Multicellular Stage Design

The Microbe Stage has received heavy attention on these forums lately. Since the reddit boom and the subsequent spark in progress, we've finally gotten the engine running, with a small (but extremely helpful!) team of coders adding in the features to the first stage. The GDD also covers the main concepts for the stage, and is pretty fleshed out.

Because of that, it appears that, at the moment, there is little in the way of game design left for the Microbe Stage. Of course, in the future, we will have more opportunities to add in new features which will stir up new discussions, but for the time being, we are ready to move on to the design of the 2D multicellular stage.

It would probably be helpful to get a GDD up and running for this stage, as we did for the Microbe Stage. Also, my post on this thread should adequately cover what we need to know about the transition from Microbe to Multicellular, as well as the transition from 2D Multicellular (henceforth referred to as Early Multicellular) to 3D Multicellular (Late Multicellular). However, if it is missing any details, please point that out so I can fill that in.

The following are the major concepts, in no particular order, we need to outline for this stage:

• Interface and Controls
  
• Compound system
  
• Organelles
  
• Cells and cell specializations
  
• Reproduction, Evolution, and a Multicellular Editor?
  
• Death, population, and continuity
  
• Emergence of animal/plant/other distinctions
  
• Progression
  
• AI and the environment
  

To stimulate the discussion I'll start with cells and cell specializations. 

Just to give some quick context, the player first enters the multicellular stage when they use the bonding enzyme in their cell to attach to another cell of their species. Nothing actually happens when you enter the new stage, this is simply the point that has been picked for categorizing the stages. However, when you first attach to another cell, it will still swim in its own directions and can randomly detach from your cell. To prevent this, you will need a specific signal agent, otherwise you'll probably not be able to get past 5-6 cells in a colony at a time before they start detaching and swimming away. Once this has all been achieved, you play as a coherent colony of cells in very similar conditions to the microbe stage. After you reproduce for the first time, when you return to the game all the cells on your colony will be merged into one entity, even though from the appearance it will look like a colony of cells working together (this could be achieved with allowing for some minor independent motion for the individual cells). Basically the computer now just treats it as one big thing moving around instead of 8 little things.

Now on to cells and cell specializations. The player starts as a collection of the same cell type attached together. This cell type is the species that the player was when they first formed their colony. However, one of the main points of multicellular evolution is the specialization of cells, and so in Thrive your cells in your colony, although they will all be your species, will start to specialize. Specialization is accomplished through the editor. I was thinking that we have a slightly modified version of the Microbe Editor for Early Multicellular. You have a hex grid, but instead of placing cytoplasm and organelles, you place cells. You can add, remove, or move cells on your colony for the next generation. What's more, you can also edit the cells of your colony into different types or specializations.

All cells start as the same type, the default cell you were playing as in the microbe editor. You can create a new type of cell, and here, you go back to accessing the Microbe Editor, except this time you are creating a specialized cell for your colony, say, better at digesting nutrients by adding the proper organelles. Then, you save the new type with a name (Digestive Cell) and when you edit your colony, you can add, remove, or move this new type of cell to the colony! Although there are no presets telling you what types of specialized cells to make, the general ones that people will make will probably be:

• Nervous Cells
  
• Digestion Cells
  
• Protective Cells
  
• Motility Cells
  
• Agent Cells
  
• Absorption/Secretion Cells
  

And so, the more you evolve and the larger your colony becomes, the more of your cells are specialized and the more diverse their specializations are. This would be a main element of the gameplay until the 2D - 3D transition, after which cells stop being simulated.

Thoughts? Questions? Concerns?

NickTheNick wrote:

To prevent this, you will need a specific signal agent, otherwise you'll probably not be able to get past 5-6 cells in a colony at a time before they start detaching and swimming away

Would signal agent or bonding agent come first? There's been some discussion of having proto-colonies of cells within the microbe stage which can be influenced by the use of signal agents, but won't form any sort of contiguous entity. As for microbial reproduction when you're part of a bonding-only (or signal-only) colony, it could be that the group of cells remain the same when you returned from the editor, with a copied version of your original cell added.

