Reproduction and the Gameplay Loop

Let me make a summary of your post one block at a time.

Update: I’m mainly doing this as a mental exercise. Please don’t judge me.

Introduction: Why not change the process of reproduction from finding ammonia & phosphate clouds for mitosis to survive until you can reproduce?

Argument 1: The current system is unpredictable, for you can spawn with a lot of ammonia & phosphate already (decreasing game length) or have to swim indefinitely to find those (increasing game length).

Counter-Argument 1: Fortunately, current development works on rebalancing the spawn and the patch systems, which should iron out these issues.

Argument 2: Higher concentrations of phosphate & ammonia may help for reproduction, yet cells don’t go looking for those specific compounds IRL; they produce enough of those from environmental compounds.

Counter-Argument 2: Too much realism can be detrimental to game development and the phosphate/ammonia reproduction mechanic can be a good balance between realism and fun.

Argument 3: More complex organisms don’t look for phosphates & ammonia; they consume them from food. Therefore, at some point in the Multicellular Stage, the reproduction requirements will have to change. This could be a problem, so why not introduce a better reproduction mechanic in the Microbe Stage?

Argument 4: Thrive’s current gameplay focuses more on finding phosphates & ammonia to reproduce when it should revolve around producing enough energy to survive and reproduce.

Solution: Similar to Survival mode from games such as Left 4 Dead, the player should survive for a specific amount of time until they can reproduce. This time may depend on the player’s adaptations as well as environmental factors.

Example: You spawn as a simple hex of cytoplasm. It should take 60 seconds to reproduce, but you gather enough phosphates and ammonia to reduce that time to 40-50 seconds. You evolve a part, which unfortunately adds 5 seconds to that time. So if you don’t gather much phosphates & ammonia, it would take you 65 seconds. This would make those two compounds much more precious, albeit not necessary.

Solution (next): Environmental factors may affect this delay as if there are more phosphates, it should reduce that time for everyone the same way that if there is a surge in volcanic activity, this delay may increase as well.

Counter-Argument A1: The player’s lifespan shouldn’t be too long.

Argument A1: It gives more control to the player and is much more simple.

Counter-Argument A2: If the time is too short, there isn’t enough of a challenge for the player.

Conclusion: Changing the reproduction system would be good for Thrive as it would fix a lot of minor issues and would bring balance to the game.

@Deus, is there anything I have misunderstood?

Also, may I show a phrase universal to every issue within Thrive.

I believe in implicit programming. Try to remember version 0.3.3 of Thrive. Your cell could produce so much glucose as a photosynthetic species that other cells would stick to yours. While symbiosis wasn’t explicitly programmed, it was implicitly programmed because of this reasoning:

  1. Cells look for glucose.
  2. Your cell outputs a surplus of glucose.

Therefore, other cells stick to you.

I think that implicit programming is the most realistic option for simulation. Animals in nature don’t interact with each other because they were programmed to, but rather because they have to. Competition doesn’t happen by itself. It happens either because of a lack of resources or simply because the local population is seemingly aggressive. I think that being too explicit about the reproduction system may be detrimental to realism.

Sorry if I can’t finish my point, I’m busy with something.


Aren’t you suggesting though the opposite, as in reducing the amount the player has impact on reproduction?

In general this suggestion to me seems to make larger cell builds completely unviable. I’ve seen pretty large successful predator builds that work. Those predator builds also already combine the energy and reproduction resource gathering as you get both from cells you eat.


You had me here, jokes aside if you look at the speedrunning scene many just stay as their blob of cytoplasm and swim in a big cloud or 2 of the “vital” compounds needed to reproduce and stay alive.

However at a certain point, very large cells fail to reproduce unless they’re lucky or the player has the patience to find a large cloud. As Hhyyryl said, this would make large cells be less viable compared to the speedrunners blob which can’t get multicellular.

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But doesn’t having phosphate and ammonia as necessary compounds for reproduction also validate such a speed running strategy? With how small of a reproductive demand the blob of cytoplasm has, it’s basically the first ounce of phosphate that gives the cell enough resources to reproduce, meaning a player can theoretically zip around their environment around other cellular threats and reproduce quickly by sticking to a phosphate cloud. The idea is that by having a certain time allotted in which you basically have to prove your cell can last/perform long enough to reproduce, the player strategy is less dependent on just swimming to a cloud of phosphate/ammonia and more dependent on making a cell that can survive long enough to reproduce - meaning they focus more on being adapted to be the most efficient in their environment rather than lucking out with clouds.

For example, right now, you can afford to move across a variety of patches as a very simple organism without adapting to said patches because you know that you don’t need to actually be metabolically viable to the environment; you can just swim around as your fast and efficient single cytoplasm until you find a phosphate/ammonia cloud and cash out of the environment.

I also think such a system - where phosphate and ammonia speeds up the rate of growth - further incentivises predatory builds as opposed to being an autotroph. Sessile autotrophs tend to grow at a slower pace than motile heterotrophs because motile animals are more readily able to look for a dense source of nutrients, while autotrophs have to rely on a much more steady but less dense metabolic system. The same incentive appears already in current Thrive, but the amount of phosphate/ammonia from cells oftentimes means that it doesn’t take long for predators to get whatever resources they need.

It is a fair point that such a time-based system would work against more complex life. I envision that it could take quite a while for more complex unicellular and multicellular life to reproduce. While the current system also has the same detriment where more complex parts means a higher reproductive demand, atleast the more active role a player has in reproduction means they can do something about it. As said, this is a pretty progressive and gigantic alteration to the existing mechanics in Thrive, so it should be taken as an extreme example representing another potential way the game should be oriented.

