Diablo – What rule system does Diablo III use

diablo-3

I am really interested in the actual calculations behind damage, how stats increase, avoidance calculations (e.g., miss chance, dodge, etc.), and so on.

How are these calculated? Is Diablo based on a role-playing system (such as GURP) whose calculations are publicly available?

Best Answer

There is no comprehensive list of rules yet, but the fine folks at MMO Mechanics have spaded a list of formulas to start off.

Player Life

Life when player level < 35 = 36 + 4 × Level + 10 × Vitality

Life when player level ≥ 35 = (level - 25) × Vitality

Damage

Damage on Character Sheet = (1 + passive skill boosts)*(Weapon DPS + ((minimum damage bonus + maximum damage bonus)/2)Attack Speed)(Weapon Damage Multipliers)(Attack Speed / Weapon Speed)(1 + ( crit% * crit damage %))*( 1 + (main stat / 100))

Spell Damage Modifier = (1 + passive skill boosts)(Weapon Damage + (minimum damage bonus + maximum damage bonus) / 2)(1 + (main stat / 100))

Defense

Total damage reduction = 1 - ((1 - DR from Armor) × (1 - DR from Resistance) × (1 - other DR))

Physical damage reduction = Armor / (50 × Monster Level + Armor)

Elemental damage reduction = Resistance / (5 × Monster Level + Resistance)

Offense

APS (attacks per second) = base weapon APS × (1 + dual wield bonus + other attack speed bonuses)

Experience

Monster level compared to character level      XP gain
3 levels higher and above                      125%
2 levels higher                                    120%
1 level higher                                     115%
Same level monster                             100%
1 level lower                                       90%
2 levels lower                                      80%
3 levels lower                                      70%
4 levels lower                                      60%
5 levels lower                                      45%
6 levels lower                                      30% (no +XP/kill from gear)
7 levels lower                                      15% (no +XP/kill from gear)
8 levels lower                                       5% (no +XP/kill from gear)
9 levels lower                                       1% (no +XP/kill from gear)

Group Mechanics

Normal

# Players   HP%    Damage %
1           100%    100%
2           175%    100%
3           250%    100%
4           325%    100%

Nightmare

# Players   HP%    Damage %
1           100%    100%
2           185%    100%
3           270%    100%
4           355%    100%

Hell

# Players   HP%    Damage %
1           100%    100%
2           195%    100%
3           290%    100%
4           385%    100%

Inferno

# Players   HP%    Damage %
1           100%    100%
2           210%    100%
3           320%    100%
4           430%    100%