D&D 5E Armor as Damage Reduction

[The Crimson Binome]

These are good points, though I don't think you should start with defining your balance needs. The reason people like Armor as DR tends to be a verisimilitude thing, so it's more important that it meets the "feels right" goal.

The typical compromise is that you want heavy armor to be good against multiple weak attacks, but make light armor better against the huge single attacks that you're better off trying to dodge entirely. It helps them feel different from each other, which is important.

If light/medium/heavy armor granted DR 1/3/4 and base AC 11/13/14, while still limiting the maximum Dex bonus to 5/2/0, then you'd probably be okay. The tank will wade through goblins like they weren't even there, and would take like half damage from orcs, but wouldn't be that much better off against giants. Rogues would still get picked apart by superior numbers of goblins, but they'd have a better chance of avoiding the massive swings from a giant.

 

[Blue]

These are good points, though I don't think you should start with defining your balance needs. The reason people like Armor as DR tends to be a verisimilitude thing, so it's more important that it meets the "feels right" goal.

I read that as the goal: "Add versimlitude as top priority, and maybe make sure the math doesn't get too wonky".

Even if you don't state it as such, you have a goal for adding it. Personally adding 10 points for verisimilitude and minus a million for breaking balance is something I'd try and avoid. (Okay, minus a million was hypebole, but I couldn't resist using the Zaphod Beeblebrox quote.)

Having the rules support the theme I want is very important - I don't put down verisimilitude at all, it's a great reason to add something. But the rules also need to support the game.

 

[Blue]

These are only really relevant if you are designing a system for everyone. I find that in home games with people who trust each other these can all be resolved on the fly on a case by case basis.

And would you be resolving them on a case-by-case basis by adjusting the rules to work fairer? Congratulations, now you're doing my suggestions, only piecemeal and after people have had enough lack-of-fun to complain. Personally, I don't see that as a bonus. Well, except for the guy who gets to be lazy upfront.

 

[Blue]

A way i saw sombody do a version of damage reduction depending on armor was the following :

Leave the AC system as it is.
remove the damage bonus from ability scores from attacks.( also the magic bonus from magic weapons only apllies to your to hit bonus not damage)
if a target is hit add the amount by witch the AC was beated to the damage dealth.
atack rolls lower then the targets ac would still miss.

so a atack roll result of 19 would have a damage bonus of +9 against a AC 10 but only a +1 damage bonus against ac 18

Mathematically interesting. The difference between a STR 10 and a STR 20 would still be the 5 points per hit on average. (Or DEX, depending on weapon.) Could leave spells with attack rolls completely unchanged.

A few concerns:

At table combat math - you need to subtract AC from roll to get the modifier, and then add it in to the damage. If the DM doesn't tell ACs he has get the damages and then modify them before tallying. Considering maybe 20 to-hit rolls a round between PCs and foes, that's a slowdown in play.

Makes bonuses to hit and AC more effective. Not items, they had a bonus to damage your stripped. But Bless will increase not just the rate of hits, but the expected damage on a hit. Shield will reduce the damage by 5 even if it still hits you. Could remove them, but it's more math.

The corrolation to that is Advantage becomes not just a better chance to do your base damage, but also a chance to increase your base damage. Disadvantage does the opposite. This multiplies the importance of these.

Damage inflation. With a 65% hit rate (seems often used for PR calculation around here), your modifier will go from +0 to +13, with +6.5 average. With ability modifiers for damage between +3 to +5, this is +116% to +30% bonus above what the ability score would normally give. This could be fixed by reducing all weapon damage by 4/3/2/1 based on tier.

 

[Jester David]

I did some armour as DR rules for a variant rules document I posted to the DMs Guild:
http://www.dmsguild.com/product/177820/5MWD-Presents-Variant-Rules?sorttest=true

If you click "full preview" you can see the text.
Pretty similar to what has come before in terms of numbers.

I've done an Armour as DR game before and it can be funky. 5e especially seems to focus on lots of small hits rather than big single hits, so it's pretty good.

 

[Edwin Suijkerbuijk]

Damage inflation. With a 65% hit rate (seems often used for PR calculation around here), your modifier will go from +0 to +13, with +6.5 average. With ability modifiers for damage between +3 to +5, this is +116% to +30% bonus above what the ability score would normally give. This could be fixed by reducing all weapon damage by 4/3/2/1 based on tier.

you seem to be good with the numbers what would the effect be if you added proficiency bonus to AC ?

 

[Blue]

you seem to be good with the numbers what would the effect be if you added proficiency bonus to AC ?

That would be a drop in expected damage per attack. It overcompensates for the damage inflation though not by too much, but then it also turns a number of hits into misses and that's what would really bring it down.

Just to give an example - let's take a d8 weapon (longsword, longbow, whatever) woth +4 Str, +3 proficiency, fairly average for a 5th thru 7th level character, vs. AC 14. (A 65% to hit chance using PHB method.) Actually, I'll ignore crits to make the math nicer but it's not a big change - that all hapen 5% of the time and add +4.5 damage.

