Path of Exile Game Mechanics Guide

Path of Exile Game Mechanics Guide by Malice

Much of the information here is obsolete as of version 0.9.3

Please post any information you discover that you think should be here. I’ll try to keep it updated and organised. The information already here is the result of testing during the alpha, and observing the many patch notes.

Skills

Skill Types
Skills currently come in two main varieties: spells, and attack skills.

Attack skills
Attack skills use your weapon damage and so their effectiveness is dependent on your weapon, attack speed, etc.. Bonus damage from rings or other gear is applied when using an attack skill.
Current attack skills:

• Cleave, Sweep, Double Strike, Dual Strike, Ground Slam, Leap Slam, Split Arrow, Frenzy, Elemental Hit, Flicker Strike, Shield Charge, Poison Arrow, Infernal Blow, Glacial Hammer, Viper Strike, Explosive Arrow

Spells
Spells do not draw their damage from your weapon in any way. They are affected by % cast speed, %fire/cold/lightning damage, %spell damage, and critical strikes. Integer damage bonuses on gear are not added to spells.
Current spells:

• Fireball, Spark, Cold Snap, Ice Spear, Ice Nova, Raise Zombie, Raise Spectre, Frost Wall, Shock Nova, Freezing Pulse, Detonate Dead, Temporal Chains, Elemental Weakness, Warlord’s Mark, Punishment, Enfeeble, Critical Weakness, Projectile Weakness, Vulnerability

Other spells
These spells never actually hit or do damage so they are unaffected by most modifiers and support gems. They are affected by cast speed, and skills with a duration are affected by %skill duration.
Other spells:

• Blood Rage, Phase Run, Enduring Cry

Other skills
These skills are not affected by attack speed, cast speed, or anything else.
Other skills:

• Town Portal

Support Gems
Support gems only affects skills where it makes sense. For instance, skills that do not already do damage (such as Temporal Chains) will not benefit from Added Cold Damage. Skills that do not already have an area of effect will not benefit from Increased Area of Effect, etc.
Here’s a list of support gems currently in the game.

Strength (red):

• Added Fire Damage, Stun, Item Quantity, Life Leech, Knockback, Melee Physical Damage, Gain Mana on Kill

Dexterity (green):

• Added Cold Damage, Increased Accuracy, Faster Projectiles, Multiple Projectiles, Mana Leech, Pierce, Faster Attacks

Intelligence (blue):

• Added Lightning Damage, Added Chaos Damage, Increased Area of Effect, Item Quality, Reduced Mana Cost, Increased Critical Strikes, Faster Cast Rate

Individual Skill Notes

Poison Arrow
Only the fired arrow gets bonus damage from support gems / modifiers, not the poison cloud. Multiple poison Clouds do not stack.
The cloud lasts a set time, increased by the “Increased Skill Duration” passives. Enemies that enter the cloud are poisoned. The ‘poisoned’ effect will deal damage over time, increased by the Buff Duration passives.
Currently the poison on monsters has no graphical effect, this will be implemented soon.

Leap Slam
Attack speed determines how fast Leap Slam activates, and how fast you fly through the air.

Shield Charge
Shield Charge’s damage is linked to the length of the charge. Charging the full length of the screen will do more damage than charging an enemy right next to you.

Provided you charge more than 20 units, the skill will have unconditional knockback and stun. The distance of knockback and duration of stun are of course affected by the bonuses if you charge far enough to get them.

Between 20 and 60 units, the bonuses are handled differently. For knockback distance and stun duration, a scaling number is calculated as (distance – 30) / 30. So for example a distance of 30 gives 0, a distance of 59 gives 0.9666… and a distance of 21 gives 0.666…
This scaling number is then multiplied by the ‘maximum charge distance’ value for the bonus which is listed on the skill. So if you charge between 20 and 30 units, you’ll do stun and knockback, but with reduced duration/distance. 30 – 60 you do progressively more until you max at 60.

