Time is on my Side

Attack Speed

Your weapon's speed is only of importance if you do attacks with it; it does nothing to your cast rate while doing spells. Some equipment does indeed affect Cast Rate base animations, but not in the manners discussed here.
The item property Increased Attack Speed - IAS - plus enhanced attack speed via Paladin's Fanaticism aura support only Punching, Throwing and Shooting. The edges are a bit burred in some cases. Amazon's Lightning Bolt does a pure lightning attack, nevertheless it's done by throwing a javelin, thus counts as an attack. Paladin's Smite skill causes him to attack with his shield, but it's subject to weapon base speed and IAS modifiers anyways. Assassin's stationary traps are comparable to spells in many ways, but are throwed, thus count as attacks.
Lots of monsters use indeed their Standard Attack animation to release spells, so they benefit, say, from a Fanaticism boss aura. This is also Necromacer's Skeleton Mages behaviour.

Don't get confused by weapon descriptions shown in the game. Those are defined in d2client.dll for each weapon class and character class combination corresponding to AnimData.d2 entries. Despite most attacks can be accelerated by any equipment and skill which increases attack speed the weapon's display will only change if a IAS breakpoint is reached by adding IAS stuff to the weapon itself. So this display is only a rough measurement, and keep in mind it'll change when looking at that weapon with another character class. Assassin's claws as an example are listed as 'very slow' on any other character class, no matter how fast they're if used by a Sin.

A german listing of items granting IAS can be found at Atair's d2wissen.

formular derivation

Unfortunately usage of terms is a bit foggy. Very common is the term Frame, which describes in this environment a single composed picture of an animation. Frame count is called Anim_Length or, according to AnimData.d2 convention, Frames per direction, and I've also read Base+1 sometimes. An animation's velocity, say, how fast the animation is shown, is called Anim_Rate, sometimes Base_Rate. The duration, say, how long the animation lasts, is called Anim_Duration, and calculates as
Anim_Duration = Anim_Length / Anim_Rate

where to find variables?
Anim_Length	extraction of AnimData.d2
Anim_Speed	extraction of AnimData.d2
Anim_Rate	`ItemStatCost.txt` (StatID 68)
IAS_Item	`ItemStatCost.txt` (StatID 93)
SIAS	`Skills.txt` (aurastates) or look ingame - Fanaticism - Burst of Speed - Werewolf - (Frenzy)
WSM	`Weapons.txt` (speed)

This calculation doesn't give integer result, but this is necessary to match ingame's timeline. So a mechanism called HitShift is used to keep rounding errors low; it is also referred to as Anim_Speed from AnimData.d2, and I liked to use v_anim in other FAQtoids (sorry ...).
Fortunately this is always 256 when referring to characters' attack speeds, so for now our formula becomes
Anim_Duration = Anim_Length * 256 / Anim_Rate

It becomes worse, since Anim_Rate is calculated while using Anim_Speed and all accelerations gained by equipment and skills, inluding slowing effects. I'll call it Anim_Acc, don't know if there's a common term somewhere which I may have missed. I've read 'ColdEffect', but consider this as misleading.
Our formula now becomes
Anim_Duration = Anim_Length * 256 / Anim_Speed * Anim_Acc

There's even more to it.
Anim_Acc of course is a percentage, so without acceleration (and slowing down) Anim_Rate = 100 to make
Anim_Speed*100 / 100 = Anim_Speed
mathematically valid.

Further we've to involve effective IAS from equipment called EIAS, IAS from skills called SIAS, and base weapon speed, which is called more precisely Weapon Speed Modifier, WSM. Our formula now becomes
Anim_Acc = (Anim_Rate + SIAS + EIAS - WSM) / 100 *

EIAS is, similar to other animation formulas involving equipment, subject to 'diminishing returns' effect, which means you'll need way larger IAS amounts from equipment the better speed you want to achieve.
[EIAS = 120 * IAS_Item / (120 + IAS_Item)]

Inserting all that stuff into our formula gives
Anim_Duration = Anim_Length * 256 / Anim_Speed * (Anim_Rate + SIAS + EIAS - WSM) / 100 *
If you don't want to calculate EIAS yourself have a look at GaiaCaT's table at the appendix of this page
Now we still need some rounding to get integers. Remember, result must fit into ingame timeline of 25fps. We use
Anim_Duration = {(Anim_Length * 256) / [Anim_Speed * (Anim_Rate + SIAS + EIAS - WSM) / 100]}

Furthermore from complete animation's Frame Count of composed pictures one is not used, since first and last picture are similar. Skipping one of them smoothes the animation. So our formula gets a -1 at the end,and becomes

main formula

Anim_Duration = {(Anim_Length * 256) / [Anim_Speed * (Anim_Rate + SIAS + EIAS - WSM) / 100]} - 1 * with [EIAS = 120 * IAS_Item / (120 + IAS_Item)]

