Secret Lesson 14

LESSON 14

Vision, Light, Darkness, Obscured Areas, Special Senses, and Hiding

Exploration, combat, hiding, spellcasting, and searching are all affected by one fundamental question:

WHAT CAN A CREATURE SEE?

Sight matters when you try to:

  • notice danger

  • find a hidden creature

  • make an attack

  • hide from an enemy

  • target certain spells

  • explore a dark environment

The SRD specifically notes that several adventuring activities are affected by sight, so anything that obscures vision can significantly change what a creature can do.

To understand vision in 5E, we need to connect several systems:

LIGHT

OBSCUREMENT

CONDITIONS

SPECIAL SENSES

HIDING

and:

UNSEEN ATTACKERS AND TARGETS

THE THREE LEVELS OF LIGHT

The SRD divides illumination into three categories:

BRIGHT LIGHT

DIM LIGHT

DARKNESS

 

Each one affects vision differently.

BRIGHT LIGHT

In Bright Light, most creatures can see normally.

Sources can include:

  • daylight

  • torches

  • lanterns

  • fires

  • other sufficiently bright sources

Even an overcast or gloomy day normally counts as Bright Light.

For most creatures:

BRIGHT LIGHT = NORMAL VISION

DIM LIGHT

Dim Light represents partial illumination.

The SRD also refers to it as:

SHADOWS

Examples include:

  • twilight

  • dawn

  • the boundary between Bright Light and Darkness

  • some moonlit environments

 

Mechanically:

DIM LIGHT CREATES A LIGHTLY OBSCURED AREA

DARKNESS

Darkness represents the absence of sufficient light.

Examples include:

  • an unlit dungeon

  • nighttime outdoors

  • certain magical effects

The SRD states:

DARKNESS CREATES A HEAVILY OBSCURED AREA

 

This distinction becomes extremely important.

LIGHT AND OBSCUREMENT ARE CONNECTED

A useful way to remember the basic relationship is:

Illumination Obscurement
Bright Light Normal vision
Dim Light Lightly Obscured
Darkness Heavily Obscured

But light is not the only thing that can obscure vision.

Fog, foliage, and other environmental effects can do it too.

LIGHTLY OBSCURED AREAS

A Lightly Obscured area makes seeing more difficult without completely blocking vision.

The SRD gives examples such as:

  • Dim Light

  • patchy fog

  • moderate foliage

When you make a:

WISDOM (PERCEPTION) CHECK THAT RELIES ON SIGHT

to see something in a Lightly Obscured area:

YOU HAVE DISADVANTAGE

 

The Rules Glossary confirms the same effect.

EXAMPLE — DIM LIGHT

You are exploring a chamber illuminated only by weak moonlight.

The area is:

Dim Light

Therefore:

Lightly Obscured

You try to notice a tiny visual clue.

The GM calls for:

Wisdom (Perception)

Because the check relies on sight in a Lightly Obscured area:

DISADVANTAGE

LIGHTLY OBSCURED DOES NOT MEAN BLIND

You can still see.

The area simply makes visual perception more difficult.

That is why the effect is:

DISADVANTAGE ON SIGHT-BASED WISDOM (PERCEPTION)

rather than complete inability to see.

HEAVILY OBSCURED AREAS

A Heavily Obscured area is effectively opaque for normal vision.

The SRD gives examples such as:

  • Darkness

  • heavy fog

  • dense foliage

When trying to see something in such an area:

YOU HAVE THE BLINDED CONDITION

 

THE BLINDED CONDITION

The Blinded condition has two important consequences.

CAN'T SEE

You cannot see.

You automatically fail any Ability Check that requires sight.

ATTACKS AFFECTED

Attack Rolls against you have:

ADVANTAGE

and your own Attack Rolls have:

DISADVANTAGE

 

EXAMPLE — HEAVY FOG

You enter an area filled with thick fog.

The fog makes the area:

Heavily Obscured

When trying to see something through it:

you have the:

BLINDED CONDITION

Therefore, a visual Ability Check automatically fails.

Your attacks against creatures you cannot see are also affected.

AUTOMATIC FAILURE APPLIES TO CHECKS THAT REQUIRE SIGHT

Notice the wording carefully.

Blinded does not mean:

automatically fail every Ability Check.

It means:

AUTOMATICALLY FAIL AN ABILITY CHECK THAT REQUIRES SIGHT

A check based on some other means of perception may be different if the rules allow it.

SPECIAL SENSES

Normal sight is not the only way creatures perceive the world.

