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Gaelbert
2008-11-30, 12:15 AM
Because it deserves a thread.
I recently got back into playing Civ, and I was wondering about any good scenarios or mods. I have Beyond the Sword, and I already have one of the Fall From Heaven mods/scenarios. If any playgrounders know of good ones, particularly steampunk/fantasy/sci-fi, that'd be great.

fendermallot
2008-11-30, 01:33 AM
I was thinking of buying civ4 but I have recently read that it has alot of problems with vista sp1... anyone have any opinions?

RPGuru1331
2008-11-30, 01:41 AM
I went and grabbed a Compsci major who uses Vista to check this; He said it ought to work fine, since Civ4 is recent. And he's played Civ4 with me post Vista..

Lord Herman
2008-11-30, 05:36 AM
I have Vista, and Civ4 runs fine on my PC. I do believe there were some problems with the initial release, but they've been fixed in a patch (which is probably integrated in Beyond the Sword).

Ash08
2008-12-01, 09:02 PM
Personally I find Civilization four a further step down for Sid Mier. It takes better graphics in exchange for yet weaker and more unrealistic gaming. If you can deal with the horrible graphics, Civilization 2 is the pinicle of all Civ type gameing. And if those graphics are just to archaic go for civ three. The game play is a little worse but there are a few cool "conquests" and its far superior to Civ 4. So to end it all, i have a very low opinion of Civ 4.

Rogue 7
2008-12-01, 09:27 PM
I got into the franchise with Civ 3. And I find 1. That I hate the graphics of Civ 4. They're ugly, they don't have the simple charm that Civ 3 did. 2. Gameplay is...different. Last night I burned through a quick (4-civ) domination victory where everything went perfectly. I had previously been playing on ridiculously large maps with ridiculously large numbers of Civs, and I felt...disconnected somehow. Taking my small empire conquering what amounted to a continent was very satisfying. Gameplay itself I find to be better. Sometimes I feel like there are too many options, but that's not necessarily bad. Really, if I could have Civ 4 with Civ 3's graphics (and some of Conquest's scenarios- I loved Sengoku and the Pacific Theatre one), it'd be perfect.

Gaelbert
2008-12-01, 09:45 PM
I used to play Civ 2 all the time. In fact, I still do.
Civ 3 on the other hand, I can't stand.
But now I love the fourth. How odd.

warty goblin
2008-12-01, 10:04 PM
Never played Civ 2 or 1. Played Civ 3 a lot, liked that game. I got Civ 4 just after Christmas the year it came out because I had a week alone and needed something to do. For some reason it never clicked with me the way that Civ 3 did. Honestly I think it was the unit upgrades, which are generally intuitive, but I find are not indicated clearly enough in the interface for me to tell one unit from another. Then I discovered Gal Civ II which I find a far more gratifying X4 game for some reason.

LoopyZebra
2008-12-01, 10:35 PM
Personally I find Civilization four a further step down for Sid Mier. It takes better graphics in exchange for yet weaker and more unrealistic gaming. If you can deal with the horrible graphics, Civilization 2 is the pinicle of all Civ type gameing. And if those graphics are just to archaic go for civ three. The game play is a little worse but there are a few cool "conquests" and its far superior to Civ 4. So to end it all, i have a very low opinion of Civ 4.

Can I ask why you feel this way? Having played both Civ 2 and 4, I cannot see how any of the changes result in worse gameplay. In fact, I'd say they made it much better.

And this isn't necessarily a graphics issue - X-Com is one of my favorite games.

Ash08
2008-12-01, 10:44 PM
I would have to say, the trading experince and buildings and such feels much more real to me in Civ 2 than in Civ 4, just building roads to get stuff places automaticly sort of ruins it for me. And I don't like it that one culture can found every religion in the game all by themselves. Also, the idea that units are groups of 4 guys... Blech I always liked to think that each blip on the health bar in Civ 3 reprsented about 100 guys. I know the guys in Civ 4 represent more guys but it doesn't really click. Also roaving hords on wild animals... please you don't need military for that, you should be able to use workers. And last I don't like the campaigns, this I don't know why, but I happen to harbor a meaningless dislike against them and its here to stay.

Gaelbert
2008-12-01, 11:09 PM
For the roving animal complaint, you have scouts. They're considered noncombatants, and they have bonuses against animals.

