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Traps - How to Trigger, Set and Disable

A trap is one of the classic challenges of role playing games such as Dungeons & Dragons. The great variety of traps a player character can encounter in their adventures is a big part of the fun. They keep players on their toes by adding uncertainty and risk to many situations. Traps add a lot of fun, danger, and an opportunity to think creatively in a good adventure. Whether the player characters set a trap or they’re trying to disable the GM’s trap, it’s as important a part of the Atomic Role Play Game as it is in Dungeons and Dragons.

There are a few major differences players will notice when it comes to traps in the Atomic RPG System. First and foremost, any player in a Atomic game can attempt to set or disarm, regardless of archetype. Also, characters can work together to set or disable traps. So if your rogue has the flu and couldn’t game with your group, you don’t have to send in the tank to disable the trap through brute force!

Secondly, the Atomic Role Play Game has a simple trap mechanic that can be used to create any trap that a player’s imagination can think up and these ideas are easily implemented. Once players know the Atomic system to set and disable traps, it will be a breeze to set them up or disable them.

What is a Trap in the Atomic RPG System?

A trap in the Atomic RPG System is a Power that is triggered when a certain condition is met. Usually this means stepping on a square or passing spot in a hallway. However, they can be more complicated with triggers that activate after a certain action is taken, something appears in a Space, or even a specific creature or object is perceived in an area. When the trigger is activated, the associated Power goes off immediately. These traps are generally do damage by removing Hit Points. They can do just about anything a Power can do such as give penalties, bonuses, heal, and more.

When a trap is triggered, it uses its Attack Modifier to attack what the trap targets, usually an area. Traps attack the Defense that is associated with the Power used. If the Power can target multiple Defenses such as Combatant or Mystic, as is the case with most damaging traps, then the trap rolls an Attack against the worse of the two Defenses.

What Skills Can You Used


This is the main Skill that will be used when dealing with traps.


Might be used for pit traps or snares in the wild.


Might be used for traps with large mechanisms or areas to dodge.


Might be used for sophisticated mechanisms or electronic traps.

A case could be made, depending on the situation and trap type, that any Skill might be what is needed. Though for the vast majority of traps, Subterfuge will be the main skill to use. 

Find, Avoid, or Disable Traps in the Atomic RPG System

To interact with a trap, players will need to roll against the Trap Difficulty.

This is a number that determines the quality, strength, and deviousness of the trap at hand. There are a couple ways to know the Trap Difficulty. This is discussed below in Set a Trap in the Atomic RPG System.

Whenever a player or non-player character wants to look for a trap, disable, or perform any other action with a trap, they will use the Trap Difficulty as a target number. There are a number of actions that may occur with traps. Trying to detect the trap (Perception Skill Check), attempting to disable a trap (Subterfuge Skill Check), jumping through a trapped area without setting it off (Athletics Skill Check), or really, just trying to figure out what the trap might do (Scholar Skill Check). The situation and the trap itself will determine what the GM may allow you to do.

The bottom line is when a player is interacting with a trap, they will roll against the Trap Difficulty.

Disabling a Trap in the Atomic RPG System

To disable the player can always use the Subterfuge Skill. The GM may allow the player to use Scholar or Athletics depending on the situation.

Traps can only be disabled during Turn Time. Disabling takes time and concentration, which is simply not an option during Battle Time. Turn Time is used because of the unknown consequences when dealing with traps. This way the game is already in a turn by turn mode.

Other players in the group are allowed to Assist the player disabling it. To Assist in disabling, the Assisting player must be in the trap area or entrance. They must also make roll against the Trap Difficulty.

Successfully Disabling a Trap

If an Assisting player rolls a Subterfuge Roll of the Trap Difficulty or higher, the player disabling the trap can add the Assisting player’s Character Tier to the roll. If the roll is a natural 20, they grant double the bonus. If the player rolls a Subterfuge Roll of the Trap Difficulty number or higher, the trap is disabled.