The SRD identifies four major special senses:

BLINDSIGHT

DARKVISION

TREMORSENSE

TRUESIGHT

 

Each works differently.

BLINDSIGHT

Blindsight allows a creature to see within a specified range:

WITHOUT RELYING ON PHYSICAL SIGHT

Within that range, the creature can see anything not behind:

TOTAL COVER

even if:

  • the creature has the Blinded condition

  • the area is in Darkness

Blindsight can also perceive things with the:

INVISIBLE CONDITION

within its range.

BLINDSIGHT EXAMPLE

A creature has:

Blindsight 30 feet

It stands in complete Darkness.

Another creature is:

20 feet away

and isn't behind Total Cover.

The creature with Blindsight can perceive it within that special-sense range without relying on ordinary vision.

BLINDSIGHT AND BLINDED

This is an important interaction.

A creature might have the:

Blinded condition

but still possess:

Blindsight

The condition prevents ordinary sight.

Blindsight provides another way to perceive within its specified range.

BLINDSIGHT AND TOTAL COVER

Blindsight does not simply perceive everything through every barrier.

The SRD specifically states that within its range it can see something that is not behind:

TOTAL COVER

 

So walls and other sources of Total Cover still matter.

DARKVISION

Darkvision improves how a creature sees in poor illumination.

Within the sense's specified range:

DIM LIGHT

is treated as:

BRIGHT LIGHT

and:

DARKNESS

is treated as:

DIM LIGHT

 

DARKVISION DOES NOT TURN DARKNESS INTO BRIGHT LIGHT

This is a common beginner mistake.

Darkvision converts:

DARKNESS → DIM LIGHT

not:

Darkness → Bright Light

Because Dim Light is Lightly Obscured, normal consequences of Dim Light can still matter.

DARKVISION EXAMPLE

A creature has:

Darkvision 60 feet

There is complete Darkness within 30 feet.

For that creature, the Darkness is perceived as:

DIM LIGHT

within its Darkvision range.

DIM LIGHT WITH DARKVISION

If an area already contains:

Dim Light

Darkvision allows the creature to see that area as though it were:

BRIGHT LIGHT

within range.

COLORS IN DARKNESS

When using Darkvision to see in Darkness:

COLORS APPEAR ONLY AS SHADES OF GRAY

 

EXAMPLE

A red symbol and a blue symbol are painted on a wall in total Darkness.

A creature relying only on Darkvision may see the symbols, but in that Darkness their colors appear as shades of gray.

That distinction could matter if identifying the actual color is important.

DARKVISION HAS A RANGE

Darkvision always has a specified distance.

Examples in the SRD include creatures with ranges such as:

60 feet

or:

120 feet

Once something lies beyond that range, Darkvision no longer helps with it.

SPECIFIC EFFECTS CAN OVERRIDE GENERAL DARKVISION

Remember:

SPECIFIC RULES OVERRIDE GENERAL RULES

Darkvision gives the general rules for seeing in Darkness.

A specific magical effect may provide its own instructions about what can or cannot see through it.

Always read the effect producing the Darkness.

TREMORSENSE

Tremorsense works very differently.

A creature with Tremorsense can pinpoint the location of:

  • creatures

  • moving objects

within a specified range when both the sensing creature and the target are in contact with:

  • the same surface

  • or the same liquid

Examples of a shared surface include:

  • ground

  • wall

  • ceiling

 

TREMORSENSE EXAMPLE

A creature has:

Tremorsense 60 feet

It stands on the ground.

Another creature walks across the same ground:

30 feet away

Tremorsense can pinpoint that creature's location.

TREMORSENSE THROUGH CONNECTED SURFACES

The shared surface does not have to mean both creatures are literally standing on the same patch of floor.

The SRD specifically mentions:

  • ground

  • walls

  • ceilings

as examples of surfaces through which Tremorsense can work when both sides are in contact with the same surface.

TREMORSENSE AND LIQUIDS

Tremorsense can also work when both the sensing creature and what it detects are in contact with:

THE SAME LIQUID

 

WHAT TREMORSENSE CANNOT DETECT

Tremorsense cannot detect creatures or objects that are:

IN THE AIR

 

For example, a flying creature that is no longer touching the shared surface isn't detected through Tremorsense merely because it is within range.

TREMORSENSE IS NOT SIGHT

This distinction is extremely important.

The SRD explicitly states:

TREMORSENSE DOESN'T COUNT AS A FORM OF SIGHT

 

It can tell you where something is under the required conditions, but it does not automatically allow you to treat that creature as though you can visually see it.

