Macroscopic Editor, Progression, and Principles

Deus · March 28, 2025, 7:42pm

CONSTRAINTS

As I discussed before, I really do think having constraints which the player must cleverly deal with fundamental challenges is going to result in the greatest amount of engagement, excitement, and diversity, with clear lessons learned from KSP. And I do think that managing these constraints should be among the largest components of editor gameplay.

Again though, it is important to have these constraints be interrelated as much as possible, and have them be approachable and universal so as to not throw 50 different factors at the player to consider at a moment’s notice.

Relating these general constraints to secondary stats can help us understand how they can manifest in gameplay, and will better inform us on how to approach providing tools in the editor.

Biodynamics

Revolves around the movement and mobility of a creature. I think this should be one of the more “active” and engaging constraints a player faces, encouraging a bunch of tweaking and playtesting. I think such a system will ultimately need to represent these aspects:

Center of Mass

If possible, assessing where along a creature’s length their center of mass would result in really interesting emergent dynamism with the editor.

Marine animals with a center of mass closer to their front (sharks, crocodiles, rays):

Have stronger limbs in the front, optimizing striking and lunging capabilities.
Find it easier to swim downwards, being generally better optimized to diving.
Spend less energy swimming since they are better able to “cruise”, reducing movement costs.
Are generally less nimble and agile.
Have more prominent fins in the front to help balance movement.
Are better able to stay attached to the ocean floor.

Marine animals with a center of mass closer to their rear (tuna, sailfish, flying fish):

Have stronger limbs in the rear, optimizing movement and explosiveness in movement.
Find it easier to swim upwards, being generally more buoyant in propulsion.
Spend more energy stabilizing orientation, thus increasing movement costs.
Are generally more nimble and agile.
Have more prominent fins in the rear to help stabilize.
Are better able to breach the water surface, escaping predators.

If we’re looking for a mechanic which makes limb location influential and dynamic, this is a good one. Along with influencing stats, including a measure of center of mass can result in incredible divergent gameplay in the editor, influencing choices made and the positioning of limbs and providing greater depth.

Note that having center of mass be relevant vertically as well will be important for land, but is generally less important for marine animals. Discerning where the center of mass is along the x-axis of an animal is good for the early macroscopic stage.

“Streamline” Measure

Having some sort of measure of being “streamline” would be an important thing to include. It is something most marine animals should generally prefer, but is traded for in certain abilities, such as armor or certain limbs. So players should balance being streamlined between potential improvements in other avenues, such as combat and maneuverability (burrowing, ability to reach land, etc.).

In general, being more streamline reduces the impact of currents, and increases top movement speed. Being less streamline means currents can grab you more, and decreases how fast you can go.

Otherwise/concurrently, the more traditional stats derived from biodynamics include:

Speed: The top speed you can reach.
Agility: Ability to turn, as well as acceleration and deceleration.
Buoyancy: How easy it is to swim upwards or float as opposed to sinking or diving. Influential in benthic v. pelagic lifestyle choices. Neutral buoyancy would probably be desired by most swimmers. Note that we should generally represent buoyancy through movement costs associated with going up or down as opposed to actually making the player sink or float upwards unless buoyancy measure is extremely towards a certain direction - it could be annoying for players to constantly press space or control.
Movement Costs: In general, more explosive movement styles require a lot more energy. Your body plan will also influence movement plan efficiency, with smart placement of limbs in response to constraints placed on your body plan going a good way in making movement more or less efficient.

Certain adaptations, such as swim bladders, can generally reduce the impact of constraints such as center of mass if a player wishes to avoid them. They won’t be impacted by the negatives, but they also won’t benefit from the positives.

Mass

Mass is probably one of the more intuitive constraints a player will face. In general, as a player grows bigger, their mass will increase.

Influences how strongly center of mass affects animal; less massive animals won’t have to worry about their center of mass as much.
Influences total health, with larger animals being better able to take damage.
In general, reduces agility and slightly increases movement speed, up to a certain point. Reduces general buoyancy, requiring more adaptations to remain neutral.
In general, increases the force production of an animal, increasing damage. Note that smaller muscles are more efficient at creating strength however, so there is a tradeoff; beyond a certain size, strength is lost.

Mass also has a strong influence on your metabolic rates. Larger animals generally need more food in terms of sheer quantity, but have reduced metabolic rates, meaning the same amount of food lasts a bit longer. However, I believe metabolism should be more specifically discussed before discussing this aspect of things.