Damage is scaled differently, since it doesn’t disappear at < 20, like stun/knockback. As before, above 60 units, you get the full maximum damage bonus. Below 60 units, a damage scaling number is calculated as (distance + 30) / 90.
So a distance of 15 gives 0.5, for example. This scaling factor is multipled but the ‘maximum distance’ value of the damage bonus to work out the damage to apply – as you can see, even if you charge 0 distance, you’ll still get 1/3 of the maximum damage increase possible.

Elemental Hit
Only one of the three elemental damage bonuses is applied with each use of this skill (chosen randomly). It gives either bonus Fire, Lightning, or Cold damage, not all three at once.

Raise Zombie / Spectre
Most support gems that affect attacks (eg Added Lightning Damage) can be used with these skills to buff the attacks of the minions.
Support gems that affect projectiles (such as multiple projectiles, faster projectiles) appear to have no effect on the attacks of ranged enemies raised as Spectres.

Infernal Blow / Glacial Hammer
Glacial Hammer and Infernal Blow do the elemental conversion before any other modifiers (including on-weapon %Enhanced Physical Damage and quality!), using only base weapon damage.
This means that any physical damage mods and passive skills only apply to whatever physical damage is left after the conversion. The exact way the damage is calculated for these skills is unknown, for instance we don’t know if the % melee damage passives from the strength tree affect the fire/cold damage portion.
Increased fire damage and cold damage mods/passives should work on the elemental portion.

Sweep
Sweep has a 30% chance to knock back on hit. It’s area of effect is a 300 degree arc (there is a 60 degree “blind spot” directly behind you).

Cleave
Cleave’s area of effect is a 180 degree arc.
When dual wielding, Cleave attacks with both weapons simultaneously, but suffers a damage penalty.

Dual Strike
Dual Strike results in two separate, simultaneous attacks – one with each weapon. Each attack has it’s own chance to hit, chance to critical, etc.

Skill gem experience gain

• Gems get experience equal to 10% of the experience you earn.
• The number of gems you have equipped has no effect on the rate of XP gain. So having less gems equipped does not cause them to gain XP faster than if you had many gems equipped

Classes
Each class gains a certain amount of life and mana per level, and also have some other bonuses.
In addition, each class gains different amounts of attributes from passive skills.

• All passive skills give 2 of each attribute, regardless of class
• Pure classes gain +6 attribute points from passives of their main attribute, and +2 for passives of other attributes
• Hybrid classes gain +4 attribute points from passives of their main attribute, and +2 for passives of other attributes

For example a Marauder taking a strength (red) passive gains 8 strength, 2 intelligence, and 2 dexterity. The same marauder taking an intelligence passive gains 2 strength, 4 intelligence, and 2 dexterity.
A Duelist will get 6/2/2 from strength or dex passives, and 4/2/2 from intelligence passives.

Life/mana per level
These are the amounts of life and mana gained by each class on level up.

Marauder: 8 life, 2 mana
Ranger: 4 life, 2 mana
Witch: 4 life, 4 mana
Duelist: 6 life, 2 mana
Templar: 6 life, 3 mana
Dex/Int: 4 life, 3 mana

Base statistics
Each class also has bonuses to certain types of armour. These are:

Marauder: +12% armour rating
Ranger: +12% evasion rating
Witch: +12% energy shield
Duelist: +12% armour rating, +12% evasion rating
Templar: +12% armour rating, +12% energy shield
Dex/Int: +12% evasion rating, +12% energy shield

Items

Attribute requirements
Most gear has attribute requirements that must be met in order to equip the gear. These requirements come from the base item type and are unaffected by magical modifiers, quality, or number of sockets. A complete list of gear and attribute requirements can be found here

Level requirements
Some items have a level requirement that must be met in order to equip the item.
There are two factors that affect level requirements.

