# Internal Trade Route Yields [pre patch]

Discussion in 'CivBE - Strategy & Tips' started by alpaca, Oct 27, 2014.

1. ### alpacaKing of Ungulates

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I played around with Firetuner to figure out the internal trade route mechanics. The results: The only variable that matters appears to be the difference between the food or production yield of the two cities. Distance doesn't matter, for food, the surplus is used. Mirroring the route doesn't make a difference in total yield. I couldn't come up with a formula that fits, but it looks more or less logarithmic. Here are the tabulated values:

Outgoing
Column 1 Column 2
Difference Value
0 0
1 1
2 2
3 3
4-5 4
6-9 5
10-16 6
17-25 7
26-41 8
42-? 9

Ingoing
Column 1 Column 2
Difference Value
0-1 0
2-4 1
5-15 2
16-? 3

2. ### AgentDibChieftain

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In my testing it looked like only the base production values (terrain + buildings) were used. Is that what you saw?

3. ### sprangWarlord

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your best food city will be the fastest growing - but not for very long, as the surplus gets reduced from growth. So to maximize food trade, you need a city with very large surplus that never grows. How? by having one city specialize in food - and then only build colonists there, so city never grows but the base is high.

4. ### AgentDibChieftain

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Trade routes get counted into surplus for food, so it is very possible to keep your capital city way ahead of your other cities. Right now I have a 19 pop outlying city growing fast with +21 food surplus but a trade route to my capital still adds +4/+9 food because my capital has +105 food surplus (from all the trade routes incoming). Because the bigger number goes in the direction of the caravan, as long as you keep sending convoys from outlying to capital it will keep snowballing.

5. ### alpacaKing of Ungulates

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Yes, it doesn't seem like percentage modifiers or trade routes count towards the value.

Are you sure about this? Edit: I just fired up the game. This seems to be incorrect. My capital has a surplus before trade routes of 3, my third city 0. The trade route provides 3 outgoing and 1 incoming food going from cap to third city. Bottom line, the third city has 3 surplus and cap has 4.

I've been thinking about this for a little while now, and min-maxing this is going to be incredibly annoying. Basically, to get the most out of your trade routes, you need to adust the yields for the cities manually. The nonlinearity makes this even worse, as you probably want to go for either a delta of 6 or 10 (6 is probably most efficient as it's close to the threshold for both in- and outgoing). This is really, really terrible design.

6. ### Martin AlvitoReal men play SMAC

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In principle you'd want to over-Worker that city to have a ton of Mines and a ton of food available, then manually juggle things every time you needed to renew a route. Which is going to be pure micro hell, as alpaca suggests.

7. ### omniclastPrince

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It seems incredibly bizarre that the yield is always given to the outgoing route, regardless of the direction of the difference in food supply. So if my 1 pop new city is sending food to 20 pop cap, it generates an insane amount of food/prod for... the cap. How does that make sense?

Not to mention the strats it seems to motivate. Here's what I propose: build three central cities and grow them big and powerful. Then build a pile of incredibly crappy 1 pop cities on the worst tiles you can find, make sure they never grow or expand borders. Buy depots and autoplants in all your crappy cities and send the 3 TRs from each of them to each of your 3 core cities. Since the larger bonuses will always go to the 3 big cities, the gap in pop will keep growing rapidly, as will the food/prod bonuses to your 3 big cities. If I may be permitted an anology... it is a free energy machine.

Makes no sense. Higher benefit should always go to the smaller food/prod city, regardless of whether it's incoming/outgoing.

(Note I would just say you should limit growth in the crappy cities but I haven't found a way to do that)

8. ### alpacaKing of Ungulates

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You're right, it doesn't make sense. It's also not great for gameplay, but there's nothing we can really do about that (barring a mod).

The food doesn't grow in your central cities as the game doesn't seem to count trade route yield into the difference.

Anyways, since the earlier builds are much more efficient hammer-wise and the more expensive buildings more efficient to buy with energy, there's really no incentive to having really crappy cities. It's probably better to spread out the wealth by specializing your cities.

I do it like this: groups of 4 cities. Two production, two gold/science. Have trade routes from the gold cities to each of the production cities. This will maximize production there. The trade routes from the prod cities go to either international or expansion. Once autoplants go up, the additional trade route will go international in most cases, as science seems to be the most useful yield. This set-up will maximize your trade route yields.

In my current game, it's turn 120 or so, I have 8 cities, 2 outposts and another two colonists waiting for my army to clear out some aliens. I have 140 beakers (115 corrected for increased tech cost, as I went down knowledge quite far). Of this, at least 60% is from international trade.

