Stealth (D&D)
Posted: Mon Jul 03, 2017 6:41 am
I've been doing a lot of off and on thinking about an actually functional stealth system, which I don't think exists in any version of D&D or any other game I've seen. This is my current work up, for D&D, it's intended to be possible to just jam this into any D&D 3e/3.5 type system you are running, and to work. You shouldn't have to recalculate monster skills, or drastically change your own character, or really, change the types of actions that seem like a good idea for you normally. It just takes a system that doesn't work, and replaces it with one that does. It's not perfect, but it probably is the best stealth system in any D&D like game, period.
Stealth
Stealth is where one creature is trying to do things without other creatures noticing that it is there. So the first major difference, is that Stealth doesn't cover when someone else knows you are there and is trying to pinpoint your location, Stealth is what you do to prevent them from finding out that someone is there, until they actually do.
Stealth replaces the Hide Skill in D&D, and ranks accordingly. This will be phrased as if from the view of PCs stealthing at enemies, but the rules are identical when monsters stealth at PCs. The Spot skill is replaced with "Awareness" as it reflects sight, sound, and scent, and touch, but racial bonuses, ranks, and items remain the same.
Fundamentally, the way it works is you roll stealth, opponent rolls awareness, and you choose to perform actions that give the enemy increasing bonuses until his awareness exceeds your stealth.
Implicit in this is that you don't know his awareness, since it's based on lots of information you probably don't have, like his spot mod, his spot roll, and if he has true seeing, then you might think you have total concealment when you don't, if he can see in dark and you don't know, ect.
So each action you take risks him responding by getting the jump on you, because you tried to do something, and he caught you. But if you are right about your risks, you can get in position, and do something messed up to him, possibly even just killing him.
Range:
For the purposes of Stealth, there are five ranges: Adjacent, Tight, Middle, Far, and Outside Far
Adjacent is being either 5ft away, or within the same square as an object or creature.
Tight Range is being less than 60ft away, but more than 5ft away.
Middle Range is being more than 60ft away but closer than 300ft.
Far Range is being more than 300ft away but less than 1200ft away.
Outside Far Range is being more than 1200ft away from something.
Any ability that previously halved range penalties to spot, now doubles each of those ranges for the purpose of acting as a detector.
If no path around exists, 10ft thick blocking terrain that provides Total Cover and Total Concealment adds one range to any detector, with additional 10ft thick blocking terrain separate or contiguous, adding another range category. If a path around exists, that path adds to the distance.
You probably can't detect someone within 60ft if 30ft of stone wall is between you.
Beginning Stealth:
When you want to approach and do something without people noticing you, you start by declaring that you being acting stealthily, and then rolling a stealth check. This creates a "Stealth Value" of 1d20+Hide Ranks+Dex Modifier+racial/item modifiers to the hide skill. This is a roll, you can take 10 on it, but you can't take 20, because there is a penalty for rolling low, you get detected sooner. You roll stealth when the PC(s) decide to start being stealthy. A specific rolled stealth session ends either when PCs stop trying to be stealthy, such as when they choose to do anything not compatible with stealth, like resting to regain spells, buying things at the market, or moving at a hustle pace, or when a bunch of enemies have all noticed them and start shouting about their presence. While characters are acting stealthily, they may not move faster than their base speed in a round. This does not limit their actions, so they can move as move action, and then spend another move action opening a door, or a standard action casting a spell. But moving at a faster pace such as making two move actions is impossible when moving stealthily.
Enemies, based on their current circumstances, should roll and have a "Base Detection Value" which is the result of a generic awareness check, before any circumstantial modifiers based on the creature they are attempting to detect. Circumstantial modifiers based on the creature making a awareness check still apply as detailed below.
This Base Detection Value is further modified each round based on which, if any, of the stealthing creatures have circumstantial modifiers with respect to the creature, creating a separate detection value for each creature using stealth.
Modifiers are presented in groups, in all cases, only the largest absolute value bonus of that group applies.
