Macroscopic Editor, Progression, and Principles

Deus · May 10, 2025, 7:37am

Integumentary System Customization

Here is the next component of an editor concept, this time focused on integumentary customization. Note that I do not discuss “brushing” or “patterning” tools here, and instead focus on a general concept/system allowing us to represent complex skin types and navigating through some of the more difficult conceptual areas to cover. Customization tools such as brushing and color customization can be discussed once we understand where and how to best apply them I think.

Discussing integumentary customization gives us base concepts for almost every part of the external editor when combined with the past few posts, so it’s an important topic to give specific focus to.

Attributes and Constraints

Here are the primary stats which are heavily influenced by the integumentary system, as well as how the system can connect to conceptualized constraints.

Attributes Involving Skin

Protection - How much your skin provides defense from attacks and harmful elements. Basically, an armor effect.
Gas Exchange - How much your skin augments respiration.
Dehydration Rate - How quickly your body loses moisture through skin, limiting terrestrial capability.
Mobility Stats - Boosts to movement stats such as buoyancy, agility, etc., more important in water, some marginal effects on land.
Environmental Tolerances - Especially for land animals, integumentary systems have a strong impact on their tolerance to climate.

Constraints

Mass - Certain skin types and customization can boost mass. For example, thicker skin, dense fur, and more defensive scales make animals bulkier.
Surface Area - Certain skin types are much more influenced by surface area. Surface area is particularly important for animals which rely on gas exchange via skin, such as amphibians, and for animals without keratin, impacting dehydration and gas exchange. It is also influential on tolerances.
Streamline Measure - Certain adaptations can increase or decrease how streamline an animal is. Teleost fish typically have integumentary adaptations to improve maneuverability in water, while bony fish trade some streamlining for better defense.

Complications

This concept was kind of complicated for me to think through, so I wanted to first bring up some of the issues I was ruminating over for a while so that my thought process might make sense in this post before getting to implementation details.

Connections to Skeletal Structure: The complicating factor is the fact that a chitinous integumentary structure leads to the evolution of an exoskeleton, but other integumentary structures do not necessitate the evolution of an endoskeleton. This has odd implications on the progression of the game, as it’s confusing to lock a skeletal structure entirely behind an integumentary style.
Transitions: There is also the question of transitioning through different integumentary bases. Variations to underlying structures exist, but so too do big jumps between different skin types. We’ve seen reptiles and mammals lose fur and feet to adapt to marine environments, but we haven’t seen reptiles and mammals lose the keratin which makes them waterproof.

Evolutionary “Checkpoints”

There appear to be certain integumentary adaptations which are much more binding and impactful.

Keratin - Generally indicates adaptation for land. Significantly reduces gas exchange in skin, but significantly reduces the rate at which you lose thirst, allowing much more terrestrial lifestyles. Allows for the evolution of reptilian scales, fur, glandular skin adapted for land, and feathers.
Chitin - Generally indicates the evolution of an exoskeleton, allowing arthropod skeletal structures and advantages and disadvantages brought by that.

Note that keratin and chitin are not exclusive to the described groups. For example, keratin is found in fish teeth and parts of their scales, as well as in the nails of amphibians; collagen, important for non-exoskeletal organisms, is present in arthropods, important for their muscular tissues and ligaments; and chitin is found in many animals who don’t necessarily have an exoskeleton, such as velvet worms.

Implementation

Skin Types

“Skin Types” are the broadest categorization of your integumentary system, typically referring to their characteristic structure. For example, one skin type is “Dermal Scales”, referring to the scales of fish, while another is “Keratinized Scales” referring to the scales of reptiles.
Each different skin type gives a fundamentally different baseline impact on your stats, and emphasizes/de-emphasizes certain constraints. For example, skin type A gives you more baseline mobility than skin type B, and skin type A is more sensitive to surface area.
Your choice of skin type defines what customization options are available to you.

