Darkvision Mechanics

Darkvision Mechanics

 Darkvision in Baldur's Gate 3 is a passive feature comprised of two distinct technical components that dictate how a character perceives and interacts with  darkness.

1. Visual vs. Mechanical Components

The game uses two different variables to handle how a character 'sees':

• ActiveCharacterLight (The Visual Cone): This is the visible cone of white light emitted from the player character in dark areas.
  • Limitation: Only one ActiveCharacterLight can be active at a time. If a character has multiple sources, the one applied first (chronologically) usually takes precedence, functionally disabling others.
• DarkvisionRangeMin (The Mechanical Range): This is a hidden value used to calculate combat modifiers.
  • Behavior: Multiple sources of DarkvisionRangeMin can affect a character simultaneously. The game automatically uses the highest value available for combat calculations.

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2. Impact on Combat

Darkvision does not simply 'grant sight'; it actively modifies the obscurity level for the character. This can determine if an attack is made with  Advantage or  Disadvantage:

• Attacking from Shadows: If the attacker has Darkvision and the defender is obscured (but within the attacker's Darkvision range), the attacker may gain Advantage.
• Too Dark: If a character lacks Darkvision or the target is beyond their Darkvision range in a heavily obscured area, they suffer Disadvantage on attack rolls.
• The Range Tiers:
  • Darkvision: Provides these benefits up to 12m.
  • Superior Darkvision: Provides these benefits up to 24m.

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3. The Duergar Interaction (known issue)

The Duergar race presents a unique mechanical overlap because they possess both Darkvision (from their base Dwarf heritage) and Superior Darkvision (from their sub-race).

• The Conflict – Because the standard 12m Darkvision is applied to the character before the 24m Superior version, the ActiveCharacterLight for 12m takes priority.
• The Result – Visually, Duergar characters only see a 12m 'light cone' in front of their character.

  Mechanically, however, Duergar characters still receive the full combat benefits of Superior Darkvision up to 24m.

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4. Race and Darkvivison At A Glance

Here is a breakdown of the Darkvision ranges for every playable race in the unmodded version Baldur's Gate 3.

Racial Darkvision Comparison

Darkvision Range	Races & Subraces	Notes
0m (None)	Human, Githyanki, Dragonborn, Halfling (all)	Requires torches, light spells, or elixirs to avoid Disadvantage in the dark.
12m (Standard)	Elf (High/Wood), Half-Elf (High/Wood/Drow), Dwarf (Gold/Shield), Gnome (Forest/Rock), Tiefling (all), Half-Orc	standard "adventurer's vision." Sufficient for most interior dungeons.
24m (Superior)	Drow (Lolth/Seldarine), Duergar, Deep Gnome	Useful for long-range archers (like the Titanstring Bow build).

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5. Non-Racial Sources of Darkvision

If the player character lacks natural darkvision sight, it can be augmented through these methods:

•  Devil's Sight: A Warlock invocation that grants 24m Darkvision and allows the character to see through magical darkness (like the  Darkness spell, which regular Darkvision cannot do).
•  Darkvision: A 2nd-level transmutation spell which grants 12m Darkvision until the next Long Rest.
•  Elixir of Darkvision: A common potion which grants 12m Darkvision until the next Long Rest.
• Equipment: Items like the  Darkvision Ring or the  Steelwatcher Helmet provide permanent toggles for these ranges.

The 'Duergar Anomaly' Reminder

As mentioned in the technical breakdown, a Duergar's character sheet lists both the 12m and 24m versions. While their visual 'light cone' might look small, their actual combat math uses the 24m range. This can be verified in the combat log by checking for the 'Under-Illuminated' penalty – it will not be shown until a target is more than 24m away.