This matters whenever a rule specifically requires:

seeing a creature

or:

a target you can see.

TRUESIGHT

Truesight is one of the most powerful senses in the SRD.

Within its specified range, it provides enhanced vision that pierces several forms of concealment or deception.

It has five major benefits.

1. DARKNESS

With Truesight, you can see through:

NORMAL DARKNESS

and:

MAGICAL DARKNESS

within the sense's range.

This is stronger and more explicit than ordinary Darkvision.

2. INVISIBILITY

Truesight allows you to see:

CREATURES AND OBJECTS WITH THE INVISIBLE CONDITION

within range.

3. VISUAL ILLUSIONS

With Truesight:

visual illusions appear transparent

and you automatically succeed on Saving Throws against them.

4. MAGICAL TRANSFORMATIONS

Truesight allows you to discern the:

TRUE FORM

of a creature or object you can see that has been transformed by magic.

5. ETHEREAL PLANE

Truesight also allows you to:

SEE INTO THE ETHEREAL PLANE

within its range.

SPECIAL SENSE COMPARISON

Sense Core Function
Blindsight See within range without relying on physical sight, including in Darkness or while Blinded; can perceive Invisible creatures
Darkvision Treat Dim Light as Bright Light and Darkness as Dim Light
Tremorsense Pinpoint creatures and moving objects through a shared surface or liquid; not sight
Truesight See through Darkness, Invisibility, visual illusions, magical transformations, and into the Ethereal Plane

HIDING

Sight and hiding are closely connected.

The SRD explains that adventurers and monsters hide for purposes such as:

  • spying

  • sneaking past a guardian

  • setting an ambush

The GM determines when circumstances are suitable for hiding.

When you try to hide:

TAKE THE HIDE ACTION

 

REQUIREMENTS TO HIDE

The Hide action has specific requirements.

You must succeed on:

DC 15 DEXTERITY (STEALTH)

while you are:

HEAVILY OBSCURED

or behind:

THREE-QUARTERS COVER

or:

TOTAL COVER

and you must be:

OUT OF EVERY ENEMY'S LINE OF SIGHT

 

YOU CAN TELL WHETHER A CREATURE CAN SEE YOU

The Hide rule includes a useful practical instruction:

if you can see a creature:

YOU CAN DISCERN WHETHER IT CAN SEE YOU

 

This helps determine whether the line-of-sight requirement for hiding has been satisfied.

HIDING IS NOT JUST “MAKE A STEALTH CHECK”

Another common beginner mistake is saying:

“I roll Stealth.”

without having somewhere or some way to hide.

The Hide action requires appropriate circumstances first.

You need:

  • the necessary obscurement or cover

  • no enemy line of sight

  • then the successful DC 15 Dexterity (Stealth) check

SUCCESSFULLY HIDING

If you succeed:

YOU HAVE THE INVISIBLE CONDITION WHILE HIDDEN

You must also record the total of your Dexterity (Stealth) check.

That total becomes:

THE DC FOR A CREATURE TO FIND YOU

using:

WISDOM (PERCEPTION)

 

EXAMPLE — HIDING

You satisfy the requirements and make:

Dexterity (Stealth)

Your total is:

19

You successfully hide.

Now:

19

becomes the DC another creature must reach with:

Wisdom (Perception)

to find you.

THE INVISIBLE CONDITION WHILE HIDDEN

While successfully hidden, you gain the Invisible condition.

The condition provides several effects.

SURPRISE

If you're Invisible when rolling Initiative:

YOU HAVE ADVANTAGE

CONCEALED

You aren't affected by an effect that requires its target to be seen unless the effect's creator can somehow see you.

Your worn and carried equipment is also concealed.

ATTACKS AFFECTED

Attack Rolls against you have:

DISADVANTAGE

and your Attack Rolls have:

ADVANTAGE

unless the other creature can somehow see you.

INVISIBLE DOES NOT MEAN IMPOSSIBLE TO DETECT

This distinction matters.

The condition says that you are concealed from sight.

But other rules may allow a creature to detect or perceive you.

For example:

  • Blindsight can see Invisible creatures within its range.

  • Truesight can see Invisible creatures within its range.

  • a creature can find a hidden creature with the appropriate Wisdom (Perception) check.

 

WHAT ENDS HIDING?

You immediately stop being hidden when any of these occurs:

YOU MAKE A SOUND LOUDER THAN A WHISPER

AN ENEMY FINDS YOU

YOU MAKE AN ATTACK ROLL

YOU CAST A SPELL WITH A VERBAL COMPONENT

 

ATTACKING FROM HIDING

Suppose you are hidden.

