BLM: A mini-guide for effective DPS

[Hystify]

Last revision: 12th September 2013

Since it's maintenance time and I'm feeling a little bored, I decided to write this mini-guide for BLM, hope it helps anyone trying to pick up the ropes of playing a BLM.

Disclaimer: Most of the information in this thread is based on my personal opinion/theorycrafting, and may not 100% hold true. Take all number crunching with a pinch of salt, and if you feel your own playstyle is more effective, feel free to share/discuss it.

Glossary of terms:

BLM = Black Mage
UI3 = Umbral Ice (3 stacks)
AF3 = Astral Fire (3 stacks)
F1,2,3 = Fire, Fire II, Fire III
B1,2,3 = Blizzard, Blizzard II, Blizzard III
T1,2,3 = Thunder, Thunder II, Thunder III

Key point to note as a BLM: MP management is key. Casting unoptimal spells at specific times is a DPS loss. Any wasted mana regen = more time spent in UI3 = less time spent in AF3 = DPS loss.

Optimal rotation/priority list (single target):

Spells in brackets dictate what spells should be used for that particular phase, and does not mean that they should be cast in that order. i.e. [ 3. Regen phase, UI3 (T1, B1) ] means that during the regen phase, either Thunder or Blizzard can be casted for that phase, and NOT to cast Thunder followed by Blizzard then transiting to AF3.

1. Burst phase, AF3 (F1, F3 w/ Firestarter procs, T3 w/ Thundercloud procs), until < 929 MP
2. Transition (AF3 > UI3, using B3)
3. Regen phase, UI3 (T1, B1)
4. Transition (UI3 > AF3, using F3)
5. Repeat from step 1

Alternatively, another way to describe the rotation, if the above is too confusing:
Fire III (for AF3) --> Fire spam, while using Thunder III on thundercloud procs and Fire III on Firestarter procs --> Blizzard III when MP < 929, to enter UI3 --> Thunder --> repeat from beginning.

This is pretty much the same as what has been discussed and agreed on as the optimal rotation for a BLM. Basically, in AF3, you use F1 as your main filler, and utilise F3 and T3 for Firestarter/Thundercloud procs respectively.
For the regen phase, you would only need to cast 1 spell (either T1 or B1), then transit back to AF3 by using a F3 at 50% reduced cast time.
The only difference here is that for the most part, T2 has been widely accepted as the main 'filler' for that single GCD in UI3, but I personally prefer to use T1 instead. More will be explained below.

Why < 929MP in AF3? 929MP is the amount of MP required to cast a Fire > Blizzard III > Thunder, when transitioning into UI3 from AF3. An alternative is to cast Blizzard instead of Thunder as the filler for the UI3 GCD if you accidentally enter UI3 with insufficient MP, as Blizzard only costs 109(?) MP instead of Thunder's 212 MP. However, casting a Thunder is still ideal, unless your target is going to die and Thunder's DoT would not be able to tick for its full duration.

Scathe usage:
Scathe should be used when your current target is about to die, and you would not be able to finish your current cast to deal damage before it dies.
Otherwise, it is also useful for situations where movement is required.

Advanced Theorycrafting:

Not all information here is going to be easily comprehendible, so if you do not wish to delve deeper into the technicalities of number crunching etc., feel free to ignore this part and just utilise the above rotation/priority list.

Fire vs Fire III as filler during AF3

Spell potency / cast time = DPS
Fire -- 150/2.5 = 60 DPS
Fire III -- 220/3.5 = ~62.9 DPS
Fire III (Instant, Firestarter proc) -- 220/2.5 = 88 DPS (This amount scales with spell speed, which lowers your GCD time.)

As the numbers show, cast for cast, Fire III is going to be just slightly (if not negligible) more effective than Fire. However, each time you gain a Firestarter proc, you get a DPS gain as compared to hardcasting a Fire III.
An instant Fire III from a Firestarter proc is roughly ~40% more DPS than a hardcasted Fire III.
A hardcasted Fire III is only ~5% more DPS than a hardcasted Fire.
Also noteworthy, a Firestarter proc'd Fire III costs 0 MP. As mentioned before, with the lower MP cost of Fire and also free instant casts of Fire III, this allows you to stay in AF3 for longer durations, thereby effectively increasing your overall DPS.
Thus, with a 40% proc chance from Firestarter, Fire is the clear winner here as the main filler during AF3.

Thunder vs Thunder II vs Thunder III (hardcasting during UI3)

Firstly, it is understood that only Thunder III should be used for thundercloud procs. The calculations below refer to hardcasting different tiers of Thunder, without a thundercloud proc.

(DoT potency * Ticks) + Initial potency / cast time = DPS
Thunder -- (35*6) + 30 / 2.5 = 96 DPS
Thunder II -- (35*7) + 50 / 3 = 98.3 DPS
Thunder III -- (35*8) + 60 / 3.5 = 97.1 DPS

The calculations seem to also concur with the widely regarded opinion that hardcasting T2 is better than T3 during UI3, but the difference is so small, which makes it negligible.
However, the main factor to consider for the choice of Thunder is the DoT's duration. DoT clipping is a DPS loss, as reapplying a DoT does not add on to the current duration, but instead overlaps it with a new DoT, and any remaining ticks of Thunder DoT remaining before it is clipped basically equates to a DPS loss.
Thus, Thunder could be more ideal than Thunder III as it reduces the chances of clipping the DoT, moreso if you get a Thundercloud proc while the DoT is still on the target.

Holding of Thundercloud procs for UI3 > AF3 transition

More often than not, when you get a Thundercloud proc during AF3, your Thunder DoT from your previous hardcast would still be remaining on the target. As mentioned above, DoT clipping is a DPS loss.
An alternative solution is to hold the Thundercloud proc until you transition into UI3, effectively using it to replace the Thunder hardcast that you would be otherwise doing.
Although having a Thundercloud proc overwrite a previous proc without using it is also a DPS loss, but with only a 5% proc chance, the chances of this scenario happening would be pretty low.
However, it is also dependant on whether the 12 second buff would be able to last until you transition into UI3.
If you're not comfortable with doing this, then it'll probably be better for you to use Thundercloud procs as and when they proc. Or else, I believe this methodology provides at least some DPS increase as it reduces DoT clipping.