Vision

Vision determines what each unit can see. Each unit has a radius that gives vision around itself, and anything beyond its vision and its allies are hidden by Fog of War. Units cannot see through trees or terrain that's in higher elevation. Clearvision allows units to ignore these limitations. Stealthed enemy units cannot be seen within vision radius unless they are Revealed. In most cases, any vision granted by allied heroes, creeps, and buildings are shared.

Fog of War

All areas outside of friendly Vision become Fog of War. Enemy units cannot be seen nor targeted as long as it's inside the Fog of War. Building locations can be seen inside the Fog of War, but any info on the building, such as Health, cannot be seen, nor can they be targeted.

Vision is shared between teams. Anything your allied heroes, creeps, buildings, Wards, and gadgets can be seen by you as well. There are abilities which unlink shared vision, which means your only source of vision comes from your hero or any other owned units (i.e. pets) for the duration. There are two abilities that can inflict unlinked vision:  The Dark Lady's Cover of Darkness and  Adrenaline's Death's Halo.

If vision of an enemy is lost during the startup animation of a single-target ability, the ability will cancelled. However, attacks will not be interrupted if vision of the enemy is lost. If an enemy unit inside Fog of War attacks, it briefly becomes Sighted.

Fog of War updates every 0.4 seconds.

Trees and Elevation

Trees block vision and units cannot see through them. In certain areas of the map, there are small gaps between trees that allow units to move through them. Utilizing this to escape an enemy is known as "juking." Trees can be destroyed to prevent them from blocking vision, although it works for both sides.

Units also cannot see areas that are in a higher elevation, while units on higher terrain can see whatever's on lower terrain. In addition, if a ranged unit attacks another unit at a higher elevation, it suffers a 25% Miss Chance, known as "uphill miss chance". Uphill miss chance can be negated with True Strike. Wards of Sight and Wards of Revelation do not benefit from uphill miss chance.

Time of Day

Many units have higher vision radius at daytime compared to nighttime. All heroes have a base vision radius of 1800 at day and 800 at night. While some non-hero units have the same vision radius regardless of time of day, currently no unit has a higher vision radius at night than at day.

Vision radius

Heroes

All heroes have a vision of 1800 at Day and 800 at Night. A few abilities can modify hero vision radius.

Vision Radius modifiers

Unit/Item	Source	Target	Vision radius	Duration	Notes
Adrenaline	Death's Halo	Enemy Hero	400	2.5 seconds	Unlinks shared vision
Flint Beastwood	Dead Eye	Passive	+100/200/300/400	N/A
Moon Queen	Lunar Glow	Passive	+200/400/600/800	N/A	Night only
The Dark Lady	Cover of Darkness	Enemy Heroes	500/450/400	4/5/6 seconds	Unlinks shared vision

Clearvision

Clearvision grants vision within its radius, but its vision is not blocked by trees or higher terrain. Many abilities, ability projectiles, or status effect that gives sight of the target grant Clearvision. There are a few sources of permanent Clearvision as well. Clearvision radius can vary between time of day as well.

Passive

Some units possess passive Clearvision.

Source	Radius
Flying Courier	400
Gawain	600
Rejuvenating Growth	500
Shiver	800/1000/1200/1400
Zorgath	1400

Buffs

These abilities grant Clearvision around the user.

Unit/Item	Source	Radius	Duration	Notes
Artesia	Dance of Death	1000	4.5/6/7.5/9 seconds (Channeling)
Corrupted Disciple	Electric Tide	700	4 seconds
Fayde	Reflection	800/1000/1200	20/40/60 seconds (Stealth)
Prophet	Raven Form	2000/2100/2200	30/45/60 seconds	Attacking or casting spells will lower the duration to 12 seconds if there are more than 12 seconds left on the state
Slither	Poison Burst	800	3 seconds
Token of Vision	Passive	900	Until death

Sighted

Applies a status effect that grants vision of and around the target(s). Vision is lost once the target is killed.

Unit/Item	Source	Radius	Duration	Notes
Arachna	Spider Sting	200	5 Spiderling's attacks or 15 seconds	Grants vision while the Spiderling is alive
Berzerker	Mark for Death	350	8 seconds	Grants vision while mark is active
Blitz	Pilfer	800	Up to 5 seconds	Applies while linked to target
Bushwack	Jungle Toxin	500	3 seconds
Corrupted Disciple	Corrupted Conduit	800	Up to 10 seconds	Applies while linked to target
Cthulhuphant	Dreams of Madness	200	1/1.5/2/2.5 seconds	Applies while target is driven mad
Emerald Warden	Hunter's Command	500	5 seconds
Geomancer	Earth's Grasp		4 seconds
Gunblade	Grappling Shot	600	Up to 4 seconds	Grants vision while grappled
Klanx	H.A.W.K.	0	2 seconds	Grants vision to enemies when autoattacking with H.A.W.K. active
Moira	Ephemeral Forge	200	2 seconds	Grants visions to enemies within 1000 units of the Spirit Mimic during initial channel time
Pestilence	Swarm	350	30 seconds
Prisoner 945	Shackled	200	Up to 3.5/4/4.5/5 seconds	Grants vision while ball n' chain is attached
Puppet Master	Puppet Show	200	2.5/3/3.5/4 seconds
Rampage	The Chains That Bind	600	2.5/3/3.5 seconds