• The level of the base item type. This is the level that the item starts appearing (and is separate from the itemlevel that affects which magical modifiers can spawn on it). See the item data link above for a list with all item levels. Some of the very low-level base items do not come with a level requirement.
• The level of the magical modifiers.
  The level requirement for magical modifiers is equal to 80% of the level of the highest-level magical modifier on the item.
• The highest level requirement of the two listed above is the one that appears on the item.

Quality
All weapons, armour, flasks and gems can randomly receive between +1% and +20% quality.
This value can be increased by Whetstones, Armour Shards, Flask Quality Upgrades, and Gem Quality Upgrades, but is capped at 20%.

The effect of quality depends on the item:

• On weapons, increased physical damage
• On armour, increased Armour rating, Evasion, Energy Shield, and Shield Block Chance
• On flasks, increased life and mana recovery
• On gems, the bonus is specific to each gem. For instance, Frenzy gets increased damage, while Cleave gets increased attack speed.

Modifiers
Modifiers are split up in to two main groups, prefixes and suffixes. A magic item can have only one prefix and one suffix, never two prefixes or two suffixes.
Rare items can have up to six modifiers, it is unknown if there is a limit on how many of these can be prefixes/suffixes.
A randomly generated rare item (from a drop or Orb of Alchemy) receives between four and six modifiers randomly, with the following odds:
1/12 chance of 6 mods
4/12 chance of 5 mods
7/12 chance of 4 mods

All modifiers have a level associated with them, and will only appear on items whos item level is greater than or equal to the modifier’s level.

Modifier Stacking
In general (but not always), percentage modifiers stack additively, and integer modifiers are applied before percentages.

Imagine I have 100 life, and two passive skills that increase total life by 15%. The total bonus will be 30%, resulting in 130 life.
Now imagine I am wearing boots that give +40 life, and have a passive skill that grants +20 life. The integer bonuses are applied first, giving me 160 life, then the percentage bonuses are applied to that subtotal, for a final total of 208 life.

One exception is the quality modifier on armour and flasks (but not weapons), which applies after all other modifiers. For example:

[there was an item linked here that has since been wiped. It had +69 armour, +9% armour, and +20% quality]

This Horned Casque has a base armour rating of 428. Then the +69 is added to get 497 armour. Then the 9% bonus raises it to 541, and finally +20% quality results in 650 armour.

Quality on weapons stacks additively with other % modifiers on the weapon.

Increased Item Rarity (IIR)
Increased Item Rarity % modifiers stack additively, and increase the chances of an item being magic, rare, or unique. For example with a total of +100% increased item rarity, For example, if you had +100% item rarity, you’d get twice as many magic items, twice as many rares and twice as many uniques.
This modifier has no effect on the number or type of currency items, scrolls, or gems that drop.
When in a party, only the modifier from the player who lands the killing blow on an enemy is counted.
If one of your minions gets a kill, the minion’s IIR is added to yours and the total is used.

Sockets
There are three types of sockets:
1. Strength (red)
2. Dexterity (green)
3. Intelligence (blue)

Sockets appear randomly on most equipable items. Higher level items can appear with more sockets than lower level items of the same type. For example, gear must have an item level of 8 or higher to receive two sockets.
The maximum amount of sockets that can appear on an item also varies by the type of item:

• Two handed weapons, body armour, and shields requiring strength can have up to 6 sockets
• Wands and daggers can have a maximum of 3 sockets
• Everything else can have a maximum of 4 sockets

One exception to this is the starting weapon that appears on the beach at the start of the game. Its item level is 1 but it always has one socket of each colour.

• Items are more likely to receive sockets that match their attribute requirements. So an item requiring only dexterity is more likely to have green sockets than red or blue sockets.
• You can only put a blue (intelligence) gem in a blue socket, red gem in a red socket, etc.
• Sockets can be linked. The links are shown as gold bars between the sockets. Support gems affect any skill gems in sockets that they are linked to.