I think ultimately, the whole 1-cytoplasm-master race issue will be solved by introducing environmental toxicity so that cells will have to adapt in order to exist across several patches.

I also think there are many much smaller and more readily implementable steps that can be taken to mitigate how unpredictable reproduction can be. Better spawning, better compound clouds, better auto-evo so predation isn’t as easy, restrictions on movement, and other fixes can be applied to help remedy the issue. If those don’t suffice, then this concept could perhaps be viable.

But I still also think that the player is currently way too focused on finding phosphate/ammonia instead of making sure their species can produce enough glucose to eat. Why should I make something that actually works for longer than a minute if I can find phosphate/ammonia in half a minute? I think having free-floating phosphate/ammonia levels in the environment gradually reduce to a lowered presence over time could be a good idea; not like glucose where it completely disappears off the planet, but just so that it settles at a less abundant presence so that players and cells are encouraged to become efficient predators/producers that don’t depend on free-floating clouds. Then fluctuations in this phosphate/ammonia level could usher in periods of hardship or evolutionary surges in diversity with more accessible resources, such as was seen in the Cambrian Explosion. Also, perhaps the player should require a certain amount of glucose along with fill phosphate-ammonia bars to reproduce.


Survival still depends on the clouds, though. Cutting down from requiring 3 different clouds to just 1 does make it easier to find just that one thing to survive. But the player will encounter a lot more “useless” clouds with that change.

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Perhaps each cloud could have a function for example, Ammonia could temporarily lower the time needed to reproduce in the next cycle

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Yeah my bad, I should have been more specific. I meant less focused on lucking out with phosphate/ammonia clouds and more focused on proving they can get glucose/food. I don’t think the microbe stage could ever move on from clouds.

And yeah that’s the point behind the more progressive idea. Phosphate/ammonia aren’t the end-all be-all compounds that trump the need for food, but sources of each are incredibly lucrative so that your cell has sufficient nutrients to get ready for reproduction at a quick pace. So while phosphate and ammonia aren’t the cream of the cop anymore, they still have the desirable effect of rapidly quickening the rate at which your cell gets ready to enter the editor. Each can also have other benefits as well. I know ammonia is essential for producing a compound that helps a cell grow and phosphate is important for supporting a cell’s structures, so perhaps this can be more explicitly outlined.

Perhaps you need a reservoir of phosphate to heal at an optimal rate, produce oxy-toxy quickly, and etc. Meanwhile, ammonia serves as the more explicit reproduction compound. Once you reach a certain amount of ammonia, you can begin the process of duplicating organelles by pressing the reproduction button, which will take a small amount of time - perhaps a range anywhere from 10 seconds to a minute, minute and thirty or so? So that larger cells obviously take longer to reproduce but aren’t penalised excessively.

Phosphate can be important by requiring a minimum amount of health to reproduce. Perhaps 50%-75% full health at minimum to reproduce? It shouldn’t be 100% health because there’s a lot that can injure you in a busy environment, so it would be pretty annoying to have to be in perfect condition.

This is something I thought of in not much time so I’m not sure how viable it would be, but it shows that phosphate and ammonia definitely have a diversity of options and functions they can be given. I also realize it still makes ammonia the end-all be-all compound it is today in Thrive, but it atleast introduces some level of complexity which means that making sure your cell is actually viable in your environment is the main focus.

I think the main issue I feel could potentially be holding back Thrive is how the player can avoid a large part of the challenge of evolution by depending on something other than proving their evolutionary fitness, and I feel this is done by making reproducing too easy. So that players don’t really have to prove they can sustain themselves and can just go straight to the editor. I think the role glucose/energy gathering has should be the main obstacle, and as such, I think that part of the game should be emphasized. There doesn’t have to be an explicit system based on a “timer” of sort, but I think the reproduction gameplay loop could serve a reevaluation.


That would certainly be a fundamental change. The game design philosophy (as far as I’ve been involved / read discussions) has been that the core gameplay loop is about managing to reproduce. So redesigning that to be basically a waiting game (after you luck out and find at least one glucose cloud so that you can just wait around) to complete the lifecycle, is a major design change.

If this is your main reasoning behind this whole idea. A simpler redesign (that has been suggested in the past but I’ve rejected due to less continuity) would be to clear the game world each time the player exits the editor. That way the player can’t just find some really good clouds and quickly get a lot of evolutions done.

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Continuing my point. I think that Deus’ idea of a time delay before reproduction is a good way of implicitly implementing cell cycles.

The cell cycle begins at the end of the M phase, supposedly when the cell is born with all the genetic material ready. However, the cell needs to accumulate enough material and power to grow all the proteins and gain mass. That is the purpose of the G1 phase (‘G’ meaning “gap”). This is where the player starts playing as their cell. According to Deus, there are factors that can increase or decrease the G1 phase time. If the conditions are harsh, G1 will take a long time. After the G1 phase stands the S phase (‘S’ for “synthesis”), which is responsible for replicating the DNA. At the end of this phase is where the player has reached the time limit. Afterwards stands the G2 phase, which is optional, yet essential for the player before entering the M phase (editor session). The player would need to accumulate enough resources to survive after the division. Sure, you can skip this phase, but the chances are you’re probably going to die.

