Unit Size

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Trees[edit]

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 block size of a 128x128 unit square.

Ignoring Collision Size[edit]

Phased Movement[edit]

These abilities provide phased movement which allows moving through units:

Phased Movement Sources

Bounty Hunter – Shadow Walk
Bounty Hunter – Friendly Shadow
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 Souls (Cast Time)
Silver Edge – Shadow Walk
Slardar – Guardian Sprint
Storm – Wind Walk
Templar Assassin – Meld
Weaver – Shukuchi

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The following units are permanently phased:

Permanently Phased Units

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Unobstructed Movement[edit]

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:

Unobstructed Movement Granting Abilities

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Flying Movement[edit]

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

When a unit turns to Flying Movement, although its hitbox and model ascend above the z-axis, both its collision size and bound radius are still on the ground. The following abilities provide Flying Movement while active:

Flying Movement Sources

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Units with Flying Movement

Bound Radius[edit]

Naga Siren and

Slark's bound radius.

The Bound Radius determines the absolute coordinates of a unit in the game and acts as a pseudo-buffer for certain ability types' cast range values and attack range-related values. A unit's bound radius can be shown with dota_unit_show_bounding_radius 1 with console enabled.

Bound radius also affects the size of an area of effect, if an ability is cast as a ground-targeted ability, the affected target's bound size is also considered as a buffer range for ability, 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 bound radius value is ignored and no buffer range is added.

Mechanics	Affected Aspect / Definition	Ability Examples
Attack Range	The bound radius of both the attacker and the attacked unit increases the actual attack range.
Cast Range (Unit-targeted Abilities)	The bound radius of both the attacker and the attacked unit increases the actual cast range for unit-targeted abilities.	Laguna Blade
Area-of-Effect Abilities	The bound radius affects the actual effect range of area-of-effect and aura-based abilities.	Song of the Siren

Equations[edit]

For normal attacks:
Actual Attack Range = Total Attack Range + Attacker Bound Radius + Target Bound Radius

For most melee heroes, the attack buffer range is defined as:
Total Melee Buffer Range = Unit Total Attack Range + Attacker Bound Radius + Target Bound Radius + 350

For abilities:
MAX Cast Range = Total Ability Cast Range + Target Bound Radius

MAX Effect Radius = Total Ability Effect Radius + Target Bound Radius

Example 1a: Maximum Distance for Attackable Range; A Tower (Tier 1) is attacking Marci. Without other attack range-increasing sources, what is the maximum distance a normal attack would hit between the attacker and the unit being attacked?

Tower (Tier 1) attack range: 700

Tower (Tier 1) bound radius: 144

Marci bound radius:

Maximum attack range against

Marci

= 700 + 144 +

= Expression error: Missing operand for +.

The

Tower (Tier 1) has a Expression error: Missing operand for +. maximum attack range against

Marci. Since the Tower cannot move, the 250 attack range buffer does not apply in this case.

Example 1b: With Attack Buffer Range; Muerta is attacking Marci. Without other attack range-increasing sources, what is the maximum distance a normal attack would hit between the attacker and the unit being attacked?

Muerta attack range: 575

Muerta bound radius:

Marci bound radius:

Motion buffer distance: 250

Maximum attack range against

Marci

= 575 + +

= Expression error: Missing operand for +.

Muerta has a Expression error: Missing operand for +. maximum attack range against

Marci, and her attack cancels when

Marci is beyond 825 distance from her.

Therefore, units with a smaller bound radius will have a lesser actual attack range value against them.

Example 2: An Ability's Maximum Effect Radius Between Two Casters

Bound Radius affecting actual effect radius.; What is the maximum area of effect range for Naga Siren's Song of the Siren affecting Rubick?; If Rubick acquires Song of the Siren via Spell Steal, what is the maximum area of effect range for Rubick's Song of the Siren affecting Naga Siren?

Song of the Siren max radius: 1400

Rubick bound radius:

Naga Siren bound radius:

Maximum effect radius against

Rubick:

= 1400 +

= Expression error: Missing operand for +.