Anim_Duration: duration of animation in (time-) frames ('fpa') Anim_Length: (picture-) frame count per cycle (Frames per Direction) Anim_Speed: HitShift to gain extra precision Anim_Rate: slowing effects SIAS: skill-based IAS WSM: Weapon Speed Modifier EIAS: effective IAS via IAS_Item IAS_Item: IAS granted by items [ ]: Floor Function { }: Ceiling Function sometimes you see SIAS and EIAS summarized as EIAS

Throwing Weapons get a penalty of 30 if they're actually thrown. Thus throwing a weapon is always slower than fighting close combat with same weapon.

serial attacks

Some attacks will use a 'rollback' animation, it starts like a Standard Attack, repeats some (picture-) frames again and again to deliver a series of single attacks, and ends with Standard Attack's ending. All (picture-) frames are taken from Standard Attack. This is how Amazon's Fend and Strafe, Paladin's Zeal, Werewolf Druid's Fury and Assassin's Dragon Talon work.

Of course there's also a special case, as always. Weaponless Amazons' and Sorceresses' Rollback Animation starts with second picture of Standard Attack. If the girls use other than missile or spear weapons it starts with third picture. See Myrdinn's extracted table from d2common.dll.

Sequence Animation

Amazon's Jab and Impale, all claw-specific Assassin attacks, Barbarian's Leap Attack and Paladin's Charge and several other, mostly spell-casting, skills use a Sequence Animation, which is composed of several parts of several animations. Some oddities here.

Anim_Duration = {(Anim_Length * 256) / [Anim_Speed * (Anim_Rate + SIAS + EIAS - WSM) / 100]} *

Same formula, isn't it?
It isn't, it omits -1, which is indeed skipped.
Also Sequences will get a penalty of +30 to WSM *.

Beware: * d2wissen lists WSM with reversed notation compared to Arreat Summit. If using d2wissen WSM values, you have to add WSM in formulas instead of substracting it!

Attack speed of the actual blow isn't influenced by weapon speed when using Leap Attack or Charge.

Barbarian's Frenzy, Double Throw and Double Swing are dual-wielding attacks described in next chapter. His Whirlwind uses an animation of its very own, which is described to an extend in various threads listed below, so I've omitted it in FAQtoids, since I don't want to include too much class-specific stuff.
Keep in mind tha Whirlwind does profit from IAS_Item only when it's socketed into the weapon.

dual-wielding attacks

- Assassin and Barbarian only -

While using dual-wielding attacks IAS_item on secondary weapon doesn't count. This is explicitly the case with that special attacks, not restricted to using a one-handed attack with weapons in both hands.

EIAS = [120 * (∑IAS_item - IAS_2nd)/(120 + ∑IAS_item - IAS_2nd)]

Frenzy acceleration formula

V_inc = 70 + (WSM_1st + WSM_2nd)/2 + ∑SIAS + EIAS fpa = {256 * 17 / [256 * V_inc / 100]} / 2

Double Swing acceleration formula

V_inc = 120 + (WSM_1st + WSM_2nd)/2 + ∑SIAS + EIAS fpa = {256 * 17 / [256 * V_inc / 100]} / 2

Double Throw acceleration formula

V_inc = 70 + (WSM_1st + WSM_2nd)/2 + ∑SIAS + EIAS fpa = {256 * 12 / [256 * V_inc / 100]} / 2

EIAS: effective IAS IAS_item: IAS granted by items IAS_2nd: IAS granted by secondary weapon V_inc: velocity increasement (aka speed increase); hardcoded limits: (175 ≥ V_inc ≥ 15) WSM_1st: Weapon Speed Modifier Primary Weapon WSM_2nd: Weapon Speed Modifier Secondary Weapon SIAS: IAS skillbonus (Frenzy, Fanaticism, Burst of Speed, Werewolf) fpa: Frames per Animation { }: Ceiling Function [ ]: Floor Function

More recent testings done by Behaart indicate some very obscure results depending on Primary and Secondary Weapon. I havn't dug deeper into this, but if you're interested compare german d2info's topic.

Shape Shifting

A character transformed into Vampire or Undead Fetish will still use the main formula, but you'll need to insert the monsters' values.
Abweichend sind also

Form	Anim_Length	AnimSpeed
Vampire	14	176
Undead Fetish	12	256

Shape Shifting to Werebear or Werewolf leads to more complications, since both the wereforms' and the original characters' values step in.

Anim_Duration = {(Anim_Length * 256) / [Anim_Speed * (Anim_Rate + SIAS + EIAS - WSM) / 100]} - 1 wobei Anim_Speed = [256 * Frames_neutral / Delay] und Delay = [256 * Frames_Char / [(100 + WIAS - WSM) * Char_Speed / 100]]

new variables: Frames_neutral: frame count of wereforms' neutral animation (NU; just standing) Frames_Char: frame count of untransformed character's attack animation * Char_Speed: Anim_Speed of untransformed character, see Excerpt from AnimData.d2 * two-handed swords (2hs) are an exception, here's always the value for 1hs in charge

Animation	Werwolf	Werbear
A1	13	12
S3	10	10
NU	09	10

Credits

Behaart
BigEyedBug
brianc84
Crystalion
GaiaCaT
Grimborn
Hammerman
JRichard
Kyrene
Myrdinn
mshannes
Nefarius
RTB
Seisset
TitanSeal
Trucidation
mishy23

