Tag Archives: hit points

Riding the power curve through D&D’s editions

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(This post continues a discussion I started in “What does D&D have to do with ironclad ships?”)

Signed Greyhawk CoverIn the very first set of Dungeons & Dragons (1974) rules, every weapon dealt 1d6 damage. Short of magic, characters could only improve their damage output by improving their bonus to hit. More hits equals more damage. Soon, Supplement I: Greyhawk (1975) gave different weapons different damage dice and introduced the strength bonus to damage. Since then, each edition seems to give characters more ways to hit for more damage.

By the fourth edition, as characters leveled, they enjoyed steep increases in to-hit bonuses matched with unprecedented increases in the damage each attack dealt. This contributed to characters increasing exponentially in power. It explains why 4E monsters only remain effective for narrow bands of levels, and it explains the nervous ticks of every DM who has run an epic table. In past editions, only the wizard saw that kind of power curve, and the non-wizards eventually grew tired of serving as wand caddies for the Wiz.

D&D Next aims to create a power curve in line with earlier editions, while preventing the runaway power traditional for wizards. If you prefer the exponential power curve created in 4E, then you might have to look for a legendary hero module in Next, or stick with 4E and bless any dungeon master eager to run a high-level game.

Greyhawk also introduced Weapon Armor Class Adjustment, a chart that granted bonuses to hit based how well your particular weapon worked against a style of armor. The table only makes sense because, in the original game, armor class really represented a particular style of armor, such as leather or chainmail. Obviously, dexterity and magical bonuses to armor class quickly turned the table into nonsense. (If you want to make sense of the table, you must apply the dexterity and magical modifiers as penalties to the attack roll.) In practice, no one used the table and the “class” in armor class lost significance.

While D&D Next thankfully steers clear of weapon armor class adjustment, the system returns to the older practice of making armor class a measure of actual armor, or at least something equivalent.

The D&D Next approach brings back a problem that has bedeviled every edition of the game except fourth. In D&D, to-hit bonuses rise automatically, level after level, while armor class remains roughly the same. Sure, as characters acquire better equipment, armor class improves a little, and in most D&D editions AC starts a little ahead. But characters gain to-hit bonuses automatically, and eventually, inevitably, to-hit bonuses outrun armor class. Everyone begins to hit all the time. As I explained in “Hitting the to-hit sweet spot,” D&D works best when combatants hit between 30% and 70% of the time.

Fourth edition fixes the problem by granting everyone automatic increases to AC to match their automatic increases in to-hit bonuses. Now armor class becomes a function of a character or monster’s role and its level. Any reasonably optimal character would boast the same AC as peers in the same role. Armor exists as the flavorful means that some characters used to reach the armor class dictated by their role. This kept armor classes on par with bonuses to hit, while making monster design simple.

armorD&D Next attacks the old problem from the opposite direction. Instead of matching automatic increase with automatic increase, D&D next limits to-hit bonuses so they never overwhelm the relatively static range of armor classes.

In 4E, in defense as in offense, characters increase exponentially in power. The fixed AC bonuses that 4E granted with each level combined with rising hit points to grant everyone steady increases to two forms of defense. You automatically get harder to hit even as the hits do less effective damage. If you’re twice as hard hit and you can sustain twice the damage, your defenses are four times better.

D&D next attempts to straighten out the logarithmic power curve by refusing to let characters double-dip. Rather than gaining steep bonuses to hit along with increases to damage, you just get increases to damage. Rather than gaining constant improvements to armor class along with additional hit points, you just gain addition hit points. Of course, I’m simplifying to make a point. Characters still gain bonuses to hit as they advance, but they gain at a fraction of the rate seen in third and fourth edition.

When we compare D&D Next to early editions of D&D, the design reins in the to-hit bonuses characters gain as they advance. In compensation, characters gain greater bonuses to the damage they inflict. Like any design decision, this strategy makes some trade offs, which I will explore in an upcoming post.

Next: Bounded accuracy and matters of taste

Hitting the to-hit sweet spot

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(This post continues a discussion I started in “What does D&D have to do with ironclad ships?”)

Through the evolution of Dungeons & Dragons, the game uses two mechanics to determine an attack’s damage output: to-hit rolls and damage rolls.

In D&D, hitting is fun, while missing feels like a bummer, particularly if you waited a while for your turn. Why not remove misses from the game?  Once characters gain enough hit points to survive a few attacks, D&D could drop to-hit rolls and─with a few adjustments─still work.

