Intro
Very special thanks to CZ47 for his help with nailing this down. I don’t visit these forums very often, so Discord for questions/comments: Stone_Swan#2717
Basics
The heart of the radsplosion calculation is 9x the radiation DOT damage per tick, or 3x the card DOT damage. (Card DOT damage is shown in damage-per-second, while actual dot ticks happen 3 times per second.) This basic formula has been known for a long time, credit to DocStrangelove’s ancient forum post. Note that if you’re using observed radiation DOT values, the DOT damage that goes into this formula ignores elemental multipliers. So if you observe a radiation DOT damage of 400 on an armored enemy, you need to use 800 in this calculation. From there, everything maths out in a manner that should be mostly familiar to those who know damage formulas.
Radsplosions take into account multiple radiation DOTs. But each source of damage can only proc one DOT. For example, a radiation gun with Urad and a 50% radiation ASE procced will still only apply a single radiation DOT, the strongest one. However, Urad or the 50% ASE can add a radiation DOT to your non-radiation grenade, and that extra DOT will combine with the radiation DOT from the gun to increase the radsplosion damage.
Radsplosion Calculation
(For the following multiplications, it is implied that you add 1 to the percentage bonus. For instance, if you have 30% increased elemental damage, its multiplier in the damage formula is 1.3.)
Initial Radsplosion from gun DOT damage:
DOT damage * 9 * gun damage * ASE status effect damage * skill status effect damage * elemental damage * Atom Balm burst damage * splash damage * V1 * global V2 * debuffs
(ASE status effect chance/damage grants +40% status effect damage, despite the card saying 75%)
Initial Radsplosion from non-gun DOT damage:
DOT damage * 9 * skill status effect damage * elemental damage * Atom Balm burst damage * splash damage * V1 * global V2 * debuffs
Add the radsplosion numbers from all sources of radiation DOTs together to get our Total Initial Radsplosion, then calculate bonus elements from this number. We calculate this way because of the differing multipliers between gun vs non-gun sources. For bonus elements, divide out the splash bonus and make a couple other adjustments:
Terror Cryo/Urad/Re-volter:
Total Initial Radsplosion result ÷ splash damage * [0.75 or 1 or 2]
50% ASE bonus elements:
Total Initial Radsplosion result ÷ splash damage * Guardian Rank gun damage * 0.5
For shock bonus elements, keep in mind Tempest’s increased bonus to shock. If Tempest has any skill points, the radsplosion needs to have elemental damage divided out (don’t forget any GR elemental damage) and multiplied back in with the appropriate amount for shock when calculating the shock bonus element. Keep in mind that Tempest adds 2% extra elemental damage to shock per skill point, not 4%, or an extra 10% with 5 points as opposed to an extra 20%.
With our explosion and its bonus elements calculated, combine numbers of the same element and apply the proper elemental multipliers based on your target’s HP bar type.
Notes
There is no mayhem scaling with Radsplosions; no true double-dipping, no funny business. If you want mayhem scaling, add Unweave the Rainbow or Fire in the Skag Den or whatever, calculated off of the Initial Radsplosion damage. This means that strong radsplosions are quite simply the result of a strong build. Zane players, note the gun damage portion. Moze players, note the gun damage and bonus element portion. Also, Torgue Cross Promotion + Atom Balm + two passive radius boosts = insane radsplosion radius. Fl4k players, note, um, everything. Amara players, I guess note the bonus element portion, and just do your best.
Radsplosions can irradiate enemies damaged by the explosion. That new DOT is equal to 3/8 or 0.375x the sum of the initial radiation DOTs on the enemy that exploded. Because the source of this new radiation DOT is a radsplosion, training all of your original sources of radiation on these newly-irradiated enemies will add to the radiation DOTs, resulting in a radsplosion stronger than the first one.
Radsplosions have a base radius of 350. For context, a regular nova shield has a radius of around 700, and the Frozen Heart (the widest-radius nova shield) has a base radius of 1500.
