Diablo 3 RoS Damage model

Benchmarking and dmg-prediction gear/spec in D3 is quite difficult... my question is in this "field"...

I would like to know how the damage model works regarding the "+ Holy/Fire/Lightning %dmg" and the "+ X% (skill name here) dmg"... consider the following scenario: I have a char that casts a fireball (fire dmg) and it hits for 100 dmg. so, consider Ring A a ring that only has 1 stat and that stat is + 10% fire dmg and Ring B gives + 15% fireball dmg

If I use Ring A (gives 10% fire dmg,) the fireball will hit for 110?
If I use Ring B (that gives 15% fireball dmg) the fireball will hit for 115?
If I use Ring A and B the fireball will hit for 110, 115, 125, 126.5?
If I crit for 2x, while using only Ring A the value of the hit will be (100*2)+10%(220) or (100*2)+(10%*2)(240)?

diablo-3

Best Answer

Here's what I know from testing and reading the Diablo 3 forums: there are several groups of buffs and each group is multiplicative with the other groups (and thus a separate multiplier). Check out this thread for more information on multipliers.

To answer your specific question using the terminology from the linked thread:

The +10% fire damage from Ring A falls in Class B
The +15% fireball damage from Ring B falls in Class A3.

Assuming you're only wearing Ring A, then your 100 damage fireball with Fire element will hit for 100 * 1.1 = 110 damage.

Assuming you're only wearing Ring B, then your 100 damage fireball, regardless of element, will hit for 100 * 1.15 = 115 damage.

Assuming you're only wearing Ring A and Ring B and no other modifiying equipment, then your 100 damage fireball with Fire element will hit for 100 * 1.1 * 1.15 = 126.5 damage, which will be rounded to 127.

When you crit for 100% damage, it will do 100 * 1.1 * 1.15 * 2 = 253 damage.