You make an Attack Roll.

Because you have the Invisible condition while hidden, your Attack Roll can have Advantage against a creature that cannot see you.

But as soon as you make the Attack Roll:

YOU STOP BEING HIDDEN

according to the Hide action rule.

UNSEEN ATTACKERS

The combat rules also provide a broader rule for attacking something you cannot see.

If you make an Attack Roll against a target you cannot see:

YOU HAVE DISADVANTAGE

This applies whether:

  • you are guessing the target's location

  • or you can hear the target but cannot see it

 

GUESSING THE WRONG LOCATION

If the unseen target is not actually in the location you targeted:

THE ATTACK MISSES

 

Your Attack Roll result doesn't matter because you attacked the wrong place.

ATTACKING A CREATURE THAT CANNOT SEE YOU

The reverse rule also applies.

When another creature cannot see you:

YOU HAVE ADVANTAGE ON ATTACK ROLLS AGAINST IT

 

IF YOU ARE HIDDEN AND ATTACK

The SRD states that if you are hidden when making an Attack Roll:

YOU GIVE AWAY YOUR LOCATION

whether the attack:

hits

or:

misses.

This is consistent with the Hide rule ending your hidden status when you make an Attack Roll.

WHEN BOTH CREATURES CANNOT SEE EACH OTHER

This creates an interesting interaction.

Suppose:

you cannot see your enemy

and:

your enemy cannot see you.

Your attack would normally have:

Disadvantage

because you cannot see the target.

But also:

Advantage

because the target cannot see you.

You already know from Lesson 8:

ADVANTAGE + DISADVANTAGE = NEITHER

So unless another rule changes the situation:

ROLL NORMALLY

This follows directly from combining the vision rules with the Advantage and Disadvantage rules.

SPECIAL SENSES CAN CHANGE UNSEEN-ATTACK RULES

Suppose someone is visually hidden in Darkness.

A creature with ordinary vision might not see them.

But another creature may possess:

Blindsight

or:

Truesight

If the special sense allows that creature to see the target within range, then the target is no longer unseen to that creature for rules that depend on seeing it.

This is why special senses can dramatically change combat and exploration.

EXAMPLE — DARKNESS WITHOUT SPECIAL SENSES

Two creatures stand inside Darkness.

Neither can see the other.

One attacks.

It has:

Disadvantage because it can't see its target.

But:

Advantage because the target can't see it.

These cancel.

Normal Attack Roll.

EXAMPLE — BLINDSIGHT

Creature A stands in Darkness.

Creature B has:

Blindsight 30 feet

and Creature A is 20 feet away, not behind Total Cover.

Creature B can perceive Creature A with Blindsight.

The Darkness does not make Creature A unseen to Creature B within that range.

EXAMPLE — DARKVISION

A character with Darkvision enters Darkness.

Within range:

the Darkness is treated as:

DIM LIGHT

The character can see there, though the area is still perceived as Dim Light rather than Bright Light, and colors in that Darkness appear as gray shades.

EXAMPLE — TREMORSENSE

A monster with Tremorsense knows where a creature walking on the same cave floor is located.

But Tremorsense:

IS NOT SIGHT

So knowing the location does not automatically satisfy a rule that specifically requires the monster to see that creature.

EXAMPLE — TRUESIGHT

A creature with Truesight encounters:

  • magical Darkness

  • an Invisible creature

  • a visual illusion

  • a magically transformed creature

Within its Truesight range, its enhanced vision can pierce all four of those effects in the ways described by the SRD.

A PRACTICAL VISION CHECKLIST

Whenever sight matters, ask:

1. WHAT IS THE LIGHT LEVEL?

Bright Light?

Dim Light?

Darkness?

2. IS THE AREA OBSCURED?

Lightly Obscured?

Heavily Obscured?

3. DOES THE CREATURE HAVE A SPECIAL SENSE?

Blindsight?

Darkvision?

Tremorsense?

Truesight?

4. IS THE TARGET HIDDEN OR INVISIBLE?

If so, can this creature perceive it anyway?

5. DOES THE RULE REQUIRE SIGHT?

Some rules specifically say:

“a creature you can see”

If so, merely knowing its location may not be enough.

6. IS AN ATTACK BEING MADE?

Check whether the attacker can see the target and whether the target can see the attacker.

That determines possible Advantage or Disadvantage.

COMMON BEGINNER MISTAKES

MISTAKE 1 — THINKING DIM LIGHT IS THE SAME AS DARKNESS

It isn't.

Dim Light

Lightly Obscured.

