Types of Senses

This page details how the senses work in combat and how they interact with stealth and invisibility.

There are many types of senses. For game purposes, all that we worry about are the 'useful' ones. We don't really need to worry about your sense of balance, or proprioception, or a monster's ability to know that it needs to take a poop. For our purposes, we just need to concern ourselves with the senses useful for playing.

In general, these senses fall into four main categories:

• Sight
• Sound
• Smell
• Exotic

Nearly all monsters have the same targeting senses as your typical human, represented as Standard Senses. The senses below define these senses, as well as the other extraordinary senses that monsters (and some player characters) might possess. Creatures which are missing one or more of the standard senses usually state that they are blind to a particular sensory group (Sight, Sound, Smell). All creatures are assumed to be Blind to the exotic sensory group unless their entry explicitly states they possess one or more exotic senses.

Table: Visual Senses

Sense	Range	Line of Sight?	Line of Effect?	Combat Targeting	vs. Stealth
Standard Vision	Varies	Yes	No	Yes	Perception check
Low-Light Vision	Varies	Yes	No	Yes	Perception check
Darkvision	Varies	Yes	No	Yes	Perception check
Heartsight	Varies	Yes	No	Yes	Perception check

Table: Audio Senses

Sense	Range	Line of Sight?	Line of Effect?	Combat Targeting	vs. Stealth
Standard Hearing	20 feet	No	Yes	Perception check vs. Total Concealment	Perception check vs. Total Concealment, ignores invisibility
Keen Hearing	60 feet	No	Yes	Perception check vs. Total Concealment	Perception check vs. Total Concealment, ignores invisibility
Precise Hearing	20 feet	No	Yes	Adjacent creatures	Perception check, ignores invisibility
Echolocation	30 feet	No	Yes	Yes	Perception check, ignores invisibility

Table: Olefactory Senses

Sense	Range	Line of Sight?	Line of Effect?	Combat Targeting	vs. Stealth
Standard Scent	10 feet	No	Yes	Perception check vs. Total Concealment	Perception check at -20 vs. Total Concealment, ignores invisibility
Scent	30 feet	No	Yes	Perception check vs. Total Concealment	Perception check vs. Total Concealment, ignores invisibility
Keen Scent	60 feet	No	Yes	Target has Partial Concealment	Perception check at +2 vs. Partial Concealment, ignores invisibility
Perfect Scent	120 feet	No	Yes	Yes	Perception check at +5, ignores invisibility

Table: Exotic Senses

Sense	Range	Line of Sight?	Line of Effect?	Combat Targeting	vs. Stealth
Airsense	Varies	No	Yes	Yes	Perception check at +5, ignores invisibility
Blindsense	Varies	No	No	Yes	Perception check at +5, ignores invisibility
Cloudsense	Varies	Special	Yes	Yes	Perception check, ignores invisibility
Lifesense	Varies	No	No	Target has Partial Concealment	Perception check at +5 vs. Partial Concealment, ignores invisibility
Mindsense	Varies	No	No	Yes	Perception check at +5, ignores invisibility
Tremorsense	Varies	No	Yes	Yes	Perception check at +5, ignores invisibility
Watersense	Varies	No	Yes	Yes	Perception check at +5, ignores invisibility

Line of Effect

A line of effect is a continuous, unblocked path that indicates what a spell can affect. A line of effect is canceled by a solid barrier. It's like line of sight for ranged weapons, except that it's not blocked by fog, darkness, and other factors that limit normal sight, and may or may not go around corners, depending on the effect.

You must have a clear line of effect to any target that you cast a spell on or to any space in which you wish to create an effect. You must have a clear line of effect to the point of origin of any spell you cast.

A burst, cone, cylinder, or emanation spell affects only an area, creature, or object to which it has line of effect from its origin (a spherical burst's center point, a cone-shaped burst's starting point, a cylinder's circle, or an emanation's point of origin).

