Vision

Line of sight!

Vision is a gameplay mechanic which determines what a unit can and cannot see. Areas a unit cannot see are filled with the Fog of War, the dark places of the map where no ally currently has vision of. Unit vision is written in a Day / Night format. If a unit has 1800 vision range during the day and 800 vision range at night, it will be written as 1800 / 800.

Invisible units cannot be seen normally, and must be spotted by a unit with True Sight.

Fog of War

All areas outside of allied vision become covered in the fog of war. Any enemy units within the fog of war cannot be seen or targeted, unless affected by Bloodseeker's Thirst in which you can.

To reveal units in the fog of war, an allied unit or ability must gain vision in that area. Observer Wards can provide vision in a large area to their team. The Roshan pit has a deep fog that cannot be seen into unless there is an ally inside it or a unit has flying vision.

If a unit in the fog of war attacks an enemy that does not have vision of them, the attacker will be revealed for a few seconds.

Day and Night cycle

Most units have different vision ranges for the day and night cycle. Generally, units see a lot farther during the day than they do at night. Most heroes have 1800 vision range during the day, and 800 at night, though there are several exceptions. This makes ganking more viable at night, because heroes can get much closer without being detected.

Below is a table of all exceptions to the 1800 / 800 hero vision rule:

Hero	Day Vision	Night Vision	Notes
Batrider	1200	800	Permanent
Bounty Hunter	1800	1000	Permanent
Luna	1800	1800*	Luna obtains 1800 night vision permanently after leveling Lunar Blessing
Lycan	1800	1800*	Lycan obtains 1800 night vision while Shapeshift is active
Night Stalker	800	1800	Permanent
Slardar	1800	1800*	With level 20 talent
Slark	1800	1800	Permanent
Sniper	1800	1400	Permanent
Spirit Breaker	1800	1400*	With level 10 talent
Winter Wyvern	1800	1200(1600)*	Winter Wyvern obtains 1200 night vision while Arctic Burn is active and an permanent 400 extra night vision with level 15 talent

Vision Types

Ground Vision

This is the default for most units. They cannot see areas that are on higher ground than themselves, and units on higher ground receive unobstructed vision below. Trees will also block vision, and can be used to escape enemies by running through small gaps in between them. Trees can be cut down or destroyed to no longer block vision.

Sources of ground vision from spells:

Hero Abilities
Hero	Ability	Ground Vision Radius	Vision Duration
Ancient Apparition	Ice Vortex	200	16
Bloodseeker	Blood Rite	200	6
Crystal Maiden	Crystal Nova	900	6
Disruptor	Kinetic Field	325	2.5 / 3 / 3.5 / 4
Elder Titan	Astral Spirit	400	8
Gyrocopter	Call Down	300	4
Kunkka	Torrent	300	3.6
Techies	Proximity Mines	64	Until detonated
	Blast Off	400	2
	Remote Mines	700	10 minutes
Item Abilities
Item	Ability	Ground Vision Radius	Duration
Observer Ward	Plant Ward	1600	7 minutes
Sentry Ward	Plant Ward	150	12
Manta Style	Mirror Image	1000	0.23

Flying Vision

This provides unobstructed vision at all levels of elevation. A unit with flying vision can see the high ground above them, and will not have their vision blocked by trees.

Sources of flying vision from spells:

Hero Abilities
Hero	Ability	Flying Vision Radius	Vision Duration
Alchemist	Unstable Concoction Throw	300	Projectile duration
Ancient Apparition	Ice Blast	500	3
	Release	650	4
Batrider	Sticky Napalm	400	2
	Flamebreak	175	Projectile duration
	Firefly	Current vision range	15 23 25
Beastmaster	Wild Axes	350	Projectile duration
Clockwerk	Rocket Flare	600	10
Faceless Void	Chronosphere	475	4 / 4.5 / 5
Invoker	Chaos Meteor	500	6
	Sun Strike	400	6
	Tornado	600	1.75
Io	Spirits	150	3
Jakiro	Ice Path	200	2.5
Juggernaut	Omnislash	200	Omnislash duration
Keeper of the Light	Illuminate	375	10.34
Kunkka	Ghost Ship	300	3
Lich	Chain Frost	800	Projectile duration
Medusa	Mystic Snake	100	Projectile duration
Meepo	Earthbind	300	Projectile duration
Mirana	Sacred Arrow	500	Projectile duration, then 3
Monkey King	Tree Dance	800	While perched
Nature's Prophet	Sprout	500	3 / 4 / 5 / 6
Phantom Assassin	Stifling Dagger	450	Projectile duration, then 3.34
Puck	Illusory Orb	450	3.34
Pudge	Meat Hook	500	4
Razor	Plasma Field	800	4.5
Shadow Demon	Shadow Poison	190	Projectile duration
Skywrath Mage	Arcane Bolt	325	Projectile duration, then 3.34
	Concussive Shot	300	Projectile duration, then 3.34
Sniper	Shrapnel	450	10.8
Spectre	Spectral Dagger	200	12
Storm Spirit	Static Remnant	500	12
	Ball Lightning	400	While in use
Techies	Proximity Mines	300	1
	Stasis Trap	300	1
	Remote Mines	500	3
Timbersaw	Chakram	300	Chakram duration
Treant Protector	Eyes In The Forest	800	Tree duration
Tusk	Ice Shards	100	2
Vengeful Spirit	Wave of Terror	500	3
Venomancer	Venomous Gale	400	Projectile duration
Windranger	Powershot	400	3.34
Zeus	lightning bolt	750	4.5
	Thundergod's Wrath	1000	3
Item Abilities
Item	Ability	Flying Vision Radius	Duration
Shiva's Guard	Arctic Blast	800	4.5

Shared Vision

Shared vision provides an area of vision over an enemy unit equal to that enemy unit's vision range.

Sources of shared vision:

Hero Abilities
Hero	Ability
Disruptor	Thunder Strike
Lifestealer	Infest
Razor	Static Link
Silencer	Last Word
Sniper	Assassinate
Spirit Breaker	Charge of Darkness

See also

• Blind
• True Sight