Collision size

Collision size ( $col$ ) is a unit's internal size that cannot be passed through by other units. This allows units to block each other with their bodies. Most heroes have the same collision size, regardless of their graphical model. Phased status allows units to ignore collision size.

Mechanics

The collision sizes of units is not directly set by a number in their data. Instead, collision sizes are standardized for all units, with the use of bounds hull names.

The following hull sizes exist, corresponding to the following collision sizes (from largest to smallest):

Hull Name	Size
DOTA_HULL_SIZE_BUILDING	298
DOTA_HULL_SIZE_TOWER	144
DOTA_HULL_SIZE_FILLER	96
DOTA_HULL_SIZE_HUGE	80
DOTA_HULL_SIZE_HERO	24
DOTA_HULL_SIZE_REGULAR DOTA_HULL_SIZE_SIEGE	16
DOTA_HULL_SIZE_SMALL	8
DOTA_HULL_SIZE_SMALLEST	2

Collision Size Comparison

Heroes

Heroes	Collision size
Hoodwink, Lycan, Meepo, Monkey King, Naga Siren, Phantom Lancer	8
Abaddon, Alchemist, Ancient Apparition, Anti-Mage, Arc Warden, Axe, Bane, Batrider, Beastmaster, Bloodseeker, Bounty Hunter, Brewmaster, Bristleback, Broodmother, Centaur Warrunner, Chaos Knight, Chen, Clinkz, Clockwerk, Crystal Maiden, Dark Seer, Dark Willow, Dawnbreaker, Dazzle, Death Prophet, Disruptor, Doom, Dragon Knight, Drow Ranger, Earth Spirit, Earthshaker, Elder Titan, Ember Spirit, Enchantress, Enigma, Faceless Void, Grimstroke, Gyrocopter, Huskar, Invoker, Io, Jakiro, Juggernaut, Keeper of the Light, Kunkka, Legion Commander, Leshrac, Lich, Lifestealer, Lina, Lion, Lone Druid, Luna, Magnus, Mars, Medusa, Mirana, Morphling, Nature's Prophet, Necrophos, Night Stalker, Nyx Assassin, Ogre Magi, Omniknight, Oracle, Outworld Destroyer, Pangolier, Phantom Assassin, Phoenix, Puck, Pudge, Pugna, Queen of Pain, Razor, Riki, Rubick, Sand King, Shadow Demon, Shadow Fiend, Shadow Shaman, Silencer, Skywrath Mage, Slardar, Slark, Snapfire, Sniper, Spectre, Spirit Breaker, Storm Spirit, Sven, Techies, Templar Assassin, Terrorblade, Tidehunter, Timbersaw, Tinker, Tiny, Treant Protector, Troll Warlord, Tusk, Underlord, Undying, Ursa, Vengeful Spirit, Venomancer, Viper, Visage, Void Spirit, Warlock, Weaver, Windranger, Winter Wyvern, Witch Doctor, Wraith King, Zeus	24

Units

Units	Collision size
Death Ward, Familiar, Forged Spirit, Greater Treant, Ice Spire, Mega Melee Creep, Melee Creep, Necronomicon Warrior, Serpent Ward, Siege Creep, Super Melee Creep, Super Siege Creep, Tombstone, Tornado, Treant	16
Undying Zombie, Wraith King Skeleton	2
Alpha Wolf, Ancient Black Dragon, Ancient Black Drake, Ancient Granite Golem, Ancient Rock Golem, Ancient Rumblehide, Ancient Thunderhide, Boar, Centaur Conqueror, Centaur Courser, Dark Troll Summoner, Fell Spirit, Ghost, Giant Wolf, Harpy Scout, Harpy Stormcrafter, Hawk, Hellbear, Hellbear Smasher, Hill Troll, Hill Troll Berserker, Hill Troll Priest, Homing Missile, Ignis Fatuus, Kobold, Kobold Foreman, Kobold Soldier, Mud Golem, Ogre Bruiser, Ogre Frostmage, Phoenix Sun, Plague Ward, Remote Mine, Roshan, Satyr Banisher, Satyr Mindstealer, Satyr Tormenter, Shard Golem, Spirit Bear, Tempest Double, Vhoul Assassin, Warlock Golem, Wildwing, Wildwing Ripper	24
Astral Spirit, Beetle, Earth, Eidolon, Fire, Frozen Sigil, Healing Ward, Lycan Lane Wolf, Lycan Wolf, Mega Ranged Creep, Necronomicon Archer, Nether Ward, Nimbus, Observer Ward, Phantom, Proximity Mine, Psionic Trap, Ranged Creep, Sentry Ward, Skeleton Archer, Skeleton Warrior, Spiderite, Spiderling, Spin Web, Stasis Trap, Storm, Super Ranged Creep, Void	8
Power Cog	80

