Sunday 11 August 2019

Static Weapon Damage: A Problem, and a Solution

If you've read my posts on D&D Without Damage Dice and Ascending Damage, you'll know I use a sort of "wound counting" or "hit counting" system, which by definition has static damage - every hit with a weapon is just "one hit". The design goal is to make combat simpler and faster, but ideally, it should still be interesting and have some variety.


What is static and variable damage?


In the olden days of Chainmail, monsters and men took a certain number of hits to kill, regardless of weapon. The effectiveness of different weapons was modeled by their ability to score a hit against each type of armor, as presented in the dreaded MAN-TO-MAN MELEE TABLE. Then came Original Dungeons & Dragons, which introduced hit dice - instead of 1 hit-to-kill, men could take d6 points before death. LIkewise, all weapons dealt d6 damage. The damage roll introduced some variety to the outcomes of attacks. However, this system is still typically called "static weapon damage" in the sense that weapons were not differentiated.


[mantoman.png]

The Greyhawk supplement introduced the "alternative combat system" with its "damage done by weapon type", or what we would call variable weapon damage. Daggers dealt d4 damage, spears d6, and swords d8, as they do to this day. This was wildly popular and was carried over to Moldvay's Basic - though it should be pointed out that it was presented as an optional rule. The default in Moldvay was still the fixed d6 damage rule.


So, the main ways of differentiating weapons are:
  • variable damage (die size, flat bonus, roll and keep...)
  • damage adjustments against different foes (e.g. bonus against large creatures)
  • adjustments to hit (e.g. against different armor or weapon types)
  • critical hit range (20, 19-20...) and damage (2x, 3x...)
  • secondary special features (spears can attack from 2nd rank, crossbows must be reloaded...)
  • number of attacks
  • tertiary properties such as weight, price, initiative adjustments, durability, social status...


What's the problem with static damage?


I'm not really a simulationist. I'm not aiming to represent historical combat faithfully. But I still want a little mechanical differentiation to support the difference in fiction, obvious to anyone, between stabbing with a dagger vs. swinging a greataxe. And, honestly, combat without damage rolls might end up feeling a bit sterile, so making weapon choice and tactics a meaningful decision will help spice it up.

In my B/X-hack-via-OD&D-and-Blackmoor (name pending), I obviously cannot vary weapon damage, since I'm not using dice for it. Certain weapons doing 2 or 3 hits (or "Wounds" as I'm calling them) instead of 1 would be far too large a difference, when most low-level monsters like skeletons and orcs can only take a single Wound.

I don't usually like double-damage critical hits in D&D, and prefer a natural 20s as simply automatic hits. But when playing with Wounds, I would consider including criticals just to add some variety to the proceedings. However, when facing monsters that always die in a single hit (HD 1 types like orcs), doing "double hits" on criticals does not matter at all.

Is there some solution, some system of differentiating weapons while keeping fixed damage? Ideally, any solution would include a minimum of three "tiers" of weapons in terms of weight/effectiveness: simple weapons like daggers, martial weapons like swords, and two-handed weapons, at least. (If spears don't have their own tier between daggers and swords, then they will have to be combined with either, becoming strictly superior in that damage tier, due to their additional property of reach.)

One possibility is to do something like what Chainmail does: give the weapons different to-hit adjustments against different armors. But that sort of thing is part of the reason I wanted to get away from LotFP in the first place. I don't want to remember what bonus which weapon gets over what AC threshold, and doubtfully do my players either. (Maybe if the LotFP adjustments were stated in terms of "against targets in metal armor" and so on, rather than AC numbers, I would've hated them less.) I don't want "weapon vs. AC" lookup tables. If my goal is to make combat fast, having to consult a table is not going to help.

Weird Tales, Jan 1946 p5.png



The solution: Variable Critical Hit Range by Weapon + Overkill


Yes, there is a solution to all this!

First, the solution to critical hits not mattering against mobs of orcs is the Overkill rule: Whenever your attack kills an enemy with Wounds left over, you can carry over the excess Wounds to another target (as long as its AC is equal or worse than the killed target's.) Thus, when you score a critical against an HD 1 orc, you now kill two of them in one blow.

