The role of Trade Routes in Rising Tide

Balance_of_Trade_splashI’ve just released the Balance of Trade mod to the Workshop (CivFanatics thread here).  It implements radical changes to how trade routes work.  The mod is an example of the kind of changes I plan to include in the Rising Tide version of New Horizons.  By releasing it separately folks will have a chance to try it out and – if it is a successful experiment – it will be incorporated into New Horizons.  Rather than repeat the workshop page here I instead want to do a deep dive into the problems with Trade Routes in Rising Tide and how Balance of Trade seeks to solve them.

Problem 1: Scaling yield

Internal Trade Routes provide a scaling amount of food and production that is calculated on the difference in non-Trade Route yield between the two cities.  The less developed city gains more out of the Trade Route.  With boosts from Diplomatic Traits, the Development Virtue and the Artifact Reward it is easy for a single Trade Route to provide 10-20 yield summed between the two cities each turn.

Problem 2: No reason to build anything else

Building a Depot costs 60 Production and the Convoy costs 70.  Together that is 130 Production.  This is comparable in cost to building two of the cheap early game buildings like a Laboratory and Recycler.  The 6 yield per turn provided by those two buildings together is only half of what the scaling yield from an Internal Trade Route would provide.  This means the first thing every new city should build is its trade routes because they will provide much more yield than any buildings.

How Balance of Trade solves these problems

It replaces the scaling yield with yield provided exclusively from buildings.  Each building provides food or production in increments of 2 (2, 4, 6…).  This makes it possible to control how much yield a single trade route can provide.  By limiting the number of buildings that boost internal trade routes it is possible to set an upper bound that can ensure trade routes never dwarf other sources of yields.

The second problem is solved by having newly built cities get yield from Internal Trade Routes that the city loses when it builds a Depot.  This gives newly planted cities a way to develop faster than older cities, allowing the new city a way to catch up and not be behind the whole game.

It also makes it reasonable to build something other than a Depot as the first building in every city.  Even if a extra Trade Route would provide more yield than a Recycler the fact that the city would lose the production bonus from any income trade routes tips the favor toward the Recycler.

Implications for International Trade Routes

Just like Internal Trade Routes International Trade Routes are completely determined by buildings.  Each building provides energy or science in increments of 2 but the bonus changes to increments of 3 if cooperating or allied with the trade partner.

In order to keep International Trade Routes from eclipsing Internal Trade Routes they need to be determined by buildings rather than scaling.  They have to provide more yield per building (3 instead of 2) because they do not provide yield for you on “both ends”.

Tying International Trade Routes to buildings means the other player benefits as much from the route for no work if they have built all the International trade buildings.  The impact of this can be minimized by making the buildings that boost International Trade Routes not useful for other purposes.

Implications for Station Trade Routes

Station Trade Routes are extremely strong in Balance of Trade.  Any building that boosts an internal or external Trade Route will also boost a Station Trade Route.  The boost will only be in increments of 1 but stations start at 4 yield and eventually scale up to 10.  This means that Station Trade Routes will provide more yield than other trade routes until there are 12 buildings that boost trade routes.  At which point (assuming every building can be built in every city) internal trade routes provide 20 yield across both cities (5 buildings), international provide 21 yield (7 buildings) and stations provide 22 yield.

Stations get even farther ahead when the Station Sentinel gets counted.  This is why in Balance of Trade the Station Sentinel provides a much smaller bonus and can’t be built in the early game due to it requiring Float Stone.

The dominance of Stations can be minimized by the fact that they plateau quickly.  Players can only have one trade route per station and stations cap out at two per player (barring some quests).  But that does mean this design is extremely sensitive to change in Station spawning mechanics.  Double the number of Stations and things could go to hell fast.

Keeping Stations under control can be encouraged through other indirect mechanics.  For example, players could be given a quest to kill a rival station that provides them a free Affinity level upon completion.  This reward could be so tempting that players are willing to lose a potential Station Trade Route to get it.

Other ways to indirectly weaken Trade Routes

20 or more yield from a single trade route is likely too much.  Currently there are only two internal boosting buildings and 3 international, which means Stations still have a big lead.  This buildings can also be built in every city which makes trade routes homogeneous.

One weakness of Trade Route yield is that it is not subject to yield multipliers (such as +10% Energy from a building).  In Rising Tide yield multipliers are relatively small compared to what they were in Civilization 5.  If yield multipliers were greatly increased it will make the yield from trade routes less valuable than normal yield that did benefit from multipliers.

What this means for New Horizons

Changing Trade Routes this radically has many second order effects that can be hard to foresee.  How much is a building that boosts trade routes in this regime worth?  How many buildings should boost trade routes?  Should they be buildable in every city?  This are non-trivial questions to answer.  Balance of Trade will provide some perspective on these questions that will be useful when seeing if this regime is worth building into New Horizons.


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