Surface Area to Volume Ratio

Surface area is multi-faceted, affecting metabolism, respiration, and movement. It will be more important for soft-bodied animals and for certain types of skins/thickness, influencing evolutionary strategy. Movement effects will be a bit more universal. Note that for every bullet, the opposite statement is true (if higher surface area to volume boosts x, then lower surface area to volume reduces x)

Higher surface area to volume increases buoyancy.
Higher surface area to volume reduces health.
Higher surface area to volume increases the impact of currents, as there is more of a “sail” to catch.
Higher surface area to volume decreases speed and increases agility due to drag.
Higher surface area to volume decreases tolerance to cold, but increases tolerance to heat.

Questionable

Square-Cube Law: The square cube law is an important constraint to represent that we surely should put some thought into. I put it here though because it is a multi-faceted feature which influences other constraints in dynamic ways, influencing metabolism, movement, growth, and more. As such, a lot of thought would need to be put into explaining this feature.

Ultimately, I think creating really well-made mechanics centered around these constraints would be really worthwhile and would go a long way in making the Macroscopic Stage really fun. Hopefully it’s manageable for auto-evo as well.

Deus · March 31, 2025, 6:51pm

Here is an example of how basing our editor around solving problems posed by constraints can lead to some really engaging editor gameplay, with a reduced need of just adding an endless number of tools for the player to interact with.

Center of Mass

Relevant information from prior post if refreshment is needed:

Marine animals with a center of mass closer to their front (sharks, crocodiles, rays):

Have stronger limbs in the front, optimizing striking and lunging capabilities.

Find it easier to swim downwards, being generally better optimized to diving.

Spend less energy swimming since they are better able to “cruise”, reducing movement costs.

Are generally less nimble and agile.

Have more prominent fins in the front to help balance movement.

Are better able to stay attached to the ocean floor.

Marine animals with a center of mass closer to their rear (tuna, sailfish, flying fish):

Have stronger limbs in the rear, optimizing movement and explosiveness in movement.

Find it easier to swim upwards, being generally more buoyant in propulsion.

Spend more energy stabilizing orientation, thus increasing movement costs.

Are generally more nimble and agile.

Have more prominent fins in the rear to help stabilize.

Are better able to breach the water surface, escaping predators.

Center of “gravity” is used more often in biomechanic circles. I’m choosing to name this factor as center of mass in order to more clearly associate it with mass itself. The center of mass in an organism is really important in determining biomechanics and gait, as well as the arrangement of a body plan.

Tools Derived from Center of Mass

Mobility Appendages Proximity to Center of Mass

In marine animals, fins closer to the center of mass often help with agility and thrust at the cost of some stability, while fins farther from the center of mass often help with stability at the cost of some leverage.

For now, I’m going to say that stability can be a stand in for a measure of ATP costs associated with movement. Learning from this, we can say that:

The closer to the center of gravity an appendage is, the more it benefits mobility at the cost of greater ATP cost. The farther it is, the more energy efficient the limb is at the cost of some mobility.

Note that the effects of a limb are additive as long as it doesn’t negatively impact your streamline measure too much. When I say “more efficient at the cost of some speed,” I don’t mean the speed of your organism goes down, I mean the limb’s speed bonus isn’t as fast as it could be.

Below are examples of fish with the same center of gravity, pretty far behind their heads. The top fish really emphasizes stability at the cost of maximum speed, while the bottom fish really emphasizes speed at the cost of some stability. As a result, the first fish is generally better suited for distance and efficient cruising, while the second fish is generally better suited for quick movement in bursts as opposed to efficiency.

Note that in actuality, stability does have an important impact on speed. So perhaps another interpretation of stability could be as a sort of coefficient to speed as well as energy, but that could be complicated to manage.

Mass-Bearing Features & Appendages

“Heavier” parts of the organism will shift the animal’s center of gravity more or less dorsally or posteriorly. An example of an aquatic organism with a high-mass section of their body is Dunkleosteus, which notably has a heavily-armored skull, shifting the center of mass forwards:

This suits its ecological role very well; an animal that was likely built for inflicting a ton of damage on armored organisms, having a forward-set center of mass really helps it to hit like a freight train. Note the strong pectoral fins, providing control to the center of gravity, and the prominent, backwards shifted tail and dorsal fin, providing greater stability.

