Basic TheoryCrafting

Malan

This article is intended to outline basic concepts and formulae behind general theorycrafting, as a primer towards more indepth concepts.

[top]General

[top]Percentage Increase/Decrease talents/buffs.

Any percentage increase will multiply by the previous value. This is true in both increasing effects (damage increasing) and decreasing (threat reduction).

Talents will increase effects after AP/damage stats
Active buffs will increase effects on top of that.

eg: for spells we would see the following
$Output=A(T(B+DC))$

Base damage
+Damage (includes +dmg temporary buffs)
Spell Co-efficient
Talents
Active percentage Buffs/Debuffs

[top]Chance to hit/crit/proc and Probabilities

A 40% chance to crit means that there is a 40% chance on each and every hit. One crit does not affect the chance for another crit to occur. The chance that any Number of Crits will occur in a row is calculated by taking the Nth power of the Crit chance.
$C^N$

[top]One Roll System

A one roll system is like a table. For a caster this would be 1% Miss, 40% Crit, 59% Hit. If the chance to hit is reduced (chance to miss increased) it would be 5% miss, 40% crit, 55% hit. Increasing that miss chance pushes some hit chances off the table.
$M+C+H=100$
A good example of this is the Shield Block ability of a warrior. It increases the chance to block an attack, which pushes the chance to receive a crushing blow off the table.

[top]Two Roll Systems

Two roll systems work as follows: If you have a 5% chance to miss, and then a 40% chance to crit, a two roll system would multiply the 95% chance to hit by the 40% chance to crit, to get an effective crit chance of 38% (i.e.: you cannot crit if you don’t hit). Believed to be used for melee special attacks, and possibly spellcasts.
$C(1-M)$

[top]Proc Effects

Proc Mechanics

[top]Melee

Average weapon damage (A) can be calculated by adding the high and low ends of the damage range, then dividing by two.
$A=\frac{high+low}{2}$
Weapon DPS is calculated by taking the average damage and dividing by the weapon speed (S).
$DPS=\frac{A}{S}$
Crits – Melee crits are a chance to add 100% of the weapon damage. To add damage from critical hits the average damage is multiplied by the Crit percentage (C).
$DPS=\frac{A(1+C)}{S}$

[top]Caster

Average spell damage is calculated the same way as weapon damage (high + low divided by two) for direct damage spells. DoT spells do not have damage ranges.
Spell DPS (or HPS) is calculated by taking the damage divided by the cast time. DoT spells are calculated by taking the total damage divided by the total DoT duration. You may also want to include the cast time if there is no direct damage portion of the spell.
DD + DoT spells will be DD/cast + DoT/duration
Spell crits – The chance to add 50% damage to a hit. To get the extra damage from spell crits, multiply the average damage by the Crit % and 0.5 (plus any talent/item Crit bonus modifier).
Spell damage – This is a bonus to the damage of spells, for details on the co-efficient calculations, see the [Article]Spell Coefficients[/Article] article.