Captain’s diary #19: New recycling and farming mechanics

Ahoy sailors, Captain Filip reporting, this time I have an update on some bigger changes we made into the game: recycling, farms changes, and new products!


COI has limited and finite resources, although the way we designed the game is that it is really really hard to run out. But that did not prevent an interesting psychological aspect where players were careful with scaling to save some of the limited resources because they might be useful later. The game also puts importance on scaling. However, scaling requires raw resources, and scaling of logistics to supply these was becoming demanding, and in later phases of the game, it might lead to bottlenecks. This all leads us to a great feature: recycling!

The new waste sorting plant!

I would like to introduce you to our sorting facility. This facility accepts a loose product called recyclables. Recyclables can be sorted into scrap iron, scrap copper, scrap gold, broken glass (scrap aluminum later on). These will all go to appropriate furnaces for recycling. So scrap iron gives you molten iron and potentially steel, copper scrap gives you molten copper, etc. Currently, the sorting facility building is one unit, but we would love to make it modular in the future.

The waste sorting plant in action

You might be wondering where you get the recyclables from and how they are implemented. The early game has no recycling to keep things simple. But once you research recycling, the maintenance depot will start giving you recyclables in exchange for all the supplied parts. The settlement will enable you to build a module for recyclables collection; these are created from all the products that you supply into your settlement. In fact, settlement recycling goes a bit deeper, but I will cover it in the future once we have more things to show. The other place providing recyclables is a research lab. Because after recent changes, advanced research labs will require research lab equipment to do their job. The used equipment gets turned into recyclables.

Some labsa now require equipment and return recyclables.

To make this all work together, we had to introduce a system in which we track how products are made so we can flip them into recyclables that also contain information of products they contain. The sorting plant then works with these data to transfer your recyclables back to raw materials. This was a fairly complex change to make, but it makes recycling possible.

Nothing in real life is 100% perfect. This means our recycling is also not 100% efficient :) You start with a humble 50% recycling efficiency. This means that half of the source materials get lost. However, the research tree provides passive unlocks to improve the efficiency, and together with edicts (that cost you unity) you can reach 90% efficiency. So recycling can heavily reduce your raw material usage.

We are also working with couple more ideas. For instance, you could enable a free edict so when you destroy a structure you get back the raw materials - scrap iron, copper, etc instead of construction parts. However, you would receive 100% of raw materials back instead of 70% of construction parts. But I’m still not clear on concrete, if it should be returned back as concrete or crushed rock.

New recipes

There are some production chain redesigns that we have made. The majority of these changes have been done for better immersion. These are still not entirely set in stone as we will play COI with new changes to get some opinion on it.

Mechanical parts & electronics

Mechanical parts are a new product that is used in maintenance and vehicles production, and we think it will bring better immersion. It has a steel alt. recipe for better efficiency. Another product is electronics. It comes very early and fixes another immersion issue where electronics came after 40 hours of gameplay. It has also a nice side-effect as it requires rubber and is used in Construction Parts II instead of just copper, and this means rubber will be used continuously. Also, the previous Electronics is now Electronics II and obviously requires Electronics I for its production.

New mechanical parts and electronics recipes.

Vehicle parts

Another immersion fix comes with vehicle parts. Instead of producing vehicles from raw resources like iron and copper (one had to admire the workers' skill in your vehicle depot), you now produce vehicle parts that are then used in your vehicle depot to assemble vehicles.

New vehicle parts recipes

Lab equipment

As mentioned in the previous chapter, some labs now require lab equipment, and the equipment has to be produced as well. You can see the new recipe in the image below.

New lab equipment recipes

New farming mechanics

Farming mechanics in the beta were quite simplistic. Every crop either used or provided a constant amount of fertility. Players had to make sure that net fertility is not negative by rotating different crops. For example, a rotating potato with green manure was net 0 for fertility, and it also was the only viable option for early game.

Flaws with farming in beta

First, crop rotation was required from the very beginning. When no crop rotation was set up (for example, due to lack of experience with farm mechanics), the farm was quickly drained of its fertility and stopped growing crops. Fertility never recovered by itself. This could result in a lost game early on. We do not want to introduce so much complexity early on so the new farm mechanics do not require crop rotation in order to have a functional farm.