In brief:

  1. G1 Phase - Player accumulates resources to survive long enough.
  2. S phase - Enough resources have been accumulated. Now, the DNA replication is in process.
  3. G2 Phase - The time limit has been reached. The player should gather enough resources to survive the division.
  4. M phase - Editor Session.

The only problem is that I don’t know if this is valid for prokaryotes.


Yes it definitely is a complete shift in the design of Thrive, so I would think it would only be considered if the problem remains despite other features being implemented. I still wonder about the transition from having a focus on just getting enough phosphate/ammonia as an abstract representation of cellular reproduction to having reproduction be based on a less abstract representation based on more multicellular methods we are more familiar with and can easily envision. Then again, that ties into a discussion of how sexual reproduction will be introduced and incentivized which is way ahead of us.

Would clearing the game world only effect compound clouds or other important aspects? If the former, I definitely think it’s conceptually good thing for the sake of Thrive, as it makes sure you aren’t spawning in the same cloud that got you to your current editor trip. Also, because the presence of various compounds such as glucose will shift throughout time, it wouldn’t make sense for the compound clouds of a more abundant/barren world to be present in a new situation. Each editor trip represents a significant jump in time anyways, so continuity isn’t a huge concern as long you don’t spawn in a completely different environment.

To remedy the whole undeservedly-rapid-evolution, I think a few ideas have been introduced in this conversation that can be realistically discussed right now. I’ve listed them from what I feel is least progressive to most progressive of a change (progressive in terms as completely shifting the system); in other words, items closer to the top are less fundamental shifts to the gameplay of Thrive than items on the bottom.

Purpose: We want to make the length between each trip to the editor is long enough to prove that their cell is evolutionary viable, but not long enough for Thrive to unnecessarily extend the gaming loop so that Thrive becomes a waiting game.

Direct Factors Contributing to This:

  • You spawn back where you reproduced from, so if there was a phosphate/ammonia cloud there already, you can just go right back to the editor.
  • You can spawn with whatever surplus phosphate/ammonia you entered the editor with.

Indirect Factors Contributing to This:

  • Same AI cells remain around you when you exit the editor, so if they are easy prey, you can consume them again.
  • Cell AI isn’t optimized yet, so certain species aren’t as challenging to attack as they should be, meaning free meals.
  • Current reproduction mechanism is a rather simplistic representation of asexual reproduction. Not necessarily a bad thing.

Potential Solutions

A.) Spawn with 0 ammonia and phosphate instead of whatever surplus you’ve gotten in a previous life

  • I don’t think this really presents any negatives and I assume it will eventually be implemented regardless. One thing to consider is how much glucose will be given to a fresh spawn cell (50% of full capacity?)

B.) Clear the game world with every reproduction

  • Essentially a new plate, with new compound cloud locations. Issues with continuity of world brought up, but at the same time, each editor represents a significant jump in time.

C.) Have the amount of freely accessible phosphate/ammonia reduce to lower levels as time goes on similar to glucose.

  • Similar to glucose where cells are forced to eventually be able to produce their own energy, reduce the amount of free-floating phosphate and ammonia so that cells are made to become more effective heterotrophs. Unlike glucose however, instead of almost completely disappearing, ammonia and phosphate reduce to a relatively low presence that fluctuates, simulating things like land runoffs bringing in nutrients, plate tectonics, erosion, marine snow, etc.
  • Makes player builds that are more sessile to be less effective, as there will be less freely-available resources. Can be a good thing which serves as a counter balance to heavier and slower autotrophs and incentivizes more motile heterotrophs.
  • Requires the implementation of a more dynamic compound fluctuation system.

D.) Require a minimum amount of health to reproduce

  • Require a certain amount of health (50%? 75%?) to reproduce so that players are further incentivised to create a robust cell build. Could lead to very annoying situations where a player constantly bumps into a predator/environmental threat and is prevented from reproducing despite meeting most requirements. Can be offset by a lower health requirement.

E.) Clicking the reproduction button starts the process of organelle replication instead of directly heading to the editor. After a small amount of time (10 seconds to 60 seconds or so) as your organelles reproduce, a second click on the reproduction button means a split and a trip to the editor.

  • I think this would be a pretty cool thing to see implemented. Phosphate/ammonia maintain the same role they have in the current game, but heading to the editor isn’t as much as a potential copout from a dangerous situation as you’d still have to survive for a little bit after you reach sufficient phosphate/ammonia levels.
  • Some players complain that organelle duplication as currently implemented oftentimes changes the nature of your cell, so this solution can both give the player the choice of when to start splitting and do it in a controlled manner.
  • As @blackjacksike outlines above, is rather realistic and can be further tweaked to more explicitly highlight the different challenges cells at different phases of life face if seen fit.
  • This can also easily transition into a decoupling of reproduction from a trip to the editor incase the player wants to play another life cycle in the same generation or wants to reproduce just to boost numbers.
  • Would require a decent player cell-split animation. Also, although capping the amount of time required helps, it still punishes larger builds as they would require more time to split everything. Larger builds already require larger amounts of phosphate ammonia.

These sound familiar. I think our reproduction progress code actually used to use these in the past. This was very confusing to the players (probably as there was really no progress indicator or anything). I think maybe 3 or even 4 years ago we moved from the model of organelles and the nucleus (it had those G1 and G2 phases, if I recall right, or something) taking time and using up resources over that time to split.

I mean everything except the player and their sister cell. Similarly to how patch moving works. It would make even less sense if somehow the compounds would disappear but cells and chunks somehow stayed.


