D&D 5E House Rule: Accuracy-Based Critical Hit Damage

[Riley37]

Accuracy-Based Criticals (EXPERIMENTAL HOUSE RULE)


When the attack roll is a natural 20:
1. Calculate the highest AC which that attack could hit (20+bonus)
2. Subtract target's AC (as calculated for that attack, including cover etc.)
3. Call the result N. The critical hit does 1dN HP of additional damage.

 

[Dausuul]

What problem are you trying to solve with this rule?

 

[Umbran]

I don't have odd-sided dice - round up or down?

I do wonder, though, if the extra calculation is worth the trouble. Why, exactly, are we doing this? What itch does this scratch?

 

[GMMichael]

Accuracy-Based Criticals (EXPERIMENTAL HOUSE RULE)


When the attack roll is a natural 20:
1. Calculate the highest AC which that attack could hit (20+bonus)
2. Subtract target's AC (as calculated for that attack, including cover etc.)
3. Call the result N. The critical hit does 1dN HP of additional damage.

The first step is extraneous - the process for making an attack roll already includes adding modifiers to the die roll, which is in this case, 20.

Subtraction will definitely slow combat down, but perhaps that's your intent: to turn a critical hit into slow-mo?

It's also clunky to turn the result of some subtraction into a die roll. Maybe just grant a 1d4 additional damage on a natural 20?

You'll want to carefully define your rule, because blunt weapons don't really depend on "accuracy." Can I use your rule while using a maul? A warhammer? Horseman's mace?

 

[seebs]

I assume the intent is to make the impact of a natural 20 vary some so you don't have as much of the "if you need a 20 to hit, you always do double damage" thing, where the percentage of hits which are critical goes up as your accuracy goes down.

 

[Aoirorentsu]

Here's what I thought and was hoping this was going to be:

1) if you hit by 10 or more, you score a critical hit.

aaaaaaand... done.

This way, there's some reward for people who bump accuracy, but it's not too easy to get that it'll happen all the time. Unfortunately, it means that you can't really have a "Down a dragon with a single desperate crit" situation, because in order to hit a creature you still have to hit it.

I don't know that I necessarily like this better than the typical crit. They're really rewarding different things: in the standard rules, they reward dumb luck;my house rule rewards character specialization; the rule posted by the OP is impossible to fulfill (since there aren't odd-numbered dice except by computer, which I guess is okay), but would more or less do the same thing.

Another alternative is to keep the current crit rules, but instead of or in addition to the normal bonus damage dice, on a natural 20 add the difference between the attack total and the target's AC to the damage dealt. This rewards both dumb luck and character specialization, and would make it (I think) more likely to one-shot a target with a crit.

 

[Dausuul]

I assume the intent is to make the impact of a natural 20 vary some so you don't have as much of the "if you need a 20 to hit, you always do double damage" thing, where the percentage of hits which are critical goes up as your accuracy goes down.

If that's the reason, I don't see it as a big enough issue to bother with; but if I had to address it, I'd go with a modified version of 3E's confirmation rolls. When you roll an attack, roll a red "crit die" alongside the attack die. If the crit die comes up 20 and the attack die hits, you crit. (I'd also double the number of bonus damage dice, since you're reducing the total number of crits.) The OP's solution requires too much calculation IMO, as well as requiring the ability to roll a d13 on occasion.

 

[thalmin]

We are just requiring a confirmation roll. Natural 20 is an auto hit, and might be a critical. Roll to hit again, and modifiers. If second roll results in a hit, Crit is confirmed, roll extra damage. If confirmation roll was another natural 20, roll an additional confirmation die to confirm yet more critical damage.

 

[Tormyr]

We are just requiring a confirmation roll. Natural 20 is an auto hit, and might be a critical. Roll to hit again, and modifiers. If second roll results in a hit, Crit is confirmed, roll extra damage. If confirmation roll was another natural 20, roll an additional confirmation die to confirm yet more critical damage.

How would you handle the expanded crit range of the Champion? 18-20 is an auto hit and then confirm?

 

[Riley37]

You'll want to carefully define your rule, because blunt weapons don't really depend on "accuracy." Can I use your rule while using a maul? A warhammer? Horseman's mace?

Citation, please?

What hard evidence can you offer, demonstrating that a blow with a maul which lands on the target's shoulder, and a whack delivered precisely behind the target's eye (where the bone is relatively thin), have equal outcome?

Sling bullets also deliver bludgeoning damage. Can you please provide hard evidence demonstrating that a bullet which hits between the target's eyes is no different from a bullet hitting on the shoulder (assuming both bullets hit with equal velocity)?

Links would be ideal, but I'm open to any evidence from any source stronger than "because I said so". If you're a tournament-level quarterstaff duellist, then personal observations would be weighed accordingly.