Collision size ( Phased status allows units to ignore 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.Contents
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[]
Units[]
Buildings[]
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 casts Surge with level 25
on Abaddon?
- Surge in this example has a maximum area of effect range of 374 in this example.
- Example 2
- Invoker with Aghanim's Scepter used Cataclysm. What's the maximum area range for enemy Meepo and 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 (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[]
- 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[]

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:
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) 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:
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 – Vendetta3
Nyx Assassin – Burrow1
Spectre – Spectral Dagger
Spectre – Haunt4
Spectre – Shadow Step1 4
Spider Legs – Scurry
Terrorblade – Reflection4
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.
- Passive Tree Search Radius: 275
Grants phased movement and tree-walking to Hoodwink within the tree search radius. - Innate ability, does not need to be learned.
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.
The following abilities provides Flying Movement while active:
- 1 Requires Aghanim's Scepter.
- 2 Requires Aghanim's Shard.
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.
- Tree Duration: 20
Creates a tree when targeting the ground.
Tango does not heal for twice as long when targeting a Acorn Shot tree. - 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. - Duration: 20
Plants a happy little tree, with a smaller collision size. The Iron Branch gets consumed in the process. - Duration: 3/4/5/6
Creates a ring of 8 trees around the targeted point or unit.
Pathing Blockers[]
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[]
- [U] Reduced Wraith King Skeleton collision size from 24 to 8.
- Increased the following heroes' collision size from 12 to 24:
- Reduced the following heroes' collision size from 24 to 12:
- Reduced Metamorphosis demon form collision size from 32 to 24.
Patch History[]
- Reduced
DOTA_HULL_SIZE_SMALLEST
size value from 4 to 2.
- Added new collision size:
DOTA_HULL_SIZE_SMALLEST
(4)
- Enemies with flying movement inside the ring of Power Cogs will now be affected by cogs when flying over the cogs or units using forced movement (i.e. Force Staff) to escape the cogs.
- Reduced Fountain collision size.
- 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 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.
- Update 4
- Improved flying units trying to stack on top of each other.
- Update 2
- Fixed Psionic Trap having collision size.
- Fixed Haunt illusions having collision size.
- Fixed Plague Ward collision size.
- 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).
- 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.
- Dominated units no longer have phased movement.
- Affects Chen, Enchantress, and Helm of the Dominator.
- Dominated units now have phased movement.
- Affects Chen, Enchantress, and Helm of the Dominator.
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