Attributes

Attributes are special designators of the general morphology of your skin type, providing unique adaptations besides those designated by your skin type. They allow us a convenient way to represent integumentary adaptations.
You can assign an “Attributes” to your skin type, augmenting that skin and providing bonus stats. These abilities can make your skin look different, and provide bonuses depending on your body plan and constraints. Only one attribute can be assigned to your skin type (?).
For example, if you have Gelatinous skin, an attribute available to you is “Mesoglea”. The Mesoglea attribute grants you buoyancy depending on your surface area, allowing you an easier time to float at such an early part of the Macroscopic Stage, but generally reduces your streamline measure. It makes your creature look more bloated when equipped, reflecting jellyfish and comb jellies.
Attributes have customization options attached to them. For example, you can customize how much Mesoglea is in your Integumentary System if it is equipped.
Your access to certain attributes depends on your skin type. For example, animals who don’t have gelatinous skin cannot equip mesoglea. Unlock conditions can also be applied to attributes if desired. For example, being hunted three times with dermal scales unlocks armored scales, reflecting the evolution of armored fish.
Attributes define the general characteristic of your skin type rather than unique adaptations. For example, a fish with a single armor plate on its skull doesn’t have the “Armored” attribute - the “Armored” attribute, once equipped, indicates that your skin as a whole is hardened, and is an additional layer of customization besides placing individual armor plates. This lets player apply stats, adaptations, and appearances to their organism which having to spam a specific customization, part, or tool on their entire organism, which would be annoying, a hassle, and not realistic to how such integumentary structures evolved.

Attributes allow us to represent pretty complicated structures and adaptations in a relatively gamified and simple way. Selection should be concise, mindful of what we choose to represent as a brush/part and what we choose to represent as an attribute.

In my head, an Attribute notifies the system of the general characteristic of your animal’s integumentary adaptations, while individual sculpting/parts are the more “unique” and individualized sections of your animal which provide an individual stat bonus. For example in the “Armored” attribute, the attribute essentially denotes the skin as being characteristically hardened and attaches a cool texture, and the player has an option to place a more intricate plate decoration which more significantly confers protection on specific sections of your body plan and gives more influential boosts. But it’s something to be mindful of for every attribute, and particular attributes I threw out there above are more vulnerable to that question: the “Spined”, “Quilled” and “Ornate” attributes, among others, are particularly sticking out in my head.

Catalogue

Here is a catalogue of skin types and attributes. As mentioned above, skin types refer to the general nature of the integumentary system, whereas attributes are customization options for the skin type which confer unique stats. Bulleted items are attributes, whereas bolded items are skin types.

Gelatinous

Our stand in for skin types before collagen and chitin. Encompasses diploblastic and simple triploblastic animals. Strong sensitivity to surface area, though may be amplified. Most simple skin type, only available to animals without a skeleton.

A potential goal to aim for with gelatinous is having the player automatically unlock/start with an attribute that reflects their membrane choice in the Microbe/Multicellular stage. This can do a good job of connecting the two stages.

Mesoglea - Gelatinous substance in skin which helps with floating. Surface area dramatically enhances buoyancy, reduces streamline measures.
Filter-Feeding - Surface area enhances uptake and ingestion rate of materials. Much more sensitive to surface area impacts.
Chitin Capsules - Bonus to defense; automatically equipped if chitin was present in microscopic stages. Reduced sensitivity to surface area, and increased mass.

Dermal

The default skin type for animals which evolve an endoskeleton, a stand in for fish integument. General boost to streamline measure and weak boost to protection compared to gelatinous skin. Without an equipped attribute, dermal skin looks smooth, such as that of a lamprey and ancestral fish. Dermal skin is the most well-suited for marine environments, having the strongest baseline boost to the streamline measure. It is also pretty widely customizable, with its attributes able to apply strong bonuses.

Armored - Skin becomes generally plated and hardened. Provides significant protection, but hampers streamline measure. Increases mass.
Placoid - Provides decent protection, less than armored, but with minimal impact on mass and a boost to streamline measure.
Leptoid - Minimal protection, but great boost to streamline measure. Reduces mass.
Spined - Similar to a pufferfish, your integumentary surface is covered in spikes which can be retracted. Damage upon contact when enabled, but considerable hit to streamline measure.
Mucuseous - Being attacked generally reduces the mobility of the attacker, similar to hagfish. Streamline and defensive measures are impacted.