I actually kind of like this idea, and would be willing to give it a try if it made the game easier to pick up for new players, and enjoyable for the old.

As deus stated, a big issue with the current game is there’s too much reliance on two separate resources that might not even be available to the player for a long time just because they are unlucky.

By introducing a passive rate of growth, we could overcome this issue, and allow players to progress as long as they find food to survive.

The current ammonia and phosphate clouds could of course remain, but as Deus mentioned; it could instead serve as a desirable bonus to growth rate instead of a mandatory resource.


I like this idea, but im just wondering how the passiv ammonia production we already have will fit into this

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A bonus to reproduction rate of course, but you would still need to find phosphate for it to make a difference

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I also do think a passive growth rate would help make progression a lot more steady and predictable. Depending on how it is set up and balanced, it can really help eliminate a lifespan that is excessively short or excessively long. Progression in Thrive right now is really dependent on the placement and frequency of both ammonia and phosphate clouds in a patch, so too little and you’re drifting through a barren wasteland for 20 minutes, too much and you’re witnessing 4 trips to the editor in 2 minutes. So having a set amount of time that a player needs to survive for and focusing the player’s gameplay on ensuring that they have enough food for that amount of time to survive makes things a lot more clear and I think presents a more accurate representation of evolution.

As hh mentions however, Thrive becomes a lot more dependent on waiting in this new design philosophy. One thing about the current system that works is that because the player is actively pursuing their means to reproduction, it is entirely in the player’s hands as to how fast they enter the editor. This avoids the pitfalls of games that simulate progression through growth like The Isle, which in extreme cases can basically turn into an idle simulator after obtaining one meal. The Isle tries to combat this by involving other things to worry about in the meantime, but the length of time needed to fully grow is a turnoff for certain people who aren’t seeking the type of simulation The Isle provides. And Thrive is definitely not that type of simulator – it doesn’t focus on the lifespan of an individual animal, it focuses on evolution.

So in one extreme, having the player be entirely responsible for their progression by having phosphate and ammonia determine it prevents the lows of an idle simulator but can create very unpredictable lifespans and can extend/shorten the gameplay loop excessively if factors aren’t well controlled. In the other extreme, having growth be dependent on some sort of time-based mechanism introduces a more steady, predictable, and ensured way for progression to occur but if improperly scaled can lead to idleness. I think the latter is more easily balanced and controlled, but I am no seasoned game developer so who knows. But obviously, some sort of mix between the two can be designed, where ammonia and/or phosphate are necessary for reproduction but don’t represent trips straight to the editor.

One idea is similar to one I previously mentioned and blackjack detailed. Instead of instantly being sent to the editor, clicking the reproduction button starts the process of DNA/organelle replication. After replication is completed, another click officially counts as reproduction and sends you to the editor (perhaps in the future when you don’t have to enter the editor everytime you reproduce, left click is a trip to the editor and right click is just reproduction).

The player can click this button anytime they want, even briefly after they freshly spawn (or after a short period of time, or whatever is seen fit). However, ammonia and/or phosphate incentivizes them to collect the two compounds. This incentive can be anything seen fit, and ammonia and phosphate could provide the same or separate benefits to the process.

I can see various possible incentives:

  • Both ammonia and phosphate do the same job and simply speed up the rate of replication.
  • Ammonia speeds up the rate of replication while phosphate minimizes negative effects a cell phases during replication (slower speed, less health, inhibited metabolism, etc.)
  • Ammonia speeds up the rate of replication. Your cell replicates faster at full health, and phosphate significantly speeds up the rate at which your cell heals from damage, so phosphate remains important for make sure your cell is at optimal functioning.
  • Phosphate and ammonia can add bonus MP points.

This is a bit more complex than just having a passive growth rate that can be increased depending on how much phosphate/ammonia you have, but it could represent a blend between the two extremes mentioned and can help fix the problem some people have with replication as is implemented being unpredictable and uncontrolled. It can also provide a chance for an emergency editor trip if you tweak your organism incorrectly so that your species becomes extremely unfit for survival; just reproduce as soon as possible and to hell with all the incentives, you need to reproduce now.

One thing that needs to be held in mind is how long the microbe and early multicellular stage should take. Replication should take long enough so that the incentives actually mean something. If it takes a minute for a complex organism to reproduce without phosphate/ammonia, a 20% reduction won’t mean much and the player might just ignore phosphate/ammonia. Note: this factor isn’t as important for the beginning of the microbe stage, as it is meant to be a simple and easy introduction to the world so lifespans can and should be short regardless and incentives shouldn’t mean too much yet.

At the same time, replication should only be as long as necessary, and not a single second longer. A player cell that is just one cytoplasm and a metabolosome in the beginning of the game isn’t going to have a lot of functions and isn’t going to face a variety of threats. If that cell’s lifespan is 5 minutes, it’ll basically be 1 minute of gameplay where the player is focused on doing something and 4 minutes of screwing around (no complex threats you need react to, low metabolic cost, etc.). This doesn’t even mention the lifespan of an even more complex organism.

As such, expected time to be spent by an average player who doesn’t want to stay at a certain stage and wants to progress to the next stage should be ironed out. For a player who doesn’t want to linger around too long and wants to get straight to the point, how long should it take to get the nucleus? How long should it take to get binding agents? How long should it take to become meaningfully multicellular? How long should it take to get 10 cells together? Underwater civs when? Growth will have to be calibrated around that.