Varying Torso Size

Animals that have segments of their body enlarged tend to have their center of gravity shift that way. In Thrive, making a segment of your torso wider can shift the center of mass in a responsive way.

Varying Torso Length

Lengthening the torso, creating a sort of “tail”, is a common strategy utilized by many animals to shift their center of gravity backwards. Representing this mechanic in Thrive can implicitly lead to similar phenomena occurring organically in Thrive.

Here, from representing a dynamic constraint, we give ourselves a framework to understanding what kind of tools could be useful in an engaging editor, and can set up these tools to result in gameplay experiences which can seriously reflect a lot of the pressures real life organisms face in a very interesting way.

I can easily imagine such a system resulting in fun personal goals for the player to achieve: build the fastest animal by shifting the center of gravity backwards, shift the center of gravity as much as you can forward and try to build an animal able to succeed with that sort of pressure, etc. It also leads to many interesting “stories” behind the body plan of an animal. Why does this clade have very prominent fins in the back? Because its ancestor was really front-heavy, or it wanted to maximize speed.

There is only so much of “finetune this mouth/leg/eye/hand" etc. we can provide to the player without it being micro-managey to the player, or without us turning development of the macroscopic stage into “how many additional things can we fit here”. Having these significant and clear constraints can naturally result in the sort of dynamism players face, without throwing their attention to 5 different things on their creature that they must adjust sliders on or shape differently in an editor trip.

I am starting to think that this is an ideal way of creating an engaging editor, and think that nailing down the macroscopic factors, parameters, mechanics, etc. dealt with in the editor will make conceptualizing it a lot easier. There are some things we need to be wary of, however:

There should be very little actual “restriction” placed on the player surrounding these mechanics; that is, instances where the editor flat out says “you can’t do that, and we won’t let you leave the editor until you fix it” should be as absent as possible surrounding these constraints. Even if there are only three or four of these larger constraints, situations where the player has an organism with multiple issues can emerge, and this can easily lead to confusion and frustration.
Information and UI elements surrounding these systems should be clear as to the statistical impact of your choices. Bonuses should be highlighted and minuses should be pointed out, and you should be able to see what your surface area, mass, where your center of gravity is, etc.
There should be ways for the player to alleviate the pressure of some of these constraints if they wish, so as to create some sort of accessibility. This can be done in a way that doesn’t harm the depth of Thrive, as long as the bonuses of these constraints are also nullified to the same extent the negatives are. It can also be done in ways that are scientifically accurate: animals with less mass don’t have to worry about their center of gravity as much, and the presence of a swim bladder in some fish helps to alleviate the buoyancy effects of their center of gravity.
It should be clear to the player when a certain constraint is more important to their organism. Animals with a certain type of skin will need to look at their surface area a bit more, while animals with another type of skin will be less affected. Smaller animals won’t have to worry about their center of gravity as much, but larger ones should. This will also reflect progression: early, primitive animals often had to focus a lot more on surface area, as an example, then different strategies related to integuments reduced this pressure.
It’s better to have three well-designed, intuitive, and engaging constraints which are interrelated than it is to have a hundred constraints, addressing the tiniest of details.

Deus · April 9, 2025, 2:09am

The Marriage of “Appendages”, “Limbs”, and “Extremities”

Here is a take on how much of the functionality revolving around limbs and appendages could work.

Appendages vs. Limbs

An “appendage” is an extension of an organism’s body, while a limb is a type of appendage which often denotes mobility or weight-bearing functionality; often, but not necessarily always, with some sort of skeleton.
Appendages and limbs are treated with the same sculpting system, with more functionality attached to limbs, and more diversity attached to appendages. Players can designate appendages into numerous tools, while limbs are among the most dynamic and important tools an appendage can be, requiring detailed thought. Appendages also offer detailed customization of a creation.
Designating an appendage as a “limb” will require the player designating that appendage as bearing a joint. Once that limb is designated, a joint will be placed at the connection point between the torso and the appendage, where movement functionality will be conferred.