Appendix

eIAS and Item_IAS
EIAS	IAS	EIAS	IAS	EIAS	IAS	EIAS	IAS	EIAS	IAS
1	2	21	26	41	63	61	125	81	250
2	3	22	27	42	65	62	129	82	259
3	4	23	29	43	68	63	133	83	270
4	5	24	30	44	70	64	138	84	280
5	6	25	32	45	72	65	142	85	292
6	7	26	34	46	75	66	147	86	304
7	8	27	35	47	78	67	152	87	317
8	9	28	37	48	80	68	157	88	330
9	10	29	39	49	83	69	163	89	345
10	11	30	40	50	86	70	168	90	360
11	13	31	42	51	89	71	174	91	377
12	14	32	44	52	92	72	180	92	395
13	15	33	46	53	95	73	187	93	414
14	16	34	48	54	99	74	194	94	434
15	18	35	50	55	102	75	200	95	456
16	19	36	52	56	105	76	208	96	480
17	20	37	54	57	109	77	215	97	507
18	22	38	56	58	113	78	223	98	535
19	23	39	58	59	117	79	232	99	566
20	24	40	60	60	120	80	240	100	600

Contact me via E-Mail, if you like.

D2library

<< FAQtoids English Home

Time is on my Side

Attack Speed

formular derivation

main formula

serial attacks

see also:

Sequence Animation

see also:

dual-wielding attacks

- Assassin and Barbarian only -

Frenzy acceleration formula

Double Swing acceleration formula

Double Throw acceleration formula

see also:

Shape Shifting

Credits

Appendix

<< FAQtoids English Home

D2library

EIAS	IAS	EIAS	IAS	EIAS	IAS	EIAS	IAS	EIAS	IAS
1	2	21	26	41	63	61	125	81	250
2	3	22	27	42	65	62	129	82	259
3	4	23	29	43	68	63	133	83	270
4	5	24	30	44	70	64	138	84	280
5	6	25	32	45	72	65	142	85	292
6	7	26	34	46	75	66	147	86	304
7	8	27	35	47	78	67	152	87	317
8	9	28	37	48	80	68	157	88	330
9	10	29	39	49	83	69	163	89	345
10	11	30	40	50	86	70	168	90	360
11	13	31	42	51	89	71	174	91	377
12	14	32	44	52	92	72	180	92	395
13	15	33	46	53	95	73	187	93	414
14	16	34	48	54	99	74	194	94	434
15	18	35	50	55	102	75	200	95	456
16	19	36	52	56	105	76	208	96	480
17	20	37	54	57	109	77	215	97	507
18	22	38	56	58	113	78	223	98	535
19	23	39	58	59	117	79	232	99	566
20	24	40	60	60	120	80	240	100	600

EIAS	IAS	EIAS	IAS	EIAS	IAS	EIAS	IAS	EIAS	IAS
1	2	21	26	41	63	61	125	81	250
2	3	22	27	42	65	62	129	82	259
3	4	23	29	43	68	63	133	83	270
4	5	24	30	44	70	64	138	84	280
5	6	25	32	45	72	65	142	85	292
6	7	26	34	46	75	66	147	86	304
7	8	27	35	47	78	67	152	87	317
8	9	28	37	48	80	68	157	88	330
9	10	29	39	49	83	69	163	89	345
10	11	30	40	50	86	70	168	90	360
11	13	31	42	51	89	71	174	91	377
12	14	32	44	52	92	72	180	92	395
13	15	33	46	53	95	73	187	93	414
14	16	34	48	54	99	74	194	94	434
15	18	35	50	55	102	75	200	95	456
16	19	36	52	56	105	76	208	96	480
17	20	37	54	57	109	77	215	97	507
18	22	38	56	58	113	78	223	98	535
19	23	39	58	59	117	79	232	99	566
20	24	40	60	60	120	80	240	100	600

EIAS	IAS	EIAS	IAS	EIAS	IAS	EIAS	IAS	EIAS	IAS
1	2	21	26	41	63	61	125	81	250
2	3	22	27	42	65	62	129	82	259
3	4	23	29	43	68	63	133	83	270
4	5	24	30	44	70	64	138	84	280
5	6	25	32	45	72	65	142	85	292
6	7	26	34	46	75	66	147	86	304
7	8	27	35	47	78	67	152	87	317
8	9	28	37	48	80	68	157	88	330
9	10	29	39	49	83	69	163	89	345
10	11	30	40	50	86	70	168	90	360
11	13	31	42	51	89	71	174	91	377
12	14	32	44	52	92	72	180	92	395
13	15	33	46	53	95	73	187	93	414
14	16	34	48	54	99	74	194	94	434
15	18	35	50	55	102	75	200	95	456
16	19	36	52	56	105	76	208	96	480
17	20	37	54	57	109	77	215	97	507
18	22	38	56	58	113	78	223	98	535
19	23	39	58	59	117	79	232	99	566
20	24	40	60	60	120	80	240	100	600