NickTheNick wrote:

The player starts as a collection of the same cell type attached together.

Then the bonding agent would have to work only between cells of the same species.

NickTheNick wrote:

All cells start as the same type, the default cell you were playing as in the microbe editor. You can create a new type of cell, and here, you go back to accessing the Microbe Editor, except this time you are creating a specialized cell for your colony, say, better at digesting nutrients by adding the proper organelles.

So it's basically a microbe editor within the multicellular editor? Having to place organelles within multiple different cells using the same method as the microbe stage sounds like it would annoy the player. Maybe it should be replaced with a drag-and-drop sort of system, where organelles specific to a particular cell specialisation can be dragged onto cells within the organism (without having to enter a separate editor), the exact make-up of the cell not important. Rearranging multiple similar cells into different types is probably a little too much detail.

NickTheNick wrote:

This would be a main element of the gameplay until the 2D - 3D transition, after which cells stop being simulated.

One of the threads stemming from what you linked put the number of cells required for this transition at 100. Do we want an arbitrary limit? It would allow balancing, but may affect immersion, and in some circumstances (say your original cell type was particular massive) wouldn't hold up.

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Other than that, you concept for the early multicellular seems fairly solid. In terms of some of the points you mentioned needed work:

Interface and controls

Compounds will still be the main information shown on the player's screen, obviously in much higher quantities - do we want the units displayed to change, or should it be represented as x*10^y, where y is equivalent to one unit of a compound in the microbe stage? A new health system is probably needed too, but since I'm no expert on metabolisms (I didn't even know what ATP was before it became part of the microbe concept), I'll leave that to someone else.

Controls-wise, the 2D portion should be pretty similar to the microbe stage. In fact, using the mouse to point in a direction and keys to move towards or away from it still holds up for a 3D environment, potentially working better than giving the player an entirely new control scheme to use.

Compound system

Some thoughts on this are covered above. Seregon did have a post somewhere outlining how compounds would be used for each stage, but I can't seem to find it.

Organelles

Do specialised cells have organelles which would be useless to an individual cell and therefore wouldn't appear in the microbe stage? As far as I can tell most are accounted for, but again I might be the least qualified person to answer. If they don't, then evolving new organelles isn't a problem. Otherwise, are the methods for developing organelles from the microbe stage still valid?

Cells and cell specialisations Yay for British spelling!

As mentioned above, I don't like the idea of an editor within the editor in this instance. Seems too labour-intensive for the player, and is probably beyond the level of detail we want at this point in the game. Adding organelles to cells will still be fine initially, as a drag-and-drop system in a single editor could be used to simplify the process.

Reproduction, Evolution, and a Multicellular Editor?

Until a reproductive system is developed (which may take quite a while of in-game time, and would probably come after the transition to 3D), entering the editor becomes a little strange. It wouldn't be creating a new organism, because every single cell in a colony can't just divide and attach back the way they were. Instead, entering the editor would have to be editing your own organism, not making a new one. Unless I don't know what I'm talking about here, which is quite possible.

As for the editor itself, it shouldn't change too much from the microbe editor, except for being able to add parts (organelles) to other parts (cells). As Nick mentioned, you'd need a method for being able to save specific cell types and add them to your organism as well. Also, I think Mutation Points should remain the mutation currency. Organelle addition could use the same values for adding them to cells (or their equivalent for adding new cells), but the starting MP amount for each editor session should be increased. A quick guess puts the new amount at about 1000, relative to the microbe stage's 100, so you could edit or add around ten cells each generation - of course at first some will require multiple edits before they can become specialised.

Death, population, and continuity

If I'm right about the above, this could be quite a problem. If I'm wrong, it'd follow the same basic outline as the microbe stage, with the player switching to another individual with lower compound stores upon death.