Secondly, and far more importantly: Critical hit range now depends on weapon type. Variable crit range, in other words. For example, daggers never score critical hits. Spears score them on a natural 20. Greatswords score critical hits on a natural 18-20.


Weapons Critical Range Other
Dagger - Riposte
Club - -
Staff - Two-handed
Rapier 20 Riposte
Spear 20 Reach
Axe/mace/shortsword 20 -
Sword 19+ -
Polearm 19+ Reach, two-handed
Greatsword/greataxe 18+ Two-handed



Sling - -
Shortbow 20 -
Longbow 19+ -
Crossbow 18+ Reload

Thirdly: Fighters score 3 Wounds on critical hits. Everyone else scores 2 Wounds.

Fourthly, a minor point: Specialists/Thieves, when landing a Sneak Attack, automatically deal a critical hit (even if the weapon is not normally capable of critting).

Rationale


Note, firstly, that weapons fit neatly into four tiers. Moving one step down in critical range will usually give you one positive feature, and vice versa: rapiers and spears aren't quite as damaging as standard swords, but they have interesting secondary features. Axes and maces, likewise, have their own situational benefits over swords. Shortswords are strictly worse than standard swords - but hobbits can wield shortswords in one hand, while they require two hands for an axe, mace or sword.

A polearm has reach, and that's why it's not quite as devastating as the undisputed king of damage, the greatsword. If polearms and greatswords were equally damaging, polearms would be the strictly superior option - which may be a historically accurate rendition, but not one I want to adhere to in my swords-and-sorcery inspired campaign.

 

In every case, players will have to choose - do they take axes to chop down doors or spears for reach? Or do they forgo these benefits, focusing on damage? In this aspect, the system works very similarly to one with variable damage dice.

However, critical hits are automatic hits, which means they have interesting interactions with AC that must be analyzed. The number of attacks that critically does not depend on target AC. But the number of regular hits does. Thus, the higher the target's AC, the larger the contribution of criticals to average damage.

The table below shows the relative damage increase from using a critically-hitting weapon, compared to a common baseline. The assumed baseline is a weapon that cannot critically hit for double damage - a dagger, in our case.

Relative improvement over non-crit damage vs. Required d20 roll to hit.
Crit range/damage 8 9 10 11 12 13 14 15 16 17 18 19 20
20 / 2x 8% 8% 9% 10% 11% 13% 14% 17% 20% 25% 33% 50% 100%
20 / 3x 15% 17% 18% 20% 22% 25% 29% 33% 40% 50% 67% 100% 200%
19+ / 2x 15% 17% 18% 20% 22% 25% 29% 33% 40% 50% 67% 100% 200%
19+ / 3x 31% 33% 36% 40% 44% 50% 57% 67% 80% 100% 133% 200% 400%
18+ / 2x 23% 25% 27% 30% 33% 38% 43% 50% 60% 75% 100% 150% 300%
18+ / 3x 46% 50% 55% 60% 67% 75% 86% 100% 120% 150% 200% 300% 600%

Note a couple things.

Firstly, a critical range/damage of 19-20/3x is better than 18-20/2x. In my system, this translates to: a Fighter deals greater (average) damage with a sword than a Thief does with a greatsword. The Thief still gains a benefit from using a greatsword, but the gain is smaller than for a Fighter. This is perfect for me, since I'm not using any class-based weapon restrictions. I want even Magic-Users to use swords if they want to - they just won't be as effective with swords as Fighters or Thieves.

Secondly, the benefit of using a heavier weapon is relatively more important when the required to-hit roll is higher - that is, when target AC is higher. In practical terms: it turns out greatswords and polearms "penetrate" armor better in this system. This may not be entirely realistic, but it's good enough for me. When you're fighting fleshy unarmored peasants, an axe or dagger will do; for dragons or armored paladins, consider bringing something heavier.

I think this system could be incredibly powerful - effectively, it is a "weapon vs. armor type" system without requiring any table lookups, nor any secondary rolls. You simply note the crit range on your sheet when you pick up a new weapon, and it stays the same no matter what foe you're fighting - though it results in different outcomes. The baked-in math does all the magic. I think this counts as following the philosophy which the GLOG states as: "Consolidate ruthlessly. Turn two rolls into one, turn one roll into none. Turn tables into formulas, turn formulas into static numbers."