RPGuru1331
2008-12-01, 11:40 PM
I would have to say, the trading experince and buildings and such feels much more real to me in Civ 2 than in Civ 4, just building roads to get stuff places automaticly sort of ruins it for me. And I don't like it that one culture can found every religion in the game all by themselves. Also, the idea that units are groups of 4 guys... Blech I always liked to think that each blip on the health bar in Civ 3 reprsented about 100 guys. I know the guys in Civ 4 represent more guys but it doesn't really click. Also roaving hords on wild animals... please you don't need military for that, you should be able to use workers. And last I don't like the campaigns, this I don't know why, but I happen to harbor a meaningless dislike against them and its here to stay.

One culture can found every religion? Dude, not only is that nearly impossible (Egypt can realistically do it with actual competition. That's about it), it's retarded strategically. ...And as to these complaints about "A unit is 4 guys".. how did you ever handle the fact that money is represented in numbers that rarely break the thousands digit? Really?

I can buy unarmed workers in the stone age being killed by wild animals, too.

Ash08
2008-12-02, 08:48 PM
One culture can found every religion? Dude, not only is that nearly impossible (Egypt can realistically do it with actual competition. That's about it), it's retarded strategically. ...And as to these complaints about "A unit is 4 guys".. how did you ever handle the fact that money is represented in numbers that rarely break the thousands digit? Really?

I can buy unarmed workers in the stone age being killed by wild animals, too.

Its just numbers really, I can deal with that, but holy graphics should not be sullied. Anyway I have not played the expansions, so to the last of my knowledge founding the religions were pretty easy for everybody, even on harder levels.
It takes alot of animals to kill workers and, realisticly they should be armed, they should simply lack the experince of "real" troops

warty goblin
2008-12-02, 08:52 PM
Its just numbers really, I can deal with that, but holy graphics should not be sullied. Anyway I have not played the expansions, so to the last of my knowledge founding the religions were pretty easy for everybody, even on harder levels.
It takes alot of animals to kill workers and, realisticly they should be armed, they should simply lack the experince of "real" troops

We're talking about a game in which it can take a hundred years to train some guys with treebranches, and then another twenty years for them to move a few hundred miles. Realism isn't the point, high level mechanics forcing interesting decisions is the point, and making workers armed would take away one of these choices, namely whether to use your warriors for recon and offense or protect your workers.

Ash08
2008-12-02, 08:55 PM
yesyesyes, I know civilization is lacking a bit of realism, but still, wild animals strong enough to kill large groups of about a hundred humans. Thats beyond unrealistic, thats makings for a hollywood movie:smallmad:

warty goblin
2008-12-02, 09:18 PM
yesyesyes, I know civilization is lacking a bit of realism, but still, wild animals strong enough to kill large groups of about a hundred humans. Thats beyond unrealistic, thats makings for a hollywood movie:smallmad:

There's kill, and then there's disorganize, disrupt and terrify enough that they stop thinking of you as the enlightened one and run back to their huts.

Selrahc
2008-12-02, 09:59 PM
Anyway I have not played the expansions, so to the last of my knowledge founding the religions were pretty easy for everybody, even on harder levels.

On the higher difficulty levels gaining any technology before the AI is a major coup. Generally if you randomize opponents, you'll come up with a few god botherers, who put a lot of stock in the early religious techs.

There is no way you'll be able to grab all 7 founding techs for religions before any AI, even if you were surrounded by grassland gems. This is true for vanilla Civ 4,and it is true for the expansions. Even if you are playing on Noble, its still pretty hard to grab even 5 out of 7 unless you prioritize religious tech, for the simple reason that the tech tree makes it hard. Theology and Divine Right are down one path, Code of Laws and Philosophy are on another, and you'd have to be a real tech leader to rush up both trees simultaneously and fast enough to be first founder. Then there is the direct roadblock, Hinduism and Buddhism are both accessible to research from the start, and if you research one someone will have the time to research the others.

If you really go for it, you can get lucky on say... Monarch(A pretty hard diffculty setting, right before the real screw you levels). Get a capital with a gold producing resource, draw some non religious opponents, and lightbulb key techs with a great prophet or scientist. In order to do so though, you'll need to cripple your starting game by losing out on multiple key technologies, and essentially slowing down your progress for hundreds of turns.



Also, the idea that units are groups of 4 guys

You can just turn it to single unit animations instead.



There's kill, and then there's disorganize, disrupt and terrify enough that they stop thinking of you as the enlightened one and run back to their huts.