For example:

This sword has 1 strength socket, 1 intelligence socket, and 2 dexterity sockets. Every socket is linked to every other socket. In this sword you could put:

• 4 skill gems. You would get access to 4 active skills.
• 3 skill gems and one support gem. You would get access to 3 active skills, and all three would be improved by the support gem.
• 2 skill gems, 2 support gems. You get 2 active skills, both are improved by both support gems
• 1 skill gem, 3 support gems. You get 1 active skill that is boosted by all 3 support gems.

So lets say you put in:
Cleave skill gem,
Raise Zombie skill gem, and
Added Cold Damage support gem.
You would get a cleave skill that does extra cold damage, and raise zombie skill with zombies that do extra cold damage.
You would not get zombies that have cleave, or raise a zombie every time you use cleave.

Additionally, two skill gems of the same type can be used in separate items to allow for more linking opportunities.

For example (thanks to tormenta):

In the above image,

• “Ice Nova” is placed in both weapon and shield (2 skill gems required)
• 2 different support gems are placed in each of those items too
• end result is that Ice Nova is affected by both support gems
• Fireball is affected by Added Lightning Damage only

When more than one gem of the same type is socketed at the same time, you always use the highest-level gem. So in the above example, if one of the Ice Nova gems was level one, and the other level six, your Ice Nova would have the stats of the level six version.

Similarly, if two of the same support gem are linked to the same skill, they do not stack. Only the highest-level gem gives a bonus.

Item level
Each item has a level associated with it that is equal to the monster level of the area it dropped in. You can check an item’s level by picking it up on the cursor and typing /itemlevel in the chat box. This item level determines which modifiers it can receive, and how many sockets it can receive.

Vendor Item levels
Items obtained from vendors will have an item level equal to the character’s level, but will not exceed the following maximums:
Normal Act 1: 15
Normal Act 2: 21
Cruel Act 1: 29
Cruel Act 2: 33
Ruthless Act 1: 41
Ruthless Act 2: 46
Merciless Act 1: ?
Merciless Act 2: ?

If you find a vendor that sells items outside of these level ranges, please post your finding.

Combat

Level scaling
Level plays a big role in many of the combat calculations in Path of Exile. Enemies higher level than you will be harder to hit, hit you more easily, do more damage, and take less damage than if you were the same level as them.
Similarly, enemies lower level than you will be easier to hit, have a harder time hitting you, take more damage, and deal less damage.
Level also affects the amount of XP you gain from killing enemies. Enemies higher or lower level than you will have their XP reward reduced. The exact formula for this is unknown. Enemies that are higher level than you, but only by 5 or less levels are not affected by this penalty. Enemies 6 or more levels above you will start to have their XP reward reduced.

Dual wielding
Dual wielding grants a +25% attack speed bonus.
The default attack and certain other skills will alternate between each weapon, striking with each hand in turn.
Some skills (such as Cleave and Dual Strike) attack with both weapons at once, while others only use the main-hand weapon.

Hit & damage calculation order of effects
There are a number of steps involved in deciding whether an attack hits or not and how much damage is done:

* Evasion is checked first
* If the attack is not evaded, then blocking is checked
* If the attack is not blocked, then calculate damage reduction and resistances
* Subtract damage from energy shield/life

Accuracy
Accuracy is compared to enemy evasion when determining if an attack hits or misses. The complete formula is below:

chance to hit = ( attacker_accuracy / ( attacker_accuracy + defender_evasion ) ) * ( 2 * attacker_level / ( attacker_level + defender_level ) )

Chance to hit can never be lower than 5%, nor higher than 95%.

This was current as of 0.8.2, however it may have changed with the 0.8.3 update.

Evasion
Evading an attack prevents all damage and other harmful effects from the attack. Only attacks and attack skills can be evaded. Spells cannot be evaded.

Blocking
Blocking an attack prevents all damage and other harmful effects from the attack. Usually, only attacks and attack skills can be blocked, but there are some passive skills that allow you to block spells.

When an attack is blocked, the game first calculates if the attack would have caused a stun were it not blocked. If it would have caused a stun, the blocking animation is played. If it would not have caused a stun, then you get a “free” block with no animation.
It is unknown how this mechanic interacts with the new stun-resistant energy shield.

