Comprehensive Tech Tree Guide (community project; come & contribute!)

[Quechua]

Ok, I put what I wrote in the spoiler. Feel free to edit or make any additions. If you already started on Iron Working I probably will have some overlap. It sounds like I'm taking a more pessimistic tone than you will about researching IW to try to discover iron alone.

Spoiler :

Jungle, Metal, and Water
Iron Working, Metal Casting, Calendar, Compass​

These are the classical technologies that follow from Sailing and Bronze Working. Metal Casting requires Pottery as an additional requirement, and Calendar is displaced from the others in the tree by requiring Mathematics.

Unlike more general technologies like Monarchy and Currency, the priority for researching these techs depends heavily on the map. These technologies unlock several worker actions which may not find much use in every game, but are particularly useful in tropical areas: clearing jungle, building plantations, and early workshops.

In maps dominated by water they also gain in value. Metal Casting allows the construction of the Colossus Wonder, which adds extra commerce to water tiles. Compass allows the construction of harbors in coastal cities, which boost health and generate extra commerce from trade. And Compass and Calendar will both be required on the path towards Astronomy, the tech allowing trade and transport over ocean. Conversely, on a map with little water or plantation resources, there is not much value to Compass and Calendar. You could delay acquiring them for a very long time, but they will eventually be necessary for Physics, a key gateway tech for the late game.

Iron Working​

Depending on the map, Iron Working can be an important technology that is researched alongside the ancient era techs. Jungle cities tend to be very poor early on, but often have major potential once the jungle is cleared - especially once you can build plantations with Calendar. Clearing jungle is very expensive in terms of worker turns, so jungle cities should typically be avoided early, but sometimes you simply must make the best use of your position. It's not rare to find rice or gems under jungle, which you can make good use of immediately.

The first thing you probably notice about this technology is not jungle, but iron. If you have no access to copper, you need iron to build the melee units of the ancient era. If you have no need to clear jungle, it is debatable whether the gamble of discovering iron is worth valuable turns of early research. It may be wise to delay any war plans and reconsider your strategy. For instance, heading towards Alphabet can improve your situation in other ways, and you can often get Iron Working easily in trade.

Iron isn't just a substitute for copper, it also allows the swordsman unit. The swordsman upgrades the city raider role of the axeman. Swordsmen are noticeably better than axemen for attacking archers in cities, and are stronger against catapults and mounted units in the field. However, swordsmen are countered very effectively by axemen, and are a little more expensive to build. It is debatable whether it is worth spending early research turns on Iron Working for swordsmen alone.

It should noted that this unit is radically different in the Aztec and Roman civilizations. The Aztec Jaguar feels much like a modified axeman. Since it requires no resources, the risk factor of researching Iron Working is eliminated....but if you do have copper, the merits of Jaguars over axemen are slim. On the other hand, the Roman Praetorian is essentially a cheap medieval maceman for the early game.

Metal Casting​

The value of the Colossus on water maps has already been mentioned...the other role of Metal Casting is increasing production. This technology is the bridge between both key military techs of the ancient and medieval eras, but has no overt military value itself. However, the forge building gives a production bonus which is very useful in military centers. The forge also can act like a temple, increasing the happiness from luxury mining resources. But be careful about building forges in non-production cities which may eventually be limited by health rather than happiness.

In regions with very low production, such as cleared jungle grassland, Metal Casting provides two limited ways to get hammers. The early workshop is a very weak improvement - it essentially turns grassland into an unimproved plains tile, and a plains tile into an unforested hill. Still, it is better than running citizen specialists, and may be the only source of production in some cities if you aren't running Slavery.

The other source of production is running an engineer, which is unlocked by the forge building. In terms of immediate production, the engineer is no better than the weak early workshop. But the real value comes from the great person points. The forge is one of the few ways to get the Great Engineer, which plays an important role in some strategies.

Compass​

Compass is a very limited technology. Its only real intrinsic benefit is the harbor building, which can only be built in coastal cities. But the harbor is one of the biggest advantages of a coastal location. Besides the health benefits, it increases commerce from trade routes, which also tends to attract your better trade routes to that city. This, as well as the commerce from water tiles, means it often makes sense to specialize your coastal cities for commerce.