Exactly. In the age when animals spawn, the turns represent hundreds of years. I'm fully prepared to believe that a group of man eating wolves could drive off some civilians over a hundred years.

warty goblin
2008-12-03, 12:42 AM
Exactly. In the age when animals spawn, the turns represent hundreds of years. I'm fully prepared to believe that a group of man eating wolves could drive off some civilians over a hundred years.

...Did we just agree? I'm not sure that's ever happened before...

RPGuru1331
2008-12-03, 01:50 AM
There is no way you'll be able to grab all 7 founding techs for religions before any AI, even if you were surrounded by grassland gems. This is true for vanilla Civ 4,and it is true for the expansions. Even if you are playing on Noble, its still pretty hard to grab even 5 out of 7 unless you prioritize religious tech, for the simple reason that the tech tree makes it hard. Theology and Divine Right are down one path, Code of Laws and Philosophy are on another, and you'd have to be a real tech leader to rush up both trees simultaneously and fast enough to be first founder. Then there is the direct roadblock, Hinduism and Buddhism are both accessible to research from the start, and if you research one someone will have the time to research the others.
Egypt. Obelisks allow 2 Priests. If you were a REAL whore, you'd give them a Phi leader, which fortunately Hatchy lacks (to my memory). Set priests to get exclusively Prophet GPP, and use Prophets to lightbulb the big techs.

It's still stupid, because you made spawning future GPPs far more expensive, and you could have just as well specifically waited for Scientists for Academies, Engies for Wonders, Merchants for Trade Missions, or settled the Prophets in your capitol and used them to not leave 100% Research for a very long time, but it can be done.

factotum
2008-12-03, 03:39 AM
It's still stupid, because you made spawning future GPPs far more expensive, and you could have just as well specifically waited for Scientists for Academies, Engies for Wonders, Merchants for Trade Missions, or settled the Prophets in your capitol and used them to not leave 100% Research for a very long time, but it can be done.

Yes, it can be done, but if you cripple your long-term development doing it, what benefit does it bring? The complaint seemed to be that founding all 7 religions would somehow be a huge benefit, which it clearly isn't.

Ash08
2008-12-03, 11:11 PM
Alright I give in, maybe Civ 4 is worth pullling out again, I'll try and see if I CAN like it

RPGuru1331
2008-12-04, 06:37 AM
Yes, it can be done, but if you cripple your long-term development doing it, what benefit does it bring? The complaint seemed to be that founding all 7 religions would somehow be a huge benefit, which it clearly isn't.

It's not even a more then minor annoyance, unless you're the type who selects their strategy before the game starts. "Oh no, -1 Happy!" Plus you'll have natural spread eventually anyway.

Now, if you're the type who picks their strategy before the game starts, and you picked Culture, you will be rightly annoyed; No (Or very few) Cathedrals means that your culture win takes exponentially longer.

Om
2008-12-05, 03:27 PM
On the higher difficulty levels gaining any technology before the AI is a major coupWhich is one of the major criticisms I had of the original game. I'm not sure if its been fixed in the expansions but watching AI nations trade techs exclusively with each other was hugely frustrating. But other than that, the graphics, and hugely unbalanced combat, CivIV was a decent game. I still rate CivII higher (and that's without even mentioning Alpha Centauri) but by and large CivIV is the game that CivIII should have been

RPGuru1331
2008-12-05, 04:10 PM
Which is one of the major criticisms I had of the original game. I'm not sure if its been fixed in the expansions but watching AI nations trade techs exclusively with each other was hugely frustrating. But other than that, the graphics, and hugely unbalanced combat, CivIV was a decent game. I still rate CivII higher (and that's without even mentioning Alpha Centauri) but by and large CivIV is the game that CivIII should have been

They don't trade techs exclusively with each other. Mansa Musa trades with EVERYONE. He is the grand slut of technology. Pretty much nobody trades exclusively with each other.

And there's no 'grand unbalancement'. Except for Cavalry.