One more thing I just realized: how are we going to explain this to the player? How are we going to tutorialize this feature?


Good question.

In the first life a player has on the planet and after the player finds glucose, goes through movement, and etc., there can be a pop-up saying “In order to reproduce, your cell first has to replicate genetic material. When ready, click on the Reproduction Button to begin this process”. Your cell then begins replicating. In the first life, your cell will spawn with adequate amounts of phosphate and ammonia to speed up replication. After the process is done, which should take barely any time at all with the added phosphate/ammonia, a pop-up says “Click again to enter the editor”.

The next time you spawn in, the extra phosphate/ammonia isn’t there anymore. A pop-up says “You can begin replication (synthesis a better word?) at any moment. However, replication is costly and can leave you in a vulnerable state. Obtaining phosphate and ammonia lessens the amount of time it takes to completely duplicate your genetic material.” Then similar to the previous life, a line appears between your cell and the closest phosphate/ammonia cloud. Once you reach an optimal level of phosphate/ammonia, a pop-up says “You have obtained adequate amounts of phosphate/ammonia. Click the Reproduction button to begin replication”.

Of course, if some sort of growth mechanic is adopted, the tutorial should change. But I think spawning in a new player with adequate phosphate/ammonia in their first generation on a planet should help them not be overwhelmed in their first life, and taking that bonus phosphate/ammonia away in their second life can introduce the reason why a player wants to find phosphate/ammonia.


I thought about this concept more and felt like it had no glaring fundamental issues in itself, it’s just a matter of balancing things to be optimal and figuring out the role of ammonia and phosphate. It’s also deciding how to deal with reproduction in the first place. Once again, this represents a dramatic shift in the gameplay design of Thrive, but, once again, I think it would benefit Thrive. I think it’s a worthy concept to have on standby for future consideration, so I wanted to fully flesh it out.

I think reproducing should be handled as previously described in this post, where clicking the reproduce button initiates the process of synthesis. This synthesis takes a specific amount of time and can be increased or decreased depending on certain performance factors, so players are rewarded for having a well-functioning build. You can click the reproduction button very soon after you first spawn in (maybe something like 10 or 20 seconds after?), allowing the player to decide when to undergo the process of synthesis.

This concept serves to take emphasis away from a cell’s evolutionary fitness being decided based on how well it gathers phosphate and ammonia to how well it stays alive long enough to reproduce, empowering energy and nerfing phosphate/ammonia.

As previously detailed, I feel this benefits the gameplay in two ways. First, it standardizes the length of each lifespan. Right now, because ammonia and phosphate are so imperative to succeeding in this game, the absence or surplus of either compounds can unnaturally lengthen or shorten the game experience. By having some rudimentary “growth” mechanic, the gameplay loop is much more controlled and can be more easily balanced by the developers towards what they deem is the best Thrive experience.

Second, I think this reproduction mechanic does better in making the player and other organisms behave “more realistically”. In nature, organisms don’t really seek things like “phosphate” and “ammonia”; they seek food, so that they may live long enough to reach the age of sexual fertility. Of course, nutrients are an essential component of this healthy maturation, but nutrients generally come with whatever food or resource is being consumed, and as a whole, are not the end-all-be-all they are in Thrive. Therefore, I think reflecting this in Thrive would benefit the simulation aspect of gameplay. And who knows, perhaps it might help with auto-evo (here’s hoping).

Role of Compounds and the Numbers Behind Growth

Role of Ammonia = Primary resource responsible for growth in that it increases the rate at which cellular replication is done. The more you have, the faster you will grow (up to a certain cap with optimal conditions).

Role of Phosphate = Replenishing feature, needed to replenish health and rapidly increases the rate at which resources for important functions, such as signaling and toxins, are created. Ties to growth because cells replicate material faster at higher health. Spent in healing and for replenishing functions, although at a lest significant rate for the latter.

At optimal conditions – meaning maximum health and maximum ammonia – I’d say something like a 50% reduction in reproductive costs cap would work well. So if your organism takes a minute to reproduce at max health with no ammonia, it would take them 30 seconds to reproduce at max health with maximum ammonia. The effect obviously scales with the amount of ammonia you have, so having 50% max ammonia would mean a 25% reduction in reproductive costs and a 45 second lifespan.

On the other end, I think reduced health should have the similar effect. Health can have up to a inverse 50% addition to reproductive costs, so having 0% health would mean the full 50% addition. Of course, this means health can effectively only increase reproductive costs by something like 49.999%, but you get the general idea. Having 50% of max health means 25% more time for reproduction, having 75% of max health means 12.5% more time for reproduction, having 25% of max health means 37.5% more reproduction time, etc.

Reproductive Costs of Parts

These can be played around with, but I think these serve as a good rough estimate.

Baseline = 10 seconds. So as LUCA, it would take you 10 seconds to reproduce with full health and no ammonia inputs.

Cytoplasm = 2 seconds added

Prokaryotic Parts = 5 seconds added

Nucleus = 20 seconds added

Organelles = 7 seconds added

This makes it so that phosphate and ammonia can reasonably be neglected at the beginning of the game and as a very simple prokaryote, but eventually makes it so that they become more essential as time goes on.

Prokaryote with 2 prokaryotic components = 20 second reproduction cost at spawn, with 10-30 second replication depending on performance. What I assume will be the average cell after a single trip to the editor.

Prokaryote with 10 prokaryotic components = 60 second reproduction cost at spawn, with 30-90 second reproduction cost depending on performance. What I assume will be the average prokaryote a few generations before the addition of the nucleus.