The other thing to note about Compass is that in many research paths it is a short step from Optics, which allows you to contact other continents and win the circumnavigation race. Compass unlocks the explorer unit which after Optics can travel via caravel to explore new lands. But the explorer itself is hardly a reason to research Compass - it plays very little role in most games.

Calendar​

The value of any of these techs is very map dependent, but this is especially true for Calendar. If you lack plantation resources there is no real reason to acquire this tech until Astronomy. Calendar centers your world map, but at this point in the game you should already have a good idea where you are with respect to the equator. More significantly, the tech obsoletes the monument/obelisk building, which is the cheapest way to expand borders in new cities. When you found new cities in this era, remember to build any needed monuments before acquiring Calendar. Fortunately, you can also get the more useful theater building with the Drama tech around this time, which is nearly as cheap as the monument.

This is not to diminish the importance of any plantation resources you do have. Unhappiness is often a problem in the early game, and Calendar can be a useful approach to the problem. The resource tiles themselves are also valuable to work. In particular, bananas are about as good of a food and health resource as grains, and dyes provide as much commerce as towns, giving double happiness with the cheap theater building.

 

[Diamondeye]

I can serve as a correction reader and add my 2, although I doubt it's worth much. I am only playing noble atm and I'm not into all these advanced maths and such... I'll try to help!


@Quecha: Obsoletion of Stonehenge/monument has been moved to Astronomy with BtS

 

[LlamaCat]

So far I read most of this thread but I might have skimmed over a few things so I'm sorry if I repeat or contradict anything but here are some thoughts (putting in spoilers)

Spoiler :

I think you should clarify if this guide is for BTS tech tree. All three versions of the game are treated separately on this site, so the information is fragmented and the trees are different in some important ways. The game has kept making changes from version to version so it would be nice to have a full screenshot of the BTS tech tree as part of your guide maybe?

Also, I sometimes think about the tech tree as a WHOLE entity before starting a game or when I get to an early point where I want to go for a certain victory.

- what are all the techs you could skip completely and get to the end? interestingly it's not that many ... you pretty much have to understand that you eventually need to research or trade for almost everything at some point

- so with that said, researching too far along one path before backtracking along another will increase beaker costs. Often that's not too big of a deal because by the time you get further along the tree, your research would be much more and older techs are cheaper. But if you wait too long to backtrack, you can lose sight of the fact that you might need a key early tech in order to use units that you thought you opened up much later in the tech tree or to get something you needed.

- the strategy for delaying the acquisition of certain techs to your advantage. the two most common that I can think of:

1. Scientific Method - the gateway to the modern era, yet it obsoletes so much good stuff.
** In general the understanding of what some techs will OBSOLETE is just as important as understanding what they will allow.

2. Liberalism - if you have a comfortable tech lead and due to espionage you are sure you can get it first, researching other techs first will give you better choices for the free tech.

Another thought I had is that I feel each of the 4 eras has 1 key tech that should be highlighted above all others, NO MATTER what kind of map or game you roll.

This doesn't mean this particular tech will always be useful, but it always somehow has a major impact on the game either via you or one of the opponents.

The first example in my opinion is Bronze Working. There is simply no other tech in the Ancient Era that impacts the game as much. It allows the first civic, Slavery; it reveals Copper; it allows forest chopping; and it allows the strongest units, by far, before you advance to the next Era with Iron Working and Swordsmen, I believe.

 

[JujuLautre]

Don't have too much time to look at everything, but I would just say that you could divide "economic techs" into:
- early worker techs (mining, agriculture, wheel, hunting, BW, fishing? pottery?)
- economy techs (pottery and writing mostly, but also alphabet, currency and CoL)

 

[Eunomiac]

Hey guys! Sorry for being a bit scarce. I was a bit too enthusiastic in starting this up when I did, exactly one day before the exam crunch hit. I'm going to try to be around as much as I can, but I won't be able to fully apply myself until Christmas break. Fortunately, two of my classes are trial practice seminars without exams, one's an easy exam... but Conflict of Laws is going to rape me. Somehow I doubt it will ask about the pros and cons of Nationhood vs. Bureaucracy ;-)

Quechua: Nice write-up! I'll add it to the Classical Era when I get the chance. It did help me better appreciate the point VoiceOfUnreason made in his first response to this thread. I hadn't considered those techs being grouped in terms of their map dependency. It's a great idea, and it shows me that there will be TONS of overlap and different ways of grouping things together.