Failing to Disable a Trap

If an Assisting player rolls a Subterfuge Roll below the Trap Difficulty, they hinder the efforts of the main player, causing the Trap Difficulty roll to increase by their Character Tier. If the Disabling player rolls a Subterfuge Roll below the Trap Difficulty, they are unable to disable the trap. No further attempts can be made to disable that particular Trap by that player or those Assisting in the attempt.

Characters that were not involved can attempt to disable the trap. Otherwise, different means will have to be taken to dodge, avoid, and maybe just take the trap damage.

If a 1 is rolled to either Assist or disable a trap, the trap will immediately be triggered, affecting every player involved and possibly other players.

Creating Traps in the Atomic RPG System

In the Atomic RPG System traps are simply Powers that are set in a specific place, triggered by a specific action.

To create a trap the player should build a Power with the effect and area they want. The player must be able to use the Power to be used for the trap, even if they do not have it in their own Power List. Level and Discipline restrictions must be followed. There is no Power Point cost cap directly associated with creating a trap.

The player needs to decide what triggers the trap. The character’s Subterfuge skill will determine the trigger types they can use for their trap. A higher Subterfuge Skill allows for use of better triggers. More sophisticated triggers increase the difficulty of the trap.

TierDifficulty IncreaseTrigger TypeExample
10Trip WireA wire strung between two trees.
25Pressure Plate, LeversA loose tile that activates when stepped on.
310Mechanically IntegratedTrapped locks that activate when the incorrect key is used.
415Light, Liquid, Sound, Abstract TriggersWave trigger when someone tries to swim through sewer.
525DetectionMotion Sensors or Powers that detect a certain creatures or objects.

Detection Traps

Detection Traps are slightly different than other traps as they act almost like a guard NPC watching an area. The Trap Difficulty is the Passive Skill that is needed for the Trap to detect whatever it is looking for. If the trap detects what it is looking for it is immediately set off. Some things a Detection Trap might look for is movement, a foreign substance, and even the intent of those in the area.

If their modified Skill Check is equal to or higher than the Trap Difficulty than they can successfully bypass the trap. If not, they set off the trap. Careful players could use Skill Checks to determine a Trap Difficulty needed before the attempt.

Determining Trap Difficulty

Once the Power has been created and the trigger type selected, it is just a matter of some simple addition to figure out the final Trap Difficulty.

First determine the difficulty for just the Power.  Take 10% of the Power Cost (rounded down). For a Power that costs 232, the Power Cost is 23. For a Power that costs 854, it is 85. For a Power that costs 32, it is 3. Simply take the last number off the cost and you have 10%.

Second, determine the trigger. Most of the time the trigger will be will be a trip wire or pressure plate (T1 or T2). For a trip wire the character will add 0. For a pressure plate the character will add 5.

Finally, add these two together to figure out the final Trap Difficulty. This is the number that must be rolled.

Here is the Power that was created for this trap.

Trap Power: 12d8 Damage 16 Space
This Power was created for use with a trap.
12d8 Damage
 Aggression: Offensive | Discipline: Combatant and Mystic | Use: BT
 Range: Self | Target: Spaces (16) | Duration: Instant | Cost: 232

A trap with a Power that costs 232 has a check of 23. This trap will have a pressure plate trigger. Add 5 for a final Trap Difficulty of 28.

Setting a Trap in the Atomic RPG System

First the player must have the supplies to set up the trap. This cost is figured out my multiplying the Difficulty by 10 for a single shot trap. For a trap that resets, multiply the Difficulty by 100. Since the Trap Difficulty is 28, the cost of this trap will be 280. If the player has the cash, they should be able to just spend the cash to get the “necessary materials”. The Atomic RPG System does not go into micromanaging the exact supplies or availability. If the player has the money, they can spend it to make the trap.

Now that the player has purchased the “necessary materials” to create the trap they need to set it. The player determines the placement of the trap effect and the trigger. In this case the trigger is placed halfway down the hall in the middle of the trap area. This is a pressure plate which comprises several squares. The trigger can be one space or many spaces, as long as it is known what space triggers the trap.