Eukaryote with a nucleus and 15 prokaryotic components = 105 second reproduction cost at spawn, with 52.5-157.5 second lifespan depending on performance. What I assume will be the average newly formed eukaryotic cell.

Eukaryote with 5 organelles and 10 prokaryotic components = 115 second reproduction cost at spawn, with 57.5 – 172.5 second lifespan depending on performance. A eukaryote beginning to take advantage of its evolutionary benefits.

Eukaryote with 10 organelles = 100 second reproduction cost at spawn, with 50-150 second lifespan depending on performance. A eukaryote that has comfortably evolved towards specialization.

What I noticed began to be introduced here was an incentive to reduce cellular bloat. Why have 2 or 3 prokaryotic components for an added penalty of 15 seconds when you can have 1 organelle which pumps out the same or more output for only 7 added seconds? This further provides a benefit for eukaryotes which is actually an incredibly realistic reflection of how evolution worked.

Prokaryotes are incentivized to remain small and rather uncomplex in comparison to eukaryotes because added complexity oftentimes means added reproductive costs. At a certain point for prokaryotes, whatever added benefit to energy acquisition/metabolism is outweighed by excessive reproductive costs – and for simple organisms who depend on reproducing fast rather than dynamic systems to deal with changing environments/competition, reproductive costs are persuasive. As such, complex processes and morphologies, whatever the benefit, are generally selected against. But since eukaryotes are able to host organelles that create an incredible amount of output, they are able to add huge leaps in energy production with minimal additions to reproductive costs through streamlining their genetic material. In Thrive, should such a mechanism be adopted, auto-evo could grow to replicate this same phenomenon.

Of course, the way reproductive costs work currently in Thrive (additional ammonia/phosphate needed for added parts), you can make the argument that this aspect is simulated. However, once again, reproductive costs aren’t adequately represented because of how imperative phosphate/ammonia are in gameplay for reproduction – being an end instead of a means to an end. Prokaryotes will frequently reproduce at the same rate as eukaryotes, as oftentimes, phosphate/ammonia is equally inaccessible to prokaryotes and eukaryotes. Making growth/reproduction a more intrinsic characteristic of each cell would help make this aspect of evolution/biology more accurately reflected within Thrive.

As such, for all the reasons listed above, I think examining the gameplay loop and how reproduction works in the game can be incredibly beneficial for all aspects of what Thrive tries to be.

One thing that needs to be looked at in the future is how multicellularity will be handled. We obviously don’t want two cells to multiply reproductive costs by two, as that can quickly result in bloated gameplay loops (I don’t think a ten-minute plus lifespan should be a mandatory part of Thrive until late in the aware stage). Perhaps we can assume that once multicellularity is achieved, an efficient way of minimizing costs had been evolved, meaning each cell can be considered a part akin to an organelle/microcomponent in terms of reproductive costs. So perhaps reaching multicellularity adds an additional +20 to your baseline reproductive cost and each cell might add something like +2 seconds. Until the point at which editing transitions to sculpting blobs. At that point, a more dynamic system would have to be utilized.

The exact numbers regarding reproduction costs might need to be played with a bit for an optimally engaging experience. But I think the general idea is demonstrated.



I wanted to add some thoughts regarding this concept.

I think the basic idea/pipeline regarding this concept is still very robust and worthwhile to consider - having the gameplay loop be based on surviving a set amount of time determined by the complexity of your organism instead of having it be dependent on finding a set amount of phosphate/ammonia, and having ammonia be capable of reducing reproduction time and phosphate be important for replenishing health and other processes like toxins. But on further thought, one aspect of the concept I think would be worth reconsidering is having the ability to reproduce immediately after spawning into the world. I’m wary of players just clicking the reproduction button as soon as they spawn, allowing them to basically skip through proving that their cell is viable in gameplay if they are simple enough organisms.

Instead, I think the player should be tasked with finding a baseline amount of ammonia before they are able to respawn, and then having the suggested reproduction mechanic, where you must wait a bit before reaching the editor, be applied. For example, you must get, say, 50 ammonia before reproducing, and then the process of cell division begins, which will take however long it takes.

Where it gets interesting is incentivizing the player to gather even more ammonia. The player can immediately begin the process of replication after they get the baseline, but if they get more ammonia, they get two benefits…

  1. As the above concept explains, reduced reproduction time, and
  2. A bonus to their auto-evo numbers.

The above will ensure that players still have to play the game if they want to succeed, but also includes a more controlled way to pace each “life” in the game. Phosphate will retain the same function as it does in the previous concept; assisting with healing your cell and generating important compounds such as toxin. Of course, reproduction times can be recalculated based on how long the added time of searching for ammonia would be with this new concept.

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I’d like to expand this topic to discuss reproduction systems more broadly. (If that’s hijacking your topic, Deus, I’m sorry and this can be moved to a new topic. I chose this topic mostly based on the title)

There’s been a lot of discussion about sessile organisms and reproduction recently, which is good to see in my opinion. I’m going to first describe the current reproduction system with its pros and cons, then talk about what goals a good reproduction system should fulfil in my opinion, and then list and evaluate some potential new reproduction systems. This’ll be focused on the microbe stage but could be useful for future stages too. I’ll use the word “sessile”, but “non-motile” could be more accurate sometimes. “Growth rate” will refer to how fast you grow, and “reproduction time” to how long it takes between birth and reproduction.

