Piecemeal Armor as Damage Reduction

I've mentioned before that I want my upcoming game to use armor as damage reduction. Here's an update on that.

So for a post-apocalyptic system, piecemeal armor is, if not essential, then at least something you'd really want to have at least for flavor purposes.  Mechanics aside, the imagery of someone wearing hockey pads covered in spikes, an old army helmet, and greaves made of scrap metal really sets a good post-apocalyptic tone.

It took me a while to figure this out but I think I basically have it now.

To recap– armor follows a step die system.  When you're hit, you roll your armor die and subtract the number rolled from the damage.  Except, ones count as zero (meaning the attack found a gap in your armor), and twos do as well if you don't have a helmet or other head protection.

Armor Values for Full Suits of Armor

One thing that helped me figure this out was starting at the end and working backwards– that is, figuring out what I wanted the armor value for a full set of armor to be and working backward from there to build the piecemeal system.  

What I decided on was d4 for light armor, d6 for medium and d8 for heavy– for medieval armor.  For armor made of modern materials, the die sizes would be one higher, so d6/d8/d10, and for futuristic materials they'd be two die sizes higher, so d8/d10/d12.  

Once I had that I could figure out what the value of the individual pieces should be– covering your whole body with medieval-quality steel should be worth d8, covering most of it with leather d4, and so on.  

The Different Types of Armor Pieces

I really want to be able to model a wide range of armor qualities, so for the sake of this system there are six types of material armor can be made out of.

Light archaic– leather, padded or hide

Heavy archaic– Iron or steel

Light modern– Kevlar or other ballistic fibers, or modern plastic

Heavy modern– Modern steel or titanium alloys, or ballistic ceramics

Light futuristic– Aerogel, genetically engineered spider silk, smart impact gel, etc.

Heavy futuristic– Liquid metal, smart steel, adamantium or whatever

All three heavy materials are equally heavy, as are all three light materials.  Modern light is as strong as archaic heavy, and futuristic light is as strong as modern heavy, so there are essentially four levels of protection they can provide.  

To be clear, armor pieces made of heavy materials usually contain a mix of heavy and light materials.  Like, a breastplate has a padded underlayer under it.  If an armor piece is made of a mix of materials, it generally counts as heavy material.  

Another clarification– modern includes stuff that's coming out in the next couple decades.  Futuristic means far off enough that we can't be sure what it will look like.  

Armor pieces could cover any portion of your body, but as a guideline I'll use five default body parts:

Torso (waist up to to shoulders)

Head and face

Arms and hands

Legs and feet

Hips and groin

So five body parts, six materials, so thirty possibilities.  Each piece of armor has a point value based on what it's made of and what part of your body it covers.

Add up the value of all the armor you're wearing, without rounding anything.  Obviously these are guidelines and you could have like a vest that doesn't cover the shoulders, or a vambrace on only one arm, so use these as guidelines but made adjustments on a case by case basis.  

Your armor die is the biggest die whose highest possible value is lower than your total armor score.  A few examples:

If you're wearing medieval plate mail, your armor score will be 8– the total of the entire "heavy archaic" column– so you roll a d8.   

If you're wearing modern military armor with a steel (modern alloy) and kevlar helmet, kevlar vest with steel plate inserts, and kevlar pads (no plates) over your hips, groin and upper thighs, along with knee and elbow pads, and maybe a really thin kevlar shirt, that's 4 for the heavy modern torso item, 2.5 for the heavy modern helmet, and 1 for the light modern hip/groin protection.  The knee and elbow pads don't cover the whole arms and legs so they're not worth 1 each, but they have to be worth at least .25 each when you add them to the shirt, so this whole getup gives you 8, maybe 8.5 armor points– so a d8 again.  

Now a real post-apocalyptic example.  Suppose you're wearing the following:

A football helmet with a big spike on top

Steel-toed, thick leather boots 

Soccer shinguards

A kevlar vest with scrap metal plates inserted into it

Plastic elbow and knee pads from a skate shop

A genetically-engineered spider silk long-sleeved shirt, thin and breathable

Fingerless leather gloves

A chainmail speedo

You're a true wastelander in that getup! Instead of doing this by item, I'll do it by body region.  

Torso– the spider silk shirt is light futuristic material, but so thin it doesn't add much.  Call that .25.  The kevlar vest would be worth 3, and with the plates it's designed for it would be worth 4.  With plates of scrap metal, let's call it 3.25.  So 3.5 total for the torso.  

Head– the football helmet is light modern material, so it's worth 2.

Arms– Fingerless gloves don't do much for you.  The long-sleeved shirt covers your entire arms but is a bit thin to really be armor, while the elbow pads are sturdy but don't cover much.  Light modern arm coverage would be worth 1, and this is maybe half that so call it .5.

Legs and feet– The steel-toed boots are basically archaic light material.  Knee pads are light modern, as are the shinguards.  Overall maybe half the leg and foot area is covered, at best.  Full coverage with light modern material would be worth 1, so let's call this another .5

Hips and groin– A chainmail speedo is heavy archaic material.  While undeniably stylish, it covers barely half this region.  So, another .5.  

So 3.5, plus 2, plus .5, .5, and .5.  That's 7 total, so this person's armor value is a d6, and because they have a helmet, twos count.  

Armor and Encumbrance

This depends on your encumbrance system.  I like the ones where you get a number of encumbrance slots equal to your strength score, more or less.  For one of those I'd say the following:

Torso coverage made of heavy material is 2 encumbrance slots

Torso pieces made of light material take 1 encumbrance slot

Other pieces made of heavy material take 1 encumbrance slot

Other pieces made of light material take half a slot  

So a full suit of heavy material armor takes six encumbrance slots– a lot, but totally doable.  

Armor Special Qualities

Armor can have special qualities other than raw damage reduction.  A few possibilities:

Full coverage: ones actually count as one because there are no gaps in the armor.  Thinner points, but not total gaps.

Damage resistance: Halve all damage of a particular type, like a bomb suit halves explosive/fire/shrapnel damage.

Environmentally sealed: this armor has its own internal air supply and you're immune to gas, pathogens, or bugs crawling into your armor, as long as you use it.

Damage vulnerability– There's a particular type of damage this armor doesn't work against, like if it's all metal then it does nothing against lightning.  

Spiked– This armor has spikes on it which can be used as daggers.  You automatically make a spike attack against anyone you grapple.  

Most of these would probably require a full set of armor to work, other than the spikes.  

Armor Degradation

I really want to have this in my game, but I haven't come up with a way of doing this that I love.  I want a method that's fast and also realistic.  I'll circle back around to this later, but I'm also open to suggestions.