Tome of Prowess (3.5e Sourcebook)/Perception

Perception

Perception is both an active and a passive skill. It is used continuously in a passive state to determine what events characters are simply aware of, from whispered conversations to bursts of light to scents drifting on the breeze. It can also be used actively to learn more about an event or detect a forgery. Those who put effort into sharpening their senses can even pierce illusions or detect magical transformations in others, sometimes automatically.

Key Attribute: Wisdom

Base DCs and Modifiers

Table: Sight DCs

Sight Event	Example	Base DC1	Standard Range	Range Increment
See 1/2 Inch Details	Recognize an unobscured sub-sub-sub-fine object against a background; Text in a book	0	1 1/2 ft.	9 in.
See 1 Inch Details	Recognize an unobscured sub-sub-fine object against a background; Recognize facial details	0	3 ft.	1 1/2 ft.
See 2 Inch Details	Recognize an unobscured sub-fine object against a background; Read a small store sign, likely inside	0	6 ft.	3 ft.
See 4 Inch Details	Recognize an unobscured fine object against a background; Read a large, overhanging store sign or waysign	0	12 ft.	6 ft.
See 8 Inch Details	Recognize an unobscured diminutive object against a background	0	25 ft.	12 ft.
See 1 1/4 Foot Details	Recognize an unobscured tiny object against a background	0	50 ft.	25 ft.
See 2 1/2 Foot Details	Recognize an unobscured small object against a background	0	100 ft.	50 ft.
See 5 Foot Details	Recognize an unobscured medium object against a background	0	200 ft.	100 ft.
See 10 Foot Details	Recognize an unobscured large object against a background; See a hill giant on the edge of a forest	0	400 ft.	200 ft.
See 20 Foot Details	Recognize an unobscured huge object against a background; See an adult red dragon flying through the sky	0	800 ft.	400 ft.
See 40 Foot Details	Recognize an unobscured gargantuan object against a background	0	1600 ft.	800 ft.
See 80 Foot Details	Recognize an unobscured colossal object against a background	0	3200 ft.	1600 ft.
Sight details that are particularly intense, such as flashes of lightning at night or bursts of darkness in a lighted room, qualify for the "intense" DC modifier as long as they are no smaller than 1/8 the size of the creature witnessing them. For example, a medium creature would qualify for this bonus on details as small as 8 inches as long as it was within range.

Table: Hearing DCs

Hearing Event	Example1	Base DC2	Standard Range	Range Increment
0 dB	Hear a cat stalking	0	4 in.	1 in.
10 dB	Hear a person breathing	0	8 in.	2 in.
20 dB	Hear a whisper	0	1 1/2 ft.	4 in.
30 dB	Hear leaves rustling; creature walking on soft ground (grass)	0	3 ft.	8 in.
40 dB	Hear a quiet conversation; creature hustling on soft ground; creature flapping wings to stay or move unhurriedly in air	0	6 ft.	1 1/2 ft.
50 dB	Hear a normal conversation; creature walking on hard ground (cobblestones); creature flapping wings to hustle; creature running on soft ground	0	12 ft.	3 ft.
60 dB	Hear a crowded inn; creature hustling on hard ground; creature flapping wings to stay or move flat-out	0	25 ft.	6 ft.
70 dB	Hear a boisterous party; creature walking on noisy ground (snapping twigs); creature running on hard ground	0	50 ft.	12 ft.
80 dB	Hear a shouted statement; creature hustling on noisy ground	0	100 ft.	25 ft.
90 dB	Hear a sword clanging against a shield or armor; creature running on noisy ground	0	200 ft.	50 ft.
100 dB	Hear a fireball exploding	0	400 ft.	100 ft.
110 dB	Hear a lion roaring	0	800 ft.	200 ft.
120 dB	Hear a large dragon roaring	0	1600 ft.	400 ft.
130 dB	Hear something so loud it hurts, like a banshee	0	3200 ft.	800 ft.
Where an example references a creature and does not mention size, it is assumed to be a medium sized creature. Bigger creatures make a noise one step up the chart for each size category different, and smaller creatures make a noise one step down the chart for each size category smaller. For each step below 0 dB, which are not listed on the table, simply add 4 to the base DC. Heard details that are particularly intense, such as those whose decibel range is 40 more than the ambient noise level, qualify for the "intense" DC modifier. For example, a fireball exploding outside of a crowded inn would come with a notice DC reduction as long as it was within range.