Armour / Damage Reduction
Damage Reduction reduces damage taken by a set percentage based on armour total, and the relative levels of attacker and defender. It applies only to physical damage.

Energy Shield
As long as you have greater than 0 Energy Shield, you are immune to stun effects.

Energy Shield acts as an additional hit point pool on top of life. If you have any Energy Shield remaining when you take damage, the damage is subtracted from the Energy Shield first. Damage is only applied to life once all Energy Shield is depleted. The exception to this is Chaos Damage, which ignores Energy Shield.

Energy Shield will recharge if you do not take any damage for a certain period of time.

Critical Strikes
Whenever you use a skill or attack, you have a chance to deal a Critical Strike. Critical Strikes are rolled on a per-action basis, not per-monster.
So each time you use a skill, the Critical Strike roll is made once and only once. If you roll a Critical Strike, you will deal Critical damage to all enemies hit by the skill.

Critical Strikes do more damage than normal, based on your Critical Strike Damage Multiplier.
All characters have a base Critical Strike multiplier of 200%, meaning a critical strike does 200% of normal damage. This multiplier can be increased with various skills and modifiers on items.

For instance, with a multiplier of 250%, if you deal a Critical Strike with attack that normally does 100 damage, you will instead deal 250 damage.

The chance to deal a critical strike is based on your Critical Strike Rating, and the level of attacker and defender. You will have a greater chance of dealing a Critical Strike against monsters lower level than you, and a reduced chance to Critical against monsters higher level than you.

The exact formula for calculating Critical Strike Chance is unknown, but it can not be less than 5% nor more than 95%.

Critical Strike Rating, spells vs weapons
Critical Strike Rating and Critical Strike Damage Multiplier are calculated separately for spells and weapon attacks.

All weapons have a base Critical Strike rating listed on them. This only affects your chance to critical for attacks made with that weapon. It does not affect your chance to critical with a spell.

Statistics affecting Critical Strikes for attacks:

• Base critical strike rating on weapons
• +X to critical strike rating
• +X to critical strike rating for all damage
• X% increased critical strike damage multiplier
• X% increased critical strike damage multiplier for all damage

Statistics affecting Critical Strikes for spells:

• +X to critical strike rating
• +X to critical strike rating for all damage
• +X to critical strike rating for spells
• X% increased critical strike damage multiplier
• X% increased critical strike damage multiplier for all damage
• X% increased critical strike damage multiplier for spells

Damage Types
There are currently 5 main types of damage, they are Physical, Fire, Cold, Lightning, and Chaos.
Fire, Cold, and Lightning are collectively known as Elemental Damage.
Damage reduction from armour and endurance charges only affects physical damage. Each of the elemental damage types has it’s own resistance value (eg “Fire resistance”) which is viewable in the character sheet. Resistances reduce damage taken, and are capped at 75%.

Fire damage
If you land a critical strike with an attack or spell that deals fire damage, the enemy begins Burning. Burning causes damage over time. Many monster types flee when burning.
Burning lasts 4 seconds, and the amount of damage over time is 1/3 of the fire damage dealt per second.

Cold damage
Hitting an enemy with cold damage can cause the enemy to be Chilled. Critical hits with cold damage can also cause the target to be Frozen. Chilled enemies move, attack, and cast slower, while frozen enemies cannot do anything.

Lightning damage
If you land a critical strike with an attack or spell that deals lightning damage, the enemy becomes Shocked. This can be stacked up to five times on one target. In this state, monsters or players take 20% additional damage per instance of Shock.

Chaos Damage
Chaos damage ignores energy shield, reducing life directly.

Burning, Chilled, Frozen, and Shocked are collectively known as Status Ailments.

The duration of the chilled, frozen, and shocked statuses is related to the amount of cold/lightning damage dealt.
If the duration based on the damage would be less that 300ms, it’s ignored entirely.

