Back by popular demand, and loads of begging on my part, TheoryCraft 101 is here once again to teach you the ins and outs of the fickle little systems that drive World of Warcraft. Due to numerous requests, we'll be tackling one of the more complex systems within the game, the melee hit table. For all of the hate that armor penetration has taken for being "too mathy," melee hit honestly isn't any better. Caster hit is very simplistic. You have a specific chance to miss a mob, and getting more hit mitigates that amount. Melee hit holds very different values than that. Why just talk about it? Saying that it's complex is all well and good, but let's actually see it, shall we?
As a preface to every TheoryCraft 101 installment, this post is going to contain calculations, figures, theoretical values/situations and other math-related information that, at times, can get a bit confusing. I will always attempt to simplify everything to the best of my abilities and explain the information as clearly as possible. After reading, if you still have any questions about the topic, then just ask. I'll do my best to address every question that you may have.
The auto attack table
|Glancing Blow *|
|Crushing Blow **|
- Only attacks made by players and pets can be glancing blows; an NPC is not capable of landing a glancing blow.
- Only NPCs are capable of landing a crushing blow; players and pets will never be able to land a crushing attack.
- Mobs cannot parry or block attacks made behind them.
- Players cannot dodge, parry or block attacks made behind them.
- There is 0.5-yard grace distance to determine whether an attacker is behind a target or not, in which all attacks occur from the front even if the attacker is technically standing behind the target.
- Incapacitated targets cannot dodge, parry or block attacks.
Chance to miss
Every attack made has a certain chance to miss the target. This chance isn't directly related to level, but rather is a check against the attack skill of the player/mob and the defense skill of the player/mob. Although you will have a higher chance to miss against targets that are a higher level than you, it is because all mobs innately have all of their "skills" maxed and each new level raises the cap of each skill. There are four different formulae for determining your base chance to miss a target, depending on the target that you are attacking and the weapon style that you are using. If the difference between your weapon skill and the target's defense skill is equal to or less than 10 (mobs two levels higher than you or less,) then your base chance to miss will be as follows:
If the difference between your weapon skill and the target's defense skill is greater than 10 (mobs three levels higher than you or more), then your base chance to miss will be as follows:Two-handed/single weapon - 5% + (Defense Skill - Weapon Skill) * 0.1%Dual-wielding - 24% + (Defense Skill - Weapon Skill) * 0.1%
Using these formula, you would get the following results for the base miss chance of a level 80 character attacking with a weapon that has 400 weapon skill:Two-handed/single weapon - 6% + (Defense Skill - Weapon Skill -10) * 0.4%
Dual-wielding - 25% + (Defense Skill - Weapon Skill -10) * 0.4%
Chance to dodge, parry, block and glancing blows
The exact chance that a boss has to dodge, parry or block any given attack isn't precisely known, and it is quite possible that the values actually vary form mob to mob. For all practical purposes, it has been determined that a majority of boss mobs have a 14% chance to parry attacks and 6.5% chance to dodge or block attacks. You can use Expertise Rating, not Hit Rating, to reduce a target's chance to parry or dodge attacks. Again, Hit Rating will have no effect on a target's ability to dodge, block or parry attacks.
Glancing blows have been a spot of contention from patch to patch for a very long time running. The last officially confirmed calculations for determining glance blows is this:
This was introduced back in patch 2.1. Using this model, a player would have a 25% chance to land a glancing blow against a raid boss. However, since patch 3.0, a vast majority of parses have placed the chance to land a glancing blow as being 24%. It is possible that the formula has been slightly changed since patch 2.1, but we cannot know for certain. When doing any form of theorycrafting, 24% chance of landing a glancing blow is the currently accepted figure.10 + Defense Skill - Weapon Skill
When you land a glancing blow, it will deal 30% less damage than normal against a raid-level mob, with the damage reduction being reduced by 10% for every level closer to yours the target is. You can only land glancing blows against targets that are equal to or greater than your own level, and there is no way to reduce either the chance to land a glancing blow nor the damage penalty. Note that you cannot land a glancing blow against another player, only against NPCs.