Mucuseous Glands

Proximating the skin of amphibians, provides boost to respiration based on surface area. Regardless of respiratory organs, respiration rate is boosted on both land and water, allowing even animals with gills some capability to breath on land, and allowing animals with lungs some capability to breath in water. Dehydration rate compared to fish scales is reduced, but still very sensitive, meaning terrestrial life is limited by access to water. Impact of surface area greatly increased.

Poisonous - Skin damages other animals if attacked. Reduced surface area impacts. Reduced surface area impacts, both good and bad.
Keratinization - Dehydration rate reduced, allowing longer habitation on land. Reduced surface area impacts, both good and bad. Enables unlocking of scales.
Armored - Hardened skin, allowing general boost to protection. Reduced surface area impacts, both good and bad. Effect not as strong as protection from amniote or fish scales.

Fur

Proximating the skin of mammals, fur provides a boosted tolerance to cooler environments, and generally minimizes the impact of surface area on the organism. Despite boost to cold tolerance, tolerance to high temperatures, though impacted, isn’t shifted significantly due to the ability to dynamically shed. Due to its unique tolerance to colder temperatures and ability to tolerate warm environments, fur is generally the most widely-adaptable skin in Thrive.

Water-Tight - Proximate for aquatic mammals who have not lost fur. Streamline measure improves.
Keratinized - Proximate for skin such as that of armadillos and pangolins. Boost to protection, mass increases.
Quilled - The fur of the mammal is generally hardened, damaging other animals upon being attacked. Increased mass, and increased surface area impacts.
Wooly - Fur is highly adapted to cold environments, strongly increasing tolerance but decreasing tolerance to the heat. Mass is significantly boosted.

Keratinous Scales

Approximating the skin of reptiles, keratinous scales provide a sizable boost to protection, and a boosted tolerance to warm environments depending on surface area at the expense of a sensitivity to cold environments. Dehydration rate is minimized. Combination of dehydration rate reduction and tolerance to heat makes this skin well-suited for arid and warm conditions.

Water-Tight - Proximate for reptiles who are aquatic. Streamline measure improves.
Osteoderms - Skin is generally covered with thickened scales, strongly enhancing protection but increasing mass.
Pycnofibers - Skin is generally covered with primitive, feather-like fuzz. Increased tolerance to cold, and increased streamlining for flight, though reduction in protection and increased sensitivity to surface area. Enables unlocking of feathers.
Glandular - Scales are minimized, replaced with smooth skin and the presence of skin glands, similar to that of synapsids. General boost to tolerance to colder environments and mobility and reduction of surface area impacts, though noticeable loss to protection. Enables unlocking of fur.

Feathers

Proximating the skin of furs, feathers provide a great boost to mobility and reduce at the cost of protection and some sensitivity to surface area effects. Strong boost to streamline measure on land, boosting advanced mobility options such as flight and gliding.

Water-Tight - Proximate for aquatic birds. Streamline measure improves considerably, but reduced bonuses to mobility.
Ornate - Feathers are iridescent and flamboyant. Reduced bonuses to mobility, but general discount for MP due to enhanced sexual pressures.

Chitin

Proximating the skin of arthropods, chitin provides great boosts to protection with a noted, but minimal impact to mobility and mass. Animals with chitin appear to be encased in hard armor, akin to arthropods in real-life, and have appendages which look more geometric.

Having chitin as an integumentary structure denotes your animal as having an “exoskeleton”, which applies unique appearances and stats to your organism’s appendages and torso, organs, mandibles, and unique discounting in the editor. In general, it is much cheaper for players with an exoskeleton to place down and modify appendages. Surface area impacts are reduced, and size-related costs are boosted, capping size a bit more, though can be mitigated through advanced respiratory structures.

Chitin also has an additional customization slider with integument thickness - rigidity - which provides a split between mobility and protection. More rigid exoskeletons appear less segmented, while more fluid exoskeletons appear more segmented, such as the skin of a trilobite or centipede. Despite having less “options” than collagen-based skin types, chitin by itself is much more customizable than any of the other skin types.

A more advanced discussion of exoskeletons, as well as their unique behavior in the editor, will be held when discussing skeletal structures.

