Bow damage formula?

[DeathsSilkyMist]

Originally Posted by Goregasmic [You must be logged in to view images. Log in or Register.]

Do we know the formula? After some googling I haven't found anything conclusive.

I can show how the damage calculation is done. P99 may have slightly different magic numbers than the EQEMU, but this formula is very close to P99 numbers.

I have some P99 parse data as well against Corudoth. Corudoth is a great test target for archery, as his model size does not match his actual size. This means his melee range is quite large, so he can hit you from far enough away to where you can just use archery in "melee" range. This will remove the need to root targets if you are testing with a Ranger.

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Talisen Bow, 1 DMG Arrow, and Weighted Axe - 60 SK, STR 206, 68 Archery Skill
AoB Worn 1x, AoB Spell 1x, Grim Aura Spell 1x, Firefist Worn 1x
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_DV = Damage Value

_DV, Count
116, 1
117, 1
118, 3
119, 6
120, 1
121, 2
122, 2
123, 4
124, 3
126, 3
127, 2
129, 2
130, 1
131, 3
132, 2
133, 1
134, 1
136, 70
137, 6
138, 7
139, 5
140, 1
141, 5
142, 8
143, 4
144, 11
145, 8
146, 3
147, 7
148, 6
149, 6
150, 3
151, 5
152, 3
153, 1
154, 2
155, 1

Here is a breakdown of the damage calculation in a hopefully simplified format. Please note that I cannot confirm all of the magic numbers for P99, so a few of them may differ slightly from the EQEMU code. This is why the formula may be a few damage points off when looking at P99 damage numbers.

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Damage Multiplier Table
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Levels 01-50 = maxExtra: 210, maxExtraChance: 49, minusFactor: 105
Levels 51-54 = maxExtra: 245, maxExtraChance: 35, minusFactor: 80
Levels 55-59 = maxExtra: 265, maxExtraChance: 28, minusFactor: 70
Levels 60-60 = maxExtra: 285, maxExtraChance: 23, minusFactor: 65

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1. Calculate Wrath
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1a. StrengthModifier = ((2 * STR) - 150) / 3
1b. If STR is less than 75, StrengthModifier = 0

Wrath = Weapon Skill + StrengthModifier + Total ATK

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2. Roll D20
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2a. Calculate how to weight the D20 (won't show that here)

RolledD20 = Weighted Dice Roll / 10

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3. Calculate DamageDone
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3a. If Wrath is less than 115, DamageDone = Weapon Damage * RolledD20
3b. Continue if Wrath is greater than or equal to 115
3c. Roll D100. If Rolled D100 is less than maxExtraChance, DamageDone = Weapon Damage * RolledD20
3d. Continue if Rolled D100 is greater than or equal to maxExtraChance
3e. Base Bonus = (Wrath - minusFactor) / 2
3f. Get Random Value between 0 and 1.0 (EX: 0.234)
3g. Extra Percent = 100 + (Base Bonus * Random Value)
3h. If Extra Percent is greater than maxExtra, Extra Percent = maxExtra

DamageDone = (Weapon Damage * RolledD20 * Extra Percent) / 100

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4. Calculate FinalDamage
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4a. If using Archery, DamageDone = DamageDone / 2
4b. If using Archery as a Ranger and target is stationary, skip 4a
4c. Do Critical Hit calculation if applicable (won't show that here)

FinalDamage = DamageDone + Main Hand Damage Bonus

As a practical example, I will plug in the variables from my Corudoth parse above, assuming a max damage hit.

1. Wrath = 68 Archery Skill + ((206 STR * 2) - 150) / 3 + 36 Total ATK = 191
2. RolledD20 = 20 / 10 = 2
3a. Base Bonus = (191 Wrath - 65 minusFactor) / 2 = 63
3b. Extra Percent = 100 + (63 Base Bonus * 1.0 Random Value) = 163
3c. DamageDone = (26 Weapon Damage * 2 RolledD20 * 163 ExtraPercent) / 100 = 85 rounded up

Max Damage = (85 DamageDone / 2 Archery Penalty) + 110 Main Hand Damage Bonus = 153 Damage rounded up

The max damage calculated is 153, and my max damage recorded was 155. As I said, this formula is close, but most likely a few of the P99 magic numbers are a bit different from EQEMU. The rounding rules may also be a factor, as I don't know for certain when they round up or down.