How does it stack up?


So within the new system, the weapons seem to work great relative to each other. But what about the damage increases overall? Aren't those percentages a bit high, you ask? To compare this to the original games, let's look at how much of a boost variable weapon damage in B/X gives you. Let's choose the d4 as the baseline for comparison, since our earlier copmarison used a non-critting dagger/staff as the baseline.

B/X weapon equivalent Die Average Improvement over d4
Unarmed d2 1.5 -40%
- d3 2 -20%
Dagger d4 2.5 0%
- d5 3 20%
Spear d6 3.5 40%
- d7 4 60%
Sword d8 4.5 80%
Greatsword d10 5.5 120%
- d12 6.5 160%
In our new system, let's say a 1st level PC (+1 to hit) is attacking an enemy in plate (AC 17, roll needed to hit = 16). In the variable crit range system, how does your choice of weapon affect your damage, and what damage die does it correspond to in the variable damage system?

Crit range/damage Damage improvement Example attacker Example weapon Equivalent variable damage  Equivalent bonus to-hit
 20 / 2x 20% Thief spear d5 +1
20 / 3x 40% Fighter spear d6 +2
19+ / 2x 40% Thief polearm/sword d6 +3
19+ / 3x 80% Fighter polearm/sword d8 +4
18+ / 2x 60% Thief greatsword d7 +5
18+ / 3x 120% Fighter greatsword d10 +6

So, against a plate-armored opponent, a Fighter's benefit (in terms of average damage) for grabbing a spear, sword or greatsword is exactly the same as in B/X variable damage! Thieves and Magic-Users are free to use swords and greatswords, but they'll effectively be using a smaller damage die - d6 or d7 - in a system without any damage rolls!

That's for 1st level PCs against a plate armor. Of course, if the enemy's armor is worse, or the attacker's to-hit is better, then weapon choice becomes de-emphasized compared to B/X. That is, greatswords give smaller improvements over daggers than they would under variable damage. Vice versa, if the target is better armored than a human in plate, then bringing a big weapon becomes even more important under this variable crit range system.


Pros and cons of Variable Crit Range


In summary, the pros of using critical hit range to differentiate weapons and critical hit damage multiplier to differentiate classes:
  • The player-facing mechanics work exactly the same regardless of the foe being fought 
  • It a sort of "armor penetration" effect without any need to consult charts
  • There is no need for weapon restrictions by class, yet Fighters still gain more of a boost
 Cons:
  • As a caveat, one should be extremely careful about implementing "advantage" rolls into this system. Effectively doubling the chances of a crit can have quite massive effects when coupled with triple-damage crits.

Minor caveats


(Just to pre-empt a minor point: Daggers not being able to critically hit may go counter to expectations. However, the special-case rule that "any sneak attack that a Specialist/Thief lands is a critical hit regardless of weapon" means that sneak attacks with daggers are just as effective as those with greatswords. If you used variable weapon damage, and doubled damage on sneak attacks, then Thieves would be incentivized to use greatswords. Unless of course you implemented class-based weapon restrictions, which I don't want to do.)

As a side bonus: in addition to, or instead of, +to hit magical weapons, you could have "keen weapons" that have a greater-than-normal critical range - keen rapiers that crit on 19-20, and so on. If you really wanted to get into the weeds incentivizing genre faithfulness, you could even give dwarves an increased critical range with axes and hammers (bringing them up to par with the sword), etc. etc.

By the way, in case you're wondering how a +1 to crit range compares with a +1 to hit, see the last column in the previous table. 20/2x is equivalent (in average damage improvement) to a +1 to hit, 20/3x and 19+/2x to a +2 to hit, and so on. So, if you're not a Fighter, each point of critical range is worth +1 to hit (+1/+2/+3). If you are a Fighter, then each point of critical range is worth +2 to hit (+2/+4/+6). Generally, +2 to hit is equivalent to +1 damage.