AIParameters*.xml files, what exactly do they do? I'm speaking specifically of the AIParameters*.xml files that accompany most mods in the .../AI/Parameters/ directory. The reason i ask is that i've never seen them linked anywhere. For example, all other xml files (save the galaxy creator files) are "initialized" in index.xml; these however, are not. As they are not specifically replacing a set of named files, as is the case with the galaxy creator files, does the game engine actually know to use them? What precisely do they do? Do they instruct the opponent AI to build the custom structures or improvements in mods or do they instruct the AI to build them if the player has turned over a star system to the AI? Or both?

In general those files are used by the AI to evaluate certain things.

They are a very valuable ressource in improving the AI.



The easiest to understand certainly is AIParametersBuilding.xml.



Each building has values for 1 or more categories and depending on how much the ai feels it needs something this affects the build-order. But it's not simply if x > y. Production-cost is also considered.

If adding new custom buildings you have to add them here aswell in order to teach the AI what these buildings are for and when to get them.

Good values for something usually are between 1 and 2.5. Buildings where the combined values are lower than 1 are rarely built and buildings where the combined values are higher than 2.5 are often prefered over other important buildings.

(A good example for that is Hydrosequencing (+1 all fids) which I had lowered to 2.4 from 4 in a mod back then in classic.)

It is important to note, that everything you do to this file also affects how the governors you can use select what they are building.



Other files here determine how the AI picks perks for their heros on levelup, what cards they play under what circumstances and how they design their ships.



All in all that's a very intersting part of modding and, as I said, it's the best position to look for if you want to improve the AI.



Also note: When you finde something here, that significantly improves the AI's performance, you can send your mod to the devs and have them have a look at it. Chances are good your changes can make it into a patch.

Ok, as i thought then. I was just slightly confused about them seemingly not being "initialized" anywhere, as the rest of the xml files are.

Yeah, I don't know why they are not in the registry-file but it somehow still worked for me.