Joints - Specifying What a Limb Is

In Thrive’s editor, joints will designate a “mobility” function. Designating an appendage as a “limb” will require the player designating that appendage as bearing a joint. Once that limb is designated, a joint will be placed at the connection point between the torso and the appendage, where movement functionality will be conferred.
A joint in the editor doesn’t necessitate the presence of an actual, skeletal joint, bony or not. Soft-bodied limbs, such as those of velvet worms and Hallucigenia, would have a joint in the Thrive editor. Skeletal joints have their own bonuses applied to them, and have more diverse function options.
In benthic animals and terrestrial animals, jointed limbs without an extremity attached to them are assumed to work like ciliated, footed, or sticky pads, flatly pressed against the ground and creating crawling movement similar to snails, starfish, and slugs. In pelagic, free-swimming animals, jointed limbs without an extremity attached to them are assumed to work like fin folds (soft-bodied/endoskeleton) on primitive fish or lobbed flaps (exoskeleton-bearing organisms) like Anomalocaris, undulating or flapping rhythmically.
After a certain level of progression, players will be able to designate the placement of additional joints on a limb. The proportion of each segment in a limb is influential to the function of an appendage, depending on the extremity.

Extremities - Attaching Function to an Appendage

An “extremity” is the absolute end of an appendage. This includes graspers, feet, fins, feathers, stingers, external gills, webbing, and more.
Placing an extremity on a limb will transform the appendage, applying different rules, behaviors, and abilities on the appendage. They will be applied on the ends of an appendage, and will alter the appearance of underlying segments of the appendage. Different extremities will emphasize different stats; for example, surface-area becomes very important for appendages with an extremity focused on flight, mass becomes very important for appendages with a weapon on the end, etc.
Certain extremities, like feet and graspers, can only be placed on jointed appendages (limbs). Other types of extremities will be locked behind certain extremities; for example, wings.
Extremities will by default be rather vague, but can be customized extensively through manipulating both the root appendage and characteristics in the extremity itself. Variations in extremities, as well as the different form of extremities, will generally alter the importance placed on certain characteristics of an appendage, requiring different handling of mass, surface area, streamline, and more.

An Emphasis of Constraints: Why Appendages, Joints, and Extremities?

Right now, I am thinking that an extremity denotes the function of an appendage, and the appendage’s form influences the extremity’s stats and effectiveness. I am approaching it this way to tie it back into the idea of dynamic constraints, where certain constraint factors of the appendage are emphasized or de-emphasized depending on the extremity.

I am doing this for these reasons:

Engaging Editor Gameplay - If done well, I think doing it this way can result in a really deep gameplay experience. Instead of flatly attaching a different type of limb or part which has fixed stats, the player will have to deliberately alter their morphology to maximize function.
Anatomy - Certain structures require different alterations of the underlying limb or appendage to become more effective. By manipulating the stats of a limb via constraints, we can reflect these anatomical considerations in a way that is approachable to the player. And by having this classifying system of extremities denoting function, differentiation of anatomy is much easier to understand.
Reflection of Evolutionary History - This could be a nice way to incorporate evolutionary story-telling, and reflect certain principles of evolution. For example, by making high surface area limbs beneficial for swimming, auto-evo naturally forces various marine animals to evolve convergent fin structures. I hope it can also lead to some cool behavior from auto-evo: if surface-area is beneficial for flight, then perhaps auto-evo will be more likely to transform a high surface area limb into a wing, therefore emphasizing the transformation of underlying structures into different functions.

In summary: I think thinking of extremities, appendages, and limbs this way will allow for some really cool emergent gameplay. By measuring the parameters of the appendage and attaching stats to these parameters - greater mass increases damage and is beneficial for x, greater surface area increases suitability for flight and is beneficial for y, etc. - we can get a really cool system which reflects evolutionary design and history. It also offers a great compromise between functionality - making sure the player is able to designate exactly what they want of something, and making sure us developers can rationally approach certain features - and customization - allowing players to apply cool visuals and shape the features of their organism.

I can go into more detail as to how constraints and more exactly interacts with appendages. But for now, I want to focus more on how that we can even go about portraying certain features before we go over how to attach gameplay function.

Additional Notes

Here are some additional concepts branching from this joint, appendage, and limb conceptualization.

