AI difficulty level bonuses

Pyrkaige

Chieftain
Joined
Nov 8, 2002
Messages
54
The following is a list of the bonuses that the AI gets in the game based on difficulty level. This is taken straight from the Civ3 game editor, where you can change all these numbers if you wish. This was primarily done in the PTW 1.04f editor, although with a quick glance the numbers looked the same in vanilla Civ3 1.29f. A great explanation of other cheating that the AI does can be found at TheNiceOne's analysis here. Perhaps if this is useful it could be added to update the information in the Info Center so it stays accurate. The next message contains some explanatory notes, pulled also from the editor and from playing the game way too much at Deity and Emperor levels. :)

Code:
[b]AI Bonuses                                    Chieftain   Warlord   Regent   Monarch   Emperor   Deity[/b]
[i]AI additional starting units[/i]
Number of extra defensive units:                  0          0         0        2         4        8
Number of extra offensive units:                  0          0         0        1         2        4
Number of extra type 1 (usually settlers):        0          0         0        0         0        1
Number of extra type 2 (usually workers):         0          0         0        0         1        2

[i]AI unit support bonuses[/i]
Additional free support for each AI civ:          0          0         0        4         8       16
Bonus for each city:                              0          0         0        1         2        4

AI max government transition in turns:            *          *         *        4         3        2
Cost factor (player is 10):                      20         12        10        9         8        6
AI to AI trade rate:                            110        120       130      140       150      160

[b]AI and player factors:[/b]
Number of citizens born content:                  4          3         2        2         1        1
Number of citizens quelled by military:           1          1         1        1         1        1
Attack bonus against barbarians:                800        400       200      100        50        0
Percentage of optimal cities for corruption:    100         95        90       85        80       70

[b]Optimal number of cities per world size (for corruption purposes):[/b]
Tiny        - 12
Small       - 14
Standard    - 16
Large       - 24
Huge        - 32
 
AI warfare unit bonuses: At Monarch and above, the AI civs get extra offensive and defensive units when they start the game. These are the best units that the Civ could build at that time; usually these will be normal units (warrior, with archer or spearman if the civ knows the appropriate tech.) These can be unique units if those can be created at the start of a game by that civ.

AI non-military unit bonuses: The AI gets an extra settler at Deity level, and either one or two extra workers at the top two levels, respectively. (Note that if you look this up in the Civ3XEdit, the help file there helpfully has the actual unit type reversed.) In my view, the extra settler is one of the greatest bonuses the AI has at the Deity difficulty level. This gives the AI a huge jump at the start of the game, where a lot of games are decided.

AI unit support bonuses: This gives the AI civs the ability to have a lot of units without paying for them. At Deity level it's 16 free units to start and 4 extra for each city it has. A large percentage of the time the AI never even has upkeep costs at this level, even once it's a great sprawling Democracy.

AI government turns in anarchy: The AI gets no bonus for the lower three difficulty levels, and has to stay in anarchy just as long as a player would. At the higher difficulty levels it gets a nice bonus; at Deity level the max turns an AI civ stays in anarchy is 2, almost as good as being Religious.

AI cost factor: This determines the cost factor for AI growth, shields and research. The cost factor for players is always 10; the lowest difficulty levels give a bonus to the player, while the top three difficulty levels give a decided bonus to the AI.

AI to AI trade rate: The AI thinks it is getting "better deals" from other AI civs than it would from you, on every difficulty level. If you're playing a Regent game and one AI civ wants something from another AI civ that would normally cost 130, the first civ only has to be able to pay 100 to get it. In the words of the editor, "This rate directly affects the frequency and aggressiveness with which AI civs trade amongst themselves."

AI and player factors: These aren't factors where the AI can get a bonus, but they're on the same screen and deal with difficulty levels so I included them. It's all pretty basic stuff, although the last one is interesting, which determines how many cities you can make before you hit the higher corruption level. Higher difficulty levels lower this number, which is based on the optimal number of cities per world size which is also listed. In short, you have to make do with fewer cities on the higher difficulty levels unless you want to deal with more corruption. This is true for both the AI civs and for players; the number of cities that can be built before corruption kicks in is also raised (by 25% post-1.29, I believe) for civs which are Commercial.

The AI bonuses are quite strong at the higher difficulty levels, apart from the other ones mentioned elsewhere (knowing where all the units are, knowing where all current and future resources will be, etc.) The fun, of course, comes in beating it even with all these bonuses. Perhaps in the next rendition (or more likely by Civ X) we can play against an AI that is adaptive enough it won't need all these bonuses to beat humans. Until then...
 
Good job. Its very good to have this information collected.

The "AI and player factors" are actually a kind of difficulty level bonus as well, if I'm not totally mistaken.

