Wednesday, April 22, 2009

Armor Penetration

One of the juiciest GC posts I've seen. But then, I'm a numbers guy. I'm copying it here in case they decide they shared too much.

Okay, here is a fairly technical explanation we put together for how armor pen works.

We didn’t want Armor Penetration Rating to be too powerful against low armor targets, like it had been in BC. We also didn’t want Armor Penetration Rating to be too powerful against high armor targets.

So, we decided on a system where there is a cap on how much armor the Armor Penetration Rating can be applied to. So, the first X armor on the target is reduced by the percentage listed in the Armor Penetration Rating tooltip, and all armor past that X is unaffected. Another way of understanding that is we multiply the percentage in the tooltip times the minimum of the two values: the cap, and the amount of armor on the target after all other modifiers.

Computing the cap is a little tricky unless you are already familiar with how World of Warcraft armor works. There is an armor constant we’ll call C. C is derived as follows (in some pseudocode):

If (level<60)

For a level 80 target, C=15232.5. For a level 83, C=16635.

The cap for Armor Penetration then is: (armor + C)/3.

A level 80 warrior creature has 9729 armor. C=15232.5. So, the cap is (9729+15232.5)/3=8320.5. Let’s say a player has 30% armor penetration from armor penetration rating and no other modifiers that complicate the calculation (talents, Battle Stance, Sunder Armor, etc.). The game chooses the minimum of 8320.5 and 9729, so 8320.5. That is multiplied by 30% = 2496.15, and so that much armor is ignored. The effective armor on the target is 7232.85 (9729-2496.15). From a player point of view, the armor penetration rating didn’t ignore the full 30%, but instead ignored 25.66%. (85.5% as effective as expected).

These equations should help you be able to test and verify that Armor Penetration Rating is working correctly and as we designed. The tooltip is not actually inaccurate, as it states: “Enemy armor reduced by up to 30.00%.” That "up to" is key.

Please be sure to test without any other effects which modify the armor calculation (Battle Stance, Sunder Armor, Mace Specialization, etc.) as they may involve other systems that add additional complexity to the calculation.


  1. Ok, now the question is, how does this effect hunters specifically. It would seem to me that a survival hunter is still better off stacking Agility, AP, Haste before worrying about Armor Pent.

  2. Hit -> AGI -> AP -> Crit -> Armor Pen -> Haste

  3. The above is so wrong. The term huntard comes to mind. Hit only until you have enough. Don't forget about heroic presence/IFF raid buffs. Agility before crit until you get way up to like high 6 to 7k ap then ap is just about useless since Blizz admits it is broken for hunters, hence the 226 item level and above ranged weapon buff to try and help hunters scale. In that case crit is best for survival above anything else. MM is different in a few ways. Mainly armor pen does more for you it seems. Haste seems to very useless for MM since most of the MM specs have Improved aspect of the hawk which procs often and puts you over haste cap depending on gear and latency.

  4. so ? whats the armor penet Cap ?

    bookrel Genjuros

  5. survival---> 9% hit->agi->crit->ap->armp->haste

  6. hunters only need 8% hit to capped

  7. Why the hell 6% if you are MM? Hunter hit cap is 8% IF you are lacking hit (you shouldn't) you can put points on Focused Aim (1st tier of MM tier talent so any hunter can have it), each point on Focused Aim give you 1% hit up to 3%, again it is better to reach the hit cap through gear because your pet don't get the hit from focused aim

  8. He is thinking of a MM hunter that takes focused aim. Focused aim was bugged where the hit didnt affect your pet but i believe that was fixed as of last patch. The hit rating cap is 8% for a lvl 80 hunter. It is way to easy to hit that hit cap to warrant putting points into Focused Aim. You get more dps value from other talents.

  9. Read throught the very technical post (damn Im not good with maths) and I still fail to figure out what the Arp cap is :)

  10. There is no Armor Penetration cap that you can gear or spec to like you do a Hit cap. The armor penetration cap refers to the percentage of the target's armor that is affected by your armor penetration rating. In the example above, if the target has a total of 9729 armor then the armor penetration cap is 8320.5. So even if your toon had a 100% armor penetration rating (is that possible?) it would only ignore 85.5% of the targets armor.

  11. thats again wrong, the arp cap is actually 75%.

  12. I believe the number you are looking for is 1400. That will give you 100% arp according to the tooltip. Above that is useless

  13. --- Armor pen vs AGI

    "What is armor pen cap?"
    "Right now its about 1400. Thats right, 1,400."

