jdog5000
Revolutionary
(You can always get the latest stable release from the download thread or sourceforge. Development versions and updated source code can also be checked out from sourceforge.)
This release feels like a big milestone in this project Between fixes in the UP and this version of BBAI, the AI's tech research rate is much improved, particularly in the late game. There undoubtedly more which can and will be done, but I think most of you will notice the change
Beyond the economy fixes, here are a few other highlights:
- AI now switches to Nationhood when facing a difficult enemy, and uses drafting both for defense and occasionally for an offensive rush
- Capitulation was tweaked from both sides, outright conquest is now a bit more common
- Began adding victory strategies to the AI (have little effect so far)
Next, there are two aspects of research rate I want to talk about more at length. The short version is that research rates have been rebalanced since the AI is now teching faster. The details are in spoiler tags below because they describe the inner workings of somewhat hidden research rate modifiers which exist in Civ4 and have been adjusted in this mod.
Known prerequisite adjustment
In Civ4 you get a 20% research rate bonus (ie, an extra beaker for every 5 you produce) for every OR prerequisite tech you know. Most of the techs in the tree have 1 OR prerequisite, some have 2, and there are only a few with none (starting techs, Astronomy, Flight).
As an example, the two OR prereqs for Civil Service are Code of Laws and Feudalism. You have to know one of these two to be able to research Civil Service. If you only know Code of Laws, you get 20% bonus for researching Civil Service. If you only know Feudalism, again you get a 20% bonus. If you know both, then you get a 40% bonus.
Now, the bonus for knowing both Feudalism and Code of Laws makes sense ... it should be easier to make the leap to Civil Service with both of those concepts already understood. However, the bonus for knowing only one of the OR prereqs is a little weirder, why should you get a +20% bonus just for having unlocked the tech? This means that after the starting techs, you're getting at least a 20% bonus all the time, except on Astronomy and Flight. It's like some kind of bizarre "SALE: 20% off Tech-Tree Wide!!!" that no one ever told you about.
Anyway, this known OR prereq bonus was how I decided to scale down tech rates. In BBAI 0.80, you get a 10% bonus for knowing one OR prereq and then +20% for each additional prereq you know. In effect, almost all techs are 10% more expensive.
Several XML variables have been exposed to control tech rate:
TECH_COST_FIRST_KNOWN_PREREQ_MODIFIER - Bonus for first known OR prereq, currently 10%.
TECH_COST_KNOWN_PREREQ_MODIFIER - Bonus for subsequent known OR prereqs, remains at 20%.
TECH_COST_MODIFIER - Allows scaling of research rate modifier for all techs, so -5 would slow everything down by 5%. Set to 0.
In the test I've run, this seems to produce about the same tech rate as vanilla BTS (with tech trading on) ... it's still maybe 5% faster than I'd personally want most of the time, but about in line with what most expect I think.
Tech diffusion
In Civ4, you receive a 30%/n bonus to research rate for every civ you've met which already knows the tech you're researching, where n is the number of civs alive in the game.
In BBAI 0.80, the formula is more complex, but here are the important points:
- Diplomatic status matters, so open borders make tech diffuse much more quickly.
- There is no longer a normalization by number of civs alive in the game, instead the added bonus for each additional civ who already knows the tech gets smaller and smaller.
This second change was made for two reasons: 1) Tech now diffuses the same early on a 2-player island on a big map as it does on a Duel map. 2) If one player pulls ahead of the pack, there's a stronger bonus to pull along the other players.
In addition, a tech welfare program was added to help out civs who fall far behind. Civs who are behind by several techs in the mid game or later now get a percentage boost based on how far behind they are. This was added to help keep smaller civs and others which can't keep up in research at least technologically relevant, so your tanks should see fewer archers and longbowman now
Several variables for controlling these features have been added to GlobalDefinesAlt.xml.
This release feels like a big milestone in this project Between fixes in the UP and this version of BBAI, the AI's tech research rate is much improved, particularly in the late game. There undoubtedly more which can and will be done, but I think most of you will notice the change
Beyond the economy fixes, here are a few other highlights:
- AI now switches to Nationhood when facing a difficult enemy, and uses drafting both for defense and occasionally for an offensive rush
- Capitulation was tweaked from both sides, outright conquest is now a bit more common
- Began adding victory strategies to the AI (have little effect so far)
Next, there are two aspects of research rate I want to talk about more at length. The short version is that research rates have been rebalanced since the AI is now teching faster. The details are in spoiler tags below because they describe the inner workings of somewhat hidden research rate modifiers which exist in Civ4 and have been adjusted in this mod.
Spoiler :
Known prerequisite adjustment
In Civ4 you get a 20% research rate bonus (ie, an extra beaker for every 5 you produce) for every OR prerequisite tech you know. Most of the techs in the tree have 1 OR prerequisite, some have 2, and there are only a few with none (starting techs, Astronomy, Flight).
As an example, the two OR prereqs for Civil Service are Code of Laws and Feudalism. You have to know one of these two to be able to research Civil Service. If you only know Code of Laws, you get 20% bonus for researching Civil Service. If you only know Feudalism, again you get a 20% bonus. If you know both, then you get a 40% bonus.
Now, the bonus for knowing both Feudalism and Code of Laws makes sense ... it should be easier to make the leap to Civil Service with both of those concepts already understood. However, the bonus for knowing only one of the OR prereqs is a little weirder, why should you get a +20% bonus just for having unlocked the tech? This means that after the starting techs, you're getting at least a 20% bonus all the time, except on Astronomy and Flight. It's like some kind of bizarre "SALE: 20% off Tech-Tree Wide!!!" that no one ever told you about.
Anyway, this known OR prereq bonus was how I decided to scale down tech rates. In BBAI 0.80, you get a 10% bonus for knowing one OR prereq and then +20% for each additional prereq you know. In effect, almost all techs are 10% more expensive.
Several XML variables have been exposed to control tech rate:
TECH_COST_FIRST_KNOWN_PREREQ_MODIFIER - Bonus for first known OR prereq, currently 10%.
TECH_COST_KNOWN_PREREQ_MODIFIER - Bonus for subsequent known OR prereqs, remains at 20%.
TECH_COST_MODIFIER - Allows scaling of research rate modifier for all techs, so -5 would slow everything down by 5%. Set to 0.
In the test I've run, this seems to produce about the same tech rate as vanilla BTS (with tech trading on) ... it's still maybe 5% faster than I'd personally want most of the time, but about in line with what most expect I think.
Spoiler :
Tech diffusion
In Civ4, you receive a 30%/n bonus to research rate for every civ you've met which already knows the tech you're researching, where n is the number of civs alive in the game.
In BBAI 0.80, the formula is more complex, but here are the important points:
- Diplomatic status matters, so open borders make tech diffuse much more quickly.
- There is no longer a normalization by number of civs alive in the game, instead the added bonus for each additional civ who already knows the tech gets smaller and smaller.
This second change was made for two reasons: 1) Tech now diffuses the same early on a 2-player island on a big map as it does on a Duel map. 2) If one player pulls ahead of the pack, there's a stronger bonus to pull along the other players.
In addition, a tech welfare program was added to help out civs who fall far behind. Civs who are behind by several techs in the mid game or later now get a percentage boost based on how far behind they are. This was added to help keep smaller civs and others which can't keep up in research at least technologically relevant, so your tanks should see fewer archers and longbowman now
Several variables for controlling these features have been added to GlobalDefinesAlt.xml.