Darkness

Heavily Obscured.

MISTAKE 2 — THINKING DARKVISION MEANS PERFECT VISION IN DARKNESS

It doesn't.

Darkvision treats Darkness as:

DIM LIGHT

and colors there appear only as shades of gray.

MISTAKE 3 — THINKING BLINDSIGHT IS ORDINARY VISION

It is a special sense that works without relying on physical sight and follows its own range and Total Cover limitations.

MISTAKE 4 — TREATING TREMORSENSE AS SIGHT

The SRD explicitly says it is:

NOT A FORM OF SIGHT

 

MISTAKE 5 — THINKING YOU CAN HIDE ANYWHERE

Hide requires appropriate obscurement or cover and being outside enemy line of sight.

MISTAKE 6 — FORGETTING THE INITIAL HIDE DC

You must first succeed on:

DC 15 DEXTERITY (STEALTH)

to hide under the required circumstances.

MISTAKE 7 — FORGETTING TO RECORD THE STEALTH TOTAL

Your successful Hide check total becomes the DC for creatures trying to find you with Wisdom (Perception).

MISTAKE 8 — THINKING INVISIBLE MEANS UNDETECTABLE

Special senses and successful attempts to find a hidden creature can still matter.

MISTAKE 9 — FORGETTING THAT ATTACKING ENDS HIDING

Making an Attack Roll ends your hidden status.

MISTAKE 10 — FORGETTING BOTH SIDES OF THE UNSEEN ATTACK RULE

If you cannot see your target:

Disadvantage.

If your target cannot see you:

Advantage.

Both can apply and therefore cancel.

LESSON 14 — KEY TAKEAWAYS

BRIGHT LIGHT

Most creatures see normally.

DIM LIGHT

Creates a:

LIGHTLY OBSCURED AREA

Sight-based Wisdom (Perception) checks have Disadvantage.

DARKNESS

Creates a:

HEAVILY OBSCURED AREA

A creature trying to see there has the Blinded condition.

BLINDED

You cannot see and automatically fail Ability Checks requiring sight.

Attacks against you have Advantage.

Your Attack Rolls have Disadvantage.

BLINDSIGHT

Allows sight within a specified range without relying on physical vision, including in Darkness and while Blinded, and can perceive Invisible creatures unless Total Cover prevents it.

DARKVISION

Within range:

Dim Light → Bright Light

Darkness → Dim Light

Colors in Darkness appear as shades of gray.

TREMORSENSE

Pinpoints creatures and moving objects through a shared surface or liquid.

It cannot detect things in the air.

It is:

NOT SIGHT

 

TRUESIGHT

Within range it pierces:

  • normal and magical Darkness

  • Invisibility

  • visual illusions

  • magical transformations

and allows vision into the:

Ethereal Plane.

HIDING

Requires:

  • DC 15 Dexterity (Stealth)

  • Heavy Obscurement, Three-Quarters Cover, or Total Cover

  • no enemy line of sight

A successful check gives you the Invisible condition while hidden.

YOUR STEALTH TOTAL BECOMES THE SEARCH DC

A creature attempting to find you uses:

Wisdom (Perception)

against your recorded Hide check total.

HIDING ENDS WHEN

  • you make a sound louder than a whisper

  • an enemy finds you

  • you make an Attack Roll

  • you cast a spell with a Verbal component

 

UNSEEN TARGET

Attack it with:

DISADVANTAGE

If you guess the wrong location:

AUTOMATIC MISS

 

UNSEEN ATTACKER

If your target cannot see you:

ADVANTAGE ON YOUR ATTACK ROLL

 

NEXT LESSON

LESSON 15 — OBJECTS: INTERACTION, SEARCHING, CARRYING, BREAKING, AND HIDDEN OBJECTS

Now that you understand how characters perceive the environment, we can focus on the things that fill that environment:

OBJECTS

In Lesson 15, we will study:

  • what counts as an object

  • ordinary object interaction

  • free object interactions when time is limited

  • when the Utilize action becomes necessary

  • searching for hidden objects

  • why the location you search matters

  • carrying ordinary gear

  • when carrying capacity becomes relevant

  • fragile objects

  • resilient objects

  • breaking and damaging objects

  • Armor Class and Hit Points for objects

  • damage thresholds and object resilience where applicable

SRD 5.2.1 ATTRIBUTION

This work includes material from the System Reference Document 5.2.1 (“SRD 5.2.1”) by Wizards of the Coast LLC, available at https://www.dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License, available at https://creativecommons.org/licenses/by/4.0/legalcode.