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Collision size ( ) 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.


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

Collision Size Comparison[]


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, Marci, Mars, Medusa, Mirana, Morphling, Nature's Prophet, Necrophos, Night Stalker, Nyx Assassin, Ogre Magi, Omniknight, Oracle, Outworld Destroyer, Pangolier, Phantom Assassin, Phoenix, Primal Beast, 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 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 Frostbitten Golem, Ancient Granite Golem, Ancient Ice Shaman, 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, Roshan, Satyr Banisher, Satyr Mindstealer, Satyr Tormenter, Shard Golem, Spirit Bear, Sticky Bomb, Tempest Double, Vhoul Assassin, Warlock Golem, Warpine Raider, Wildwing, Wildwing Ripper 24
Astral Spirit, Beetle, Courier, Earth, Eidolon, Fire, Healing Ward, Jex, 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, Storm, Super Ranged Creep, Void, Wraith Pact Totem 8
Power Cog 80
Fiend's Gate 96


Buildings Collision size
Fountain, Melee Barracks, Ranged Barracks, Tower (Tier 1), Tower (Tier 2), Tower (Tier 3), Tower (Tier 4) 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:

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 minimap icon.png Dark Seer casts Surge with level 25 Talent on Abaddon minimap icon.png Abaddon?
Range values:
  • Level 25 Surge Talent talent radius: 350
Collision size values:
Surge in this example has a maximum area of effect range of 374 in this example.
Example 2
Invoker minimap icon.png Invoker with Aghanim's Scepter icon.png Aghanim's Scepter used Cataclysm. What's the maximum area range for enemy Meepo minimap icon.png Meepo and Abaddon minimap icon.png Abaddon?
Example 3

Targeted actions have a different range than non-targeted actions. Every targeted action considers the ordered unit's and the targeted unit's collision sizes.

A Tower Radiant icon.png Tower (Tier 1) tower has a collision size of 144 with a 700 attack range can attack units up to 844 at the minimum.

Considering most heroes have a collision size of 24, it has 868 attack range against most heroes.

The green/red range indicators around towers show this effective range of 844.

As for auras, they do not consider a source of origin, but do consider the collision size of the units they effect. So most heroes are affected by Tower Protection aura when within 924 range of the tower.


Abilities Based on Collision Size
  • Fissure icon.png
    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

Ignoring Collision Size[]

Shukuchi icon.png

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.

Abilities Providing Phased Movement[]

These abilities provide phased movement which allows moving through units:

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

Abilities Providing Unobstructed Movement[]

Free pathing (also known as unobstructed movement) allows 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 only a tiny amount of spells will block them. All sources of flying movement give units unobstructed movement. Uphill miss chance does not apply to flying units.

The following abilities provide unobstructed movement:

1 Requires Aghanim's Scepter icon.png Aghanim's Scepter.
2 Requires Aghanim's Shard icon.png Aghanim's Shard.
3 Requires Talent talent.
4 Illusions created by these abilities have unobstructed pathing.


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

Tree-walking Granting Abilities

Permanently Phased[]

The following units are permanently phased:

Flying Movement[]

Flying movement is similar to unobstructed movement, with only very small differences, one being that flying units hover a certain distance above the ground and that even less spells block flying movement.

Units with Flying Movement

The following abilities provides Flying Movement while active:

1 Requires Aghanim's Scepter icon.png Aghanim's Scepter.
2 Requires Aghanim's Shard icon.png Aghanim's Shard.


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 icon.png Tango has an amplified effect when used on a planted tree.

Planted Tree Sources
  • Acorn Shot icon.png
    Tree Duration: 20
    Creates a tree when targeting the ground.
    Tango icon.png Tango does not heal for twice as long when targeting a Acorn Shot tree.
  • Decoy icon.png
    Tree Duration: 20
    Requires Aghanim's Scepter icon.png 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 icon.png
    Duration: 20
    Plants a happy little tree, with a smaller collision size. The Iron Branch gets consumed in the process.
  • Sprout icon.png
    Duration: 3/4/5/6
    Creates a ring of 8 trees around the targeted point or unit.

Pathing Blockers[]

Main Article: Trap

A pathing blocker is an invisible entity with a collision size that physically blocks other units. Walking against a pathing blocker is akin to walking against any other unit that is not phased or flying, or walking against trees.

Version History[]

  • Reduced Meepo minimap icon.png Meepo's collision size from 24 to 8.
  • Increased Dire icon.png Dire towers collision size from 120 to 144.

Patch History[]

  • Reduced DOTA_HULL_SIZE_SMALLEST size value from 4 to 2.
  • Added new collision size: DOTA_HULL_SIZE_SMALLEST (4)
  • Made various collision adjustments to the Dota map.
  • Fixed units with flying movement not moving correctly when issued move orders off the playable area of the map.
  • Fixed trees not being destroyed properly when the phased movement is dispelled after damage.
  • Fixed a case where leaving and rejoining the Spectral Dagger path could cause Spectre minimap icon.png Spectre to temporarily lose no-collision.
  • Added a short grace period to walking off the Spectral Dagger path before collision size is restored.
  • Fixed Meld not removing collision.
  • Fixed Haunt illusions having collision size.
  • Fixed the following buildings' collision size:
  • Trees are now temporarily prevented from respawning if there are any player-controlled units whose collision are within 250 units of the center of the tree.
  • Fixed various pathing issues around Towers.
  • Fixed various pathing issues around Towers.
  • Pathfinding
    • Fixed bug mostly affecting narrow passages between trees, where a unit from certain positions, could incorrectly consider the narrow passage blocked, thus taking a different, longer path to the destination.
      • This also fixes certain areas where spam-right-clicking a target position would cause your character to run back and forth, such as in the tree clump below the river mid-lane.
    • Fixed bug that was preventing heroes from finding paths through certain 1-tile-wide corridors, such as among trees, when their primary path was blocked (such as by units).