Om
2008-12-05, 04:38 PM
They don't trade techs exclusively with each otherYou're correct, I left out an "almost"

The reason that AI nations tend to advance through the ages so quickly is that the costs of sharing techs with other AIs is ridiculously low. The human player will have to offer a very good deal in comparison. Try turning off the tech trading (I think in BtS you could limit trading to advances that you had discovered yourself) and you'll immediately notice the difference


And there's no 'grand unbalancement'. Except for Cavalry.And longbowmen. And the uselessness of artillery, aka 'medieval cruise missiles'

RPGuru1331
2008-12-05, 04:42 PM
You're correct, I left out an "almost"

The reason that AI nations tend to advance through the ages so quickly is that the costs of sharing techs with other AIs is ridiculously low. The human player will have to offer a very good deal in comparison. Try turning off the tech trading (I think in BtS you could limit trading to advances that you had discovered yourself) and you'll immediately notice the difference
Just turn off Tech Brokerring. And by the way, you're not barred from tech brokering either. It's an extremely effective tactic in MP games. You're just too lazy to do it.


And longbowmen. And the uselessness of artillery, aka 'medieval cruise missiles'

Longbowmen aren't broken. And artillery are awesome, if you bring 2.

Selrahc
2008-12-05, 04:44 PM
They don't trade techs exclusively with each other. Mansa Musa trades with EVERYONE. He is the grand slut of technology. Pretty much nobody trades exclusively with each other.

And there's no 'grand unbalancement'. Except for Cavalry.

I think he means on Emperor or Deity where you'll be way behind everyone in tech until a late stage. Nobody will trade with you, because you have nothing they need.

Every time you do get a tech early on the higher difficulty levels you can trade it out for many times its value in slightly worse techs.

Also, I think they've dealt with the Cavlary thing pretty well by shifting it along the tech tree. Now you get cuirassers where you used to get cavalry, nice but not game breaking.



...Did we just agree? I'm not sure that's ever happened before...

Apparently. Don't worry, I'll try not to let it happen again. :smalltongue:

EDIT:

Artillery as useless? I take it you don't mean catapults and cannons, because without them you'd take large losses in every military campaign in the game. A bit of bombardment and some suicide cats and you can waltz it.

Actual artillery is a bit useless, since you get bombers at about the same time. But it isn't really medieval.

RPGuru1331
2008-12-05, 04:46 PM
I think he means on Emperor or Deity where you'll be way behind everyone in tech until a late stage. Nobody will trade with you, because you have nothing they need.

Every time you do get a tech early on the higher difficulty levels you can trade it out for many times its value in slightly worse techs.

Also, I think they've dealt with the Cavlary thing pretty well by shifting it along the tech tree. Now you get cuirassers where you used to get cavalry, nice but not game breaking.
I actually meant Cavalry suck, as a rule. Pikemen and their ilk negate them too easily.

And no, he's referring to tech trading period. He can't mean Emperor/Deity; anyone could tell you that they're just getting huge discounts on techs as part of the game code for Emperor/Deity. That's how it's ALWAYS been in Civ. And its true, the Computer doesn't necessarily come to you first.. unless you're a big tech leader.

Rogue 7
2008-12-05, 04:56 PM
I actually meant Cavalry suck, as a rule. Pikemen and their ilk negate them too easily.


Cavalry the unit? Not to my experience. And artillery (catapults and the like) rock. You just need a bunch of them and to consider them fully expendable. Throw two or three at a heavily defended city and you can march right in.

RPGuru1331
2008-12-05, 05:08 PM
Cavalry the unit? Not to my experience. And artillery (catapults and the like) rock. You just need a bunch of them and to consider them fully expendable. Throw two or three at a heavily defended city and you can march right in.

Cavalry the Unit themselves aren't quite as bad, but Horsemen (Non-Numidian Cavalry), Knights, and Cuirassers get eaten by Spearmen and Pikemen. Much cheaper, but much more likely to win. Now, Cossacks are pretty rocking..

Om
2008-12-05, 05:54 PM
Just turn off Tech Brokerring. And by the way, you're not barred from tech brokering either. It's an extremely effective tactic in MP games. You're just too lazy to do itIts true that I am indeed too lazy to play MP. Hence my repeated references to AI nations. And Tech Brokering is exactly the option that I was referring to above. Perhaps you are too lazy to read my posts?