Tails

Tails are posterior segments of an organism which often are adapted to assist an organism’s movement, occasionally being used as weapons.
Tails are designated by the placement of a joint on an organism’s torso. If a joint is placed on a torso, then every part of the torso behind that joint is considered a tail. Players cannot place additional limbs on segments of the torso designated as a tail. They can place additional appendages.
In water, longer tails will provide greater agility, while shorter tails will provide greater speed and explosiveness. On land, tails will have much less of a direct effect on mobility, but will have a stronger effect on the center of gravity of an organism.
Note that “length” here refers to the portion of the torso which is tail or not tail, not necessarily the length of the extremity on the end of the tail. A long-tailed Thrivian organism would be an “eel” or rattail fish, which uses the majority of its body as a tail while swimming. A big-eye thresher shark would be considered to have a shorter tail, similar to other sharks, as the majority of its tail’s length is on the extremity rather than the actual, musculated tail.
Attaching different extremities on a tail can alter the function of the tail. For example, placing a fin on a tail indicates its use in active propulsion in marine environments, while attaching a stinger or weapon informs a function as an offensive or defensive tool, such as in scorpions, stinging insects, and stegosaurs/ankylosaurs. Certain extremity attachments can also attach items to the sides of the tail in total, allowing things like ribboned fins.

General Progression Ideas

Appendages will first appear in the macroscopic stage as a soft-bodied extension of the body which primarily affect attributes like surface area, volume, and movement. Players will be able to broadly manipulate the shape of the appendages and attach some different functions, such as stinging extensions seen in jellyfish/other marine animals, very basic limbs/fins, and antennae/sensory organs. However, placing multiple joints on a limb, which is needed for more advanced functionality, will be locked behind a skeletal structure.
Evolving a skeletal structure will unlock more advanced extremities and limb options, as well as generally enhance the abilities of a limb. Before the evolution of a skeletal structure, tails will be really important for pelagic movement. Tails will remain powerful tools for creating propulsion, but there will also be greater options for the player to utilize.

SAMPLE CATALOGUE OF EXTREMITIES

Feet & Graspers

Feet are structures used by benthic marine animals to stay rooted to the ocean floor, and by terrestrial animals for general mobility. Graspers are extremities which allow the ability to grasp, enabling grappling with other animals and interaction with the environment. Graspers generally evolve from feet.

These parts indicate the use of an appendage as a limb, and may only be placed on jointed appendages.

Weaponry

Certain extremities enable offensive, or defensive, capabilities, such as stringers and spikes. Attaching a spike to the end of an appendage transforms that entire appendage into a large spike or horn, similar to those seen on trilobites, certain reptiles, and mammals. Attaching a stinger on an appendage enables a more active, offensive capability, allowing animals to strike at range with their appendage, similar to scorpions, spiders, and wasps. Greater mass in these parts can strongly influence stats.

Sensory

Certain extremities transform an appendage into a sensory organ. For example, attaching sensilla to an appendage transforms that appendage into an antenna, similar to those seen on arthropods, enabling greater detection of a certain input. Electroreceptors, whiskers, and other tools can also provide detection abilities. Surface area can have a strong effect on sensory organs.

Mobility

Certain extremities transform a limb into a fin, wing, or digging structure. These emphasize certain attributes, such as streamline measure, surface area, and more.

Questions and Considerations

Should a tail be dealt with like a limb, or just as an extension of the torso? I assume a tail being an appendage can make it really easy to represent multiple things, such as fins on a tail, stingers, capabilities, and more. However, it can also lead to confusion on the player’s end if not explained well, or might be an unneeded complication of things.
When imagining a sort of “editor catalogue” this approach with appendages and extremities, though dynamic, does result in a model which might make including other categories of structures awkward if they don’t fit well with appendage sculpting. For example, eyes are an important sensory organ which frequently aren’t attached to the evolution of an appendage; where does that part fit in with this? There are other parts - ears and noses jump out immediately to me, but I’m sure we’d find other such structures as the stage progresses - which would probably need to be treated differently. This isn’t necessarily something that is a huge or unavoidable flaw, but it does mean we need to be thoughtful about what goes into the catalogue of tools in Thrive so that we don’t just end up with a hodgepodge section of the editor.
We need to be mindful of how interrelated many extremities often are, and the fact that certain structures evolve from other structures. For example, wings come from more traditional limb structures, feet from fins, graspers from feet, etc. etc. A lot of thought would need to be put up in portraying this progression and

Applications

Attached below are some mediocre concepts illustrating some points I tried to make above.

A pretty traditional fish body plan. The lighter green indicates an appendage; here, there are two unmotile appendages assisting with the movement of an organism in a dorsal and anal fin, and another front appendage with dark green circles in them. The darker green circles represent the placement of a jointed limb segment, which are the fins on which movement animations will be applied, and where stronger movement boosts will be applied. The dark red indicates the part of the body identified as a tail, and the dark red circle indicates a placed joint, indicating the start of a tail. The orange (or light red?) indicates an extremity, which is providing information on the function of a limb; indicating a dorsal tail fin, used for movement, and a pectoral fin, also used for movement.