Table: Smell DCs

Smelling Event	Example	Base DC	Standard Range	Range Increment
Unmissable Smell	Rotting garbage, decaying bodies	-5	40 ft.	10 ft.
Overpowering Smell	Smoke	0	40 ft.	10 ft.
Strong Smell	Strong flowers	0	20 ft.	5 ft.
Pungent Smell	Unwashed or sweaty person	0	10 ft.	2 1/2 ft.
Smell	Washed person, fresh air	0	5 ft.	1 ft.
Faint Smell	Blood	0	5 ft.	1 ft.

Table: Taste DCs

Tasting Event	Example	Base DC
Overpowering Ingredient	Salt by itself	-15
Strong Ingredient	Garlic in chicken	-10
Ingredient	Onions in roast beef	-5
Faint Ingredient	Lavender in soup	0

Table: Touch DCs

Touch Event	Example	Base DC
Faintest of touches	A faint breeze across the skin	10
Light glancing touch	A feather run across your arm; pierced by acupuncture needle in a "painless" spot	5
Casual touch	Arm around the shoulder of a friend; a lover's kiss	0
Non-lethal damage; very small piercing attacks	Sparring with fists; blows from padded swords; whoops, dart in your neck	-5
Piercing or slashing wound from an object two or more size categories smaller; blunt damage from an object one or more size category smaller	Arrow wound; thrown dagger lodging in your arm; hitting your thumb with a hammer	-10
Piercing or slashing wound from an object one size category smaller; blunt damage from an object of your size category	Longsword in your side; whacked by a quarterstaff	-15
Piercing or slashing wound from an object of your size category; blunt damage from an object of a larger size category	Greatsword in your neck; clubbed by a larger creature	-20

Table: DC Modifiers

Circumstance	DC Modifier
Sound is traveling through an object, like a door or water.1	+Interposing Object's HP/10
Background noise stronger than listening event.1	+2 per 10 dB difference
Additional range increment to event for primary sense used to notice event.2	+2
Intense event occurs inside the standard range.	-4
Intense event occurs inside half of the standard range.	-8
Ambient conditions impair the primary sense used to notice event.	+2
Ambient conditions block a sense used to notice event3	—
Ambient conditions block all senses that could notice event4	N/A
This penalty only applies if the primary sense to notice the event is hearing. If using another sense to notice the event would provide a lower total penalty, that penalty is used instead. This penalty stacks and applies for every range increment to the event, based on the sense used for detection. If using another sense to notice the event would provide a lower total penalty, that penalty is used instead. If you don't have access to a sense that could detect an event, you must use another sense to detect the event. You use the lowest total detection penalty from the other available senses. If you don't have access to any sense that could detect an event, you have no method of detecting that event.

Table: Check Modifiers

Circumstance	Check Modifier	Example
Minimal knowledge of subject	+2	A second hand or minimal familiarity with subject, a description or very few previous interactions
Fair knowledge of subject	+5	First hand familiarity with subject, many previous interactions within the recent past
Substantial knowledge of subject	+10	Very familiar with subject, a lot of previous interactions stretching over a long period of time
Distracted and not fully focused	-5	Being talked to, using your standard action on another task
Extremely distracted and barely focused	-10	Being yelled at, defending against an obvious threat in combat, using your full round action on another task
Sleeping or otherwise unconscious1	-10	Being asleep or unconscious, intentionally or otherwise.
Rushing a 1 round or full-round action to a standard action	-3	—
Rushing a standard action to a move action	-2	—
Rushing a standard or move action to a swift action	-5	—
Sleeping creatures generally only have access to their sense of hearing and touch. These senses are not considered impaired or blocked, and sleeping characters may notice events with these senses without suffering an increased DC as well. Most other senses are automatically considered impaired or blocked, and events that primarily rely on those senses will have increased DCs for sleeping characters.