Artillery as useless? I take it you don't mean catapults and cannons, because without them you'd take large losses in every military campaign in the game. A bit of bombardment and some suicide cats and you can waltz it.Useless was a poor turn of phrase. Obviously the only alternative to slaughtering maceman after maceman is to sacrifice artillery unit after artillery unit but therein lies the rub. Because longbowmen are so hopelessly overpowered (a suitably promoted unit remaining a viable defender right up to the appearance of infantry) any offensive requires you to bring along a large artillery train of disposable catapults/cannons/etc. Of course each city will cost a few artillery units to seize so you'll either have a very large reserve of them or advance at a snail's pace as reinforcements trickle in from the homelands

Now this is actually a step backwards from CivIII (and Alpha Centauri) which introduced artillery with ranged combat. I have no idea why this was dropped from CivIV, otherwise far superior to its predecessor, but I feel that the combination of tough defenders and disposable artillery makes for a very poor and unbalanced combat model

I think there's a mod out that restores ranged artillery combat but, as with Tech Brokering, its a measure needed to fix a flaw in the gameplay mechanics

RPGuru1331
2008-12-05, 05:56 PM
Its true that I am indeed too lazy to play MP. Hence my repeated references to AI nations. And Tech Brokering is exactly the option that I was referring to above. Perhaps you are too lazy to read my posts?

No, I got it. I just found it suspect that one would complain about the AI doing something that you could do yourself, and are too lazy to do, as a balance issue.



I think there's a mod out that restores ranged artillery combat but, as with Tech Brokering, its a measure needed to fix a flaw in the gameplay mechanics
Tech Brokering isn't a gameplay mechanics flaw. It's a medium between No Tech Trading (You know, the option directly above it) and, well, diplomacy.

Om
2008-12-06, 10:31 AM
No, I got it. I just found it suspect that one would complain about the AI doing something that you could do yourself, and are too lazy to do, as a balance issueOf course! I never realised that I could trade techs with the AI! Boy do I feel silly. I was wondering why they had removed a feature that I'd seen in every Civ game since the original but now I can see I was too lazy to spot that trade option. Isn't my face red... :smallredface:


Tech Brokering isn't a gameplay mechanics flaw. It's a medium between No Tech Trading (You know, the option directly above it) and, well, diplomacy.Either I'm phrasing my posts extremely poorly or you are deliberately misinterpreting my posts. I'll assume the former although your barbs are trying my patience. So for the last time:

I do not consider Tech Brokering to be a "gameplay mechanics flaw". It is a solution, not an entirely satisfactory one, to the unbalanced tech trading system. I complain about the latter because (I'm lazy, hur hur) the costs of inter-AI trading are significant lower than human-AI trading. In other words the AI nations will happily make many trade techs with each other at very cheap rates. In comparison they will rarely trade with humans and when they do the cost to the latter is significantly higher

The result of this is that techs are very rapidly disseminated amongst AI nations which greatly increases their tech levels. Seeing as human players are not included in this 'tech loop', what with their tech trades with AIs being far more infrequent, it makes for an inherent disadvantage. This ties me back to my original point where on higher difficulties you will often see the AI, as a bloc, outstrip the human player in tech no matter the efforts of the latter to join the trading. When this trading is disabled - either entirely or through Tech Brokering - there is a marked difference in AI performance and the game becomes far more balanced

But while Tech Brokering is something of a solution I would far rather that the original problem be fixed. I do after all enjoy playing the role of tech broker in other 4X games

RPGuru1331
2008-12-06, 04:09 PM
I do not consider Tech Brokering to be a "gameplay mechanics flaw". It is a solution, not an entirely satisfactory one, to the unbalanced tech trading system. I complain about the latter because (I'm lazy, hur hur) the costs of inter-AI trading are significant lower than human-AI trading. In other words the AI nations will happily make many trade techs with each other at very cheap rates. In comparison they will rarely trade with humans and when they do the cost to the latter is significantly higher
No! They don't! Have you EVER played with a tech lead over the computer? Or had techs they consider vital? They will sell their left arm for it. I'm telling you right now, AI don't make significant discounts with each other on a regular basis because they're AI!



The result of this is that techs are very rapidly disseminated amongst AI nations which greatly increases their tech levels. Seeing as human players are not included in this 'tech loop', what with their tech trades with AIs being far more infrequent, it makes for an inherent disadvantage.
Their offers come infrequently; Their willingness to trade is still there. You just have to make the offer.


This ties me back to my original point where on higher difficulties you will often see the AI, as a bloc, outstrip the human player in tech no matter the efforts of the latter to join the trading.
So between two options, "The AI is a massive bloc! despite their actual competition against each other! Discounts abound, and they hate you" and "The AI gets a massive research boost over you, and you have nothing it wants".. you choose the more complex option? Civ4 AI behaves absolutely no differently at higher levels, with the possible exception of Barbarians. Civ4 AI gets Research, hammer, and starting unit bonuses at higher difficulty levels. That's it. They're not smarter, they're not faster, they're just better.

