everywhere and they need to make room for my industries!

[NotRexButCaesar]

Literally, biters are generated from thin (polluted) air, right? As each as a cost in pollution. But they are also definitively generated without pollution, so how it works, this generation over time?

Yes, biters in attack groups are generated from pollution. The ones generated without pollution are assigned to a specific nest and will not leave to attack your factory.

Culling the herd. When I pass around a biter base, and I kill a hundred or so pursuing me, does it achieves anything? It will raise slightly evolution, but are losses a real loss to the base? Or will they be compensated, because of generation over time?

It doesn’t really do much in the long term. It can absorb some pollution or prevent an attack in the near future, but overall they will regenerate quickly.

Killing the biters themselves doesn’t affect pollution. Only the nests do.

Is evolution speed logarithmic ?
I fear the worse soon, i.e. facing Behemoths while not prepared for them. Clearing 'only' 12 bases and Evolution is already at 0.4. Does it means that clearing 20 more is evolution 1? That would be terrible, as I play on a Death World and they are everywhere and they need to make room for my industries!

I don’t know if it is logarithmic, but it definitely slows over time. The last 0.1% can take hundreds of bases.

[JimBarracus]

Literally, biters are generated from thin (polluted) air, right? As each as a cost in pollution. But they are also definitively generated without pollution, so how it works, this generation over time?

"If a chunk's pollution is greater than 20, each enemy spawner absorbs 20 + 0.01 * [chunk's pollution] every game second (60 ticks), otherwise it absorbs 3 times the amount of pollution needed for the most expensive unit it can spawn for the current evolution factor."

https://wiki.factorio.com/Pollution

Evolution is not affected by the absorbed pollution. It is calculated from your produced pollution, no matter where it was produced or if it reached a nest.
You can think of it like the air quality directly affects the development of the biters.

[jodokus31]

Is evolution speed logarithmic ?
I fear the worse soon, i.e. facing Behemoths while not prepared for them. Clearing 'only' 12 bases and Evolution is already at 0.4. Does it means that clearing 20 more is evolution 1? That would be terrible, as I play on a Death World and they are everywhere and they need to make room for my industries!

Concrete answer: Clearing 20 additional bases will increase evolution only slightly.

Background:
https://wiki.factorio.com/Enemies#Evolution

The percentages are applied on the base of (1 - current_evolution_factor)². So for instance destroying enemy spawners in the beginning of the game results in increase of evolution factor by 0.002 (0.2%) while doing this when the evolution factor is 0.5 the increase is only 0.0005 (0.05%).

Also, deathworld is pretty tough on time-based evolution. Evolution rises very fast anyway.
if you type in :

Code: Select all

/evolution

you will see the percentages, what has cause the evolution to rise.

[Porter65]

Thanks a lot guys, much appreciated. I now get a clearer picture of the 'situation'.

I'm playing a half-death world I guess, as I reduced to 40 evolution over time. But to my defense , I left the rest intact, and doubled base-size. Also, mineral setting are on ultra-low, so I'll need to cross vast expanse of terrains.

One thing I remember from my 2018 foray into Factorio, is that over time biters bases tend to cover all the map and you are thus faced with a sea of bases everywhere, with no room to explore in a kind of freeroam with a buggy, is it still the truth? Does chunks not revealed by radars are still simulated and populate over time, or it affects only chunks who where generated?

Because this can change completely my radar strategy, where I drop a self-sustaining base deep in enemy territory so it reveals further a lot of squares over time. I would need to stop doing that, as I'm shooting myself in the foot if it triggered biter expansion.

[astroshak]

Explored space does not “trigger” biter expansion. Biter expansion is purely time-based, as determined by the settings when you started the map.

Exploring more space does, however, allow for more options for biter expansion. Left unchecked, eventually yes, biters will fill in all the explored area with nests. That can potentially take a very very long time, however, depending on the map’s settings and how quickly you explore. The more you explore, the more options that biters have to expand into, so it takes longer for them to expand into each one. They only launch one expansion party per time interval, after all.

The disadvantage of exploring more of the map is an increase in the save file size, which directly increases the time spent paused while the game auto saves.

All that aside, the game automatically generates some chunks under the black fog of war. If there is pollution in that chunk, that chunk exists, whether you’ve used a radar to reveal it or not. If the pollution cloud, and you, your radar, have not reached a chunk, it won’t be generated. I want to say that due to pollution dissipation, a couple chunks around the cloud have been generated, not just the ones directly covered by it, but I’m not 100% positive on that.

There is a debug option that allows you to see expansion options for the biters, what sites they would prefer to expand into. You can mess around with that a bit if you want.

[jodokus31]

Personally, I explore with the car and use radars rather for live observation in factory or outposts.

I don't know, if they expand more often with a bigger area. If not, it's more likely they expand to a place, which is farer away from the factory. So it would reduce the pressure a bit, but not reduce the spawners overall.
EDIT: Based on the previous post, this seems to be like that

At certain distance from center, spawners are very dense anyway.
This is a nice minigame: Try to drive in a far as possible without getting killed

[Serenity]

I kill a hundred or so pursuing me, does it achieves anything? It will raise slightly evolution, but are losses a real loss to the base?

Killing biters does not increase evolution. Time, absorbed pollution and killing spawners does


Biter expansion can be fine tuned during map generation:
https://wiki.factorio.com/Map_generator#Enemy

One easy setting is the cooldown. If you want slower expansion you can increase the minimum time, so it takes for example at least 10 minutes between each expansion group.

Expansion can also be turned completely off. So if you clear an area once it stays clear