Blade Vortex

Blade Vortex (often referred to as BV) is a spell that creates an ethereal blade that spins around the caster that deals physical damage, each blade lasting for the minimum duration of 5 seconds.

Skill functions and interactions
Blade Vortex's base damage is boosted by, , , and.

Interaction w/ Blade Blast: When targeted by, the blades will detonate in sequence, increasing in AoE with subsequent detonations. The damage from these detonations scale solely from the Blade Blast skill.

Physical Damage: Because Blade Vortex deals physical damage, it can be boosted by supports and skills that are more commonly used to modify attacks, such as the gem and the  aura.

Spell Damage: Despite the fact that it does physical damage, Blade Vortex is a spell and not an attack. It does not utilize weapon damage in any way. Blade Vortex is one of several skills that work in this manner. The others include, , and. Its damage can be amplified by Spell Damage on items and passives from the skill tree, as well as support gems that increase spell damage.

Leech: Leech effects that apply to Spell damage and to damage types dealt by Blade Vortex (Physical by default) will work as usual. Note that leech effects which apply to attacks do not apply to Blade Vortex because it is a spell, not an attack.

Area of Effect: Increases and decreases in to Area of Effect from support gems, passives, and equipment will augment the radius in which the skill deals damage (e.g., and ).

Cast Speed:, , and Cast Speed from passives and gear will increase the rate at which blades are generated.

Duration:, , and duration-modifying passives and equipment will affect the duration of the blades (including on yourself. ) It is possible to have multiple blades active at the same time, up to a maximum of 10 blades. Once the limit is reached, creating a new blade will simply remove the oldest existing active blade, similar to.

Poison: As Blade Vortex deals physical damage, it can easily scale poison damage.

Visual effect: Blade vortex's visual effect does not scale with Area of effect modifiers. Instead, to give a rough indication of radius, there are several versions of the knife effect, each rotating at a different radius. The skill will always try to have one knife using the largest-radius effect that's not larger than the actual radius of the skill, but that skill results in discrete visual changes where you need to reach a certain threshold before the next wider effect can be used. The full radius is always used mechanically.

Multiple casts: When Blade Vortex is linked to, the damage is defined by the initial cast and does not inherit the less damage multiplier. This behavior includes the Greater Spell Echo Support from.

Calculating DPS
Blade Vortex's in-game tooltip DPS gives the average damage of one hit from one Blade Vortex instance, multiplied by casts per second. This value is misleading primarily because Blade Vortex can hit more than once over its duration, thus not cast speed must be used, but hits per second (rounds per second, spin rate), over the duration of the stacks.

Math and tables
Base spin rate of Blade Vortex is 600 ms. Blade Vortex hit more frequently with more stacks it has. As gem says: 35% increased Hit Rate for each blade. So spin time is calculated as

Spin Time = {Base Spin Time \over (1 + Spin Time Reduction \times Stacks Count) }

Rounds Per Second = {1 \over Spin Time} = { ( 1 + Spin Time Reduction \times Stacks Count) \over Base Spin Time}

Assuming spin rate increases for 35% for each stack, we have the following data:

Each stack of Blade Vortex increases hit damage with the following formula:

Hit Damage = {Base Hit Damage \times { (1 + F \times Stacks Count ) } }

Where

F

is per-stack damage increase factor.

Then we need just multiply hits per second with hit damage.

Damage Per Second Multiplier = {Hit Damage \times Rounds Per Second }

Assuming 35% more damage per stack, then using base hit damage as 1, we would expect the following per-hit damage increases:

Finally, to obtain sustained DPS from tooltip use the following formula:

Sustained DPS = { { Damage Per Second Multipier \times Tooltip DPS } \over Casts Per Second}

or in expanded form

Sustained DPS = { { { ( 1 + {Per Stack Damage Increase Factor \times Stacks Count} ) \times ( 1 + {Spin Time Reduction \times Stacks Count} ) } \times Tooltip DPS} \over ( {Casts Per Second \times Base Spin Time} ) }

Version history

 * Blades created by this skill can now be destroyed with.


 * Mana Cost at gem level 20 is now 16 (was 19).
 * Now deals 3 to 5 Physical damage at gem level 1 (from 7 to 10) and 101 to 151 Physical damage at gem level 20 (from 123 to 185).
 * Now has an added damage effectiveness of 25% (from 30%).


 * Added physics interactions.


 * Now has 35% increased hit rate for each blade (up from 10%).
 * Now deals 35% more damage with hits and ailments for each blade (up from 30% for hits and 20% for ailments).
 * Now has 10% increased critical strike chance for each blade.
 * Now has a limit of 10 active spinning blades (down from 20).


 * Blade Vortex had its 'more spell damage' scaling modifier changed to 'more damage with hits for each blade', and separately 'more damage with ailments for each blade'.


 * Blade Vortex's radius has increased from 14 to 15 units.
 * Blade Vortex gains 1 additional unit of radius every 5 levels.
 * No longer gain increased area of effect radius.
 * You can now only have one instance of Blade Vortex active at once.


 * Blade Vortex's "More Damage per Blade" modifier has been changed to apply only to spell damage instead of all damage types. This will remove a double-dipping effect that should not have been occurring.


 * Blade Vortex has been refactored. Instead of separate hits for each active blade, the blades now increase the frequency at which all enemies in the radius take damage, and the amount of damage they take. The skill now has a base hit frequency of 600ms and has 10% increased hit rate per active blade. Its damage has been reduced by 30% at all levels and it deals 30% more damage per active blade.


 * Blade Vortex now has a stack limit of 20 (down from 50). It now deals 63% more damage at level 20.


 * The frequency with which Blade Vortex's can repeatedly hit the same enemy has been halved, but its damage and damage effectiveness have been doubled.


 * Extra Gore now doesn't trigger every time Blade Vortex hits.
 * Fixed a bug where some of the visual effects on Blade Vortex weren't being updated when swapping in and out support gems which modified the area of effect.
 * Fixed a bug where some of the effects of Blade Vortex weren't finishing their animations smoothly.


 * Added to the game.
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