Material System

I got sidetracked.

I was working on tying volumes to bones in order to calculate mass from volume and density, when I suddenly realised I was going to have to get density from somewhere. I was this close to following the original plan and adding a simple constant “creature density” value to the game… but…

Well, quite frankly, I’m tired of making placeholders and putting the interesting stuff off until I’ve finished the boring stuff. So I decided not to, and dived headfirst into the new material system. I wonder how many of these I can fit in? Any preferences?

My initial thought was to take a leaf out of Dwarf Fortress’ book, and define materials generically, to amplify the possibility of weird, interesting and utterly horrific combinations. The problem with this, though, is that they need to texture differently depending on how they’re applied, especially for things like fur and claws. So it’s more likely we’ll need to split them up based on how they’re applied…

• Skin
    – The furry/feathery/skinny/slimy surface covering. Has a strong influence on friction and insulation. Mass determined by Surface Area * Thickness * Density. Immediately visually apparent by virtue of body texture, obviously.
• Flesh
    – The goo and meat and muscle inside the creatures body. Influences the creatures strength and flexibility, as well as their optimal operating temperature and how endothermic they are. Mass determined by Volume * Density. Visual markers are mouth-textures and corpse meat textures.
• Hard Tissue
    – Skeleton and weapons (I’ll probably split these into two seperate items, so a creature can have different claw and bone material). Density and compressive/shear strength will be the most influential settings for the skeleton, while density and sharpness will be important for weapons and chewing. Visible on hands and feet, teeth and in corpse bone textures.

These three categories will make up the outer covering (fur, feathers, skin), inner covering/organs (fibrous, porous, fatty) and skeleton/claws/teeth (keratin, chitin, osseous tissue, enamel), respectively. Each item will have its own texture/spritesheet, and a position in the mutation map.

I will likely have to have duplicates so as to allow, for example, chitin to be used as either endoskeleton or exoskeleton. One idea I’m leaning towards is storing materials as three texture objects in the same asset folder, so chitin could be a single Material asset but still be applied as Skin, Flesh or Hard Tissue. I imagine making your internal organs and muscles out of chitin wouldn’t end well, but why should we stop creatures from trying?

And as a bonus, this means creatures can have body coverings and flesh made entirely out of materials I hadn’t considered before now, like fibrous muscle, or bone tissue, or eyeball fluid or retina cords!

Wow. I am a horrible person.

This material system will likely become one of the sources of tangential learning for Species. Much the same as how playing Dwarf Fortress is an extremely effective way to drill into you what Magnetite, Hematite and Limonite are, Species will happily throw a bunch of terms I’ve stolen from Wikipedia at you until you bloody well remember what Osseous Tissue is, damn it.

The system will also have a few additional per-material values. Most of these will be placeholders until their appropriate systems are in place, but it doesn’t hurt in the long run to define them early. So far ‘m thinking these ones look good:

Density,
Compressive, Tensile and Shear Strength,
YieldRatio (a simpler way to represent Compressive, Tensile and Shear Yield Strength),
Coefficient Of Friction,
IgnitionTemperature, BurningEmission (that is, the amount of heat this material will emit while burning),
Melting and Boiling Point,
Thermal Capacity and Conductivity,
OperatingTemperature (flesh and muscle specific: determines the optimal body temperature for this creature),
HeatOutput (per unit of mass. This will be what establishes Endotherminess!),
and AcousticalAbsorption.

Of course, finding values some of these numbers is gonna be all sorts of fun. “What’s the compression strength of fibrous muscle? What’s the melting point of eyeball fluid?” It won’t be easy, but there’s plenty of dogs and cats in the area.

Or, y’know, I could just ask The Google. But where’s the fun in that?

FOR SCIENCE!!
Qu

 

 

(Edit) Oh wow. I think I promised to let somebody kick me if I did exactly what I’m doing right now.

http://speciesdevblog.wordpress.com/2012/06/13/plans-for-the-next-version/#comment-673

Yep. Yep I did. Who wants to do the honours?

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  1. #1 by Adam Benton on May 22, 2014 - 8:48 am

    Will evolving a material for one aspect influence it’s chance of evolving for another, representing evolutions habit of co-opting structures for other functions. For example, a creature with cartilage claws might be more likely to mutate and get cartilage skins (assuming selection pressures are all equal and all that?)

  2. #2 by ququasar on May 22, 2014 - 11:27 am

    I’d like to implement something like that: it’s quite noticable at the moment that legs, for example, evolve completely independantly from one another. It’s makes me think we’ve got point mutations, but no copy mutations.

    Some sort of method to link up similar body parts and enable them to occasionally take genes from each when they mutate seems called for: I just need to work out the best way to implement it.

  3. #3 by Loweren on May 22, 2014 - 1:57 pm

    Wait, do you mean it will be possible to melt and boil creatures?

  4. #4 by ququasar on May 23, 2014 - 2:55 pm

    Possibly. Not sure yet whether that level of detail is necessary, or whether I just stick with a single ‘ignitionTemperature’ value. While it would be interesting to see physical differences when burning a transparent jellyfish vs a wooly sheep, the end result is pretty much the same either way. If I can’t work out a way for it to actually affect gameplay, I may forgo it.

    … which, giving it some thought, would mean extending the entire concept even further. Thus far I’ve been thinking of materials as solids, but the material inside the skin can (and probably *should* for some primitive creatures) be liquid. Liquified flesh would have completely different properties to solids: creatures evolved to use it would likely die if it solidified.

    Oh wow. This opens up a whole new potential branch of extremophiles on both ends of the temperature spectrum. I shall have to give this some thought…

  5. #5 by Blake on May 24, 2014 - 3:47 pm

    I tried to search out an answer for this and failed so I’ll ask here: Are there any plans to implement a way to allow the player to name the various species emerging in their ecosystem, letting him or her change the taxonomical name from the randomly-generated one if a certain species becomes of particular interest. I really am enamored with the idea of playing a Linnaeus type figure with the omnipotence to categorize species as they appear.
    Anyways was very glad to know this game is being actively produced. It’s a great idea being executed wonderfully.

  6. #6 by Inarius on May 25, 2014 - 8:22 am

    I love this thing. A “life generator” inspired by the procedural-Dwarf-Fortress rules. Will some creature breathe fire, to make other creatures melt ? :)

  7. #7 by seo optimization on August 18, 2014 - 1:22 pm

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