Finally the player must roll a Subterfuge Check to equal to or above what is needed. In this case it is a 28.

Successfully Setting a Trap

If the player rolls the Trap Difficulty or above, the trap is set and ready to be triggered.

Determining the Final Trap Difficulty

The final Subterfuge roll total will set the new Trap Difficulty number. If the player rolled a total of 35 for this trap, the Trap Difficulty becomes 35. If the player rolls a natural 20 on the roll, the trap becomes a Critical Trap. Critical Traps do maximum damage.

GM traps should use the base Trap Difficulty as the final Trap Difficulty. GM’s don’t need to roll for traps. It makes things faster and easier.

The final Trap Difficulty number should be recorded for future use during game play. The Trap Difficulty will be the number that has to be rolled when interacting with the trap.

Determining the Final Trap Attack and Damage Modifier

The Attack and Damage Modifier for a trap is the same as the Trap Difficulty. EX: A Trap Difficulty of 33 would have an Attack and Damage Modifier of +33. A Trap Difficulty of 22 would have an Attack and Damage Modifier of +22.

This attack is against the Defense that matches the Power Discipline. If the the Power has two Disciplines it will target the lowest Defense of the target. EX: A trap that does just damage will have a Discipline of Combatant or Mystic. This means the trap will attack the targets Body Defense or Mind Defense, whichever is lower.

Now the trap is set. Here is what it would look like for a player and GM.

The image to the right has this trap placed in a hallway. The entire hallway is trapped with the pressure plates in the center. When a player moves to one of these Spaces with the pressure plates, the trap will go off.

If the player sets the trap they should draw it out and record it. If the GM put the trap in the hallway it should not be drawn out until it is explicitly detected.

 Tier 3 Character (9-12th Level)GM
TriggerPressure Plate in center 16 SpacesPressure Plate in center 16 Spaces
Where2×8 Hallway2×8 Hallway
Power  + Bonus Damage12d8 Damage in a 16 Space Area +35 Damage12d8 Damage in a 16 Space Area +28 Damage
Trap Difficulty3528
Trap Attack+35+28
DefensesCombatant or MysticCombatant or Mystic
Cost350GM’s don’t need cash!
DescriptionStepping on the pressure plate pops the pins out of the grenades left for our pursuers! The explosion rocks the tunnel and tells us our enemies are close behind.Stepping on the stone, you feel it sink beneath your feet. You begin to cry out but your cries are drowned out as those in the hallway are drenched in thick oil. Torches hanging in on the walls ignite it and burn everyone in the hallway!

Failure in Trap Setting

If a character attempts to set a trap but rolls below the needed Trap Difficulty number, there are several possible outcomes.

If the roll is failed then the player loses 25% of the cash required for the trap. They may attempt to set the trap again but first must purchase more “necessary materials”.

If the roll is Fumbled, a natural 1 on a d20, there is a catastrophic failure: it goes off on the player setting it. It may even affect players around them. The player takes all of the effects of the Power. All cash used on the attempt is lost. The area of the trap is affected in a way so no further trap can be placed in the same area. This can be remedied by using Crafting to repair the area, but Players should only worry about this if they survived the trap explosion and the embarrassment.

Tips with Traps

The same trap is used in this example. It is used in a few different ways.

The Atomic RPG System makes it so just about any Archetype of character can set and disarm traps.

Some might be better than others but ultimately players do not have to have play a “rogue” in the party to tackle traps. Since the Atomic RPG System opens this up it allows players and GM both to tackle them during their games.

Players don’t have to fear when traps are used and introduced. When they are used, everyone can participate in handling them. GM’s don’t have to be careful with traps or worry they are using them too much or too little. They can and should be a part of many Atomic RPG System adventures. With the simplified and expanded Atomic RPG System system, it should be a breeze for any player to use traps!

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