[Rogue] Backstab damage calculation

Karmon · 11/04/07, 10:34 AM

The backstab/sinister strike damage calculation in both Rogue-DPS and Rogue-Gear spreadsheet
seem to be wrong for the current live and PTR servers.

What started this was the observation that the tooltip information for backstab did not match
the conventional wisdom as shown in the sheets.
With a 15/41/5 combat dagger build on live the tooltip for backstab is:

195% weapon dmg +255

and on PTR with added aggression:

204% weapon dmg +255

Now the spreadsheets calculate:

150*(1+opportunity)*(1+suprise attacks)*(1+aggression)

For live this comes out to 198% (opportunity and surpise attacks) and for PTR to 208%

So is this only a fluke in the frontend or a real issue?
I went to respec a couple of times on the PTR observing for every point spent the backstab tooltip.
From that it looks like the backstab multiplier is computed as:

150% *(1+opportunity+surprise+aggression)

That matches the BS tooltip for live and PTR in all combinations of spending points.

Now does the server calculate the same?
Seems so!
I got me a starting dagger (1-2 dmg 1.6 speed) and teste with some mobs on live and PTR.
Attack sequence was:
Cheap Shot, BS, Kick and of course the autoattacks.
Kick to get a guess of the armor reduction.

Spec was 15/41/5, 1735 AP no "on proc AP" trinkets.
First subject was an undead mage on hellfire peninsula:

Kick showed 85 dmg, backstab 578

From the kick dmg we can compute the armorreduction.
Since I dont know how Blizz rounds dmg numbers, I computed an upper and lower bound for dmg reduction:

(85-0.5)/110 = .768182 (to account for proper roundig up)
(85+0.99999)/110 = 0.78181 (to account for truncation).

(Sidenote: I purposly did not account for murder talent and wordlbuff in this computation. They will cancle out later anyway)

  Observed BS dmg = BS Basedmg *(1+Murder)*(1+Worldbuff) * Kickdmg/(110*(1+Murder)*(1+wordlbuff))

Now for the damage calculations

Weapon dmg =1.5+1735/14*1.7 =212.178571
BS Dmg (per Sheets) = (1.5*wdmg+255)*1.2*1.1 = 756.71357
BS Dmg (per WoW)    = (1.5*wdmg+255)*1.3 = 745.248214

Facor in the two damage reduction values we get  
Sheet dmg range:  581.293607	591.612428
WoW dmg range:   572.486128    582.648603

The observed dmg of 578 fits nicely in the second dmg range.

My conclusion: WoW really computes the backstab damge different than the current sheets do.
I dont think that is a stealth nerf in one of the last versions. Rather I think the formulas
were not correctly tested when rogue theocrafting started.

What seems to be necessary now is to reestablish the order of application of different talents/set boni; are they really multiplikativ or rather additive?

Note on armor reduction values obtained via 'kick' method:
When this was done, did everyone took into account "Murder", "Worldbuff" and possibly other global dmg enhancinge buffs?

While testing with different mobs (unded/human) it looks like at least "Murder" and the worldbuffs still factor in multiplicative.