Second, crop rotation was not that deep. Before the player unlocked fertilizer, it was a simple zero-sum game. There were a small number of possible rotation schedules that resulted in non-negative net fertility. And once you figured it out, it was always the same. The new fertility mechanics improve this, and many different schedules are now viable, some offer trade-offs compared to others. There is no one best rotation schedule.

New farm mechanics

Now, how did we manage to make farming more interesting? The concept revolves around better farm simulation, especially regarding fertility. In the new system, crop growth is simulated daily. Each day, growing crops consume a certain amount of fertility and water (fixed amount per crop) and accumulate yield based on the current farm fertility level. Additionally, the farm recovers 1% of missing fertility (missing from 100%). We call this natural replenishment of fertility. Think of it as soil recovering over time.

New farm UI

This simulation has many interesting properties. For example, assuming that a crop never takes more than 1% of fertility per day, no crop will be able to drain a farm off fertility fully. Another interesting property is that fertility will stabilize on some value and stay there. For example, say that potatoes require 0.4% fertility per day. When farm fertility is at 60%, missing fertility is 40%, and natural replenishment is 1% of 40%, which is 0.4% – the same as what potatoes require to grow! So regardless of initial fertility value, farm fertility will always converge to 40% when growing potatoes. This value is significant and we call it fertility equilibrium (it is shown in UI).

Crop rotation makes this even more interesting. Since natural fertility replenishment is happening even if the farm is not growing anything, it now makes some sense to not grow any crops on the farm to replenish some fertility before growing another round of crops. If we compare potato-only and potato-nothing rotation, the potato-only schedule produces more food per year but costs more water per food on average. This is because in the potato-nothing schedule, potatoes are growing in a higher fertility environment so yielding more per harvest, but growing less often. So the potato-nothing makes sense when you want to conserve water at all costs.

When the same crop is planted twice in a row, it will consume extra 50% fertility (as before). This means that planting different crops is very desirable. Now consider that there will be 10+ crops available and based on crop parameters, different rotation schedules will have different characteristics. Some will yield more but consume more water. Some will conserve water but will yield less often causing longer delays between harvests. I hope you can see how this makes setting up farms more interesting by giving you many more viable options with trade-offs! But don’t worry, all the important information will be nicely presented to you, including values of fertility equilibrium, natural replenishment, avg yields, etc.

One last thing I’d like to mention is the premature harvest mechanic. It is now possible to harvest a crop prematurely if it is at least 50% grown up. This could be handy if you are in desperate need of food or other products, but there is a penalty equal to the missing growth percentage. So if a crop that is 80% grown is prematurely harvested, it will yield 20% less. Premature harvest rules also apply when crops dry out due to lack of water.


Fertilizers are used to boost farm fertility above its equilibrium. Newly, farms can also be over-fertilized. This is a way to further increase yields but it will cost you extra fertilizer. This gets closer to reality where fertilizers can really boost production.

We are planning to introduce 3 tiers of fertilizer, each with different fertilization parameters such as strength and max fertilization. You can even mix them to have hybrid ones. For example, organic fertilizer is relatively cheap to manufacture but cannot raise fertility over 100%. You could mix more expensive synthetic fertilizer that has max fertilization of 140% with an organic fertilizer in 1:1 ratio and get 120% of max fertilization for cheaper! Worth noting that the Fertilizer II will most likely contain limestone and sulfur. This is going to address feedback from beta that sulfur was in great excess.

Example of fertilizers overview, icons are still work in progress.

Water schedule

Related to farms we are also making changes in weather and water management. The weather used to be scheduled on a monthly basis. Meaning you would get 1 month of just rain or sun. We are changing this to 14 days period. This will make the weather more dynamic and also reduce some of the extremes it was causing (overflowing storages collecting water or the opposite - prolonged periods of dry weather).

Our weather in the Alpha, Beta was generated with the following rule: the longer you play, the drier it gets until you end up with one rainy month per year. It was helping to “force” players to appreciate the value of water, but it felt artificial. We are changing this as well by reducing those extreme conditions and making sure that water scaling is more progressive on how big you build instead of on a fixed scenario.

That’s it from me for today. Thanks for reading and see you in our next update!