Armor-Plated - Similar to the skin of scorpions and trilobites, exoskeleton is incredibly adapted towards withstanding damage. Very strong impact on mass, and reduced streamline measure.
Lightened - Exoskeleton is made of lightweight material, increasing streamline measure and reducing mass, but decreasing protection. Surface area becomes a bit more impactful.
Calcium-Enriched - Skeleton embedded with calcium carbonate, strongly boosting protection with little impact on streamline measure. Strong impact on mass.

Additional Potential Skin Types and Attributes

The only thing I can think of currently is something to proximate the skin type of mollusks, such as snails and octopi. I can see it being linked to the unlocking of a “hydrostatic skeleton”, but that is something that should be conceptualized when we have a better understanding of progression in the Macroscopic stage.

In general though, I think the attribute system is really beneficial because it lets us add different unique adaptations with a relatively simplified tweaking of stats, constraints, and in some cases, abilities. There are additional attributes I can think of on the spot now which would be cool to represent - the skin of chameleons and other animals which can change skin color for example, or the skin of hagfish - but those depend on our priorities at the time of implementation. In general, I wanted to illustrate the premises of the concept with the suggested attributes and skin types; it isn’t meant to be a conclusive or comprehensive list.

Solving the “Exoskeleton” Problem

As I mentioned above, one problem we face with the integumentary system is related to chitin - choosing chitin as your primary skin results in a fundamental change to your skeletal structure, giving you an exoskeleton. That complicates things, as it’s an awkward way to deal with an important piece of progression in Thrive. So, how do we deal with this?

At first, we don’t really give much information about integumentary structures to the player. We start them off by assuming that their skin is gelatinous, akin to a very basal macroscopic animal.
The first determiner of your integumentary evolution isn’t presented as related to the skin itself, but instead a choice about the skeletal structure. That way, the more apparent binding nature of your skeleton also intuitively leads to more bound integumentary evolution. Once you choose a skeleton structure, your skin changes to a basal chitin or dermal covering depending on your choice.
This fits in nicely with theory anyways; chitin obviously corresponds with an exoskeleton, but collagen and fish scales - which started the evolutionary path of keratinized and collagen-based skin, such as dermal scales, feathers, fur, and reptilian scales - are heavily tied to mineralized tissues as well.

That takes care of the most major “binding” between integuments, if you wish to revert to the other big integumentary type, you have to undo all skeletal structures associated with your skeleton. Once you build onto your skeletal structure, it becomes harder to switch to the opposite skin type.

We can apply similar principles to more “minor” binding questions - for example, reverting from fur to scales, scales/fur to amphibian skin, etc. Certain structures can be placed only with certain integumentary structures, and must be replaced before reverting. But that is a more delicate matter which I think would best be discussed later, and can be dealt with in other ways.

Questions, Concerns, and Concluding Thoughts

I think this is a solid way to deal with pretty complicated morphological structures, setting up a system that can be added upon pretty easily compared to creating very specific, handled sculpting mechanics, or requiring the placement of many, many smaller parts. It does bring up some questions regarding the philosophy of our editor however; particularly, in the “sculpting v. parameterized” area.

The ultimate question: what is dealt with via the more intricate sculpting tools we offer the player, and what is dealt with via the “Skin Attribute” system? For example, the “Armored” attribute for fish scales: how do we allow detailed sculpting of prominent dermal plating, such as is seen in many basal fish species?

All in all, this system is meant to make it easy to represent certain things which might be difficult to represent traditionally. This could make certain things, like a very dynamic brush system where you can apply a texture on your organism, less influential. I think both can be implemented - attributes informing the system of the general characteristics of your skin, and brush providing bonus stats and customization options - but such a parametrized system does ultimately reduce some customization options.

There are also lingering questions on how to limit progression and switching between the “collagen-based” skin types. It’s pretty hard to de-evolve fur and feathers and revert to being completely scaled, it’s pretty hard to revert to amphibious skin if you have keratin, it’s pretty hard to revert to fish scales if you have amphibious skin, etc. I do have some ideas there, but I want to make sure the basic premises of this idea don’t have any glaring issues first.

This can be a starting point for discussing a complex topic, and can be clarified further as we understand the goals and expectations for our integumentary system. Nailing this down alongside the prior posts gets us further along understanding having an initial master concept for how our editor will deal with the “External” parts of an organism - the internal editor, which focuses on organs, is another conversation which should be discussed once we understand what the sculpting tools will look like.