The AI players play as regent players when it comes to these factors. It means that on emperor/deity you have only your first citizen born content, while the AI still has two, and the AI has still a 200% bonus against barbarians even though the human player loses its entire bonus on deity.
 
Good job. I almost did the same thing this weekend.

Originally posted by TheNiceOne
The AI players play as regent players when it comes to these factors. It means that on emperor/deity you have only your first citizen born content, while the AI still has two, and the AI has still a 200% bonus against barbarians even though the human player loses its entire bonus on deity.

TheNiceOne is absolutely right. Also, I believe that the same concept applies to the percentage of optimal cities -- so above Regent the AI also enjoys the freedom to build larger empires with less corruption than the human player.
 
Very nice article. TheNiceOne is correct about the AI playing by regent level rules. This is in the general settings page under 'default AI intelligence'.
But about the cost factor, I thought they changed it in one of the patches, so that the human gets penalized (or helped) in tech research based on difficulty level. So the cost factor for the AI in tech research is always 10, but the human's gets adjusted based on difficulty level.
 
Bamspeedy asks a good question. It seems to me that on deity the player researches slower and the AI reserches faster. But that's jsut what it seems like from playing the game. Also aren't the things you get from goody huts dependent on the difficulty level? I know that I almost always get barbarians from huts on Deity, but do the AIs get better things from huts since they're playing by regent rules?
 
Yes, results from goody huts is also dependant on difficulty level, and since the AI is playing with regent rules, they would get better results.
The tech research was changed in one of the patches, to prevent the AI from launching spaceships at 1000 A.D. (or earlier), like what happened in the early versions of the game. So now the AI researches at somewhat the same speed on any difficulty level, but the human is penalized. Which makes sense in theory, because if you are a better player, you would be able to get more out of your territory (micromanaging).
Note: The tech speed is still faster on the higher levels, though, because of the cheaper building costs the AI gets cheaper libraries, universities and has faster growth and the AI to AI trade ratio, etc..
 
Originally posted by Pyrkaige
AI warfare unit bonuses: At Monarch and above, the AI civs get extra offensive and defensive units when they start the game. These are the best units that the Civ could build at that time; usually these will be normal units (warrior, with archer or spearman if the civ knows the appropriate tech.) These can be unique units if those can be created at the start of a game by that civ.

AI non-military unit bonuses: The AI gets an extra settler at Deity level, and either one or two extra workers at the top two levels, respectively. (Note that if you look this up in the Civ3XEdit, the help file there helpfully has the actual unit type reversed.) In my view, the extra settler is one of the greatest bonuses the AI has at the Deity difficulty level. This gives the AI a huge jump at the start of the game, where a lot of games are decided.


Not only at the start of a game -- they also get these unit bonuses if they respawn! So if you lose almost all your units taking the AI's last city on deity level, they get 8 spearmen, 4 archers (or possibly more advanced units) (plus 2 settlers and 3 workers -- and a scout for expansionist). They might respawn in a place you wouldn't like!
 
maximum science, 1 adavance every 4 turns does not seem to apply to ALs. When I got to Modern age at like 100 BC or 200 BC, I had to buy most of my technology and my science was at one every 4 turn the whole time.
 
Originally posted by Sayounara
maximum science, 1 adavance every 4 turns does not seem to apply to ALs. When I got to Modern age at like 100 BC or 200 BC, I had to buy most of my technology and my science was at one every 4 turn the whole time.
I'm quite sure it applies to AIs, but nothing stops the AI civs from researching different techs and then trading. If two AIs does this effectively, they will both get two new techs every fourth turn.
 
The human palyers 'cost rate' is always a fixed rate of 10 at Regent or above.

Ision
 
Thank for enabling the search features. By just searching keywords on titles I was able to get exactly what I wanted, this thread, in a few minutes.

Great article/research.
 
I'm going nuts trying to find the info for demigod and sid. I keep getting back to this thread. Does anyone have a chart that includes these levels?

bruce
 
Demigod (down the column) is 3, 6, 1, 2; 12, 3; 2, 7, 160; 1, 1, 25, 70.
Sid (down the column) is 6, 12, 2, 4; 24, 8; 1, 4, 200; 1, 1, 0, 50.

Maybe, someday, I'll get motivated and put it into the nice column form.

Arathorn
 
The AI must be able to research at faster than 4, because I played a game against just one Civ and despite the fact that my research was at 4 for hundreds of turns, they were at least a dozen techs ahead of me.
 
@Lazarus - is it possible that...
1) the AI got the tech advance with goody huts and/or when your research rate was slower and then just mantained it?
2) the AI civ was scientific (1 free advance per era) ?!?
 
When I asked Soren about the trade factor, that is not the description he gave me. He said that it only applied if the AI didn't have the cash to pay full price. In your example if the price were 130 and the AI trade partner had it they'd pay 130. If they only had 100, the deal would still go through for 100.
 
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