Special

”Roll a perception check…”

Those are words you should never say again unless the player asks if they can make something out. When you volunteer those words you ruin immersion, break the mood, and alert the players that there’s something they should be looking for that they weren’t previously. The “Take 0” rule for perception ensures that some players will simply become aware of things that happen and you can just tell them about it. If there’s a brief flash of lightning that outlines the villain’s army against the dark night or a faint scream from somewhere deep in the dungeon, you can just tell the player with a perception bonus that would allow them to notice it, and thus deepen the atmosphere. If they want to try to make something out of it, and it’s going on long enough for them to get the rest of the party to quit being a distraction, they will get their perception check to learn more about it. In this way the check is an active thing in response to a set piece instead of a reactive thing that serves as a warning, just like it should be.

All conscious characters are considered to be taking 0 on their perception checks, all of the time, and this does not require an action. They may not be actively paying attention to a particular thing, but they don’t ignore everything either. This is true whether they are walking down the street, chatting with a friend, or even sleeping. This change allows us to do away with reactive perception checks and instead make it an active choice to attempt to pay more attention to their surroundings, as a character no longer needs to spend an action or make a check to detect or notice something that they could not fail a check to notice.

This means that anytime a character is not distracted and is exposed to an event with a DC no greater than their perception ranks +5, they are at least aware of it. If the event has a notice DC no greater than their perception ranks, they detect it clearly. And if the event has a DC no greater than their ranks in perception -5, they know details about it because they can make them out. Being distracted just means that the characters have one step less information. This is simply the effects of the Notice ability applied to taking 0 on a roll.

At lower levels, there is not a large change in the game as a result of this, aside from the elimination of reactive perception checks. At higher levels, however, a character might automatically detect poor magical forgeries or see right through low level illusions. It is possible for a high level character to automatically see a low rank sneak without even rolling or announcing that they are keeping a wary eye, and all of that is both fine and good. It’s part of what makes higher-level characters harder to manipulate in social settings, and also the only way to write a perception skill so that actually keeping a wary eye or actively trying to see what's going on means anything.

This is such an important concept that there’s even a sidebar here to reinforce it.

Untrained Uses

Discern Fraud

Forged documents are as good a liar as any silver tongued devil, but they sit in front of you and let you examine them for a longer time. Disguised individuals aren’t much different, since they practically parade in front of you. With a full-round action and a perception check, you can spot counterfeit objects and creatures, and deal with those who would pass them off on you appropriately. The base DC for this check is determined by whoever created the falsehood, and modified by your distance as indicated in the table above. You gain a modifier to your check based upon your circumstances. Attempting to discern fraud requires you to concentrate on the subject, and you are considered distracted for any notice checks, passive or active, that you perform during the same turn. Note that you can not use this ability on creatures or objects that you have not clearly noticed, so it is rather difficult to use except up close.

Base DC: Check result of forgery or disguise + conditions
Check Result:

• DC+5 and above: You recognize if it is a fake and can even point out several places they went wrong, if you’re into mocking people who try to slip one by you. You automatically succeed at convincing others that it is a counterfeit.
• DC+0 to DC+4: You realize if the thing in front of you is a fake. If you attempt to convince someone else that it is a fake, they gain a +4 bonus on their check.
• DC-1 and below: You believe that it’s genuine, and can not retry this check unless you have a new reason to suspect the object. Note that if you make this check on an authentic object, you will still get this result, so you shouldn’t discount it just because you think something is up. Sometimes you’re just paranoid.

Notice

You have eyes, ears, and various other sense organs that allow you to notice things going on in your world. While you are always assumed to be paying some attention to the world, and thus taking 0 with the ability, actually making a check with this ability implies that you are focusing on your senses to better understand something in your surroundings. This ability is constantly in use as a free action, in which you "Take 0" on your roll. This allows you to perceive quite a lot of things, and interact with the world in a normal way as a result. If you get a bonus to a particular sense, then that bonus applies to this ability whenever that sense would help you notice the event.

Sometimes you will want to perceive a particular thing more clearly, like a figure on a distant hill outlined by a campfire or the sound of commotion from a street over. At these times you may make a perception check as a standard action. The DC to notice or detect something is dependent on the type of event, and modified by local conditions like distance and interposing objects. You gain a bonus or penalty to this check based upon your circumstances, and may rush your attempt. Sample DCs are listed above, as are the conditions that provide a penalty to your check. Attempting to better perceive a particular thing causes you to tune other things out, however. Even though you continue to "Take 0" on your passive perception checks while you focus on a particular event, you are distracted from the background and suffer the −5 distracted penalty to those events.