I'm thinking I'll incorporate submissions into each Era by listing them by Tech - Perspective. I've added yours to the Classical Era so you can see what I mean -- when someone adds more info on Iron Working (or groups it with other techs in a new way), another "Iron Working - <Whatever>" paragraph can be added beneath the existing one, and each paragraph edited for any redundancies. When we feel like an Era is more-or-less complete, we can then figure out the best way to organize everything into a comprehensive whole.

This also helps break things down even further: People don't even have to commit to a single Tech; they can opt to write as little as a certain aspect of a single Tech.

Obsoletion of Stonehenge/monument has been moved to Astronomy with BtS

I think you should clarify if this guide is for BTS tech tree.

Yeah, I did just take that for granted, and it's a very important point. BTS rocks, it's the one I'm most familiar with, and I think it's counter-intuitive to write a guide as big as this one about an earlier incarnation of Civ IV. I'll edit the title and first post accordingly.

I like the idea of including a screenshot of the Tech Tree guide, perhaps with some added color to define the eras. I've made a note of that in my Google Notebook, but it probably won't appear until the tech guide is near completion (so it can be edited to account for however we organize things).

Also, I sometimes think about the tech tree as a WHOLE entity before starting a game or when I get to an early point where I want to go for a certain victory.

True, but it's important to realize that the goal of this guide is not to present entire strategies to players. Instead, it's to give people a general understanding of the tech tree so that they can come up with their own strategies (or better understand the give-and-take of the strategies they've learned). So you won't find statements like "A Cottage Economy doesn't need X, X and Biology." Instead, you'll find "Biology is particularly useful if you're running a lot of specialists; the less farms you're running, however, the less useful it becomes." (don't comment on my understanding of Biology -- I rarely run CE's, so I'm probably wrong in assessing necessary techs; you get the idea though).

... you can lose sight of the fact that you might need a key early tech in order to use units that you thought you opened up much later in the tech tree ... [or] delaying the acquisition of certain techs to your advantage

This is exactly the sort of thing this guide will be aimed at. One of my biggest frustrations ever was beelining to Astronomy for Privateers, not realizing that Chemistry was another requirement (and stupidly losing the Liberalism race in the process... this was a long time ago; I've grown as a person). These sorts of things aren't strategy-specific, though, and would fit perfectly into the scope of this guide. Ditto on obsoleting techs, as well as best using Liberalism; the Sci Method write-up would include a warning, as would any other such tech.

Another thought I had is that I feel each of the 4 eras has 1 key tech that should be highlighted above all others, NO MATTER what kind of map or game you roll.

I really like this idea; sort of a running 'star Tech' theme, maybe even a 'Runner Up' as well. I'd come just a tiny bit short of 'NO MATTER what,' though (and you appear to agree in your next paragraph): One of the values of this could actually be describing where and why you might NOT beeline such an important tech (i.e. Bronze Working when you're Wonderspamming as Qin Shi Huang [Protective/Industrious] from a capital surrounded by hills, Stone, little food and few forests). At the very least, the extreme nature of those limited circumstances where you wouldn't prioritize the tech would showcase how important the tech normally is.

You're right about Bronze Working, and it will be treated as such when I finally get to it. In fact I think Bronze Working is a bit too pivotal. I don't like how they recently 'balanced' it by making Copper rarer, since it just makes the early game more frustrating/swingy. I agree with someone else's suggestion that Slavery be moved to Masonry. It makes flavorful sense, too, since Slavery is conventionally associated with the Egyptians and the Pyramids. But I digress... expect to see that in the 'Eunomiac Becomes Supreme Leader Of Civ IV' Mod.

JujuLautre: I haven't started writing up those techs yet, but I expected to be wrestling with the huge number of "Improvement Techs" and I like your idea -- it fits well with the proposed divisions for later eras, since Writing has more in common with the Economic Techs of the Classical Era than it does with, say, Agriculture. A definite possibility, unless the questions implied by your question marks lead me in a different direction.

Thanks for the interest, everybody Wow, this might actually work!

 

[Quechua]

Well, their research priority is map specific, but I grouped them because they all follow from Sailing and BW. I'm not sure how many paragraphs you'll get on the other nuances of Compass

 

[marius312]

By late game, what do you mean? Do you mean post-construction? Or the modern era? Btw, this is a great effort. It's time someone clarified the later techs, because I dont think many people know much about them.