Factorio Forums

I want to make biters get weaker over time, but stronger with more pollution. Or weaker when I destroy their bases, but much stronger with more pollution. Etc.

This is easily possible by creating a mod or simply using the following console commands:
I have tried to set the values so that they fit well with your suggestion, but I have not tested them much. Unfortunately, the /evolution console command does not work when using negative values, so monitoring the effects of negative evolution is not easy.

Please note that using these console commands will disable achievements. So I suggest you make a backup of your game, before you start playing around with evolution settings.

For more information on using console commands, see the following link:
https://wiki.factorio.com/Console

For more information on the evolution factor, see the following link:
https://wiki.factorio.com/Enemies#Evolution

Is there any technical reason to not allow negative numbers in the game setup for evolution factors?

I'd like to have a negative factor for the time, for example.
That allows for a more casual early game since the biters would slowly calm down and chill out if I stop polluting, but still get upset as the factory grows.
(With a positive time factor, why didn't they max out in the years before you arrived?)

SuicideJunkie wrote: ↑Sun Mar 10, 2019 7:31 pm Is there any technical reason to not allow negative numbers in the game setup for evolution factors?

Yes. Negative evolution factors trigger at least one bug, because the game was not designed for negative evolution factors. See this bug report thread for further information.

Although it would be possible, it would require a bit of redesigning work, at least if you don't want the /evolution command to provide false information. I'm not sure if there are any other bugs caused by negative evolution factors.

SuicideJunkie wrote: ↑Sun Mar 10, 2019 7:31 pm I'd like to have a negative factor for the time, for example.
That allows for a more casual early game since the biters would slowly calm down and chill out if I stop polluting, but still get upset as the factory grows.

This has already been suggested two years ago in the following thread:

viewtopic.php?t=48769 Allow negative evolution values

EDIT: Meanwhile, the threads have been merged. Therefore, my above link now points to the current thread.

I like having a negative evolution factor for destroying spawners.
It feels more natural to have biters become more aggressive and tougher by pollution and time but regress when their nests are destroyed.

I did try searching for negative evolution but nothing came up. I'm not sure what I did wrong there, but thanks.
I'm not concerned with achievements and have never used the /evolution command, so that works for me.

SuicideJunkie wrote: ↑Sun Mar 10, 2019 9:24 pm I did try searching for negative evolution but nothing came up. I'm not sure what I did wrong there, but thanks.

It is unlikely that you you did anything wrong. The forum's search function has been broken for the past 4 days. See the following thread for more information:

viewtopic.php?f=55&t=67087 Forum search fails to find all results

I would also like the option of negative numbers, plz.

Myself as well. I wanted to do a game where pollution was the major factor in biter evolution, with time having a negative value. Heavy pollution would result in biters quickly becoming dangerous, but if I kept pollution values down biters would actually become less dangerous over time. I'd still like to do this in the future, with some more dangerous biter mods. Really give me a serious reason to consider different methods of avoiding pollution.

For reference, the links dig down to getting a nice cooldown with: (also .pollution_factor and .destroyfactor)