Maximum effect radius against

Naga Siren:

= 1400 +

= Expression error: Missing operand for +.

Therefore, Naga Siren's

Song of the Siren has a greater area of effect of Expression error: Missing operand for +. compared to

Rubick's.

Assuming both Rubick and Naga Siren are at ±1400 distance apart, an acquired Song of the Siren via

Spell Steal might not affect Naga Siren if she is not within the actual effect radius since Naga Siren has a smaller bound radius as shown in the diagram on the right.

Selection Box[edit]

Selection boxes.

The selection box (or hitbox) is the range size of a unit being clickable, or when ⇱⇲ Drag is used to select units.

Most units have a minimum of two selection boxes, one exterior big cuboid, and at least one cuboid on the inside. For buildings, the cuboid inside might be larger than the exterior cuboid. Clicking outside the unit's selection box will not select the unit.

The selection box is bound to the unit's model and its values can be found using Workshop Tools. The selection boxes' size also scales with the current unit's model size. A unit's selection boxes can be shown with dota_unit_show_selection_boxes 1 with console enabled.

Certain cosmetic items change the value of the selection boxes due to having a different model as follows:

Acolyte of the Lost Arts of Invoker's.
Custom Observer and Sentry Wards.

Has the following priority when the selection boxes of multiple units overlap:

The internal cuboid(s) ➤ The external cuboid ➤ The unit closest to the player's camera.

Hexed

Windranger, collision size stays unchanged, but the selection boxes change based on the Hex model.

Selection Boxes `Left Click`	Mechanics
Exterior Cube	The unit is selected as long it is clicked within the range of the exterior cube. Target Unit abilities are cast as long as it is clicked within the range of the exterior cube. The exterior cube's size scales with the current unit's model size.
Internal Cube	The unit is selected as long it is clicked within the range of the internal cube as well. The unit is selected as long `⇱⇲ Drag` within the range of the internal cube as well.
Hollow Ring	Every unit has a hollow ring under the selected unit. The radius of this hollow ring cannot be changed and it is set as `RingRadius` in `npc_abilities.txt` or `npc_units.txt`.

Unselectable[edit]

Main Article: Unselectability

Unselectability makes the unit not selectable, and selectable only in a few cases. Most abilities/items treat unselectable units as if they were invisible, except in a few cases. Some sources of unselectability may remove a unit's selection box, grant attack immunity, and may prevent allies or enemies or both from targeting them.

Although Hide sources also cause the unit to be unselectable and non-targetable, they are considered a different mechanic.

Model Size[edit]

Model Size

A unit's Model Size is stored as a fixed scale value in npc_abilities.txt or npc_units.txt. Model Size can be shown with both ent_text and debug_overlay_fullposition 1 with console enabled.

Model Size shown in ent_text is equal to 1.12 * Model Scale in either npc_abilities.txt or npc_units.txt.

It has no correlation with a unit's collision size or bound radius. However, increasing the model size increases the size of a unit's selection boxes.

Also, a unit's model animations do not determine the unit's current facing direction, certain ability interactions with the current unit's model may not correctly represent the current facing direction of the unit.

In most cases, ability animations with special model animations do not change the unit's facing direction. This includes all Taunt (Equipment) and the following abilities:

Abilities with Special Model Animations

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Different Model[edit]

Main Articles: Transformation Abilities and Hex

The following sources directly change or replace the unit's current model. Certain abilities increase the model size as an effect as well, with more details can be found on their respective ability notes.

Abilities Changing Current Unit's Model

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Percentage-Based Changes[edit]

Avatar increases model size by 30%.

All percentage-based model scale sources stack independently and additively of each other.

Total Model Size = Base Scale × (1 + Percentage-Based Scale _i)

Example: Axe currently has a model scale of 1.12. What is his current model scale upon activating Avatar?

Avatar model scale increase: 30%

1.12 × (1 + 0.3)

= 1.456

Axe has a model scale of 1.456 upon activating

Avatar as shown in the picture example on the left.

Percentage Bonuses[edit]

Model Size Changing Sources

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