Snippet from combatlog

11/4 13:44:48.375 Ihr bekommt 'Verstohlenheit'.
11/4 13:45:10.890 'Verstohlenheit' schwindet von Euch.
11/4 13:45:10.890 Ihr bekommt 'Hast'.
11/4 13:45:11.000 Ihr trefft Unerschütterlicher Zauberhexer kritisch für 309 Schaden.
11/4 13:45:11.296 Unerschütterlicher Zauberhexer ist von Fieser Trick betroffen.
11/4 13:45:12.359 Ihr trefft Unerschütterlicher Zauberhexer. Schaden: 155.
11/4 13:45:13.843 Meucheln von Euch trifft Unerschütterlicher Zauberhexer für 578 Schaden.
11/4 13:45:13.843 Ihr trefft Unerschütterlicher Zauberhexer kritisch für 310 Schaden.
11/4 13:45:15.234 Ihr trefft Unerschütterlicher Zauberhexer. Schaden: 154.
11/4 13:45:15.406 Ihr scheitert beim Ausführen von Tritt: Nicht genug Energie.
11/4 13:45:15.453 Fieser Trick schwindet von Unerschütterlicher Zauberhexer.
11/4 13:45:16.078 Unerschütterlicher Zauberhexer trifft Euch für 114 Schaden.
11/4 13:45:16.656 Ihr trefft Unerschütterlicher Zauberhexer. Schaden: 155.
11/4 13:45:17.562 Tritt von Euch trifft Unerschütterlicher Zauberhexer für 85 Schaden.
11/4 13:45:17.953 Ihr trefft Unerschütterlicher Zauberhexer kritisch für 309 Schaden.
11/4 13:45:18.156 Unerschütterlicher Zauberhexer greift an. Ihr pariert.
11/4 13:45:18.562 Unerschütterlicher Zauberhexer beginnt Feuerball zu wirken.
11/4 13:45:18.765 Ihr trefft Unerschütterlicher Zauberhexer. Schaden: 155.
11/4 13:45:19.109 Ihr scheitert beim Ausführen von Finsterer Stoß: Nicht genug Energie.
11/4 13:45:20.078 Ihr trefft Unerschütterlicher Zauberhexer. Schaden: 155.
11/4 13:45:20.781 Finsterer Stoß trifft Unerschütterlicher Zauberhexer kritisch: 593 Schaden.
11/4 13:45:20.984 'Hast' schwindet von Euch.
11/4 13:45:21.578 Ihr trefft Unerschütterlicher Zauberhexer. Schaden: 155.
11/4 13:45:21.781 Unerschütterlicher Zauberhexer trifft Euch mit 'Feuerball' für 452 Feuerschaden.
11/4 13:45:22.656 Unerschütterlicher Zauberhexer beginnt Feuerball zu wirken.
11/4 13:45:23.140 Ihr scheitert beim Ausführen von Finsterer Stoß: Nicht genug Energie.
11/4 13:45:23.296 Ihr trefft Unerschütterlicher Zauberhexer. Schaden: 155.
11/4 13:45:24.906 Ihr trefft Unerschütterlicher Zauberhexer. Schaden: 154.
11/4 13:45:25.093 Finsterer Stoß von Euch trifft Unerschütterlicher Zauberhexer für 264 Schaden.
11/4 13:45:25.484 Unerschütterlicher Zauberhexer versucht es mit Feuerball... widerstanden.
11/4 13:45:25.921 Unerschütterlicher Zauberhexer beginnt Flammenstoß zu wirken.
11/4 13:45:26.515 Ihr trefft Unerschütterlicher Zauberhexer. Schaden: 154.
11/4 13:45:26.578 Ihr scheitert beim Wirken von Hast: Gegenstand ist noch nicht bereit..
11/4 13:45:27.015 Ihr bekommt 25 Energie durch Unerbittliche Stöße.
11/4 13:45:27.515 Unerschütterlicher Zauberhexer ist von Nierenhieb betroffen.
11/4 13:45:28.125 Ihr trefft Unerschütterlicher Zauberhexer. Schaden: 155.
11/4 13:45:28.187 Ihr habt Unerschütterlicher Zauberhexer getötet!
11/4 13:45:28.656 Unerschütterlicher Zauberhexer stirbt.

Rosvall · 11/04/07, 12:04 PM

Interesting find. I'll go and do some tests myself and see if I can post em here.

PTR Seems to be moving slowly, So I'll just do some on Live.

Okey, Done.

Shows 1332 Ap, 123 hit, ALMOST 20% armor reduction, Miner/eng = no +weapondamage on ring. No trinkets, no meta gem (Meh w/e) Also Deequiped items with armor reduce.

So let's do the values.

(1332/14)*1,7 + 1,5 = 163,243

WoW Values (163,243*1,5+255) * 1,3 = 649,824 With armor
649,824 * 0,8 = 519,859. Taking the small armor difference from 20, and truncations ~520 is very close to 521.

Take the sheets values, (163,243*1,5+255) * 1,2 * 1,1 = 659,821 With armor 659,821 * 0,8 = 527,857. Not as close. I think we can conclude that the sheets need some tuning =).

Thanks krystah for your time testing.

sp00n · 11/04/07, 1:33 PM

Maybe helpful:
Roguecraft 101
[Rogue] DPS Spreadsheet

Dontmindme · 11/04/07, 3:47 PM

We now have 3 people who have tested this and come to the same conclusion...
Truth be told, I tested this when Surprise Attacks was first added and found it to be additive with Opportunity. Although, when the 41 point talents first got added prior to the expansion, the +255 was not multiplied (it is now).

Karmon · 11/04/07, 6:18 PM

Originally Posted by sp00n

Maybe helpful:
Roguecraft 101
[Rogue] DPS Spreadsheet

Mehh:/
Missed that.
Truth is lastly I did not follow the sheet threads because they were derailing IMO

Dontmindme · 11/04/07, 6:22 PM

Originally Posted by Karmon

Mehh:/
Missed that.
Truth is lastly I did not follow the sheet threads because they were derailing IMO

Not a problem at all. I'm glad you put up this post with such a well-documented display. Further documentation is always good.