An organism with a body plan like an Anomalocaris, with limbs represented as simple jointed pelagic limbs with no extremity attached to its end. Since the limbs have no appendages, they will undulate, similar to the animal I was trying to replicate. It also has a shorter tail.

An organism with a body plan like very primitive chordates, having a long, undulating fin attached to its very long tail. This illustrates the benefit of handling the tail link up with extremities; it allows the player to customize their organism in a way that would be difficult with traditional appendages and limbs.

An organism with a body plan similar to a scorpion. The light red indicates an extremity focused on stinging, thereby transforming the tail into an offensive weapon. Illustrates the diversity of features which can be applied to a tail.

An organism with a body plan similar to a trilobite. The light red indicates the placement of a spike extremity on the end of an appendage, therefore transforming the entire underlying appendage into a spike structure. Illustrates the customization options available should we diversify the function of extremities to be beyond just hands and feet, and the benefit of unifying appendages and limbs.

Introducing: a weird crab thing with legs. Note the orange extremities offering differentiation of appendage functions; all are limbs, but the front bottom limb operates as a claw/grasper, the bottom three posterior limbs operate as legs, and the top limb operates as a wing, transforming the appearance of the appendage into a wing. Note that for the appendage operating as a wing, surface area is maximized, whereas for other limbs, surface area isn’t as important. Meanwhile, we can infer that the front claw probably isn’t used very offensively, as it has little mass. Illustrates how we can attach constraints to this feature to increase play diversity.

A jellyfish-like organism. It has five appendages, four serving as offensive, stinging appendages, and the larger middle one serving to increase surface area to assist with a metabolic process. Note that the stinging appendages are designated as offensive by the placement of stinging extremities, therefore making constraints behave differently for those appendages as opposed to the more traditional, surface-area boosting appendage. Illustrates differentiation of appendage functions.

Deus · April 12, 2025, 9:21pm

Mouths, Mandibles, and Teeth

Mouths and jaws are something I imagine to be more modularized/parametric-part based than appendages just going off the fact that the majority of mandibles and mouths are slight alterations to existing structures.

There are clear evolutionary chapters on our planet’s history regarding the use and diversity of mouths. They reveal a story on how the majority of animals got their food. I’ll go over these briefly to provide context.

STATS AND ABILITIES

These are the major abilities and stats which mouths and modifications to mouths will generally revolve around. Note that the general constraints are also at play here, but I will be focusing on the actual, mouth and mandible-specific tools.

Abilities

These are the major abilities attached to the jaw of an animal.

Eat - Ability to engulf items. Available to all mouths; prior to the evolution of a mouth, eating works through contact of plankton clouds and substrate with skin.
Suction - Ability to absorb material and small enough prey. Available early on to some animals without and with jaws, though effectiveness dissipates at larger masses.
Bite - General chomp ability, inflicting damage on other animals. Available to mouths with some sort of jaw.
Grasp - The ability to grab items and, if discrepancy in mass is big enough, prey. Requires a jaw.

Attributes

These are the major stats influenced by mandibles. For more on ingestion rates, look at this post: Metabolic Rate System - #5 by Deus

Ingestion Rate - Essentially what component of whatever you eat is accessible or digestible by your organism. Eating plants with carnivore teeth results in only 40% of the nutrition, eating armored animals with teeth not able to break the armor results in only 20% of the nutrition,eating shrubbery with teeth designed to graze grass results in 50%, etc.
Raw Damage - How much damage your jaw structure is able to apply. Shorter, wider jaws generally are able to create more baseline raw damage.
“Effectiveness Coefficients” - Essentially, stats which changes damage applied to an organism depending on your jaw. Wider jaws are more effective against tougher material, while narrower jaws are more effective against flesh.
Range - The range at which effects can be applied. Longer snouts provide greater range.
Grasp-Related Factors - How well a mandible is at grabbing items. Generally revolves around how long you can hold an item, and the maximum size of item you can hold. Duration of grasp is more relevant to prey items, while maximum size is influential for both carnivores and animals which can interact with their environment. Narrower jaws are generally better for grasp.

MOUTH CATALOGUE

These are the general major types of “mouths” available to players.

Mouthless - Absorption of material occurs through the skin, meaning other stats, like surface area and appendages, are more important.

