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.

Standard Senses

All monster are assumed to have a 'package' of Standard Senses which includes Standard Vision, Standard Hearing, and Standard Scent (see below). These standard senses also include a sense of touch, balance, proprioception and that truly essential 'poop sense' mentioned above, but such things don't normally have any impact on play. IF a player wants to be able to climb up a Stone Golem while invisible, claiming 'it doesn't have a sense of touch', then the referee should refer to the Standard Senses, which actually means Stone Golems could have a magical sense of touch. In all such oddball cases, the referee is encouraged to rule in the interest of fun. The main rule is, have fun!

Defined Senses

In general, these senses fall into four main categories:

• Sight
• Sound
• Smell
• Exotic

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	Provides a 10' radius of light emanating from each humanoid in range

Table: Audio Senses

Sense	Range	Line of Sight?	Line of Effect?	Combat Targeting	vs. Stealth
Standard Hearing	20 feet	No	Yes	Perception check, 50% miss chance	Perception check, 50% miss chance, ignores invisibility
Keen Hearing	60 feet	No	Yes	Perception check, 50% miss chance	Perception check, 50% miss chance, 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	Survival check, 50% miss chance	Survival check -20, 50% miss chance, ignores invisibility
Scent	30 feet	No	Yes	Survival check, 50% miss chance	Survival check, 50% miss chance, ignores invisibility
Keen Scent	60 feet	No	Yes	20% miss chance	Survival check +4, 20% miss chance, ignores invisibility
Perfect Scent	120 feet	No	Yes	Yes	Survival check with bonus equal to hit dice, ignores invisibility

Table: Exotic Senses

Sense	Range	Line of Sight?	Line of Effect?	Combat Targeting	vs. Stealth
Tremorsense	Varies	No	Yes	Yes	Perception check with bonus equal to hit dice, ignores invisibility
Blindsense	Varies	No	No	Yes	Perception check with bonus equal to hit dice, ignores invisibility
Lifesense	Varies	No	No	20% miss chance	Perception check with bonus equal to hit dice, 20% miss chance, ignores invisibility

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 (as with the Deeper Darkness spell).

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.

Normal Light

This has been removed from the game. Spells or abilities which reference normal light should be amended to state 'bright light'.

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 magical spells, such as the Darkness spell. In this case, unless the spell 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 (50% miss chance) against any visual senses.