I figured I may as well re-collect all the info I got other thread.

This is a reference of what I currently know about WoW combat mechanics. It should be useful for people in evaluating build/gear choices. If you ever come across any information that isn't included here, tell me and I'll add it in.

The primary concern is PvE combat at level 60. Some of the formulae scale to lower levels in obvious ways, but I've left out the dependences on level for cleanliness. Also, some fundamental things are different in PvP (for example, weapon and defense skill have no effect).

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I. Basics

Every attack has an initial roll that determines whether it hits, crits, or misses (or is dodged, blocked, or parried). After that, there is a mitigation phase, which consists of a flat armor reduction for a melee attack, and a resist-based saving roll for a magic attack.

To be clear, if your hit chance is H and your crit chance is C, your actual chance to score a non-crit hit is (H-C).

Note that, for magical attacks, a "miss" and a successful saving throw both appear as "Resist."


II. Magical Combat

A. Base spell hit chance = .96, .95, .94, .83 against level 60,61,62,63 mobs.

B. Base spell crit = Int/59.5

C. Spell damage = TooltipDamage + (spelldmg)*X

X is a scaling factor for each spell, generally given by max(1,CastTime/3.5). Instant spells have a cast time of 1.5, and channeled spells and DoTs receive the full value, divided over all the ticks. For AoE spells, multiply by 1/3. Sometimes, multiply by yet another factor for spells with secondary abilities (for example, .95 for Frostbolt, .8 for Cone of Cold, and .2 for Frost Nova).

% increases from talents are added after damage bonuses from gear.

D. Avg mitigation due to resists = .15*resist/casterlevel. Capped at .75.

This means that, for a binary spell like Frostbolt, this fraction of the spells that "hit" are resisted anyway. For a spell like Fireball, you will see, 0%, 25%, 50%, 75%, and full resists, but the average amount resisted is given by this value.

E. Mana regen per tick = 13 + Spi/4 (except for Druids, who get 13 + Spi/5 for Druids)
A tick is 2 seconds.
[This needs to be re-examined ~H]

Reduced mana regen applies for 5 sceonds after spending mana. Among other things, this means that you can actually get some full ticks while chaincasting (i.e. if you Clearcast an Arcane Missiles).

III. Weapon combat

A. Hit chance
Base hit chance = .76 for white hits while Dual Wielding, .95 for all other attacks. Unknown how this is affacted by level or skill.

B. Crit Chance
Base crit chance (%) = X + Agi/Y + (WeaponSkill - Defense)/25

Y = 53 for Hunters, 29 for Rogues, and 20 for all other classes.
X = 0 for Warriors, Rogues, and Hunters, 0.9 for Druids. It is higher (3-4%) for casters, so that they have nonvanishing melee crit chances. Someone remind me to check what is it for Paladins.

To compute your crit chance in the spellbook, it assumes the target has 5*level defense skill. This is why you appear to lose .2 to crit when you level; the tooltip is simply recalculated for a target with 5 more Defense. (And remember to add back in talents, gear, and stances).

A Cat or Bear always has 5*level skill.

C. Attack Power
Melee Attack Power:
160 + 2*Str, for Warrior, Paladin, and Bear
100 + 2*Str, for Shaman
100 + Str + Agi, for Rogue, Hunter
100 + 2*Str + Agi for Cat

Ranged Attack Power:
100 + 2*Agi for Hunter
2*Agi for Warrior, Rogue

D. Damage
White hit:
Weapon Damage + AtkPwr*Speed/14
(*.5 if off-hand)

Special Attack (before attack-specific modifiers):
Weapon Damage + AttPwr*NormalizedSpeed/14

E. Armor Mitigation
Every attack is mitigated by the target's armor.
Base Armor (before gear) = 2*Agi
Mitigation = A/(A+85*AtkrLevel+400)

F. Base Chance to Parry/Block (%) = 5 + (Defense-300)/25
Amount Blocked (before gear) = Str/22

G. Base Chance to Dodge = Base chance to Crit. Except for Rogues and Hunters, for whom it's twice their base chance to crit.