And because I can't really think of anything for the next two points right now:

AI and the environment

Would all initial AI species be made up of your own original cell as well, seeing as it would have to have the necessary mutations to be able to bond properly? In which case, should the AI in the microbe stage be prevented from gaining this mutation so none of them start steamrolling you with stage-overlapping madness? An alternative would be to allow the AI to develop this mutation in the late microbe stage, but still have each cell function autonomously rather than as a coherent organism, preventing them from going down the path to 3D, which would mess up all logistics if you were still a 2D cell.

Oliveriver wrote:

NickTheNick wrote:

To prevent this, you will need a specific signal agent, otherwise you'll probably not be able to get past 5-6 cells in a colony at a time before they start detaching and swimming away

Would signal agent or bonding agent come first? There's been some discussion of having proto-colonies of cells within the microbe stage which can be influenced by the use of signal agents, but won't form any sort of contiguous entity.

How'd a signal-only colony work? Just asking.

Oliveriver wrote:

NickTheNick wrote:

The player starts as a collection of the same cell type attached together.

Then the bonding agent would have to work only between cells of the same species.

Isn't that what you guys are going for?

Oliveriver wrote:

NickTheNick wrote:

This would be a main element of the gameplay until the 2D - 3D transition, after which cells stop being simulated.

One of the threads stemming from what you linked put the number of cells required for this transition at 100. Do we want an arbitrary limit? It would allow balancing, but may affect immersion, and in some circumstances (say your original cell type was particular massive) wouldn't hold up.

Could increase the breaking point as one solution (nematodes have around 1,000 cells, could go for something smaller), just to make sure the cells are hard to see by that time. Also, the cell editor boundaries could be the saving grace here; they won't be THAT massive as long as that's there. If all else fails, could go for surface area. There's got to be SOME trigger for the transition.

Will the "tiny" niche size be expanded to accommodate the player organism immediately after the 2D-3D transition, or is it technically not part of whatever ecosystem is there until it gets a big larger? Will the player organism automatically swell during the transition, leaving cells and smaller colonies behind?

Oliveriver wrote:

Controls-wise, the 2D portion should be pretty similar to the microbe stage. In fact, using the mouse to point in a direction and keys to move towards or away from it still holds up for a 3D environment, potentially working better than giving the player an entirely new control scheme to use.

QFT.

Is the 3D segment still going to be part of the Multicellular Stage, or is the whole "colony" thing over at that point and the single organism goes into the Aware Stage?

Also, just a little side idea; as your colony grows larger and more specialized Try them toucans!, what if the blue background slowly zooms out and fades into whatever sandy ground texture you're going to use?

Oliveriver wrote:

Would signal agent or bonding agent come first? There's been some discussion of having proto-colonies of cells within the microbe stage which can be influenced by the use of signal agents, but won't form any sort of contiguous entity. As for microbial reproduction when you're part of a bonding-only (or signal-only) colony, it could be that the group of cells remain the same when you returned from the editor, with a copied version of your original cell added.

It depends on the playthrough. Both the communal membrane proteins and the signal agents are randomly "unlocked" after several generations of evolution by the player, and even when they are unlocked it's up to the player which to evolve first. However, the communal membrane proteins are necessary to form a colony. With only signal agents, you will only be able to attract other cells from your species to follow you to a limited degree.

Oliveriver wrote:

Then the bonding agent would have to work only between cells of the same species.

It's actually interesting to consider what it would be like if you could bond to cells of other species, but for now let's just stick with only sticking to your species with the membrane proteins.

Oliveriver wrote:

So it's basically a microbe editor within the multicellular editor? Having to place organelles within multiple different cells using the same method as the microbe stage sounds like it would annoy the player. Maybe it should be replaced with a drag-and-drop sort of system, where organelles specific to a particular cell specialisation can be dragged onto cells within the organism (without having to enter a separate editor), the exact make-up of the cell not important. Rearranging multiple similar cells into different types is probably a little too much detail.

I don't think it would be that complicated. The player would customize the different cell types using a Microbe Editor interface, but then once they've done that they just drag and drop them onto the colony. Also, one of the main points of the stage is specializing the cells of your colony as you evolve, and I think we should give the player the full freedom to do that. You can then edit a cell type that already exists in your colony, and when you save that type all the cells of that type update to match the latest evolutionary change. What's going to be a little tricky is figuring out the MP budgeting for all of this, considering there's two layers to the editing (editing the cell types, and editing the colony). I think it's better to keep the budget at 100 MP which represents 100% change, since that cap of 100 will be consistent through all the later stages.