Buildings

Buildings	Collision size
Fountain, Melee Barracks, Ranged Barracks, Tier 1 Tower, Tier 2 Tower, Tier 3 Tower, Tier 4 Tower	144
Ancient	298
Effigy Building, Outpost	96

Area of Effect

Indicator of area target spells

Collision size affects the size of an area of effect, if an ability is cast as a ground-targeted ability, the affected target's collision size is also considered as a buffer range for ability, and therefore increasing the ability's maximum area of effect range.

However, if an ability is cast centered on the caster (with ↓↓ Double-tapping), the caster's collision size is ignored and no buffer range is added.

The maximum area of effect for area-targeted abilities is defined as:

$max\{aoe\}={aoe}_{b}+{col}_{t}$

With aoeb being the base effect radius and colt the target's collision size.

Example 1

What is the maximum area of effect range if Dark Seer casts Surge with level 25 on Abaddon?

Range values:

• Level 25 Surge talent radius: 320

Collision size values:

• Abaddon: 24

$max\{c\}=320+24=344$

Surge in this example has a maximum area of effect range of 344 in this example.

Example 2

Invoker with Aghanim's Scepter used Cataclysm. What's the maximum area range for enemy Meepo and Abaddon?

Abilities

Abilities Based on Collision Size

• Earthshaker - Fissure
  
  Fissure Pathing Block Radius: 24
  The segments have a collision size of 24, and a distance of 8.25 between each other, with the first one being placed 8.25 range in front of Earthshaker.
  This means the actual length of the Fissure can only be a factor of 56.25.
  The length factor is defined as ${\text{sides}}\times col+d$

Ignoring Collision Size

Phased is a status that allows units to pass through other units, ignoring collision size. Phased units can freely walk through any other unit, including wards, but excluding buildings and trees. Other units can also walk through a stationary phased unit as if it is not there.

There are two different kinds of phased movement, pathing through units, and the rare kind which allows the unit to walk through anything, including buildings, cliffs and trees, which is more commonly referred to as unobstructed movement.

Flying movement is similar to phased movement, with only very small differences, one being that flying units hover a certain distance above the ground.

Abilities Providing Phased Movement

These abilities provide phased movement which allows moving through units:

• Anti-Mage – Blink illusion (talent)
• Bounty Hunter – Shadow Walk
• Clinkz – Skeleton Walk
• Dark Willow – Shadow Realm
• Faceless Void – Chronosphere
• Glimmer Cape – Glimmer
• Invoker – Ghost Walk
• Nyx Assassin – Vendetta
• Phase Boots – Phase
• Shadow Amulet – Fade
• Slardar – Guardian Sprint
• Shadow Blade – Shadow Walk
• Shadow Fiend – Requiem of Souls¹
• Silver Edge – Shadow Walk
• Slardar – Guardian Sprint
• Storm – Wind Walk
• Templar Assassin – Meld
• Weaver – Shukuchi

¹ Shadow Fiend becomes phased during the cast time of Requiem of Souls.

Abilities Providing Unobstructed Movement

Free pathing (also known as unobstructed movement or flying movement) allow affected units to path through buildings, cliffs and trees, on top of allowing them to path through other units. There is no limit to their movement and nothing will block them, all sources of flying give units unobstructed movement. Uphill miss chance does not apply to flying units.

The following abilities provide unobstructed movement:

• Batrider – Firefly
• Broodmother – Spin Web
• Centaur Warrunner – Stampede¹
• Dragon Knight – Elder Dragon Form¹
• Giant's Ring – Giant's Foot
• Lich – Sinister Gaze
• Legion Commander – Duel
• Nyx Assassin – Vendetta
• Nyx Assassin – Burrow¹
• Spectre – Spectral Dagger
• Spectre – Dispersion^{2 4}
• Spectre – Haunt⁴
• Spectre – Shadow Step^{1 4}
• Spider Legs – Scurry
• Terrorblade – Reflection⁴
• Visage – Silent as the Grave¹
• Wraith King – Wraith Delay¹

¹ Requires Aghanim's Scepter.

