CDR to Round Robin skills.

[Ishar]

Method:
In order to round robin a skill your effective cooldown must at least be equal to the duration of the ability times the number of characters you have to round robin with. Ergo, for 4 characters and an ability with duration 10, effective cooldown must be 40 or less.

Given the following formula for calculating the effective cooldown (cooldown - reduction) of an ability:
Effective CD = CD - CD * (CDR/100)

This yields the formula:

CD - CD * (CDR/100) = duration * Characters

apply some simple algebra:
Characters Needed = (CD-CD* (CDR/100))/duration
CDR Needed = -100 * ((duration*Characters-CD)/CD)

Feel free to correct if I've mucked up the algebra somewhere. But I'm pretty sure it's right. Additionally, as there is an ability listed with a 7.5 second CD, I assume partial seconds are preserved when Diablo 3 calculates your effective CD.

See below for table form. Spreadsheet is here (https://docs.google.com/file/d/0B-yhEchT6_q8UUVhSXdFbXVqeTA/edit). Note that spreadsheet has a slot for inputting your current minimum CDR; which yields the number of characters you require to round-robin a given ability at that minimum CDR. It is not editable to avoid defacement; just download it and use it locally.

Note that total CDR is not additive; a calculator for it is here (http://bannedofgamers.com/index.php?cdr/).

Edit: Added link to CDR calculator, thanks Dev.
Edit: Updated for 2.0.5



Skill
Rune
Class
Dur
CD
1
2
3
4


Law of Valor

Crusader
10
30
66.67
33.33
0.00
0.00


Law of Justice

Crusader
10
30
66.67
33.33
0.00
0.00


Law of Hope

Crusader
8
30
73.33
46.67
20.00
0.00


Judgement

Crusader
6
20
70.00
40.00
10.00
0.00


Shield Glare

Crusader
4
12
66.67
33.33
0.00
0.00


Consecration

Crusader
10
30
66.67
33.33
0.00
0.00


Condemn
Vacuum
Crusader
3
15
80.00
60.00
40.00
20.00


Breath of Heaven
Zephyr
Monk
3
15
80.00
60.00
40.00
20.00


Breath of Heaven
Infused with Light
Monk
5
15
66.67
33.33
0.00
0.00


Breath of Heaven
Blazing Wrath
Monk
10
15
33.33
0.00
0.00
0.00


Blinding Flash

Monk
3
15
80.00
60.00
40.00
20.00


Blinding Flash
Self Reflection
Monk
6
15
60.00
20.00
0.00
0.00


Blinding Flash
Replenish
Monk
5
15
66.67
33.33
0.00
0.00


Epiphany

Monk
15
60
75.00
50.00
25.00
0.00


Serenity

Monk
3
20
85.00
70.00
55.00
40.00


Serenity
Ascension
Monk
4
20
80.00
60.00
40.00
20.00


Inner Sanctuary

Monk
6
20
70.00
40.00
10.00
0.00


Inner Sanctuary
Sanctified Ground
Monk
8
20
60.00
20.00
0.00
0.00


Frost Nova

Wizard
2
11
81.82
63.64
45.45
27.27


Frost Nova
Cold Snap
Wizard
3
7.5
60.00
20.00
0.00
0.00


Black Hole

Wizard
2
12
83.33
66.67
50.00
33.33


Ground Stop

Barbarian
4
12
66.67
33.33
0.00
0.00


Ignore Pain
Mob Rule
Barbarian
5
30
83.33
66.67
50.00
33.33


Avalanche
Snow Capped Mountain
Barbarian
3
30
90.00
80.00
70.00
60.00


Hex

Witch Doctor
12
15
20.00
0.00
0.00
0.00


Mass Confusion
Paranoia
Witch Doctor
12
60
80.00
60.00
40.00
20.00


Horrify

Witch Doctor
3
12
75.00
50.00
25.00
0.00


Horrify
Phobia
Witch Doctor
6
12
50.00
0.00
0.00
0.00


Big Bad Voodoo

Witch Doctor
20
120
83.33
66.67
50.00
33.33

[bushido685]

Forgive me for my newbness, I am interested in the whole round robin concept.

Is this correct: 4 chars with different Cooldown reductions can chain a skill (i.e. frost nova in sequence for longer freeze duration) ??

[Ishar]

more or less; yes.

Or more exactly, if 4 characters all have an individual CDR of 27.27% [on the skill sheet; since total CDR is not exactly additive] then yes, in theory.

In practice, meeting the minimum isn't always enough to prevent staggering (http://www.dual-boxing.com/threads/51147-Multiboxing-Crusaders?p=389883&viewfull=1#post389883); it's better to have a bit of a buffer sometimes.

[Devile]

For the CDR calculation alone, this is the best site I've found so far:

http://bannedofgamers.com/index.php?cdr/

It can count passives, specific items, paragon, etc. for all classes.

[Ellay]

Additionally I think this is one of the strongest aspects of multiboxing especially in Diablo 3. By controlling the entire party you are able to pull off very fluid combos or chains where a coordinated group couldn't get close to this efficiency.