http://elitistjerks.com/f75/t129638-...ge_compendium/
Combustion
Thanks to Angayelle for writing the following section.
Managing Combustion well is an important part of optimal play for a Fire Mage.
How does Combustion actually work?
The tooltip states, "Instantly deals X to Y Fire damage and creates a new periodic fire effect on the target, lasting 10 sec and dealing the same damage per time as all your existing periodic fire effects".
Combustion take in account the power of your four possibles DOTs (Living Bomb, Pyroblast dot, glyphed FrostFire Bolt dot and Ignite) on your target and create a new powerful DOT which will burn for 10 seconds ticking a number of time depending on your haste at the moment of cast. Usually the FrostFire part is not used as its DOT is very low dps and it require to waste a Prime Glyph slot.
Some important information often overlooked :
- This is not exactly the DPS of the DOTs which matter, only their potential power.
- Duration remaining on either DOT doesn't matter.
- Size of the LB, Pyro and FFB DOTs doesn't matter.
- Combustion can be spread via Impact. Impact-Combustion can be incredibly powerful.
- Combustion damage is NOT directly modified by the Flashburn Mastery but other DOTs are when taken in account for damage calculation.
- The damage-over-time portion of Flamestrike does not leave a debuff on affected targets, therefore it does not interact with Combustion.
The formula :
Tick damage = PyroDotPower/3 + LbDotPower/3 + IgniteTickDamage/2
The Ignite tick damage is self explanatory, it's the value you see happening on your combat log, nothing else. The power of the living bomb DOT and the pyro DOT on the hand are much complicated to calculate. Keep in mind that Combustion only check for the presence of the LB and pyro dot as it will recalculate their power with your current stats at the time of casting Combustion, not the ones you had when casting the DOTs.
LbDotPower = (234 + (0.258*SpellBonusDamage))*(FirePowerTalentRank)*(1 .25)*(CriticalMassTalent)*((0.00015 618*MasteryRating) + 1.224)
PyroDotPower = (164 + (0.180*SpellBonusDamage))*(FirePowerTalentRank)*(1 .25)*((0.00015618*MasteryRating) + 1.224)
Multiply this Tick damage by the number of ticks you can expect depending of your haste, add in a critical chance for each dot, add the front damage from the Combustion spell and you'll have your potential total Combustion damage.