I think, frankly, that you think it discounts because the AI checks both ways. That is, you're used to the AI just saying "Hay, want this for this?" and not checking with them on the same. But the AI being a computer, the tech check is performed both ways. Every turn.

Rogue 7
2008-12-12, 07:35 PM
My main complaint about the trading system in Civ 4 is that you can't trade one-time trades for continuous and that you can't go into the red when trading GPT.

Saying that, I'm really enjoying the game I'm playing right now. I'm India, on noble, playing the Eastern North America map. I've got something like a 3-400 point lead, and almost every improvement built in all my cities. Two-thirds of the world is currently Buddhist thanks to my many missionaries, meaning most of the world is friendly. I think I need to up the difficulty, though having my entire map as grasslands helps.

Izmir Stinger
2008-12-30, 12:11 PM
I do not consider Tech Brokering to be a "gameplay mechanics flaw". It is a solution, not an entirely satisfactory one, to the unbalanced tech trading system. I complain about the latter because (I'm lazy, hur hur) the costs of inter-AI trading are significant lower than human-AI trading. In other words the AI nations will happily make many trade techs with each other at very cheap rates. In comparison they will rarely trade with humans and when they do the cost to the latter is significantly higher

Read up on these mechanics over at Civ fanatics. It actually does not take your status as a human controlled civ into the equation. The price is based on a universally perceived value of a tech (which lowers the more people know it, and if wonders associated with it have been built), a civ-specific value assessment for some techs (the ones that unlock their "favorite civic" or unique unit) and your diplomatic status with them (furious, annoyed, cautious, pleased or friendly) with warmer relations granting fairer trades. I think what is happening in your games is either:

A) You are pissing off the AI more than they are pissing off each other. Try being nicer.

AND/OR

B) You are missing the most optimal trades because you don't check for good trades every turn and they do. The fewer people know a tech the more valuable it is, so trading earlier rather than later is better. If you and Mansu Mansu are the only ones with Monarchy, and when you discover it nobody has anything worth trading for it, you may forget about it but he doesn't. As soon as someone that doesn't have Monarchy discovers something that he doesn't have, he offers a trade within 2-10 turns. If it is accepted, not only are you prevented from making that same trade yourself, because the third civ now has Monarchy, but monarchy is considered less valuable by all other civs because more people have it now and if you do get anything for it, it will probably be a worse trade. The best players check the trade screen every single turn after discovering Alphabet looking for potential deals.

AND/OR

3) Trading is not the only way techs proliferate between civs. This freaked me the hell out the first time it worked for me - but you can approach a civ that has pleased or friendly status and request low value items (gold or obsolete techs you skipped) in exchange for nothing but your undying affection... and they will sometimes accept! Similarly, you can demand stuff from civs as tribute if they are cautious or worse (though if they accept you cannot go to war with them for 10 turns) and they accept or decline based on an assessment of whether they think they can take you in a war or not. You can get a decent number of techs with nothing more than a sufficiently threatening army. Its cruel, but a civ that is at war with a third party is a great target for this because their army is suffering losses from another war. The AI civs are doing these sorts of non-trade tech proliferation to each other behind the scenes, too, which accounts somewhat for your perception that they are trading unfairly behind your back. You may refuse every request for a free tech as a matter of principle, but AIs will accept sometimes. You can get in on this deal, but you have to open up that diplomacy screen alot more often.

Also, certain non-tech items have value that can traded for techs. Gold is an obvious one, but you rarely have enough to buy a tech outright (but you can use it to supplement other trades). If you are winning a war, the loser considers a Peace Treaty to have value and might trade techs for it. Most players have figured that one out, but others they may not have considered are:

A declaration of war. If two AI civs are fighting each other one of them, especially the looser, will consider giving you techs for joining the war on their side.

Cities. Sure they show up on the trade screen but why would you ever trade them? Well, say you are on a continent with two other civs. You are on the west, another is on the east, and the one in the center is currently being conquered by you. When you finish conquering him, his easternmost cities are going to be mostly useless because the Eastern civ will have more cultural influence on them than you (their brutal oppressor) does. You can trade those potential problem cities to the eastern civ for techs, and create a buffer between your newly conquered land and their deeply entrenched culture.

Defensive pacts. A militarily weak civ might give you techs to join a defensive pact with them to protect them from a militarily strong civ that hates them because they worship the wrong gods or something.