Oliveriver wrote:

One of the threads stemming from what you linked put the number of cells required for this transition at 100. Do we want an arbitrary limit? It would allow balancing, but may affect immersion, and in some circumstances (say your original cell type was particular massive) wouldn't hold up.

I've asked around for other solutions before, and since no one had any other ideas I just stuck it at 100 until we could come up with a better idea (also around that point your colony will be pretty big and it would be good to move you into the 3d portion).

Also, as you said, I think it makes sense for the UI and controls to be generally the same as in the Microbe Stage.

Oliveriver wrote:

Do specialised cells have organelles which would be useless to an individual cell and therefore wouldn't appear in the microbe stage? As far as I can tell most are accounted for, but again I might be the least qualified person to answer. If they don't, then evolving new organelles isn't a problem. Otherwise, are the methods for developing organelles from the microbe stage still valid?

From what I know, no. They are all the same organelles, however now there is actually a reason to make a cell type of all just cilia (whereas before you'd probably kill yourself off that way). The means by which to unlock organelles can stay the same, unless we see any conflicts.

Oliveriver wrote:

Reproduction, Evolution, and a Multicellular Editor?

Until a reproductive system is developed (which may take quite a while of in-game time, and would probably come after the transition to 3D), entering the editor becomes a little strange. It wouldn't be creating a new organism, because every single cell in a colony can't just divide and attach back the way they were. Instead, entering the editor would have to be editing your own organism, not making a new one. Unless I don't know what I'm talking about here, which is quite possible.

As for the editor itself, it shouldn't change too much from the microbe editor, except for being able to add parts (organelles) to other parts (cells). As Nick mentioned, you'd need a method for being able to save specific cell types and add them to your organism as well. Also, I think Mutation Points should remain the mutation currency. Organelle addition could use the same values for adding them to cells (or their equivalent for adding new cells), but the starting MP amount for each editor session should be increased. A quick guess puts the new amount at about 1000, relative to the microbe stage's 100, so you could edit or add around ten cells each generation - of course at first some will require multiple edits before they can become specialised.

Actually, the way the colonies would reproduce would be similar to what you thought it wasn't. It depends on what the player did when in the microbe stage. If the player evolved conjugal nuclei (which allows for sexual reproduction), then the colony can reproduce by releasing an offspring cell, which combines with an offspring cell of another colony to multiply and grow into its own colony (that's not final yet). Otherwise, the colony must reproduce asexually, which means it will reproduce all of its cells until a separate colony breaks off.

Oliveriver wrote:

AI and the environment

Would all initial AI species be made up of your own original cell as well, seeing as it would have to have the necessary mutations to be able to bond properly? In which case, should the AI in the microbe stage be prevented from gaining this mutation so none of them start steamrolling you with stage-overlapping madness? An alternative would be to allow the AI to develop this mutation in the late microbe stage, but still have each cell function autonomously rather than as a coherent organism, preventing them from going down the path to 3D, which would mess up all logistics if you were still a 2D cell.

No, at first the environment will be still populated by everyone that you had just seen prior to reaching early multicellular. However, what changes is that now some of the other species will also start becoming colonies. However, none of them will become 3D organisms before you do. We can later, if we find it's not too imbalanced, make it so that AI cell colonies can evolve before you do, or make that a difficulty setting, but for now the AI will match your progress per stage.

~Assorted thoughts~

Reproduction
When I think early multicellular I think Volvox and slime molds (among other things). So we certainly need to be able to handle all sorts of reproduction methods. Early on, your colony is more of a loose association of independent organisms, possibly brought into groups by necessity (lack of food meaning resources should be pooled, perhaps?), and thus able to split up into the individual organisms again when conditions are good. In such a case, reproduction can clearly be handled by the same Microbe-Stage mechanics. Even when we evolvesome basic differeniation of cells, it can still be possible to reproduce the same way; as long as every cell is still totipotent (able to beget cells of any type). Then once we get non-totipotent cell lineages (which happens once differentiation is strong enough), then you need to use a more complicated method to reproduce.