Projectile

These projectiles or gadgets grant Clearvision while it is on the map. Some projectiles give vision for a short time after it expires.

Unit/Item	Source	Radius	Duration	Notes
Aluna	Power Throw	800	N/A
Amun-Ra	Path of Destruction	800	N/A	Grants vision around the meteor's landing point
Andromeda	Aurora	500	5 seconds
Artesia	Arcane Missile	280	3 seconds	Vision lingers after impact
Bombardier	Air Strike!	350	5 seconds	SotM version only; Grants vision around napalm
Bubbles	Shell Surf	800	3.34 seconds
Calamity	Sunder's Vault	550	4.5 seconds
Chronos	Chronofield	500	3/4/5 (5/6/7) seconds
Circe	Entrapment	400/800	1.5 seconds
Doctor Repulsor	Magnetic Contraption	400	Up to 16 seconds	Lasts until Contraption is detonated
Doctor Repulsor	Opposite Charges	300	3 seconds	Grants vision around magnet
Ellonia	Glacial Spike	200/500	2 seconds	Grants lingering vision around impacted targets
Ellonia	Frigid Field	300	4 seconds
Ellonia	Absolute Zero	1000	0 (6) seconds
Empath	Illusory Veil	650x200 (Vector)	3/4/5/6 seconds
Fayde	Burning Shadows	200	N/A
Fayde	Deep Shadows	600	5 seconds
Flint Beastwood	Explosive Flare	800	4 seconds
Flux	Discharge	1000/700	3 seconds	Grants vision around enemy heroes' locations
Frostfield Plate	Activation	800	2 seconds
Gauntlet	Grapple	600	N/A
Gauntlet	Gauntlet Blast	600	N/A
Geomancer	Quicksand	600	6 seconds
Kraken	Tsunami Charge	500	5 seconds	Grants vision around where charge stopped
Kraken	Release the Kraken!	200	3/4/5 seconds
Maliken	Sword Throw	700	N/A
Moira	Arcane Vortex	350	4 seconds
Monarch	Noxious Cloud	400	4 seconds
Monarch	Cleansing Wind	800	1 (4) seconds
Moraxus	More Axes	100	N/A
Myrmidon	Magic Carp	800	3.34 seconds	Vision lingers on impact
Pearl	Whirlbubble	500	1.3 seconds	Grants vision around end point
Pearl	Preservation	600	8/10/12 seconds
Pharaoh	Tormented Soul	500	10 seconds
Ravenor	Ball Lightning	500	N/A
Rhapsody	Disco Inferno	400	6.5 seconds
Riftwalker	Cascade Event	400	2 seconds	Grants vision after delay
Riptide	Undertow	350	N/A	Grants vision inside puddles
Sacrificial Stone	Passive	700/50	5 seconds	Clearvision is reduced to 50 until respawn
Sand Wraith	Desert's Curse	500	12 seconds
Shadowblade	Soul's Sight	800	6 seconds
Silhouette	Tree Grapple	400	Up to 6 seconds	Grants vision around hooked tree
Solstice	Shining Rays	700	8 seconds
Solstice	Luminescence	700	0.5 seconds
Succubus	Cursed Embrace	300	5.1 seconds (Channeling)
Tarot	Far Scry	200	8/10/12/14 seconds
Tempest	Elemental Void	400	4 seconds
The Chipper	Rocket Barrage	400/800	1.5 seconds	Vision lingers after impact
The Chipper	Sawblade Showdown	800x200 (Vector)	8 seconds
The Gladiator	Pitfall	400	4 seconds	Grants vision after delay
The Gladiator	Call to Arms	800	3.34 seconds
Thunderbringer	Blast of Lightning	1000/700	3 seconds	Grants vision around target's location
Thunderbringer	Lightning Storm	1000/700	3 seconds	Grants vision around targets' locations
Tundra	Piercing Shards	500	N/A
Valkyrie	Javelin of Light	800	3.34 seconds
Werebeast Enchanter	Far Sight	700	8 seconds
Zephyr	Typhoon	600	8/10/12 seconds