What are the "rules" of power attacking?

[Meds]

The math to optimize power attack is relatively easy I think with a few simplifying assumptions (like ignoring criticals). I don't know of anyone who'd do it this way over the table as it seems pretty unrealistic, plus you'd need to make a fair guess at the AC of monster you're hitting. But anyway, for what it's worth:

For a one-handed weapon, you want to adjust your attack bonus and damage so that your average damage is the same as the number of faces on the d20 that successfully hit.

E.g. Let's say you're hitting at +12 for 2d4+3 damage vs. AC 19. You do an average of 8 damage if you hit. But you hit with a 7 or above (that's 14 faces on the d20). So, 8 vs. 14. (Expected damage turns out to be 5.6. That's calculated as 8x14/20)

However, optimal is 3 points of power attack. That increases your average damage on a hit to 11, and reduces the number of faces that hit to 11. (Expected damage rises to 6.05.) Anything more than 3, and your expected damage starts to tail off again, as the decrease in accuracy starts to outweigh the additional damage.

(In geometry terms, this is the same as maximizing the area of a rectangle with a fixed perimeter. The maximum is when the sides are equal, i.e. a square.)

For a two-handed weapon, you want to adjust so that your average damage is twice the number of faces on the d20 that successfully hit.

So, in the example above, optimal would be 5 points of power attack. That would increase your average damage on a hit to 18, and reduce the number of faces that hit to 9. (Expected damage is 8.1.)

Like I said, I don't feel this sort of math is necessarily appropriate (or fun) over the table. YMMV.

 

[Stalker0]

- Power attack is actually great, but only in special circumstances (like a charging, raging barbarian).
--Steve

The thing your missing is, that this is good enough. Powering Attack when you have iterative attacks is normally not the way to go, but so what. I don't use combat expertise everytime I attack, I don't get to trip every creature with my improved trip...and man if I didn't take a lot of damage that combat my improved toughness was just worthless.

But there are plenty of situations where you do get to Power attack. If your facing high DR, iterative attacks don't mean squat. If your moving or charging, you only get 1 attack anyway. If the AC of your opponent is so high your only going to hit on a 1 or close to it, swinging for the fences doesn't have a penalty. And of course, breaking objects is all about power attack.

There are enough scenarios that I can use the feat at least in 50% of combats, and that's plenty of usefulness.

 

[Darklone]

Yup.

But it's fun to watch people's faces who aren't used to the big numbers... they deal their 5 and 9 point attacks nice and consistently, while you miss twice each round... and then pull out the 'Ooh, a hit! ... for... thirty-two points of damage'.

If they haven't realised that they've actually dealt somewhat more than that over the course of several rounds, the reactions can be amusing

-Hyp.

In most of the games I played in, FPAATT was not only fun but pretty effective. Take the bard above. The typical opponents in this city based game were human NPCs level 3-6 with ACs mostly lower than 20 (due to normal point buy).

Attacking with Power Attack meant for the bard: One hit, one kill, one Cleave. Without Power Attack he hit a little bit better (often negligible) but always needed two hits to kill.

Can't remember how often he whined that he took Combat Reflexes and not Great Cleave (not that he didn't love to "let them come!").

 

[frankthedm]

1. Make arguments against critical failures on natural ones. Those will only hurt you, your allies and most importantly, your weapon.
2. Foster an attitude of PCs should not die in your gaming group so you can take greater risks with power attacking.
3. Whine, complain and act like a kicked puppy if the subject of house ruling power attack ever comes up.

 

[the_mighty_agrippa]

Power Attack is suboptimal without a two-handed weapon. As several people have pointed out, most characters with PA have good attack modifiers even after PA has been factored in. I generally PA for 2 points and then step up the damage if my bonuses get higher.

For example:

My current PC is a Paladin 5/Pious Templar 3

BAB +8
STR +5
Weapon Focus +1
Weapon Enhancement +1 = +15 Standard

Add in...

Smite Evil (+4 to hit)
Smite (+4 to hit)

If I smite using either version, I step up to a full PA. If I charge, I usually move up 2 points to offset the bonus for charging. If I critical an evil creature with a charging smite evil, the damage goes through the roof. Even buffed BBEGs can't handle more than 1-2 hits on full PA.

For other characters, the bonuses from charging, raging, Bull's Strength, Bless, Inspire Courage, etc more than make up for the loss attack bonuses from PA.

 

[SteveC]

The thing your missing is, that this is good enough. Powering Attack when you have iterative attacks is normally not the way to go, but so what. I don't use combat expertise everytime I attack, I don't get to trip every creature with my improved trip...and man if I didn't take a lot of damage that combat my improved toughness was just worthless.

But there are plenty of situations where you do get to Power attack. If your facing high DR, iterative attacks don't mean squat. If your moving or charging, you only get 1 attack anyway. If the AC of your opponent is so high your only going to hit on a 1 or close to it, swinging for the fences doesn't have a penalty. And of course, breaking objects is all about power attack.

There are enough scenarios that I can use the feat at least in 50% of combats, and that's plenty of usefulness.

Thanks Stalker (and to everyone else) I think that makes a lot of sense. I will make use of it accordingly.

--Steve