Jawless

Simple jawless mouth which basically enables engulfment, with no bite, no suction, and very little range.

Suction - Boost to suction, though reduces size of engulfable matter.
Toothed - Believe it or not, teeth-like structures likely evolved before mandibles, with conodonts especially displaying these capabilities. Allows for a very limited bite function.

Jawed

In general, jaws can be modified in a parametrized way like this:

Length - Longer jaws decrease bite damage, but increase range. Shorter jaws increase bite damage, but decrease range.
Width - Wider jaws increase max damage and impact on tougher skin as opposed to narrower jaws. Narrower jaws increase grasp strength and impact on less tough skin as opposed to wider jaws.

Arthropod Mandibles - Accessible relatively early on, the mandibles of arthropods will be extremely customizable, with the potential for more extensive abilities attached to them. More modification and specialization options available to arthropods in comparison to animals with an endoskeleton. Arthropod mandible raw damage doesn’t scale up with mass as strongly as high mass endoskeletal animals.

Proboscis - A more advanced mouthpiece available later on in the Aware Stage. Takes away bite ability, but opens up interactions with unique flora, as well as parasitism. Allows access to ubiquitous food sources, such as productive plant species and parasitism, but with practically no capability for predation.

Endoskeletal Mandibles - Generally allows the highest amount of stats when specialized, though more elaborate and expensive to develop/modify than arthropod mandibles, and generally less adaptable.

Teleost Jaw - Extendable jaw, like in the majority of extent fish today. In general, strong boost to suction, range, and grasp ability underwater in exchange for raw damage. Increased streamline measure. Incredibly useful for highly-adapted marine animals who pursue nimble prey, less efficient for larger animals which hunt larger prey or terrestrial animals, where suction is completely nullified.
Beak - Less raw damage and no access to teeth, but strong boosts to ingestion and efficiency rates, and much less impact on mass and center of gravity. Incredibly efficient for animals that are highly specialized around a food source and for animals which prioritize mobility.

Chitinous Beak - Available to soft-bodied organisms. High damage with some suction ability, and limited grasping. Much less diversifiable than either of the other two mandible options; provides decent stats, but the stats, with perhaps a tiny bit of modification, are largely what you’re gonna get.

TEETH

Teeth will be available to animals with an endoskeleton that don’t have beaks, and will allow for further diversification or amplification of the stats of the mandible. Adaptations to chitinous beaks and arthropod mandibles can reflect the function of teeth - for example, serrations in beetle mandibles - but are alterations to the underlying mandible structure itself. True teeth allow for an additional layer of customization to a mandible beyond its shape, allowing for more diverse function.

Once players unlock teeth, a modification option opens up for the player’s jaw. Players will be able to specify the shape of teeth, as well as their distribution in the jaw. Teeth placed near the front of the mouth are more influential on stats related to interaction with the world and other animals (grasping, damage, effectiveness coefficients, etc.) while teeth placed in the back of the mouth are more influential on ingestion rate. The shape of teeth will alter the stats discussed below in different ways - conical teeth increasing grasping, thicker teeth being more effective against armored animals, shorter teeth being more efficient for plant matter, etc.

Teeth augment and manipulate these stats:

Ingestion Rate - Influential in the diets you can eat, with flatter teeth better at grinding plant matter, and sharper teeth better at tearing meat.
Raw Damage - Effective teeth can damage prey items well.
Grasp-Related Factors - Certain teeth arrangements enhance grasping ability, such as conical teeth.
Effectiveness Coefficient - Certain teeth are better at damaging certain mediums; for example, wider teeth being better at damaging armor, and skinnier teeth being better at cutting through flesh.

When a tooth type is specified, players will be able to place and drag that tooth onto the mandible. Players will have sliders that allow control on the location and frequency of teeth. In the below concept, players can increase the distribution of teeth by pulling the arrows on the end of the lines, and can move the location of the teeth by dragging the circle in the middle of the range:

Players will be able to create additional teeth types once a certain level of progression is unlocked. Similar to the multicellular editor, creating another tooth type starts as a duplication of an existing tooth. Players will then drag that tooth onto the jaw, which will replace existing underlying teeth, or populate un-toothed areas:

Additional Notes on Teeth

Increasing the size of a tooth type visually means less of that tooth in a given region of the jaw, and decreasing the size visually means the opposite.
An unpopulated space on your mandible can mean forgoing some stat bonuses, but can also increase the max size of whatever teeth you have in your jaw, which can also enhance stats. That opens up space for animals like Dunkleostus, who have prominent, giant bony teeth in the front of their jaw, but no such teeth in the back.
Certain teeth can be modified to attach certain benefits; for example, being able to envenomate prey, or the ability to chop through wood. These will be more important in later portions of the stage.