Circumstantial Modifiers to Base Detection Value based on the spotting creature.
-5 if detector is focused on another subject.
-10 if detector is concentrating on another task.
-20 if detector is asleep or otherwise in a state of extreme nonsensory perception.
Circumstantial Modifiers to Detection Value based on the stealthing creature.
+0 Within Far Range
+2 Within Middle Range
+5 Within Tight Range
+10 Within Adjacent Range
-4 for every size category the stealther is smaller than than the detector.
+4 for every size category the stealther is larger than the detector.
+5 if the stealther is within the detectors Scent range.
+10 if the stealther is within the detectors Blindsense range. (Or otherwise a detection method that gives the square, but not full information, such as Tremorsense, Touchsight, Mindsight, ect.)
+20 if the stealther is within the detectors Blindsight range. (Or comparable detection method.)
-10 if the stealther has a minor impediment to a primary sense of the enemy, such as Cover, Concealment, or supernatural or magical flight that reduces movement noise.
-20 if the stealther has a major impediment to a primary sense of the enemy, such as Total Cover, Total Concealment, or a Silence Field.
Ultimately, at the end of all this, you have a Stealth Value for each PC, and a Detection Value for each enemy against each PC.
If, at the onset of stealth, the PCs are Outside Far Range with respect to any detectors, then they are automatically not detected. If on the other hand, they are Far Range or closer, check to see if the Detection Value exceeds the Stealth Value, if it does so, they are detected. If they are detected, then provide the detecting enemies with a surprise round, and proceed to "In Conflict Uncertainty."
Taking Actions While in Stealth
The list of actions that can be taken from stealth is below. There is no possibility to pass time without taking actions, if the stealther wishes to wait, then they must choose the waiting action for the appropriate time period listed below.
When a stealther chooses to perform an action from below, the associated bonus is provided to all detectors within at least far range until they leave far range for that detectors Detection Value against them. Successive actions provide cumulative bonuses that stack with each other without end.
If after resolving any non attack action, the Detection Value of an detector would exceed the Stealth Value of the corresponding stealther, then the detector may take a standard action as a surprise action, at any point before or during that action. After that, you should probably start rolling initiative. Apply this to the action of casting spells, but not if the result of the spells casting is what alerts the enemy, in which case, resolve the action of casting the spell, the spells result, and then roll initiative.
If after resolving an attack action but before resolving the attack, the Detection Value of a detector would exceed the Stealth Value of the corresponding stealther, you should roll initiative.
If after resolving an attack action and the attack, the Detection Value of a detector would exceed the Stealth Value of the corresponding stealther, you should resolve the action, the attack, and then roll initiative.
Bonuses Accrued to Detector for Actions Taken By Stealther: (Grouping rules from above still apply)
Wait: If you wait for a time, you may cease waiting and take other actions at any point, however, the bonuses accrued to detectors remain the same based on the originally chosen time.
+2 one minute
+5 10 minutes.
+10 1 hour.
+20 8 hours.
+40 one day.
+80 one week.
+1 Casting a spell with no components.
+5 Casting a spell with a somatic component.
+10 Casting a spell with a verbal component.
+5 whispering to a creature within 10ft.
+10 for moving an object in the detector's zone that predated your arrival.
+20 otherwise significantly effecting the enviroment in a highly noticeable manner for the detector (IE, your silence field overlaps them personally, or you cause a cave in or summon a wall, you kill someone in the area).
+5 Making an attack action.
+30 Detector is subject of an attack roll, and survives.
In Conflict Uncertainty
Once a creature knows you are around, the nature of identification changes. If you have been detected out of your stealth, then if you do not have total cover or total concealment, the (sighted creature) knows your square. If you do have total cover or total concealment, the sighted creature is aware of your general presence in their zone of control, and you roll a Move Silent check which is opposed by their listen check. Failing by 40 or more gives them no specific information about your location. Failing by 20 gives them a 180 degree field in which you are located (roll 1d2 if you are diagonal on the grid). Failing by 10 gives them a 90 degree arc. Failing by 5 gives them a a 90 degree arc distance within 1d4 squares (roll like splash weapon miss). Hitting exactly the DC gives them the square.