    Agility is better than armor pen unless you have endgame gear and you are able to hit the hardcap. untill then i suggest you stack Agi. You will be able to keep your dps up while moving. As well all know, most endgame fights in icc require lots of moving :)

  14. Hit cap is 8%, armor pen soft cap is 800, armor pen hard cap is 1400. There's a trinket that, when is activated, gives ~700 ArP, so it's easy to hit soft cap if you feel like making it a dump stat.

    Now, your crit cap is at 104.8%. So keep stacking agil and haste as an SV/MM hunter, because you're going to want all the extra crit and attack power you can get.

    Now, for those who gem Armor Pen, yes, it's a great thing, but when it boils down to it, once you're in full tier gear sitting over 6k gear score, the ones who stacked agility will still pull just as much DPS as you.

  15. its kinda hard to tell which one that in the end is the best.
    so much depending on other stuff than just the gear.
    rotation, constant lag/lag spikes, rotation fails and so on.
    kinda fun to see how much the lag mess it up for some players.
    a friend borrowed my comp in a raid and raised his dps with quite alot.
    Tho myself prefer arp. its harder to get good dps and gear which results in a bigger challange ^^

  16. LOL posts are fun to read through, after studying this post and others for a while here's what i've come to a conclusion to:

    gemming- NO MATTER WHAT, stack agility unless you are for some reason trying to get the gem bonus in which you stack agility/crit gems. Granted if you are not hit capped you should probably seek other means then gemming to get it up but last case scenario you could waste a couple gems on hit.....if you really really really had to.

    haste- i've found really doesn't effect much at all except the rate at which you fire normally (not linked to using your abilities) and a couple particular shots liked steady shot, aimed shot, and i believe there is another but none of these shots are you main dps ones. basically its probably better to choose gear that has additional atk pow, crit, and armor pen bonuses; over ones that have atk pow, crit, and haste.

    beyond this i've found a good goal to get crit to is perhaps 50% and then maybe consider stacking some stuff on arm pen (for example getting dif trinkets or rings to help arm pen, not gemming mind you), however this is purely my opinion and has nothing to do with hard calculated numbers

    anyways feel free to call me out or tear this up but its just somethings i've concluded on for myself and i hope it is of some intellectual use.

  17. All is coming to an end anyway once cat comes out. No armor pen and everything is dummied down. So where are we left but to reinvent the game. Thanks blizzard. I really like having the last three years of hard work all being thrown away to have to do it all again. Lets calculate this. You are allowed one talent tree til 31 then you got 10 left. No more tweaking you just put it in and go. If you look each talent tree per class is not equal either. Where aff lock in the first three lvls you use all but 2 talents and in MM hunter you have more flexibility. Everything that we have done to this point will now end and there will be no more unique or hybrid styles. We are all going to be made equal to a certain extent. So this is probably the conclusion for a lot and a beginning for a much younger less sophisticated crowd. I will try it and make my own assessment but until then good luck to you.

  18. The following lines are like laws, if our hunter is hit-capped and has items having iLvL with a minimum of 264:

    BM: Haste > Crit = ArP > Agi

    MM: AP > ArP > Crit > Agi

    Surv: Crit > Agi > Haste (ArP is as useless for you as a bucket of water is for a burning building)

    All and all - the universal stat for every spec is AGILITY. It gives you Crit+Ap, so until you reach like 5,5-6k AP (self-buffed) I strongly suggest that you stack Agi in sockets and enchants.

    Also - as the person above had stated - you MUST get your crit chance above 50% for MM/Surv. You can't quite do that for your BM spec having items with iLvL less than 251, though :)

  19. Awesomely smart, I'd say. Hypothetically, if I were a BM hunter, I'd be a. near haste cap thanks to Imp Asp b. moving onto crit and armor pen, even though armor pen does not get transferred to your pet and c. if I had a surv spec, I'd disregard armor pen, even though it helps Steady Shot, Auto Shot, Aimed Shot (Aimed Shot is taken due to the cookie cutter specs, and is quite nice to have) thus discarding any buffs to some of my high dmg attacks. I am so0ooo gonna follow the above advice cuz it sounds so sensible! (sarcasm :P)

  20. My 5684 gs hunter raid buffed with my current gear in survival spec shows based on Rawr numbers as budgeted points = (Hit cap>Agil>ArP>Crit>AP>Haste)
    1 Agil = 0.7 ArP = 0.625 Crit = 0.30 AP = 0.45 Haste

    The two Arp trinkets Deathbringer’s Will and Sharpened Twilight Scale are the BIS for Survival. With those trinkets 1 Agil = 0.8 ArP

  21. ArP trinkets are better then Crit trinkets for all hunter specs. It is true that Arp trinkets scales better with BM and MM spec but Deathbringer’s Will (264) > Whispering Fang Skull (264) for hunters.

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