² Requires Aghanim's Shard.

³ Requires talent.

⁴ Illusions created by these abilities have unobstructed pathing.

Tree-walking

The following abilities grants tree-walking, a buff that allows unobstructed movement through trees.

Tree-walking Granting Abilities

• Hoodwink - Scurry
  
  Passive Tree Search Radius: 275
  Grants phased movement and tree-walking to Hoodwink within the tree search radius.
• Treant Protector - Nature's Guise
  
  Innate ability, does not need to be learned.

Permanently Phased

The following units are permanently phased:

Permanently Phased Units

• Spin Web – Phased
• Courier – Phased
• Beetle – Phased
• Hawk – Phased
• Fire – Phased
• Observer Ward – Phased
• Sentry Ward – Phased
• Healing Ward – Phased
• Ignis Fatuus – Phased
• Phoenix Sun – Phased
• Proximity Mines – Phased
• Stasis Trap – Phased
• Minefield Sign – Phased
• Remote Mines – Phased
• Roshan – Strength of the Immortal
• Psionic Trap – Phased

Flying Movement

• Familiar
• Flying Courier
• Hawk

Abilities that turn the caster into a flying unit

• Clockwerk – Jetpack²
• Night Stalker – Dark Ascension
• Winter Wyvern – Arctic Burn

Trees

Main Article: Trees

Trees are a prominent terrain feature in Dota 2. They make up a large amount of the map, and are very prominent in the forests that separate the lanes and border the map. Trees block vision and are normally impassable.

Despite the varying appearance and apparent size of the various trees, all permanent trees have an identical collision size of a 128x128 unit square.

Planted Trees

Planted trees have a smaller collision size and block less vision than regular trees. Tango has an amplified effect when used on a planted tree.

• Hoodwink - Acorn Shot
  
  Tree Duration: 20
  Creates a tree when targeting the ground.
  Tango does not heal for twice as long when targeting a Acorn Shot tree.
• Hoodwink - Decoy
  
  Tree Duration: 20
  Requires Aghanim's Scepter.
  Send a decoy illusion to the target location. When the illusion is attacked or hit by a targeted ability, it is destroyed and plants a tree in its place that applies a lesser Bushwhack to enemy heroes around it.
• Iron Branch - Plant Tree
  
  Duration: 20
  Plants a happy little tree, with a smaller collision size. The Iron Branch gets consumed in the process.
• Ironwood Tree - Plant Tree
  
  Duration: 20
  Plants a happy little tree, with a smaller collision size.
• Nature's Prophet - Sprout
  
  Duration: 3/4/5/6
  Creates a ring of 8 trees around the targeted point or unit.

Version History

Version

Description

7.29

• Reduced Meepo's collision size from 24 to 8

Patch History

Patch

Description

26 Nov 2019

• Reduced DOTA_HULL_SIZE_SMALLEST size value from 4 to 2.

31 Oct 2017

• Added new collision size: DOTA_HULL_SIZE_SMALLEST (4)

04 Aug 2011

• Dominated units no longer have phased movement.
  • Affects Chen, Enchantress, and Helm of the Dominator.

08 Jul 2011

• Dominated units now have phased movement.
  • Affects Chen, Enchantress, and Helm of the Dominator.

Mechanics Stats Armor Attributes (Strength / Agility / Intelligence) Collision size Health (Health regeneration) Magic resistance Mana (Mana regeneration) Movement speed Status resistance Turn rate Vision Attack Attack animation Attack damage Attack modifier (Bash / Cleave & Splash / Critical strike / Lifesteal / Mana break) Attack range Attack speed Cast animation Cast range Damage types Motion buffer range Projectile speed Spell damage Spell lifesteal Abilities Abilities Aura Channeling Cooldown Damage block Damage manipulation Damage over time Evasion Talents Teleport Status effects Attack immunity Break Cyclone Disable Disarm Ethereal Fear Forced movement Hex Hide Hypnosis Invisibility Invulnerability Leash Phased Root Silence Sleep Slow Spell immunity Stun Taunt World Experience Gold Glyph of Fortification Map (Minimap) River Scan Runes Time of day Trees Gameplay Creep control techniques Denying Disjoint Dispel Ganking Harassment Hero complexity Initiating Item passive stacking Item sharing Jungling Lane Pushing Random distribution Roles Trap Units Ancient creeps Buildings Couriers Creep-heroes Heroes Illusions Lane creeps Neutral creeps Roshan Summons & Wards