The listen roll receives a -10 penalty if you have total cover relative to the detector.
Stealth
Stealth is where one creature is trying to do things without other creatures noticing that it is there. So the first major difference, is that Stealth doesn't cover when someone else knows you are there and is trying to pinpoint your location, Stealth is what you do to prevent them from finding out that someone is there, until they actually do.
Stealth replaces the Hide Skill in D&D, and ranks accordingly. This will be phrased as if from the view of PCs stealthing at enemies, but the rules are identical when monsters stealth at PCs. The Spot skill is replaced with "Awareness" as it reflects sight, sound, and scent, and touch, but racial bonuses, ranks, and items remain the same.
Fundamentally, the way it works is you roll stealth, opponent rolls awareness, and you choose to perform actions that give the enemy increasing bonuses until his awareness exceeds your stealth.
Implicit in this is that you don't know his awareness, since it's based on lots of information you probably don't have, like his spot mod, his spot roll, and if he has true seeing, then you might think you have total concealment when you don't, if he can see in dark and you don't know, ect.
So each action you take risks him responding by getting the jump on you, because you tried to do something, and he caught you. But if you are right about your risks, you can get in position, and do something messed up to him, possibly even just killing him.
Range:
For the purposes of Stealth, there are five ranges: Adjacent, Tight, Middle, Far, and Outside Far
Adjacent is being either 5ft away, or within the same square as an object or creature.
Tight Range is being less than 60ft away, but more than 5ft away.
Middle Range is being more than 60ft away but closer than 300ft.
Far Range is being more than 300ft away but less than 1200ft away.
Outside Far Range is being more than 1200ft away from something.
Any ability that previously halved range penalties to spot, now doubles each of those ranges for the purpose of acting as a detector.
If no path around exists, 10ft thick blocking terrain that provides Total Cover and Total Concealment adds one range to any detector, with additional 10ft thick blocking terrain separate or contiguous, adding another range category. If a path around exists, that path adds to the distance.
You probably can't detect someone within 60ft if 30ft of stone wall is between you.
Beginning Stealth:
When you want to approach and do something without people noticing you, you start by declaring that you being acting stealthily, and then rolling a stealth check. This creates a "Stealth Value" of 1d20+Hide Ranks+Dex Modifier+racial/item modifiers to the hide skill. This is a roll, you can take 10 on it, but you can't take 20, because there is a penalty for rolling low, you get detected sooner. You roll stealth when the PC(s) decide to start being stealthy. A specific rolled stealth session ends either when PCs stop trying to be stealthy, such as when they choose to do anything not compatible with stealth, like resting to regain spells, buying things at the market, or moving at a hustle pace, or when a bunch of enemies have all noticed them and start shouting about their presence. While characters are acting stealthily, they may not move faster than their base speed in a round. This does not limit their actions, so they can move as move action, and then spend another move action opening a door, or a standard action casting a spell. But moving at a faster pace such as making two move actions is impossible when moving stealthily.
Enemies, based on their current circumstances, should roll and have a "Base Detection Value" which is the result of a generic awareness check, before any circumstantial modifiers based on the creature they are attempting to detect. Circumstantial modifiers based on the creature making a awareness check still apply as detailed below.
This Base Detection Value is further modified each round based on which, if any, of the stealthing creatures have circumstantial modifiers with respect to the creature, creating a separate detection value for each creature using stealth.
Modifiers are presented in groups, in all cases, only the largest absolute value bonus of that group applies.
Circumstantial Modifiers to Base Detection Value based on the spotting creature.
-5 if detector is focused on another subject.
-10 if detector is concentrating on another task.
-20 if detector is asleep or otherwise in a state of extreme nonsensory perception.
Circumstantial Modifiers to Detection Value based on the stealthing creature.