Differentiated vs. Regrowable

Differentiated teeth are a unique characteristic of synapsids (proto-mammals and mammals), who have sections of their mouth uniquely catered towards different functions. Though some non-synapsid animals have differentiation in dental structure - fangs in certain fish and reptiles - the degree of differentiation is much less, and there is much less sectional specialization.

Differentiated teeth obviously allow for a lot more diversity in mandibles, but also come with a cost; in general, the more your teeth are differentiated, the more significant losing a tooth is. Animals with less differentiated teeth, like sharks, are often able to regrow lost teeth rapidly, while animals with more differentiated teeth have limited ability to replace teeth. For animals like sabretooth cats, losing one of their fangs was essentially a life-long disability.

It’s difficult to think of a way to proxy this in Thrive. An immediate idea popping into my head is that trying to bite material that your organism doesn’t have a good ingestion rates or coefficient factors for can debuff your stats derived from teeth temporarily, and this debuff can last longer the more different your teeth are. That way, it is implied that less differentiated teeth are repaired quickly, while more differentiated teeth don’t recover as fast. This concept sounds fine on paper, but it involves another mechanic, and it might be bothersome or too much detail for the type of detail we’re focused on.

Another idea I have is that the more differentiated your teeth are, the more severe the disparity in ingestion rates and effectiveness coefficients are. So for animals with undifferentiated teeth, you might be able to get atleast some nutritional value from items that fall under your digestive system’s diet even if you don’t have well adapted teeth for that purpose, and can more generally inflict damage on more types of armor and flesh than animals with specialized teeth. On the other hand, for animals with differentiated teeth: if your teeth aren’t suited for it, then you get basically nothing from it. This fits in well with the stats I brought up, but it might have a weird effect on balancing; with this system, would animals which first evolve teeth be the most versatile, and animals which have more evolved teeth be less versatile?

So that’s one area I’m not super certain on. I am more inclined to second idea just because it fits neatly, but I think this is something we’ll have more answers for as we get a clearer understanding of the macroscopic stage.

Concluding Thoughts

I think the above concepts are pretty straight-forward and concise. Jaws, teeth, and all that sort of stuff related to the mouth are one of the more obvious “form = function” trends we see in nature, and there’s a good amount of comparative anatomy research surrounding jaws.

The more confusing part with jaws revolves around progression. As I mentioned, adaptations in jaws are the result of adaptations even more incremental in nature than adaptations to appendages and limbs. With appendages, there’s a lot more of a “place and tweak” application there. By that I mean in arthropods, limbs are pretty frequently added and removed; and even in vertebrates, who do regularly stick with the two or four limb body plan, segments on the limb are added and removed somewhat frequently. So providing the player with more significant tools related to limbs is pretty intuitive.

With mandibles, the mandible is much less frequently messed around with; once a mouth is placed, alterations are frequently very slight. So the tools we provide to the player will also likely have to be slight as well, and progression through different “variants” of jaw - for example, going from a mouth opening to a jaw, then from a jaw to a beak - is pretty binding. We’ve seen the progression and reversion of a limb into a foot and back into a fin much, much more frequently than we’ve seen the progression and reversion of a mouth from a mandibulated, advanced jaw to a simple opening, or a beak back into a normal, toothed, jaw, etc.

Writing this out and thinking about this more, I realize that this isn’t really something that requires super-specific handling, or hard locks, or anything like that. If we set it up so that jaws are really beneficial, and make it so that jaws are pretty influential, players and auto-evo will naturally treat them as significant pieces of anatomy and reside in small tweaks.

I think I’m just trying to say that, even though we are arguing for a more part-driven, parametrized system, we cannot think of it as just placing and dropping another part to increase a jaw like in Spore. Variations in appendages, jaws, and limbs have to revolve around altering existing structures in a way that unlocks a different variation. For example, instead of going into a “Variant” menu like we have with organelles right now, turning your beak into a jaw will have to involve the player losing teeth, then turning the segment of jaw without teeth into a keratinized bony structure, with different bonuses applied.

MirrorMonkey2 · April 15, 2025, 8:05pm

These two posts are really great!