What factors affect AI behaviour?

[techumseh]

I've seen this in all versions. I've always considered it just part of the game.

[Sore Loser]

Does it also apply when the deficit is caused by settlers? It doesn't happen to me.

[techumseh]

Not sure, 'cause I've never studied it. In a scenario situation, I have seen a city under AI control keep producing settlers until it's only 3 or 4 in size, but that was caused by setller creation, not starvation.

[Case]

I've seen it as well - starving cities is a useful siege tactic in the game. As the city shrinks, the number of units it can support shrinks and an attack becomes a lot easier.

[Mercator]

@Catfish... I've done some testing on that myself too. See here:

http://www.civgaming.net/mercator/reference/mapstruct.htm

http://apolyton.net/forums/showthread.php?s=&threadid=92070

http://apolyton.net/forums/showthread.php?s=&threadid=94575&highlight=fertility

For the AI, 0-7 is infertile (only grassland and plains ever have values higher than this), 8-15 is fertile (the AI only builds cities on those).

By the way, I think MapCopy could sort of be made to work with ToT in combination with some hex-editing. And if you also have another civ2 version. Start your scenario in both FW/MGE and ToT, "MapCopy" the FW/MGE savegame, and then copy-paste the map (just the 6-byte section) to the ToT savegame.

[:) Smiley]

Why the need for such a large range though if the only criteria is whether or not its grass or plains?

[Catfish]

@Mercator
Thanks, Mercator, I'll have a look at those links.

MapCopy lumps plains/grasslands in one group and the remaining terrains in another group. I was thinking about a utility that could alter each terrain slot separately. I'm thinking in terms of Curt's Bitterfrost scenario where I'm guessing he wanted at least 3 of his terrains to be arable - Thawland (Plains), Hearthland (Grassland) and Richland (Swamp). Of course Richland misses out.

Originally posted by Smiley
Why the need for such a large range though if the only criteria is whether or not its grass or plains?

The criterion for settlement is actually fertility, not terrain type. Even though grassland/plains are the only slots that receive a fertility value at the beginning of the game, theoretically, fertility values for non-grassland/plains terrains may be able to be increased beyond 7 with terrain improvements and possibly other factors (see my first post and the document on hex editing). Similarly, fertility values for grassland/plains can be decreased below 8. Example: the AI is more likely to build a city on grassland with a river and other improvements, even though it lies within another city’s radius, than basic grassland (almost no chance).

Why is there a range at the beginning of the game? Variety is the spice of life. A degree of randomness gets built into the AI via initial fertility values. As I said, many values will be modified down to the settlement threshold as the game progresses. Why is the range as large as it is? I guess it was probably tweaked to compliment the AI’s behaviour.

[Mercator]

Originally posted by Catfish
I'm thinking in terms of Curt's Bitterfrost scenario where I'm guessing he wanted at least 3 of his terrains to be arable - Thawland (Plains), Hearthland (Grassland) and Richland (Swamp). Of course Richland misses out.

Not necessarily. MapCopy can also copy fertility data from one map to another. Curt could make a copy of his map, turn all Thawland, Heartland and Richland into Grassland, and turn the rest into Desert (also make sure to use the "Analyze map" option in the map editor to set the fertility values). You can then simply copy that map's fertility data into the scenario.

That still has its limitations, of course, but it's more versatile than you thought it was.

[Catfish]

Originally posted by Mercator
That still has its limitations, of course, but it's more versatile than you thought it was.

Sorry, I’ve never used MapCopy and being a dumb arse, overlooked this possibility in the Readme. That piece of knowledge could save a lot of people’s scenarios.

Wouldn't Curt just need to change swamp (Richland) into grassland/plains? The other values are already correct.

BTW, earlier you said, "0-7 is infertile (only grassland and plains ever have values higher than this)". The hex editing article (you wrote the map section?) states: "Fertility values of terrains other than Grassland or Plains can, however, increase because of tile improvements". Are these increases always < 8 or have you since found out that there are none at all?