So how’s the reproduction system currently? It’s pretty simple: You collect enough ammonia and phosphates to divide your organelles and then click a button to reproduce. You get ammonia and phosphates from compound clouds or other cells. This works great for the average cell that’s of medium size and decent mobility. It usually isn’t too slow or too fast. It’s active, easy to learn, pretty fun and teaches something about real biology. Sometimes however, it’s a different story. You can get lucky with spawns or store nutrients from the previous patch and reproduce so fast that you barely see the patch, effectively skipping it and its challenges. On the other side of the spectrum, you have cells that are slow, big, or unlucky and can take dozens of times longer to reproduce. And then sessile autotrophs can’t reproduce at all. All this even though big, slow and sessile cells all exist on Earth perfectly fine. This feels unnecessarily limiting, punishing and boring. Simply put, reproduction takes too long for some organisms and too little for others.

To better understand the issue, let’s take a step deeper. What is the purpose of reproduction and the time it takes in the game? Personally, I think it’s to both show the full life cycle of the player species (or at least its most important parts) and to give the player an interesting challenge: to prove that their species really is viable. How much should it be like real life? For example, should a whale like creature take dozens of times longer to reproduce than a mouse like creature? Probably not, as that doesn’t sound very fun. Time is very abstract in games and I don’t think that this abstraction really hurts scientific realism. I think that many different kinds of reproduction systems fit under a simplified, abstracted reality, so we can pretty freely focus on what’s best from a gameplay perspective. In real life, growth requires time, energy, and nutrients, but for gameplay reasons we may choose any of them and abstract away the rest, like how the game already does. If we still want bigger organisms to take longer to reproduce for scientific reasons, that’s fine, but only so long as it doesn’t hurt gameplay. So the difference in reproduction time should probably be relatively small. With the purpose in mind, what makes a potential reproduction system good?

Goals for a good reproduction system

  1. All organisms should reproduce in a reasonable amount of time. This means that you can’t reproduce so fast that you skip on the challenge, nor so slow that it gets too boring. Reproduction time should probably be pretty consistent across different kinds of organisms too keep different strategies interesting. So big, sessile and/or autotrophic organisms should take a pretty similar amount of time to reproduce as small, motile and/or heterotrophic ones. Otherwise the game would be punishing those strategies with boredom. I think it’s much more effective and fun to “punish” bad strategies with poorer ability to get enough energy to survive.
  2. The player should have some agency in their reproduction time. Agency feels good and fun, having no control feels bad or boring. Agency lets players play in their own style. New or casual players can take the scenic route where as experienced players and speedrunners can try to go as fast as possible. Without agency the game can easily become a waiting simulator if survival isn’t challenging enough.
  3. It should aim to be scientifically realistic without sacrificing fun, like everything in Thrive. It’s fine to simplify things for the sake of gameplay or ease of learning. Straight up inaccurate things like phosphate generating organelles are a big no-no.
  4. It should be intuitive and easy to learn. New Thrive players are confused enough as is.
  5. It should be feasible to implement. Everyone wants the microbe stage to be “finished” at some point. If a new system is going to require redoing a lot of code, testing and balancing, then it’s going to require good justification as well. We don’t want to burden the developers with unnecessary work.

Concepts for possible reproduction systems (in no particular order):

Wait for currents

Change nothing about the current system and just wait until water currents are implemented. They’d make sessile cells capable of reproduction by making them hit nutrient clouds sooner or (more likely) later. It’d basically be like random, slow movement for them. Currents would also make the world more fun and visually interesting for all cells. However, many cells would still take a very long time to reproduce, especially in patches with slower currents. That’s why I don’t think that this is a sufficient solution.

Passive absorption

Do what Thim did in his fork or what the devs are discussing in Revamping Compound Clouds. Make cells passively absorb ammonia and phosphates. The absorption rate could be affected by membrane type, surface area, patch, etc. This would give all cells a consistent maximum time for reproduction while leaving motile cells the option to pursue nutrients to grow faster. This is a pretty simple change that solves a lot of problems without breaking old stuff too much. It’s also easily modifiable with just a couple of tweakable constants needed. I think that this is a great idea to test first and collect some feedback. Does it affect player behavior or fun for normal cells and if so, in what way? Does it make sessile enthusiasts happy? What kind of absorption rates are good? Is it intuitive or confusing to have both passive absorption and compound clouds? So many questions, I’m curious!

Time-based growth

This is pretty similar to the previous one but more ambitious. Each species would have a specific reproduction time based on its morphology. Ammonia and phosphates would just boost the growth rate or have other uses. You can read more from Deus’s previous posts in this topic. This would put the focus on survival instead of collecting ammonia and phosphates. This is a bigger change and would require a lot of thought and testing. It would make reproduction nicely consistent. On the other hand, it could end up as a waiting simulator if surviving is too easy or growing takes too long, but that could be diminished with balancing. Personally I think that size shouldn’t have much impact on reproduction time because it affects fun a lot.

Time-based growth could make ammonia and phosphates feel a bit useless sometimes. If that’s the case, I’d suggest making both ammonia and phosphates boost growth rate, healing, and toxin production (and maybe even more things). If you had both, the boosts would be added together. Alternatively, you could straight up get rid of ammonia and phosphates and boost growth with energy. If you find a big chunk of food, you should probably be able to reproduce pretty quickly rather than having to wait with a full storage (although defending that food pile from competitors could be interesting). Maybe a button boosts growth at the cost of ATP or excess food goes straight to growth. Overall, I think this could have potential with some tweaking, but it’s hard to tell yet.