PHB method: 65% chance to hit, d8+4 (avg 8.5) = 5.525 expected damage per attack.

No strength to damage, add to-hit extra to damage: 65% chance to hit. Attack Roll of 8-20 adds +0 to +12 damage. Average damage on hit is 10.5, expected damage per attack (10.5*.65) = 6.825. (23% higher)

Same as above, but increase AC by proficiency: 50% chance to hit, attack roll of 11-20 adds +0 to +9. Average damage on hit is 9, expected damage per attack (9 * .5) = 4.5 (18% lower)

As the base damage goes up (say, larger weapons, barbarian rage bonus, etc.) the difference becomes larger.

For all that, it's definitely in the range of playable.

 

[dave2008]

And would you be resolving them on a case-by-case basis by adjusting the rules to work fairer? Congratulations, now you're doing my suggestions, only piecemeal and after people have had enough lack-of-fun to complain. Personally, I don't see that as a bonus. Well, except for the guy who gets to be lazy upfront.

Yes and no. Since each DM only has to deal with the particular characters and combinations of characters of his or her players, he or she does not need to worry about all the possible issues that could occur. It greatly simplifies the process. In addition, as someone else pointed out, we made the change because it feels more natural to us (we have also modified hit points). We are not even overly concerned with balance.

Also, there is no lack of fun, in the process. I feel sorry for you if that is how you assume it would go down (my assumption is you are speaking from experience and not purely from oddly cynical speculation). In fact, it is because we are having fun playing a game that minor imbalances are virtually irrelevant. And , because we respect each other, we are all willing to say "oops, that is not working as intended, lets try something different."

For example, when we started using DR we said it applied to all damage except psychic and metal armor was only half as effective against cold attacks (unless it was magical armor). However, after playing a little while it just didn't feel right, so we made the switch mid combat and never looked back. No issue.

Another example, we don't have a monk in our party so I haven't had to deal with how DR would apply to a stunning blow. I could spend time figuring out how it would work, but why?

 

[Blue]

Also, there is no lack of fun, in the process. I feel sorry for you if that is how you assume it would go down (my assumption is you are speaking from experience and not purely from oddly cynical speculation). In fact, it is because we are having fun playing a game that minor imbalances are virtually irrelevant. And , because we respect each other, we are all willing to say "oops, that is not working as intended, lets try something different."

Excellent! I'm glad you have a group that's mature and communicate.

I've seen problems. For something simple like "before me and Joe's PC were even and after the change he does more and I do less" is easy to fix moving forward. But I've played with players that didn't want to make a scene or were non-confrontational in real life whom would suffer in silence for weeks before bringing it up.

But even with a mature group I'd dread killing off a character and then getting hit with a "those creatures special attack worked wonky with how we reworked AC and I don't think they should have killed my character". At that point do you bring the character back to life? And what if that upsets another player, whom thinks it was a legit death?

If I'm redesigning subsystems for a game in progress I try to put in the time upfront to let it run smoothly. But not everyone cares, and it seems like you've got a great table that's not worried about it. Fantastic.

Another example, we don't have a monk in our party so I haven't had to deal with how DR would apply to a stunning blow. I could spend time figuring out how it would work, but why?

Oh, I agree. That's why I only posted very common situations that should come up in every game. Weapons vs. spells (point #1). Big & small attacks (points 2-4). Might come up the same night, maybe even the same combat. Seems like the minimum bar to make sure that the math works.

 

[dave2008]

I've got a little more time. Here is how we handle your cases.

1. Weapon vs. caster PCs: Does expected damage vs. DR (after changes to hit and reduction) stay the same relative to magic damage?

We have not noticed any issues

1a. Remember, some spells target AC. Do they get reduced by the armor DR regardless of damage type?

Yes, except psychic which ignores DR. Damage from save spells is also reduced by DR.

2. Many small attacks: Does this make lots of little creatures either a lot more powerful or a lot weaker?

Possibly, However, we allow characters (and monsters) to spend HD to increase the damage on their attacks (must spend a bonus action as well).

3. Few large attacks: Does this make creatures with a few big attacks like giants a lot more powerful or a lot weaker?

We have not noticed any difference. We also allow trading multiple attacks for one stronger attack.

4. Many small vs. few large: How does a dual wielder end up vs. a greataxe users?

We don't have a greataxe wielder, but we do have a greatsword user. We have not noticed any issues. Perhaps it is mitigated by our solution to #2

4a. Including criticals? (Twice as often vs. twice as big)

We have not noticed any issues

4b. How does this affect expected damage from the -5/+10 feats?

We don't have these feats, but we do allow anyone to take a -4 to hit for a +8 in weapon damage. My players don't use this often, but they do it sometimes.

If the answer to any of those is true, then you're shifting the balance.

Balance hasn't been a concern or an issue for us.