AI settling behavior

[Nothingontv]

Does anyone know what rules (if any) the AI uses to settle new cities? I can understand resources are key here but do they value certain resources over others?

Also i'm wondering if distance to their other cities matter.

The reason i'm asking is because i started a game as Victoria and Ragnar planted a city relatively far from his own territory and close to mine. The only reason i can understand him doing this is the iron (he already had some). Am i missing something here or is it more or less random which sites they pick for new cities?

Spoiler :

 

[lymond]

I don't know the code behind it, but from my experience the AI always settles blue circles. (the exception being if you have a settler in the vicinity of a target blue circle)

Rags looks boxed in so it is not that surprising to me that he settled relatively far away, although something around cow/rice/copper looks better.

 

[VoiceOfUnreason]

My starting points for understanding AI settling behavior would be....

• http://forums.civfanatics.com/search.php?searchid=2199766
• http://forums.civfanatics.com/showthread.php?t=191685
• http://forums.civfanatics.com/forumdisplay.php?f=245

Blake did a lot of trailblazing in the old AI code, which included improving their settling behaviors.

 

[nfw]

AI loves to settle on strategic resources(pretty sure it cheats WRT undiscovered resources) and hills. Also, if you have a small island good for 1 city, chances are it'll make 2 crappy ones.

 

[Tempesta13]

AI loves to settle on strategic resources(pretty sure it cheats WRT undiscovered resources) and hills. Also, if you have a small island good for 1 city, chances are it'll make 2 crappy ones.

I don't think this is true. I remember a thread from a couple years ago (couldn't find it with search) that tested this. Basically it was something like an AI starting on a small island with a bunch of seafood around it (I think) and a bunch of horses in the middle. The AI settled the seafood but in a second game (same map) it settled inland when given AH at the start. The AI cheats in a lot of ways (at higher levels anyway) but I don't think it knows where resources are before it has the techs to see them.

 

[lymond]

Again, I think it goes back to the blue circles. I'm sure there are other factors in the code like which direction they will settle first or how far way, but ultimately they always seem to target blue circles. And blue circles do appear on tiles with strat resources...that is not uncommon. You will even notice that the AI will often send a unit out to fortify on a blue circle tile...and good indicator of where they will settle next.

 

[Tempesta13]

Here's an example showing that the AI does not cheat with regards to unrevealed resources...

Spoiler :

Sitting Bull settles the corn/clam/gems up North (all which he can see).


I give him a bunch of horses and iron to his SE right before he gets out his 1st settler. I also give him AH and IW techs.


Sure enough he settles it (smart guy)


I give him the same goodness (horses and iron to his SE) but don't give him AH and IW techs and he settles the same spot in the 1st game.

 

[Fippy]

I think they value hills, green land, rivers and such high besides obvious resources.
They will not care much about growing potential thou..so cities with 3 wine and no food look good to them
Yep basically what blue circles do, they also like coastal access.
Can confirm what Tempesta showed, they should not cheat with hidden res. from my experience.

 

[Japsnap]

I have seen agressive AI doing this quite often on higher difficulties.
- Ragnar has researched iron working => he wants to deprive you from iron
- AI Ragnar has probably determined you're the best pushover on this continent
- That city is also an outpost = he plans to settle more cities in between (already producing other settlers)

So no matter what you're going to do next (accepting tributes), he will definitely attack you soon