+0 Within Far Range
+2 Within Middle Range
+5 Within Tight Range
+10 Within Adjacent Range
-4 for every size category the stealther is smaller than than the detector.
+4 for every size category the stealther is larger than the detector.
+5 if the stealther is within the detectors Scent range.
+10 if the stealther is within the detectors Blindsense range. (Or otherwise a detection method that gives the square, but not full information, such as Tremorsense, Touchsight, Mindsight, ect.)
+20 if the stealther is within the detectors Blindsight range. (Or comparable detection method.)
-10 if the stealther has a minor impediment to a primary sense of the enemy, such as Cover, Concealment, or supernatural or magical flight that reduces movement noise.
-20 if the stealther has a major impediment to a primary sense of the enemy, such as Total Cover, Total Concealment, or a Silence Field.
Ultimately, at the end of all this, you have a Stealth Value for each PC, and a Detection Value for each enemy against each PC.
If, at the onset of stealth, the PCs are Outside Far Range with respect to any detectors, then they are automatically not detected. If on the other hand, they are Far Range or closer, check to see if the Detection Value exceeds the Stealth Value, if it does so, they are detected. If they are detected, then provide the detecting enemies with a surprise round, and proceed to "In Conflict Uncertainty."
Taking Actions While in Stealth
The list of actions that can be taken from stealth is below. There is no possibility to pass time without taking actions, if the stealther wishes to wait, then they must choose the waiting action for the appropriate time period listed below.
When a stealther chooses to perform an action from below, the associated bonus is provided to all detectors within at least far range until they leave far range for that detectors Detection Value against them. Successive actions provide cumulative bonuses that stack with each other without end.
If after resolving any non attack action, the Detection Value of an detector would exceed the Stealth Value of the corresponding stealther, then the detector may take a standard action as a surprise action, at any point before or during that action. After that, you should probably start rolling initiative. Apply this to the action of casting spells, but not if the result of the spells casting is what alerts the enemy, in which case, resolve the action of casting the spell, the spells result, and then roll initiative.
If after resolving an attack action but before resolving the attack, the Detection Value of a detector would exceed the Stealth Value of the corresponding stealther, you should roll initiative.
If after resolving an attack action and the attack, the Detection Value of a detector would exceed the Stealth Value of the corresponding stealther, you should resolve the action, the attack, and then roll initiative.
Bonuses Accrued to Detector for Actions Taken By Stealther: (Grouping rules from above still apply)
Wait: If you wait for a time, you may cease waiting and take other actions at any point, however, the bonuses accrued to detectors remain the same based on the originally chosen time.
+2 one minute
+5 10 minutes.
+10 1 hour.
+20 8 hours.
+40 one day.
+80 one week.
+1 Casting a spell with no components.
+5 Casting a spell with a somatic component.
+10 Casting a spell with a verbal component.
+5 whispering to a creature within 10ft.
+10 for moving an object in the detector's zone that predated your arrival.
+20 otherwise significantly effecting the enviroment in a highly noticeable manner for the detector (IE, your silence field overlaps them personally, or you cause a cave in or summon a wall, you kill someone in the area).
+5 Making an attack action.
+30 Detector is subject of an attack roll, and survives.
In Conflict Uncertainty
Once a creature knows you are around, the nature of identification changes. If you have been detected out of your stealth, then if you do not have total cover or total concealment, the (sighted creature) knows your square. If you do have total cover or total concealment, the sighted creature is aware of your general presence in their zone of control, and you roll a Move Silent check which is opposed by their listen check. Failing by 40 or more gives them no specific information about your location. Failing by 20 gives them a 180 degree field in which you are located (roll 1d2 if you are diagonal on the grid). Failing by 10 gives them a 90 degree arc. Failing by 5 gives them a a 90 degree arc distance within 1d4 squares (roll like splash weapon miss). Hitting exactly the DC gives them the square.
The listen roll receives a -10 penalty if you have total cover relative to the detector.