The radiation proximity aura does not apply a DOT to nearby enemies - each tick is its own instance of damage. Because of this, however, each tick gets bonus elements, and those bonus elements can proc DOTs while the original aura cannot. A 50% radiation ASE or Urad anointment, therefore, can spread true radiation DOTs around without the need for radsplosions.
Shields like the Red Suit or the Ember’s Blaze with Urad create negligible radsplosions. Though their damaging aura is mayhem-scaled, the actual radiation DOTs that they can proc are between 300 and 400 damage per tick with a level 72 shield before applying any bonuses. Even with lots of bonuses, a base radiation DOT that low will have practically no impact on Mayhem 10/11, outside of possible Harmageddon benefits.
A radiation Hex, commonly used to add radsplosions to the field, can proc one of two radiation DOTs. A weaker one, procced by the beams, that has a base radiation DOT between 500 and 600 damage for a level 72 mayhem 10 Hex - negligible. The much more respectable card DOT damage is procced when the grenade itself impacts an enemy, either when it’s flying around and makes contact or when it explodes out of existence at the end of its life. With light field testing, it seemed about 50/50 which DOT got procced, if one procced at all.
Things that don’t increase or add to radsplosion damage: ASE 75/40 status effect chance/damage on non-gun sources, 40% Siren radiation ASE anointment, grenade damage boosts, Forceful Expression, On Grenade Thrown anoint, critical hits
Fine Print for Calculating Radiation DOTs
For cryo guns that proc a radiation DOT through Urad or Next Two Mags radiation or a 50% radiation ASE, you can find your gun’s card DOT damage by multiplying its card damage by the cryo efficiency. For example, a cryo gun that lists 10,000 card damage with a cryo efficiency of 150% has, effectively, 15,000 card DOT damage, and a 50% radiation ASE used in conjunction with this gun would deal 7,500 radiation damage per second (or 2,500 per tick).
For kinetic guns, you would have to compare it to an elemental version, and apply the same DOT damage (or cryo efficiency) to card damage ratio that you see on the elemental version to the kinetic version’s card damage.
For kinetic grenades, the same applies, however on all grenades a 50% ASE calculates as 100% as far as the DOT it procs is concerned. For example, you have a 10,000 damage kinetic grenade with 50% radiation ASE. To find out the DOT damage that the ASE would apply, you have to compare it to an elemental version of the grenade. Let’s say a corrosive version of the grenade has 8,000 card damage and 6,000 card DOT damage. Taking that same 4:3 ratio to the kinetic version we calculate that it has a hidden card DOT damage of 7,500. And since the 50% ASE calculates as 100% for grenade DOTs, the ASE would apply a radiation DOT that does 7,500 damage per second (or 2,500 per tick).
Cryo grenades, unlike cryo guns, have their cryo efficiency disconnected from the card/DOT damage of all other elements (including kinetic) of the same grenade. Taking the above example, while we might think a cryo version of that grenade has 75% efficiency, it will more than likely be significantly higher, like 100%. Therefore, a cryo version of the above grenade, with 8,500 card damage and 100% efficiency will have its 50% radiation ASE (calculated as 100% for the DOT it applies) proc a DOT of 8,500 damage per second (or 2,833 per tick), an amount greater than the kinetic version of the grenade.
Precise Atom Balm Calculation
The Aura Burst Damage and Aura Burst Radius percentages are calculated based on item level and rounded on the card. For a more precise number, use the following formula:
0.1 + (0.00333 * (Level - 27))
Atom Balm Stacking
If you unequip and re-equip the same Atom Balm artifact, the Aura Damage bonus (and the Aura Damage bonus only) stacks, and it keeps stacking every time you do so. Even if you drop the artifact and pick it up again, the game remembers how many times it has been equipped and keeps the appropriate amount of stacks for the Aura Damage. Each individual Atom Balm has its own stack counter. The stacks persist through fast travel and death. They are only lost upon save/quit.