The first would be asexual budding-off of daughter organisms. This raises a couple questions.

• Are these daughters a product of a single germ cell from the mother? This is the standard case for all multicellular organisms I know of; importantly, it keeps the entire genome together.
  
• If not, are they produced from a couple different lines of pluripotent stem cells (each of which is responsible for a certain subset of all tissues)? In this case, after a few million years the genome for the different tissue groups could end up diverging wildly.
  
• If not, is each tissue replicated vegetatively from more cells of the same tissue? This is the most extreme case, and would, after a few million years, result in organisms that are really patchworks of many different symbiotic colonies. It's unlikely to be viable at higher complexity than, say, a hydra, since any mutation involving interaction between cell lines would need multiple evolutions in each.
  
• Most importantly, do we care about these distinctions? Probably not, I don't really since only the first is long-term evolutionarily viable.
  

The next would be sexual reproduction. For sexual reproduction, the child organism needs to develop from one zygote due to the constraints of recombination and so on, so we can immediately toss out all those distinctions above. In this case then, we pretty much need a germ line -- cells whose descendants include gametes. How do the gametes of two mating organisms meet though? One way is to present them on the exterior, and bump into potential mates, hoping that some gametes will touch. The other, giving much more freedom in body design but requiring evolution of a complicated cell line, is spermies. If your gametes can swim on their own and find mates (or other gametes to fuse with) that way, then you're much less restricted in how you develop your main organism.

The prospect of sperm-like free-swimming gametes leads to another important idea -- multi-stage organisms, like jellyfish, or ferns, which have life cycles that seem to go through several different organisms, each begetting the next.

And now for the difficult question: How do we turn all the stuff above into mechanics?

Emergence of Animal/Plant/other distinctions
To me, this is patently unnecessary. A split between sessile autotrophs and motile heterotrophs, for example, can arise just because autotrophs tend not to be able to collect enough energy to be motile, whereas many heterotrophs wouldn't be able to survive unless they were motile and could thus go after more sources of energy. Thanks to the existence of large multicellular sessile heterotrophs, at least, the distinctions blur even more when you restrict yourself to simple observation. So in the end the distinctions that you seem to be thinking of codifying are often incorrect even on Earth, and could easily be way off the mark on some other planet. Humans are already natural-born pattern-matchers (and correct me if I'm wrong but I am quite sure the vast majority of our players will be human), and our players are already naming the things they discover, so why not let them be the ones to make the distinctions? Players keen on letting their inner taxonomist loose will have a field day if they're allowed to do all the studying and naming and categorizing and theorizing themselves. And by the time we get to Aware, we'll be catering to kids raised on games like No Man's Sky, so believe me, we'll have taxonomists.

~More to follow~

The daughter cell method sounds the most like what I was thinking of for reproduction too, but we can later add in other types of reproduction too, to add in diversity.

For sexual reproduction, I think both of those means should be possible, because they would affect how you would reproduce later in the late multicellular and aware stages.

For taxonomy, what you said sounds excellent to me. If the mechanics of the game naturally create different types of organisms, that would be great. It would also be important for us to, down the line, build a GUI that allows engaged players to name, record, and classify the species they meet, although that would need its own thread and discussion.

Okay I'm going to try to address the evolution and editor issue of this stage.

So prior to this there has never been a mention of a Multicellular Editor anywhere on the forums or wiki. I assume it was assumed that this stage would be covered first by the Microbe Editor, and then by the Organism Editor. We could try to make the editor for this stage just an expanded form of the Microbe Editor, because they are both hex based (unless we decide to change that in this stage) and creating cell types functions almost entirely the same as editing your cell. 