Also, the article states that the AI’s fertility threshold (can build) is 7. You now say it’s 8. Which is it? I’m guessing the article is incorrect.

Edit: Clarified a point. Must... go... to... bed...

[Mercator]

Oh, damn... I'm not sure anymore now... But I guess the article is incorrect (your findings also confirm that, since city radius squares drop to 7).

I can't do any testing (not to mention making utilities )at the moment because my computer died last Friday.

[Varwnos]

hi

Does anyone know how you can prevent the AI from founding new cities? Empirically i know that if the tech level is already high the AI just doesnt bother to found any more cities even if it has huge lands between it and the other nations. But even if that is so i dont know at what level the tech starts to be preventing that.

ps i need this for my own scenario

[Catfish]

Originally posted by Mercator
(your findings also confirm that, since city radius squares drop to 7)

That's one of the reasons I was asking. Bad luck about the computer. I've just finished rebuilding my OS after ditching a dodgy HD.

Originally posted by varwnos
Does anyone know how you can prevent the AI from founding new cities?

I’m going to make the assumption that you still want the civs to have settlers (for land improvement purposes). Am I right? Otherwise, make the settler prerequisite tech unavailable (via tree or trading) using "no, no". Just give it to the appropriate civs at the start or via events. See, if you had ToT, cough, you could just ban settlers from specific civs using the Advanced Units section without the need for stuffing around with your tech tree. Now, just hope they don’t get bribed. Wait a minute… you can also make units unbribable in ToT.

If my assumption is correct, Mercator’s just shown you the way. Export your map from the scenario. Fire up the Civ2 Map Editor. Change all the plains and grasslands tiles to something else. Run the Analyze Map option in the Map menu to reset the fertility values. Import the new fertility values (only) back into the scenario, using the MapCopy utility. MapCopy can be found here. The AI will now be faced with a sea of infertility (all zeros).

[Varwnos]

hm

yes, but this way i should have to edit all of the tiles everywhere apart from those in the existant cities, (map and city placement is complete already) which would have to be different ones. So i think that this isnt very practical, although doable. The AI doesnt create cities very near the already existant friendly ones, but can create ones only 2 squares next to the enemy ones. In some scenarios however it doesnt do anything, as in DAROE and i guess that that had to do with the tech. I plan to have settlers, since it is boring not to have them, so as the player has some goal to achieve other than conquest, and the illusion that developing his cities will make things better

i can make them advanced units in my civ2fw, or obsolete units, so that isnt a problem, but then that would only work if only one nation was playable, the one with the settlers.

i think that the easiest way to solve this problem is to have advanced techs for everyone, and a very slow rate of research.

thank you for the quick reply!

(not sure if what you meant about your version of civ2 isnt unique, but i think that in civfw you can easily create units that are independant of the techtree, i just havent yet done that since its my first scenario)

[Catfish]

Re: hm

Originally posted by varwnos
yes, but this way i should have to edit all of the tiles everywhere apart from those in the existant cities, (map and city placement is complete already) which would have to be different ones. So i think that this isnt very practical, although doable.

Actually, forget what I said about the Map Editor (which wouldn't take as long as you think, anyway). Use the ZERO option in MapCopy (apologies for my Alzheimer's) to change the fertility values to 0 for the entire map. The fertility values only affect the AI, so the human player can happily build away until the cows come home.

Originally posted by varwnos
(not sure if what you meant about your version of civ2 isnt unique, but i think that in civfw you can easily create units that are independant of the techtree, i just havent yet done that since its my first scenario)

?

[Mercator]

Re: hm

Originally posted by varwnos
yes, but this way i should have to edit all of the tiles everywhere apart from those in the existant cities, (map and city placement is complete already) which would have to be different ones.

No you don't. Making the entire map "infertile" prevents the AI from building cities, nothing more and nothing less. It won't affect existing cities.

Fertility values have absolutely nothing to do with the terrain properties in the rules.txt.

So as Catfish has just pointed out, using MapCopy's ZERO option is the thing you need.