An otherwise solid barrier with a hole of at least 1 square foot through it does not block a spell's line of effect. Such an opening means that the 5-foot length of wall containing the hole is no longer considered a barrier for purposes of a spell's line of effect.

Line of Sight

A line of sight is the same as a Line of Effect but with the additional restriction that that it is blocked by fog, darkness, and other factors that limit normal sight (such as Partial Concealment), and it takes a non-visual sense to go around corners. Yes, you can trace Line of Sight around corners with senses such as hearing and smell. Combined with an attack that can trace Line of Effect around corners, this is a potent combination!

A classic example is hearing an enemy in a tavern, and casting a fireball through the window. Ouch.

Light and Darkness

The visual senses use light of various spectrums to allow the creature using it to see. Light is divided into bright light, dim light, darkness, and true darkness.

Bright Light

Any creature with a visual sensory organ can see an unlimited distance in bright light, assuming that no object blocks line of sight (which can include the curvature of the planet). The visual horizon is the critical determinant for distance of vision in bright light when viewing distant objects in vast, open spaces:

• For an observer standing on the ground with average height, the horizon is at a distance of 2.9 miles.
• For an observer standing on the second story of a building or a ship's deck (10 feet), the horizon is at a distance of 3.8 miles.
• For an observer standing on a hill or tower (100 feet), the horizon is at a distance of 12.2 miles.
• For an observer standing at the top of an average mountain (13,000 ft), the horizon is at a distance of 139 miles.
• For an observer atop the tallest of mountains (30,000 ft), the horizon is at a distance of 211 miles.

Daylight / Sunlight

Bright light can be caused by sunlight or spells which produce sunlight effects, but bright light is not the same as sunlight or daylight, for purposes of dealing damage to certain undead (e.g. Vampire Dilettantes). Unless a spell or effect explicitly states that it creates sunlight or daylight, or the light is coming from the actual sun (or relevant local star), it isn't daylight or sunlight (for purposes of harming certain undead), it's just bright light.

Note also that Sunlight damage is different from natural or magical daylight, as the Sunlight damage type directs the forces of the sun's fire, heat, and radiation directly at a target, as though the target were coming into direct contact with the surface of the sun itself (yikes!). Creatures that take extra effects from daylight and/or sunlight do not necessarily take extra damage from Sunlight-based damage. Spells and abilities that inflict Sunlight-based damage may include additional effects versus undead, and some creature entries in the Bestiary may state that a creature takes additional damage when the target of Sunlight damage, but otherwise, do not assume that additional damage occurs. The GM should be the final arbiter of such things, as always.

Dim Light

Standard visual sensory organs function poorly in dim light, and creatures in dim light gain concealment against creatures with standard vision. Concealment grants the concealed creature a 20% chance to be missed by attacks in combat.

Typically, a bright source of light, such as a torch, provides dim light an equal distance to its bright light radius, beginning at the edge of that bright light radius. Thus, a torch provides bright light to 30 feet, and dim light beyond 30 feet out to 60 feet. Moonlight and starlight are the most common sources of dim light that do not provide a commensurate amount of bright light. Some magic items are also capable of producing dim light without bright light.

Darkness

The area outside of any light source, beyond the reach of dim light, is considered darkness. Darkness grants total concealment to creatures within it, when perceived by creatures with standard vision. Total concealment grants the concealed creature a 50% chance to be missed by attacks in combat.

Darkness can also be created by spells or creature abilities. In this case, unless the ability specifically states otherwise, Darkvision still functions within the darkness.

True Darkness

This is magical or elemental darkness, and cannot be penetrated by visual senses. It goes beyond the absence of all spectrums of light, to the point of being anathema to light, actively absorbing or destroying it. All creatures in True Darkness gain total concealment (automatically miss on a natural result of a 12 or less on the d20, and you must be attacking the square your target actually occupies) against any visual senses. Furthermore, any creature relying on visual senses becomes quelled at the end of any movement greater than 50% of its speed (round down to the nearest 5' square).