I've read mixed opinions on when to use combustion. This thread states that at a bare minimum Ignite and LB should be on the target, which makes sense given that there is minimum wait time for these spells. My concerns are regarding a Hot Streak proc. At the beginning of the fight, I've played around with waiting for Hot Streak to proc vs using combustion with only LB and ignite present. Sometimes you can wait a long time for Hot Streak to proc, and I'm concerned that this makes us only more reliant on if we get two critical strikes in a row. What I have been doing is opening with a Pyroblast to get the Pyroblast (minus !) on the target, and using my combustion then, as well as whenever the 2 minute cooldown is up. I know that the original post states it doesn't hurt to wait to use combustion for when more DoTs are on the target, but I'm curious if anyone else is doing this, and if anyone has looked into the math to see if it is worth it?

There's no argument that that would be the best time to use combustion. However, the issue I'm trying to conquer is whether or not to wait to use combustion. You could wait a whole fight for the 'best' time to use combustion, but what is the dps lost by waiting for this opportunity? I'm suggesting using a pyroblast to get the DoT ticking, in order to control my damage output, rather than relying on RNG (and possibly having to wait).

In the OP, the movement rotation is this:

Movement Rotation: This is a rotation you can cast 100% while moving: Scorch, Pyroblast!, Living Bomb, Flamestrike, Blastwave.

Why is flamestrike mentioned, but fire blast isn't? especially with impact?

The answer is quite simple, to break it down into even more manageable chunks:

Assuming a 359 geared fire mage on a standard fight here is the breakdown of damage combustion does by components:

Combustion: 7374 tick - [100%]
----
Ignite: 9704.8/2 = 4852.4 [65.8%]
Living Bomb: 5612/3 = 1870.6 [25.35%]
Pyroblast! dot: 1953/3 = 651 [8.8%]

As can be plainly seen the contribution of the Pyroblast! dot is very small compared to how large your Ignite is, the general rule of thumb is if you get a good Ignite and Living Bomb is ticking it's not worth waiting for a P! to proc and risk loosing the Ignite damage. The better your gear is the less P! dot would contribute, same applies to 'special' fights eg. Halfus where LB and P! dot would contribute much much less.

Regarding Ignite Munching - is there any concentrated effort to bring the data to Blizzard? I'm just reviewing some of my WoL parses and seeing 28% ignite damage lost over a nights raiding, with up to 34% on a single boss.

I had no idea it was this severe until reading the details of the way Ignite interacts with the DoT anti-clipping mechanics. This is so completely broken I don't even want to play a Fire spec anymore.

P.S. Thanks to mysteltainn for the well written analysis on the ignite bugs.

After some PM discussion with you, it's clear there are actually two questions here. Firstly the line you've quoted is from the "mana management" section, and can't be taken as "forbidding" the use of fire blast especially since the rest of the OP constantly waxes lyrical about the use of impact. Secondly, you've done calculations that show me that the inclusion of fire blast into a scorch rotation is possibly a dps gain with improved fire blast talent, especially after the patch where the high-mana rotation will be cheaper. Kavan is aware of the suggestion, but he reports that Rawr.mage isn't currently able to model movement rotations correctly.

This makes it crystal clear that Ignite is the most important component of Combustion. However the munching appears to be something we cannot easily identify in real-time. The author of Combustion Helper (which I would presume the great majority of us use to guide Combustion usage) has said that his code does not attempt to account for munching at this time. Yet most reports I have seen here (such as the one two replies down from the quoted post) claim an average loss due to munching in the 30% territory. This is an averaged value and the actual loss at any given moment has a very wide range of variance.

So even if we do everything correctly, and we closely monitor the Combustion Helper readout, there is still a high chance that our Combustion will not be as strong as advertised - and a lesser (though not insignificant) chance that it will hit like a wet noodle. For some encounters this isn't such a huge deal, but for a select few (heroic Halfus and Maloriak come to mind) this is contributing to wild swings in performance from one pull to the next.

I have looked around the various addon sites and have not found anything that claims to be able to track Ignite while accounting for the munching scenarios.