Food-based growth

We could abstract away the nutrients and focus on energy from food. Many games make animals grow instantaneously by eating food. It’s active, simple, pretty fun and keeps focus on something that’s necessary for survival. This is more complicated in Thrive however, because not every organism is a normal animal. I guess plants could consider the glucose they make food, making them grow at a consistent rate as they produce more of it. Heterotrophs would grow whenever they eat other cells. But what about a heterotroph that has a single rusticyanin? Should it grow just as well from eating iron? Probably not.

Maybe the instant growth is calculated based on how many metabolizing organelles you have. Maybe growth could happen at the rate you metabolize the food for energy, but that could increase waiting again. Or maybe you need glucose to grow. But that would hinder iron eaters unless you can synthesize glucose with energy from inorganic compounds like CO2, in which case glucose is kind of an unnecessary middleman. I think that this is a harder system to figure out, but if it were to work out, it could make sessile organisms viable without risking a waiting simulator for motile cells.

Static ATP consumption

Constantly consume ATP to grow. You could tweak the rate of growth in the microbe editor, within some reasonable minimum and maximum values. Big cells could grow at a similar rate to small cells since they have more ATP to spend. Autotrophs could sacrifice movement to grow faster. This system is essentially passive growth, so perhaps active cells could have a button that makes them grow faster at the cost of more ATP, that way they could choose their growth rate based on how much food they find and get back some agency. Passive growth makes ammonia and phosphates unnecessary, so they could either boost growth, have some other purpose or be removed.

This system would work pretty similarly to passive absorption and time-based growth, just putting the focus more on energy rather than nutrients. It does give a nice freedom to choose your rate of growth, but it could perhaps be awkward for new players to think about how much ATP they spend on growth. I guess they could just ignore it if the default rate of ATP to growth goes up as you add organelles to your cell. This could work, it’s mostly a matter of which things the reproduction system wants to focus on.

Dynamic ATP consumption

Grow based on how fast you consume ATP during gameplay. If you move, you grow faster. If you make toxins, you grow faster. If you have a higher osmoregulation cost, you grow faster. This makes growth automatically scale with size. This also makes it so you never have a reason sit still once you have enough food to grow until reproduction, since that would just slow you down and it wouldn’t affect how much food you need to reproduce. This gives players who want to go fast the interesting challenge of maximizing how much energy they gain and consume. However, species with little energy would grow slower, which could be unfun for them. Also, it may be weird that moving speeds up your growth. This would also make ammonia and phosphates useless. I don’t know if this idea makes sense, I just found it interesting.

Remove phosphates from the game

We could just abstract phosphates away from the game by assuming that the player passively absorbs enough of them. This would actually make gameplay very similar to the Phosphate Generation mod. If you’re a normal cell, you can play the exact same, just worry about one less compound. If you need help with growing, you can add nitrogen fixing organelles to your cell. This would be a bold but simple change. It’d certainly work, but it does have its flaws. It would mean that all sessile cells would need nitrogen fixing organelles. New players would probably miss those organelles and wonder why they can’t reproduce. We wouldn’t have the chance to teach about phosphates being essential for growth. There would be less diversity in needed compounds (this is both a pro and a con). I wouldn’t personally go with this one.

TL;DR: Sessile, slow and big cells struggle to get phosphates. Surviving from birth to reproduction should be an interesting challenge. Reproduction time shouldn’t be too long or too short. We could try new systems like passive absorption. We should be wary of breaking the game loop, confusing new players or causing too much work for the devs. We can diminish the risk of a waiting simulator with challenging survival, more ambiance and player agency in their rate of growth. All things considered, I think a new system is a good idea, maybe even a necessary one.

Now that’s probably enough for a conversation starter. If you didn’t guess, I’m pretty passionate about this stuff. It’s one of the reasons I got into messing around with Thrive’s code and made the Phosphate Generation mod. I hope that one day life in Thrive will be as diverse as possible. Biodiversity makes for interesting alien environments and gives players more creative freedom and strategic options. Ideally all viable life forms would be fun to play as at least for some people. I think that with all this is mind, a new reproduction system is necessary sooner or later. I don’t know which system is best, which is why I made this post. I want to encourage people to think about this stuff and share their thoughts. I think that it’s a good idea to start trying to figure this stuff out sooner rather than later, because changing reproduction could affect the whole game. For example, if sessile cells could reproduce, then the developers would be freer to add things that encourage or require slowness or sessility, like tankier cell walls. That could change the whole balance of the game. If we leave reproduction changes until later, there may not be much time to do them before 1.0, or plenty of things could end up having to be reworked.

Of course, it could be that none of these proposed reproduction systems make the game better, and some of them could be too much work even if they did. I’m not demanding anything from the busy developers. I just think that there’s a lot of real potential and that it’s a worthwhile idea to test some simple options. When it comes to some of the wilder ideas, I may make some kind of prototypes for them myself one day if they seem promising enough, but that would be still long ways of, and it may well be that the simplest ideas turn out to be the best ones.

I think that testing out simple passive absorption in practice is a good start. If you can, please add the rate of absorption as a tweakable constant in new game settings. That way players can experiment with different values and offer lot of feedback quickly.

If anyone has any thoughts, please share them! Also if anyone has feedback on how reproduction feels with the phosphate mod or Thim’s fork, that would be great to hear as well!