My idea of how it would look is that you enter the editor with a view of your colony, and one of the buttons on the GUI opens a list of cell types. From here the player can click "Add new cell type", which will prompt the player to pick one of the existing cell types as a template. This means that when you first make a new cell specialization, it has to be based off of your original cell. The colony is replaced by the chosen template cell, and the UI changes, and now the player can create a specialized cell. 

Budgeting

Entering the Multicellular Editor (Let's just call it that for now) gives the player 100 Mutation Points to spend. However, it also gives them the ability to create one cell type, or edit one existing cell type, that session. When either a template cell is chosen, or an existing cell type is chosen, the player can spend up to 100 Mutation Points to evolve that cell type. 

This means that the player effectively has two budgets. When they finish with their cell type, they can return to viewing their colony, and then spend their 100 MP adding, moving, or removing cells to the colony. 

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I feel like having two budgets makes the editor feel more complicated, but it's the only way I could think of to allow the player to both specialize cells and edit their colony. If you guys have any suggestions to improve it, or different approaches, that would be very much appreciated.


EDIT: Let me give an example of the budgeting I mentioned above. 

You enter the editor for the first time in the multicellular stage and have a colony of 5 cells with all of them being of the original type. You as of yet have no specialized cells. You choose to create a new cell type, selecting the original as a template. You then spend 100 MP adding long tendrils of cytoplasm to the new cell type to make it have lots of surface area, and then you save the cell as "Absorption Cell" (The idea is with lots of surface area you can absorb nutrients fast and expel waste fast). Now, upon returning to the view of the colony, you have another 100 MP to spend evolving your colony at large. You spend all 100 placing these new absorption cells at the front of your cell, so it can absorb nutrients more effectively as it swims through them.

Just as an idea, adding, moving, or removing a cell costs 33 MP each, regardless of the type. If an existing cell type was changed, all cells of those type in the colony are immediately updated and no remaining MP is left to spend on the colony that session.

I think that with each cell you add, it slowly decreases the cost of the mutation points per add/edit as the multicellular being becomes more advanced and complicated, it can handle more mutations as it becomes from single cell changes to chunks of certain cell types changing. But with more cells, the more maintenance of energy you need to keep them alive, although it won't be much of a problem once you get to larger creatures to eat/absorb. Just adding an idea of how mutation becomes more large-scale.

That sounds like a good idea, but do you have any idea how we could implement it into the game? We could make the cost of adding/moving/deleting cells decrease with each generation you enter the editor, or we could make it decrease based on how many cells are in your colony for the next time you're in the editor.

So, based off of what's been said so far I'll try to summarize the stage's main concepts so we can move on to making a GDD (By the way, this is all only early multicellular).

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Interface and Controls

The player controls the colony just as they do a microbe, using the same controls and with mostly the same inteface (refer to the Microbe Stage GDD, or play the game). Compounds now shows a total of all the compounds held by all the cells in the colony. Also, until the proper signal agents are acquired, cells in your colony will swim in their own direction and occasionally break off from the colony.

Compound System

Cells that are part of the same colony will share compounds together. The game will still have to keep track of where the compounds are, as in which cell they are stored in, or where they are as they travel between cells, but they will be in essence traded between the cells to keep the colony alive. The compound stores the player sees will thus be that of the entire colony and not of just one microbe. The common compounds of this stage will be largely the same as in the previous stage, such as oxygen, ATP, glucose, amino acids, carbon dioxide, but will be found in much larger quantities.

Organelles

Although the focus of the player will now shift towards the management of an entire colony as opposed to a single cell, organelles still are simulated and play an important roles in the functions that cells can perform. The player can zoom in to examine the organelles of the cells in their colony, and in the editor can customize the organelles found in the different specializations of cells his colony is composed of. The organelles are all the same as they were in the Microbe Stage.

Cells and Cell Specializations

The player must specialize the cells in their colony in order to compete with the other colonies in the environment. Although it's possible to try and get by with using all the default cell type, it's much more effective to have cells designed for digestion, secretion/absorption, protection, etc. The editor will allow the player to do this, by allowing the player to create new cell types and edit existing ones, and then place, move, or delete cells of these types from the colony for the next generation.

More to come tomorrow...