D&D (2024) Crazy armor idea

[Flobby]

I had this idea to have armor give Armor Points instead of a bonus to AC. Armor Points would act like Hit Points. First you lose Armor Points, then Hit Points. When your Armor Points reach zero, you need to repair your armor before you can gain its benefits again.

Assuming this is a good idea--let's pretend it is for now--what would a good AC bonus to Armor Points conversion be? Something like +1 AC = 5 Armor Points, +2 AC = 10 Armor Points, etc.

Any math geeks out there who can help?

 

[Horwath]

I had this idea to have armor give Armor Points instead of a bonus to AC. Armor Points would act like Hit Points. First you lose Armor Points, then Hit Points. When your Armor Points reach zero, you need to repair your armor before you can gain its benefits again.

Assuming this is a good idea--let's pretend it is for now--what would a good AC bonus to Armor Points conversion be? Something like +1 AC = 5 Armor Points, +2 AC = 10 Armor Points, etc.

Any math geeks out there who can help?

not for all armor, but I did crunch it for magical armor to keep "bounded accuracy"

weapons instead of +X/+X just add +1d6 damage per plus

armor +1/+2/+3 gives +5/+10/+15 plus 1/2/3 per level of HPs

there are no +X shields, only +1 shield that is special and requires attunement.

 

[GrimCo]

I would take a look at Grim&Gritty rules. It's similar idea to armor as DR, as both reduce damage to HP.

Without adjusting base HP, at lower levels, it gives significant bonus. On the other hand you would need some sort of defense modifier cause PCs will get hit a lot.

 

[Horwath]

I would take a look at Grim&Gritty rules. It's similar idea to armor as DR, as both reduce damage to HP.

Without adjusting base HP, at lower levels, it gives significant bonus. On the other hand you would need some sort of defense modifier cause PCs will get hit a lot.

I would be careful with stacking too much damage reduction.

it could make creatures with lots of low damage attacks completely useless.

10 DR might help vs a cloud giant, but it would make CR 1/2 or CR 1 creatures completely irrelevant.

extra 100 HP works the same vs 20 attacks for 1d4+2 and 2 attacks of 10d6+10.

 

[EzekielRaiden]

I had this idea to have armor give Armor Points instead of a bonus to AC. Armor Points would act like Hit Points. First you lose Armor Points, then Hit Points. When your Armor Points reach zero, you need to repair your armor before you can gain its benefits again.

Assuming this is a good idea--let's pretend it is for now--what would a good AC bonus to Armor Points conversion be? Something like +1 AC = 5 Armor Points, +2 AC = 10 Armor Points, etc.

Any math geeks out there who can help?

Unless the damage output is massively decreased, you've just made sure nobody bothers wearing expensive armor--ever. Because they're going to take more than 5/10/15 points of damage in any given fight, and now their armor is just useless. Particularly for front-line fighters.

 

[Horwath]

Unless the damage output is massively decreased, you've just made sure nobody bothers wearing expensive armor--ever. Because they're going to take more than 5/10/15 points of damage in any given fight, and now their armor is just useless. Particularly for front-line fighters.

these numbers surely need to be playtested, even just in theory white room.

maybe "armor HP" is reset after short rest.

if removing AC bonus turns hit rate on your from 60% to 90%, then you are taking +50% damage and your HPs need to be 50% higher, so 5th level fighter with 50HP should get +25HP from armor.

maybe light armor could increase HP by 25%
medium by 50%
and heavy by 75%

dex limit would apply normally.

shield is +2 AC normally

 

[strawpberry]

I've been reading into the Witcher TRPG lately, and their armour systems kinda work like this. Instead of an attack roll against AC, there's an attack roll against a defensive manoeuvre roll - but then if the attack connects, you compare the damage with the armour's damage reduction. If the damage is less than the DR, nothing happens. If the damage is more than the DR, any excess damage is done to HP,  and the armour's DR is reduced by 1 (cumulatively, until you can get it repaired). Heavy armour has massive DR, but it's expensive to buy, it's expensive to repair, and it comes with dexterity downsides.

There are also rules about armour ablation from certain weapon types, and poisons circumventing armour... I haven't had a chance to play the system yet, but these rules seem to support their intended vibes of "hurting someone heavily armoured means you need big swings", as well as "you need to maintain your armour to survive". Could be adaptable to 5e, if those vibes are what you're going for!

 

[aco175]

What would be easier to track?

Bonus HP that reset each fight appears easy. Say I have leather armor and get 5hp or plate and get 30hp, it would be easy to have a side column to track this on next to me real HP column.

What about just tracking a number of hits. Leather armor lets you negate one hit and plate might get 4 hits per short rest. Per encounter might be a bit swingy for this. There is also a problem in math with a goblin hit and a giant hit.

Whatever it is, it should be easy to use. There is an optional rule that lets you destroy your shield to turn away a critical hit. It is easy and comes with a bit of disadvantage since now you have no shield.

 

[MarkB]

Divinity Original Sin 2 used a concept like this. Creatures had levels of physical and/or magical armour, and until the armour HP had been depleted they were immune to the secondary effects of attacks, such as being pushed or tripped. You could do something similar here - opponents must deplete your armour HP before they can apply weapon mastery effects or similar rider effects against you.

 

[Oofta]

A lot of people have tried to come up with "better" armor rules and it's not easy. If you were to be realistic, leather and studded armor basically don't exist. Padded armor was the low end armor, made of several layers of fabric. The next step up (putting aside many, many alternatives) was chain armor. While quality varied, it was better at stopping piercing or slashing damage, but didn't do much for the concussive blows. That, and the weight distribution wasn't great because most of the weight was on your shoulders. That arrow may not pierce the chain armor, but it's still going to leave a bruise.

High quality plate armor on the other hand, was practically impervious to most blows. The scene in movies where someone stabs someone in the chest and it easily gets through the breastplate isn't at all realistic. It was even pretty effective against early firearms. But even in that high end armor concussive blows could still hurt, although unlike chain armor it could spread the force of the blow out. For the most part the way to kill someone in high quality plate was to wrestle them to the ground, pull of their helmet and stab them in the face. But that's not very exciting.

Which is my long winded way of saying, there's just not a good solution. If I were to change things I'd probably go with some sort of combination. Retain traditional AC indicating that the blow landing effectively then combine it with armor HP reflecting how well the armor is absorbing the impact. Of course you'd also want to throw in repairs and patches, especially to the lower end armors.

But it would take a lot of playtesting and some armors should be vastly more effective than others which isn't necessarily a good thing for the game. In other words, you're hardly the first person to go down this road and while I understand why people want to do it I just don't think there will ever be a great way to model armor for something as over-simplified as D&D.