Skipping damage rolls

Back in the third-edition era, Jonathan Tweet advised dungeon masters to speed high-level fights by substituting average damage for rolled damage. In fourth edition, first-level characters have enough hit points to make this approach possible at any level. In a The Dungeon Master Experience post, Chris Perkins explains how he uses nearly average damage plus 1d6, added for a bit of flavor.

The Chivalry & Sorcery game (1977) skipped damage rolls, assuming “that the damage inflicted by a particular weapon in the hands of given character will be more or less constant.”

The notion of dropping to-hit rolls may seem strange but here’s the crux: Against high hit points, to-hit rolls just turn into another damage-reduction mechanic. In fourth edition, everyone but minions has fairly high hit points and everyone hits about 60% of the time. The damage dealt in combat would work out about the same if we just assumed everyone always hits and multiplied everyone’s hit points by 1.67.

Of course, your to-hit percentage varies from a set percentage, because armor can make hitting more difficult. How can a system without to hit rolls account for armor class? In my post, “The brilliance of unrealistic hit points,” I explained how hit points in D&D function as an ingenious damage-reduction mechanic. Virtually every tabletop role-playing game that aimed for realism made armor reduce damage. In our hypothetical rules variant, why not use D&D’s damage-reduction mechanic to represent protective armor? Suppose different types of armor multiplied your hit points. Suppose high dexterity increased hit points, giving more ability to “turn deadly strikes into glancing blows,” just like the game says.

Does abandoning to-hit rolls seem crazy? It has been done.

Tunnels & TrollsTunnels and Trolls (1975) stands as the one early system that defied RPG hobby’s early mania for realism. Ken St Andre, T&T’s designer, aimed for greater simplicity. T&T drops the to-hit roll entirely. Combatants simply weigh damage rolls against each other. Like Tunnels & Trolls, most RPG-inspired video games seem to drop anything equivalent to a to-hit roll. The damage simply rises as you click away at your enemy.

Drawbacks of always hitting

While undeniably simpler, and probably about as realistic as D&D, the you-always-hit approach suffers three problems:

  • Especially with ranged attacks, rolling to hit fits real-world experience much closer than assuming a hit and skipping straight to damage. Technically speaking, skipping the to-hit roll feels bogus.
  • The two possible outcomes of a to-hit roll offer more drama than the mostly-average damage roll.
  • The to-hit roll provides intermittent, positive reinforcement to the process of making an attack.

You know all about positive reinforcement. It makes you stay up late chasing one more level when you should be in bed. Reinforcement that randomly rewards a behavior is more powerful than reinforcement that occurs every time. In a casino, the best bet comes from the change machines, which pay 1-for-1 every single time. Intermittent, positive reinforcement drives people to the slot machines. As the Id DM might say, “The variable ratio schedule produces both the highest rate of responding and the greatest resistance to extinction.” In short, hitting on some attacks is more fun than hitting on every attack.

Although D&D uses a d20 roll to hit, the game plays best when the odds of hitting stand closer to a coin flip. At the extremes, the math gets strange. For combatants who almost always hit, bonuses and penalties become insignificant. For combatants looking for a lucky roll, small bonuses can double or triple their chance to hit. Also, the game plays better when your chance of hitting sits around 60%. When your nears 95%, the roll becomes a formality. When your chance dwindles toward 5%, then the to-hit the roll feels like a waste of time, especially because beating the long odds probably still earns minimal damage.

When the chance of hitting stays between, say, 30% and 70%, the game reaps play benefits:

  • The to-hit roll provides intermittent, positive reinforcement to the process of making an attack.
  • Many attacks can hit and inflict damage, providing constant, positive feedback to players while everyone contributes to the fight.

So D&D designers face the challenge of arranging to-hit bonuses and armor classes so to-hit rolls require a result between a 6 and 14, a precious small sweet spot for all the levels, magic, and armor classes encompassed by the game. In practice, designers like to push your chance to hit toward the top of the 30-70% range, because while missing remains part of the game, it’s no fun.

The Palladium Role-Playing Game (1983) recognized the play value of the to-hit roll, but it avoided D&D’s problem of finessing to-hit bonuses and armor classes to reach a sweet spot. The game simply declares that “any [d20] roll above four (5 to 20) hits doing damage to the opponent.” Armor in the game takes damage, effectively serving as an additional pool of hit points.

In upcoming posts, I’ll discuss the very different steps the D&D Next and 4E designers took to find the to-hit sweet spot.

Next: Riding the power curve

The brilliance of unrealistic hit points

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(This post continues a discussion I started in “What does D&D have to do with ironclad ships?”)

