Biter Expansion Mechanics

[Mehve]

I'm currently in the process of a megabase build, and I figured that I'd do the laser-wall thing on a couple sides to give me some safe area to work on. But strangely enough, the walls are getting no action. Further viewing, with the help of the Big Brother mod, reveals that I'm getting virtually no biter encroachment. Sure, there's the occasional little expansion within their territories. But nothing towards my base.

See image below. I pushed the biters back that far, back in the 3rd or 4th hour of playing. It's now the 26th hour, and they haven't even tried to expand closer. Evolution is now sitting at 86%, I'm using no resource or enemy mods.



So what exactly is supposed to trigger an expansion attempt in the first place?

[DaveMcW]

Sure, there's the occasional little expansion within their territories. But nothing towards my base.

Then it's working correctly. They don't intentionally expand towards you, they just pick a random circle (usually a green one) and go there.

If you want more biter action, set the enemy density higher so the only green circles are by your base.

There might also be an issue with keeping your pollution cloud away from them. I've noticed biter bases are much less active when they aren't in a pollution cloud.

[Mehve]

Really? I can accept some statistical variance, but you'd think there would be at least ONE attempt at moving in a base-wards direction. Seriously, those green circles around my base in the picture have literally not budged in nearly 24 hours. Maybe I should buy a lottery ticket...

Hmm... does each nest have its own timer/RNG to determine when an expansion attempt is made (more nests revealed = more potential expansion attempts)? Or is it a single decider for all the nests collectively (constant number of attempts, only the originating nest varies)? Because if the latter, expanding the visible map could indirectly thin out the expansion attempts?

Edit: Now that I think about it, Big Brother mod is likely partially responsible, since at higher research levels, it reveals massive amounts of territory, creating lots of extra green circles that normally wouldn't be exposed without getting past the first line of nests.

[orzelek]

Really? I can accept some statistical variance, but you'd think there would be at least ONE attempt at moving in a base-wards direction. Seriously, those green circles around my base in the picture have literally not budged in nearly 24 hours. Maybe I should buy a lottery ticket...

Hmm... does each nest have its own timer/RNG to determine when an expansion attempt is made (more nests revealed = more potential expansion attempts)? Or is it a single decider for all the nests collectively (constant number of attempts, only the originating nest varies)? Because if the latter, expanding the visible map could indirectly thin out the expansion attempts?

Edit: Now that I think about it, Big Brother mod is likely partially responsible, since at higher research levels, it reveals massive amounts of territory, creating lots of extra green circles that normally wouldn't be exposed without getting past the first line of nests.

You are spot on on the effect of big brother mod.
Other thing is that in my prolonged test (game speed 100+ ) it seemed that for some strange reason biters seemeed to prefer outer areas first. Might be simple sampling issue since I did this only two times.