A notice check uses all of your relevant senses. You do not roll multiple times in a round for multiple senses, and you may not roll multiple times even if you attempt to spend multiple actions on the checks.

Special: Some creatures have enhanced senses, like tremorsense, blindsense, blindsight, and scent. Blindsense and blindsight are resolved as if they were sight, but they ignore cover and concealment. They can not penetrate sealed enclosures, though. Tremorsense is resolved as if it was sight, and it ignores cover, concealment, and even walls and floors. It can not detect anything that is not in contact with the same surface as the creature, however, nor can it detect stationary or unattended inanimate objects. These senses are only able to determine the shape, size, and structure of a thing, and not its color or color variations. It should go without saying that they are useless for reading. Scent is resolved as if it were smell, with double the base range and range increments. Additionally, any check that meets or exceeds the DC allows the creature with scent to determine the exact location of the source.

These senses are checked whenever a notice check is made, and generally reveal more than the normal senses would because they suffer less interference or offer greater fidelity. As a result, passive notice checks are likely to provide the exact location of a creature or object within range regardless of interfering conditions. There are some creatures and objects that show poorly against one or more of these special senses, however. Passive notice checks are unlikely to reveal these targets, and actual checks may be necessary. The results for these abilities are listed in the check results below, as a special entry.

Base DC: Event DC, + conditions
Check Result:

• DC+5 and above: You notice the event very clearly, and can make out fine details about it that others might have difficulty with.
• DC+0 to DC+4: You notice the thing in question, and are rather clear about what it is.
• DC−1 to DC−5: You noticed... something. You’re not sure of any details, but there was definitely something there. You know the general direction it came from, and if it’s still there next round, you may be able to find out more with another check.
  Special: If a creature detected with this result shows poorly against an enhanced sense, they have full concealment against that sense. This applies to you in general unless you can locate them more exactly with another sense.
• DC−6 and below: You didn’t notice a thing.
  Special: If the thing in question shows poorly against an enhanced sense, they do not register for those senses at all. The enhanced sense doesn't even help you locate what square the target is in, so the target may as well not even exist unless you can sense it in another fashion.

Rank 1 Uses

Stand Guard

As a standard action, you may "take 10" instead of 0 on your passive perception checks. If you wish to perceive something more clearly, you must make the check as normal and "take 0" with your passive perception checks for the round instead.

Rank 4 Uses

Uncover Secrets

People hide secret doors, caches, triggers, traps, and similar bits all over the place. If you want to use, loot, or avoid them, you have to be able to find them first, and you have a knack for locating them. Searching a 5' by 5' section of the floor, wall, ceiling, or the surface of an object for these hidden things requires 1 round. Searching a compartment of an object for secrets requires 1 standard action if it is smaller than a 1' cube, and a 1-round action if it is as large as a 2' cube. The DC to find a secret door, a hidden cache, a trap trigger or effect, or an obscured sign or object is determined by their construction or conditions. Finding a trap does not grant you any special ability to disable it, though you can plug holes, wedge blocks, trigger it from a distance, or perform other sorts of really crude sabotage if you'd rather not just avoid it entirely.

Note: This ability does not help you find things that have not been deliberately hidden in or on a physical object. It is not used to determine if you find the treasure hidden in the rubble, the gems in the pants in the corner of the room, or the sheet of condemning evidence in the stack, as those simply require adequate time to look through. Any published references to using search in this fashion should be instead treated as allowing characters to find the indicated items if they spend 2 rounds searching for every 5 points of the DC.

Base DC: Determined by hidden object or trap
Check Result:

• DC+5 and above: You find any hidden caches or triggers in the space, as well as the general direction to other local connected devices. If you discovered a hidden catch, for example, you would know the direction to the release if it was not in the same space. If there is nothing hidden there, you recognize that instead.
• DC+0 to DC+4: You find the hidden cache or trigger in the space. You gain no insight into how it is connected to anything else. If there is nothing hidden there, you recognize that instead.
• DC-1 to DC-5: You do not uncover any secrets within the space, even if there are some.
• DC-6 and below: If there is something in the space, you believe that it is empty. If there is nothing in it, you believe that there is something in the space connected to a trigger elsewhere. You can only get this result if you spend an action to uncover secrets, not if you are simply taking 0. Sometimes, if you look too hard at things, you see what you want to.

