I'm going to assume you have no issue coming up with traps along the lines of creating mechanics for Cube.
So your issue is "There's not really an individual to contest the roll against"
So you want to know how to set the difficulty, for non-contested actions.
Difficulty Modifiers
Standard Practice is in world of darkness, rolling a success means you succeed.
There is usually no difference between one success and two successes, except if it is a exceptional success.
to allow for difficulty, the GM should ask the player to roll appropriate skill at -X.
Take a look at page 122 of WoD.
Most tasks involved in traps that are meant to be solved, would be between -3 — +3. Difficulty modifiers are restricted to between -5 — +5.
Where -5 is for almost impossible. I recommend saving those -5s for if something is not really intended (by the God Machine's plans) to be removed -- but it is intended by your plans to be removed.
If appropriate rolls can be retried at -1 cumulative penalty.
Dramatic Failure
The difficulty penalty is a important mechanic as it allows people to be forced to a chance die -- which gives the chance for a dramatic failure -- things could literally blow up in there faces.
Without a dramatic failure, by RAW, you basically could not accidentally set of the trap.
You might like to, for more danger associated with failing, bring in a houserule to make dramatic failure more likely.
- The GMC way of awarding XP for a player choosing to dramatic fail, probably doesn't get the right feel across -- it adds safety.
- I suggest something along the lines of: "If you fail, and more than 3 (or all) of the dice, show 1s, then it is a dramatic fail"
- Page 222 of Mirrors suggests several variations on this -- and is generally worth a read if you are interested in messing around with the skill mechanics.
Degree of Success [Houserule]
As a common houserule, some skill checks that have well graduated degrees of success, may have varying required number of successes.
For example: Say your players were rolling Wits+Investigation to take a look for traps.
- 1 Success: Something is up with the door, not sure exactly what, but there is some wires leading away from the frame.
- 2 successes: You can work out the wires are attached to some kind of device in the the door handle.
- 3 successes: looks like that is plastic explosives. +1 to the check to deal with them.
- 5 successes: You notice a second much smaller set of electronics in another part of the room, looks like this isn't a trap but a recording device. You are being watched.
If using this, I recommend it only for things that have a clearly varying degree of success. Also remember that each success required beyond the first, is equivalent to making a -3 to the dice pool. So requiring 3 successes, it equivalent to putting the roll at a -6 penalty -- very harsh. Even when using graduated successes, getting 1 success should never get you nothing.
Extended Action
An extended action is for a roll that will:
- Take a while
- Have varying degree of success
- be possible to keep chipping away at to do better.
Every extended action has 2 Parameters to set:
- Required number of successes
- Usually between 5 and 20
- It could have multiple values as described above
- You have a maximum number of rolls equal to number of Skill dots + Attribute dots (before penalties)
- Time per roll
- Most of the time, once you have a extended action, if the character is reasonably skilled he will get it, sooner or later
- That is where the time comes in
- In an extended action there is a time per roll.
- And running out of time brings the tension
- "The clock on the wall reads 10 Minutes, til the room is filled with deadly neuro-toxin. It is 2 minutes per roll to try to hot wire the electronic doors"
Team work rolls.
Don't forget Teamwork rolls -- they can be done on extended as well as normal rolls.
Once participant (Generally the one with the best dice pool, if possible), is the Primary Actor.
The others are secondary actors. The secondary actors roll the dice pool to do the action.
They count there number of successes.
The primary actor then rolls the dicepool, with a bonus equal to the number of successes the secondary actors got.
You are with-in your rights as a GM to restrict the number of seconary actors.
It might make sense when hacking a computer to have 1 person looking over your shoulder to make sure you don't miss anything.
It is not so reasonable to have everyone in the party all "Helping".
A common house rule is to use different assist dicepools,
eg When building something,
the Scientist character might roll as assist with a Int+Science to make a good plan.
The Body-builder might roll assist with Stregth+ Crafts, because he isn't doing the main job he is just bringing stuff into place (you might give him a penalty and there is only so much manual labour can help).
The Technician as primary actor brings the stuff together and rolls the Dex + Craft to do the welding, getting bonus dice from the assistance of the secondary actors.
A primer on the skills for interacting with traps
You might like to call for some of these rolls, as any of the above types of actions.
Often in these circumstances the appropriate roll will overlap.
If you think it is just as valid to use either, then let the player roll there higher pool.
If you think a knowledge of both is requires, make them roll the smaller.
Some of these rolls you may want to do as extended.
Some your might want to use varying degrees of success.
- Wits + Composure: A quick glance — what is obvious
- Wits + Investigate: A search roll
- Wits + Science: Identifying chemicals by smell
- Int + Science: Work out how something works; "Ah it is triggered by magnetism. We can get through if we leave all out metal equipment behind"
- Int + Investigate: Logic out what the trap does, indirectly.
- Int + Larceny: hack a electronic security system
- Int + Computer: hack a computer system
- Dex + Larceny Pick a lock or similar, carefully remove trap
- Dex + Athletics: Dodge around the pressure plates/Lasers
- Strength + Crafts: Leaver this pile of old heavy planks into a bridge across the pit of acid.
- Dex + Crafts: Construct a clamp that will hold the tripwire in place after we cut it, so that we can drag our wounded though.
- Int + Wits: Pure and direct thinking
- Wits + Dex: Reflexes