Charges

Some skills grant Endurance (strength), Frenzy (dexterity), or Power (intelligence) charges.
Each charge lasts a short duration before it disappears. Gaining a charge resets the duration of all accumulated charges.

Endurance charges are related to the strength attribute and grant +4% damage reduction, and +3% to all resistances per charge.

Frenzy charges are related to the dexterity attribute and grant +5% attack speed and +5% cast speed per charge.

Power charges are related to the intelligence attribute and grant +2% critical strike chance (not rating) per charge.

By default the maximum number of charges a player can have at one time depends on class. The pure classes can have up to five charges of their main attribute, and two charges of the other two attributes.
Hybrid classes can have up to four charges of each of their main attribute, and two of their off-attribute.
For example a Duelist can gain a maximum of four Endurance Charges, four Frenzy Charges, and two Power Charges. These maximums can be increased by certain passive skills.

Parties

The maximum party size is 6 players.

Effect on monsters
Monsters gain extra life for each additional player in the party. The exact amount is not known, and it is unknown what other buffs (if any) are applied.

Effect on loot
Each player in a party after the first gives the equivalent of +50% item quantity modifier on drops. So a party of three will see twice as many drops as a lone character.
Increased Item Rarity & Quantity modifiers are only counted from the player who lands the killing blow.

Effect on experience
Players in a party gain less experience for each monster kill than if they were alone. The amount of experience gained is currently proportional to character level+4. For example a level 10 and level 12 character are partied. The level 10 character gets 14/30 and the level 12 character gets 16/30 of the total experience. Only party members actually in the instance count toward getting XP. If one member is in town he gets no XP.

Monsters give +75% base XP for every party member after the first.

Effect on flasks
Only the character landing the killing blow on an enemy will gain flask charges. The same is true for all +life and +mana gained on enemy death modifiers.

Flasks have a +75% charge recovery bonus for each party member after the first.

Areas

Wraeclast area map
See this thread for an area map of Wraeclast.

Instances
All areas in Path of Exile are instanced. When you enter an area, a new instance is created. Once you leave the area, the instance will remain in it’s current state for 15 minutes – if 15 minutes passes with no players entering the instance, it will be closed. Entering the same area again will create a new instance with a new randomly generated map.

Instances you create are private, and cannot be entered by other players unless they join your party. However, once a player has entered an instance, that instance remains associated with the player even if they leave the party. So it is possible to share an instance with non-party members in some circumstances.

Some areas have waypoints. Once activated (by clicking on the waypoint), waypoints allow you to travel instantly to any other waypoint you have activated.

Ctrl-clicking on a waypoint destination in the waypoint menu, or an area transition will bring up the instance management screen. This screen lists all available instances of the area you ctrl-clicked on, and the time remaining until they are closed. It also allows you to create new instances, and close existing ones.
Using the instance management screen you can have more than once instance of the same area open at one time, and choose which available instance you want to enter.

Unanswered questions

• Mana regeneration formula
• Do %increased item quantity mods stack with the party bonus?
• Does the stun immunity from energy shield affect whether or not the blocking animation is played when an attack is blocked?
• Is damage reduction taken into consideration when deciding whether or not to play the blocking animation?
• chilled, frozen, and shocked duration formulas
• exact effects of partying on monster difficulty
• chance to stun & stun threshold formulas
• stun length formulas
• block & stun recovery formulas
• knockback distance formula
• energy shield delay and recharge speed formulas
• effect of attributes on other stats are unknown (a lot of “+x from your base stats” on character sheet tooltips)
• How does stun work if the remaining energy shield is less than the total damage dealt? Is there no chance for a stun, or is the stun calculated based on the total damage, or calculated based on the leftover damage actually dealt to hp?
• Exact effect of relative monster level on XP rewards
• Critical strike damage calulation – is it applied to base weapon/spell damage or final damage?
• Chance of X number of sockets, and minimum levels for X number of sockets appearing
• Chances of linked sockets
• Amount of bias in socket color for different types of armor