Is there a reasonable way to get this information (in-game, and in real time)? I get the impression that there is not a way to get this information currently, but I hold out hope. Right now Combustion Helper is telling me whether an Ignite is active or not, but I don't feel I can trust the number it shows. I have already taken the precaution of not using Flame Orb or Scorch prior to stacking dots in preparation for a Combustion, but feel that if only I were more confident about the size of that Ignite stack then I could improve my performance.

The most helpful predictor might simply be a line of text that calculates "Predicted Tick" based on the past ticks + current crits, and then include an approximation of what will be lost to munching. Something like this:

[Total Crit Damage] - Expected Ignite Tick: [Total Crit Damage * 0.4 * Mastery / (Duration of Ignite Buff / 2)], Expected Ignite After Munching [That value *0.75].

This could allow for the mod to track damage lost to munching in the same way that it tracks unused hotstreaks and early LB refreshes. (Keep a running total of crit damage, and one of every ignite tick, and output how much was lost at the end)

I'm not sure how to post a full excel document in this forums, so here is a google documents link to my calculations. Its for a single rotation, obviously the more you use the chain, to more often you'll get access to the increased crit chances of fire blast.

Here is hoping this link works.


For Fire Blast I used 42.86% as the coefficient, and for Scorch I used 51.2%, as those numbers were posted on wow head as being the correct coefficients for the spells in question. Fire Blast is getting an additional 8% crit from Improved Fire Blast, and scorch doesn't have any additional crit, so the base crit is just that.

For the calculations on how I figured out the minimum and maximum damages with the crit accounted for I used:

(((Spell minimum/maximum damage * 240%)* crit chance as a decimal)+(spell minimum/maximum damage * non crit spells as a decimal)

So for fire blast, at 5,000 spell power, and 25% base crit the equation is (((3,098 * 240%) * .33) + (3,098 * .67)) or 4,529.28 damage, minimal.

That same equation is repeated at the different spell power levels, as well as crit levels to give the totals throughout the spreadsheet.

Now, in the 4:1 ratio, I simply took 4 scorches to every 1 fire blast, and added them together to get the minimal damage, so at 5,000 spell power its merely ((4,360.50*4)+4,529.28) which equals 21,971.28 damage. For the crit I averaged out the chances evenly per spell, so that you had something like this, for the 25% crit chance ((25%*4)+33%)/5 or 26.6% overall. While that average remains the same, no matter how many rotations you use, this does translate into more crits over time, so in 100 casts (80 of them scorches, 20 of them fire blasts) you have an expected 20 crits from scorch, and 6.6 crits from fire blast, while at 100 casts of just scorch you would only expect 25 crits from, averaging out to about 1.6 more crits (or 2 if you round up, as you either crit or you don't, you can't half crit) which can translate to more pyroblast!s due to hot streak.

Its not a huge increase, as indicated on the spreadsheet itself where you can compare the rotations side by side, but with the additional crit, i feel that while when one is forced to move, adding a fire blast to every 4 scorches will increase the overall movement DPS, as long as you have the mana available to spare on fire blasts, which with the current PTR changes, that mana becomes available.

Of course you still want to keep living bomb active, and pyroblast! every proc.

I tried to include an Ignite predictor into CombustionHelper but in the end I had no way to have an accurate estimate of it.

The prediction ranged from calculating the expected ignite without taking munching into account, to taking the last result and applying an predetermined percentage off based on a average of ignite loss from WoL like Inoko suggested (though his formula don't take in account 3 ticks scenario). I even tried to simulate munching by taking in account the timestamp of every critical hits but the time reported by combat log events is notably inaccurate too...

Both solutions leaded to completely inaccurate numbers as the first would give higher results than it should due to munching, the second one would be lower because of removing damage even when no munching would occur. I decided not to use theses formula because I prefer to not give wrong results.

Now, if we want to have a report of actual munching this is completely different and doable but not in the scope of what I wanted to do with my addon : help improve fire playstyle.

Thinking of it, having all the users of CombustionHelper (35k+) know how much damage they lost due to buggy mechanics may be a good way to show Blizzard that this problem is the biggest we have currently.

I'll get in touch with Zaldinar to include his ignite parser into the next version.