After the role-playing game hobby’s first 10 years, designers turned from strict realism and began to design rules that both supported a game’s flavor and encouraged its core activities. Runequest‘s realistically lethal combat systemParanoia 1st edition game fit the fearful world of Call of Cthulhu (1981), as did a new sanity system. Paranoia (1984) built in rules that encouraged a core activity of treachery, while giving each character enough clones to avoid hard feelings.

Today, this innovation carries through stronger then ever. Dungeons and Dragons’ fourth-edition designers saw D&D’s fun in dynamic battles and showing off your character’s flashy capabilities, so they optimized rules that heightened that aspect of the game, possibly to the expense of other aspects.

When Dave Arneson mashed rules for ironclads into Chainmail, he probably gave little thought to supporting the D&D play style that would launch a hobby, but he created some brilliant conventions.

Chainmail gameThe best idea was to give characters steadily increasing hit point totals that “reflect both the actual physical ability of the character to withstand damage─as indicated by constitution bonuses─and a commensurate increase in such areas as skill in combat and similar life-or-death situations, the ‘sixth sense’ which warns the individual of otherwise unforeseen events, sheer luck and the fantastic provisions of magical protections and/or divine protection.” (Gary wrote this rationale for hit points in the first edition Dungeon Master’s Guide.)

Every “realistic” system to follow D&D used hit points to measure a character’s body’s physical capacity to survive injury. In D&D, rising hit points work as an elegant damage-reduction mechanic. Using hit points for damage reduction boasts a number of virtues:

  • Combat plays fast because players do not have to calculate reduced damage for every single hit.
  • Although damage is effectively reduced, the reduction never makes a combatant impervious to damage.
  • Once characters gain enough points to survive a few blows, hit points provide a predictable way to see the course of battle. If a fight begins to go badly, the players can see their peril and bring more resources like spells and potions to the fight, or they can run. In a realistic fight, things can go bad in an instant, with a single misstep resulting in death.
  • Most attacks can hit and inflict damage, providing constant, positive feedback to players while everyone contributes to the fight. Realistic combatants do not wear down from dozens of damaging blows; instead each hit is likely to kill or maim. In more realistic systems like Runequest and GURPS, when two very skilled combatants face off, they block or dodge virtually all attacks. The duels turn static until someone muffs a defense roll and lets a killing blow slip through. This model may be realistic─it reminds me of those Olympic competitions where years of training turn on a single, split-second misstep─but the realistic model lacks fun. No popular sports begin as sudden-death competitions where the first to score wins.
  • Battles can gain a dramatic arc. Fights climax with bloodied and battle-worn combatants striving to put their remaining strength into a killing blow. No one likes to see the climactic battle fizzle with a handful of bad rolls, especially at their character’s expense.

Bottom line: Using hit points for damage reduction enables a combat system where you can hit a lot, and hitting is fun.

Critics of inflated hit points still had a point. Using hit points as a damage-reduction mechanic can strain credulity, especially when you cannot explain how a character could reasonably reduce the damage he takes. Why should an unconscious or falling hero be so much more durable than a first-level mook?  Why does cure light wounds completely heal the shopkeeper and barely help a legendary hero? Over the years, we’ve seen attempts to patch these problems. For example, I liked how fourth edition’s healing surge value made healing proportional to hit points, so I’m sorry to see D&D Next turn back to the traditional hierarchy of cure spells.

D&D maintains a deliberate vagueness about the injuries inflicted by a hit. This abstraction makes possible D&D’s brilliant use of hit points as a damage-reduction mechanic. Fourth edition exploits the ambiguity more than ever, making plausible the second wind and the healing power of a warlord’s inspiration. 4E explicitly makes hit points as much a measure of resolve as of skill, luck and physical endurance. Damage apparently exists as enough of an abstraction that even if a hit deals damage, it doesn’t necessarily draw blood.

Even as 4E aims for the loosest possible interpretation of a hit, it makes the hit roll more important than in any prior edition. In 4E, melee hits can inflict crippling effects without saves. Just getting hit automatically subjects you to poison, or paralysis, or whatever. In past editions, if the spider bit or the ghoul clawed, you took the damage, but you still got an immediate save.

In the early days of the RPG hobby, many games attempted to fuse D&D’s fantastic setting with a more realistic model of combat damage. Although a few of these games enjoyed success, none recreated the combat-intensive, dungeon-bashing play style pioneered by D&D. At the time, no one seemed to realize that the clever damage-reduction mechanism built into game enabled the game’s play style.

Video game designers figured it out. Virtually every video game that combines fighting with character improvement features D&D-style rising hit points.

Next: Hitting the to-hit sweet spot