Rank 8 Uses

See the Invisible, Hear the Silenced

By focusing on one of your senses, you can ignore illusory sensation and instead notice the reality beneath. You can pierce illusions affecting only one sense at a time: sight, smell, taste, touch, or hearing. You can not pierce illusions with multiple senses at a time with this ability. Attempting to pierce illusions is a standard action; the DC for this check is 15 + caster level of the illusion, and your check is modified based on your circumstances. A special exception is made for being distracted, however, and you do not suffer that penalty when you use this ability.

This check is valid against all illusions that interact with the selected sense while you maintain your focus, and so your check is compared against the DC of any effect in range. Any illusion with a DC lower than your check is treated as an illusion for your selected sense. Since it only works against a single sense at a time, this is mostly useful for piercing single sense illusions like invisibility or silence. Against anything affecting more senses, a save is really your only option. Even though one sense recognizes the falsehood, your other senses are still firmly convinced that the sensation is real. This means you can’t simply ignore multi-sense illusions that you have partially pierced. Piercing an illusion counts as interacting with it, however, and you may then attempt a will save to disbelieve as per normal rules. Since you know that it is an illusion, you gain a +4 bonus on this save.

Base DC: 15 + caster level, + conditions
Check Result:

• DC+0 and above: The chosen sense pierces the illusion and understands it to be such. The illusion is persistent, however, and you must spend a swift action every round following to maintain the level of focus, carrying your check result into each new round. You must spend another standard action if you would like to attempt a new check.
• DC-1 and below: Whether it was cast by someone more skilled than yourself or you simply lack the necessary concentration, you fail to pierce the illusory sensory component for the illusion. There is nothing stopping you from retrying next round if you want though.

Rank 10 Uses

Discern Transmutation

Magical transmutations of objects are basically forgeries as well, since they could revert to their original form at some point in the future. And the most skilled of transformation artists don't simply put on suits of scales, they actually coax them from their skin. You can discern these magical alterations, in both people and objects. Like the discern fraud ability, this is a full-round action and you are considered distracted for any notice checks, passive or active, that you perform during your turn. The DC is 15 + caster level, or the DC of the transfiguration. and the check results are the same as for the mundane ability.

Base DC: 15 + caster level or transfiguration DC, + conditions
Check Result:

• DC+10 and above: You recognize that subject has been magically altered, and even have a good sense of how they did it. If the subject used a spell, you can grant a +5 bonus to a targeted dispel, or similar caster level based check, to remove the effect. If the subject used a transfiguration, you may disable it with a successful melee attack that deals no damage.
• DC+5 to DC+9: You recognize the subject has been magically altered, and can even point out several places where they could have done a better job if you’re into mocking people who try to slip one by you. You automatically succeed at convincing others that it is a counterfeit.
• DC+0 to DC+4: You realize if the thing in front of you is a fake, magical or mundane. If you attempt to convince someone else that it is a fake, they gain a +4 bonus on their check.
• DC-1 and below: You believe that it’s genuine, and can not retry this check unless you have new reason to suspect the object. Note that if you make this check on an authentic object you will still get this result, so you shouldn’t discount it just because you think something is up. Sometimes you’re just paranoid.

Rank 14 Uses

Sight Beyond Sight

Perception is strong with you, so strong that you can pierce illusions affecting all of your senses at once. Even without focusing your senses can pierce an illusory veil, even those that wouldn’t normally allow a save. Using this ability actively is a standard action; the DC for this check is 15 + caster level. You are assumed to be always "taking 0" with this ability, however, so it is possible that you will just see right though the illusions of less trained casters. Once an illusion is shattered for you with this ability, it remains so. Unlike the See the Invisible, Hear the Silenced ability, this ability only targets a single illusion at a time when used actively. It targets every illusion you experience when used passively while "taking 0".

Base DC:15 + caster level, + conditions
Check Result:

• DC+0 and above: You recognize the illusion for what it is, and effectively disbelieve it.
• DC-1 to DC-5: You recognize that something is odd with the sensation, and that it might be an illusion, but are unable to actually pierce it. You may focus and retry, however.
• DC-6 and below: You fail to pierce the illusion, and may not attempt to do so again with this ability for at least 1 hour. You may still defeat portions of the illusion with the See the invisible, Hear the Silenced ability, however.

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