H. Rage Generation
1 Rage generated per 30 damage dealt
1 Rage generated per 90 damage taken
(Before Rage generated by the talents Unbridled Wrath and Anger Management).

I. Crushing Blows
A level 63 mob has a 15% chance to Crush. This is not reduced by high Defense.

IV. Threat

NOTE: I'm unaware of the overall scaling Blizzard uses for their aggro numbers. Might try to figure this out by checking Thottbot at some point. For now, I'll use the convention that 1 damage (from a non War/Rog) = 1 aggro.

A. Damage Threat
Dealing damage to a mob generates threat with it. Threat is proportional to the amount of damage actually dealt. The amount of threat for 1 damage:

Rogue: .8
War (Bat/Bers): .8
Anyone else: 1
War (Def): 1.3
Bear: 1.3
War (Defiance): 1.45

DoT's generate threat with each tick.

B. Crits
Critical strikes generate a disproportionate amount of threat per point dealt. On average, a crit generates 1.5 times as much threat as a non-crit of the same size.

C. Healing Threat
You gain threat with a mob by healing any person on that mob's aggro list. "Healing" is defined as any ability that directly raises person's HP, Mana, or Rage.
Amount of threat per point of healing:

Pst/Dru: .5
(with Subtlety): .4
Paladin: .325

You gain extra threat for healing yourself, compared to healing others. Not sure of the amount.

HoT's generate threat with each tick.
Exception: Regrowth. Regrowth seems to generate the bulk of its threat upon casting, possibly with an additional penalty on top of that. Basically, think of Regrowth as a very high-aggro spell.

D. Overheals
The threat generated is determined by the amount of HP/mana actually healed. In other words, overheals generate no threat at all.

E. Skills
Many skills have a constant amount of threat associated with them, which is added to any damage they may do. Examples are Mind Blast, Counterspell, and Revenge. I haven't yet found a good table of bonus threat for various abilities, and figuring them out myself would be rather tedious.

F. Taunt
Taunt and Growl have a unique effect: they insantly raise your total threat to be equal to highest person on the mob's hate list at the time the spell is cast.

G. Mocking
Mocking Blow and Challenging Shout force the mob to attack you temporarily, but have no effect on threat levels.

Good thread on threat values

https://forums.worldofwarcraft.com/thread.a...mp=1#post735732

There is an interesting addon for threat measuring

https://forums.worldofwarcraft.com/thread.a...mp=1#post328904

!

If this is true, I never even noticed.

Yeah, I've been watching this guy's work. Looking forward to trying out the threat addon in practical situations, once it's a bit more polished.

Point of order on the Spell Crit:

Tseric was badgered into explaining the role of INT in spell crit, and he said that it's all based on the expected INT for your class at 60. He didn't elaborate on whether or not it was naked or with a "standard" equipment set.

What that means is for mages, the INT/59.5 = spell crit is correct.

However, for classes with a different level of expected intelligence, the divisor will change.

For example, with warlocks, they'd probably assume that they'd have a bit less intelligence at 60, so I'd say that their divisor might be a bit smaller, meaning that every point of intelligence counts for more.

Summary:
"INT/59.5 = spell crit" only applies to mages, with other classes having different numbers.

This is from memory from reading the mage forum at WoW.com around 1-3 months ago.

Eh, just for completeness sake:

Threat for Bear with Feral Instinct is also 1.45

From what I can gather from my own testing, white resists are either level-based resists OR failing a binary resist check (e.g. Frost spells that have the snare portion resisted will come up as a white resist). Yellow resists are resistance-based it seems.

I never noticed this until I spec'ed Frost on one of my Mages.

Hmm, I never knew about that, outside of the context of things listed here:
http://www.thottbot.com/?s=Mod+threat

Does this happen for any non-Shaman abilities?

Yes -- all druid bearform specials work multiplicatively. Druids are actually better at generatng threat than warriors under some circumstances, and this will increasingly become the case with better gear.

Ahh, interesting. We had a long discussion recently about Druid tanking. We actually want to have our resident Feral druid start tanking Broodlord regularly, which is why I was trying to sort out above whether he could crit.

Spi/12, maybe?

Should not be very hard at all to determine. Assume it's linear, and just check your regen at two different levels of Spi.