9. ### TheMeInTeamTop Logic

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The base use of trade routes itself is micro hell in a wide empire.

That type of stuff is HoF strats only, at least until prosperity + internal trade eats a nerf bat to the skull. You'd never need this kind of micro to win otherwise, excepting maybe MP.

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11. ### alpacaKing of Ungulates

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The difference between T120 (it was actually 115, which I found out after continuing the game) and T150 is huge as this is usually the time your second expansion wave comes online and you can afford to turn more trade routes toward science rather than production. Agreed, T150, 300bpt can easily be achieved.

A heads up for everyone: from my in-game observations, it seems that external trade route yield is also based on the yield difference for the most part. I'm not sure if technological discrepancy is a factor (it was in Civ5), but so far it doesn't really look like it has a major impact.

12. ### AimeryanChieftain

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Does anyone know if trade routes are dynamic?

In other words, does the trade route yield (incoming/outgoing) change while in use as the difference between the cities of the trade route changes?

13. ### alpacaKing of Ungulates

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Yes, it most certainly does.

14. ### AimeryanChieftain

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Odd, given that we have no ability to change the trade route until it ends. On the other hand, they are fairly short so you aren't making any long term commitments.

15. ### alpacaKing of Ungulates

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The base design creates very undesirable incentives. In this case, it follows from the difference-based yields that neither option is good. If you lock yields in, you would micro even more because you want to re-arrange your yields the moment you initiate the route. If you could retract trade routes, you would have to go through the list every turn and see if any become unprofitable. If you do it as it is, you want to micro your yields to not reduce your trade route income too much.

16. ### AimeryanChieftain

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Indeed... lot of micro however you look at it, both re-sending trade routes (once you have a number of cities) and in making sure the yields work for at least the majority of the trade route's duration.

Think I will work on some mod ideas to see if there is anything I can come up with that I would find both balanced and requiring far less micro.

17. ### KrikkitTwoImmortal

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To make less micro (and prevent trade routes from overwhelming tiles/buildings)

Yield=20% of sending city base (distributed between both cities)

18. ### alpacaKing of Ungulates

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This might be a good idea if you don't want to change the base design too much. But unless you can get rid of the rounding shenanigans, it'd also create a lot of micromanagement because you want your yield to always be a multiple of 5. Of course, it's rather mood for a mod at this point as we have no DLL access.

Without changing the base design, I doubt there's very much you can do. The best of the three options is perhaps to just leave trade routes in place without time limit, add a re-assign button to the overview, and add an optional alert that is fired when a much better trade route of the same type is available.

You could replace the whole system with some other representation of trade, but this would likely be annoying with Lua hacks only (AI integration, mostly). Speaking as someone who did something similar for bulbing in Civ5.

19. ### TomicePassionate Smart-Ass

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@ alpaca:
So this suggestion I made in another thread would be impossible without dll access?

20. ### alpacaKing of Ungulates

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I saw that suggestion, actually, but didn't get around to answering it yet. The yield formula is almost certainly in the DLL. It is in the DLL for Civ5 and it's highly unusual for calculations like this to be done in a game script.

As far as I can tell, without ripping out the whole trade route system and replacing it with a Lua-based version, you can't mod the basic design. Perhaps you can change the total yield, but it will always be the same difference-based formula.

There are some things you could conceivably do, like implementing a hack to make sure that trade routes always go from the high-yield to the low-yield side, and probably adding a recall button, but you can't just change the yields to 10% of the production for each city.

If I may offer some comments, I don't think I'm a big fan of your design, as I rather feel that it doesn't quite address what's basically wrong with trade routes. If additional yields are created, you will always want to hook your city up to the best existing production city, which is part of what makes trade route management boring for me in its current form. There's little real optimizing going on, it's mostly micromanagement and a little bit of juggling marginal gains.

In my opinion, it would be better if trade didn't create any additional production or food at all, but just moved it around. There could, perhaps, be a small energy yield (representing tariffs or whatever), but for hammers and food the use is already in an increased marginal gain as long as the early builds and pop increases remain more efficient and health mostly remains local. On the other hand, losing production in your hammer city means you don't want to allow an arbitrary amount of trade from it. This would also go some ways to make ICS more difficult by putting production back to the cities and making it harder to set up multiple cities at once.

International trade should also be done differently. For one, it should depend on the diplomatic status more and should only go along roads, rivers or the sea. I agree with you that having to protect trade would also be very interesting for a high-risk/high-reward situation. I'd also add some kind of distance tax that makes very distant trade routes less efficient.