Traps and randomness

One thing occured to me while I was reading the latest of the old-school threads, and the first post mentioned traps. Finding traps in D&D is rather non-random - either you have a good enough Search skill to find it, or you don't. The easy fix for this is to disallow taking 20 on traps - however, the problem with this is that the traps in the system are designed to allow taking 20 (which is why the DCs for finding them is infernally high - 20 or higher).

The easy fix for THAT is to drop the DC of traps. However, that leads to another issue - it SHOULD be easier to find traps if you take your time doing it.

So, I got an idea. What if you reduced the DC of various traps by 5-15, and allowed multiple Search attempts at a cumulative -1 penalty (-1 on the second attempt, -2 on the third, and so on). I tossed some values into a spreadsheet to determine the cumulative probability of detecting traps whose DC are X points away from your skill (rounded to two decimals - for X of 5 or less, it's rounded to 100%):

So, let's say that with the old rules you were up against a trap that was on the edge of your ability to detect: you needed a 20 to find it. You would automatically find it after 2 minutes of searching. If the trap had been 1 point harder to detect, you would automatically fail.

If you instead reduce the DCs by 5 (for example), a long inspection of the trapped object would give a total of ~70% chance of finding it - a pretty good chance, but no longer certain. Meanwhile, the trap that has a DC 1 step higher is now no longer impossible to find, but instead you have a ~40% chance of finding it (note the way the probabilities drop rather sharply).

So, what do people think? The main disadvantage I see with this is that it will make searching for traps take longer in real time, since you can't just say "I'll take 20 and search it everywhere" - you actually have to roll the dice. On the other hand, dicerolling is fun, so I don't see that as a problem

The main disadvantage I see with this is that it will make searching for traps take longer in real time, since you can't just say "I'll take 20 and search it everywhere" - you actually have to roll the dice.

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This is exactly what the "take 20" rule was designed to avoid in the first place. Rolling dice is fun, but rolling a die a dozen times just to accomplish one task is tremendously boring-- especially for the other players, who have to just sit there and watch.

If you want to make searching for traps more random, you can use a "take approximately 20" house rule, where searching for 2 minutes allows a roll of 1d8+15. This is not nearly as sure an option as the automatic max, but it still averages much higher than a straight d20 roll.

AuraSeer said:

...you can use a "take approximately 20" house rule, where searching for 2 minutes allows a roll of 1d8+15. This is not nearly as sure an option as the automatic max, but it still averages much higher than a straight d20 roll.

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Nifty, simple idea!

Tony M

I never thought that you could take 20 when searching for traps. The take 20 rule seems designed to bypass gobs of dicerolling where there is no penalty for failure. But in the case of traps I can see that there is a penalty for failure - at least in some cases. If it's a trip wire on the floor, then fail to find it on the search roll might mean that you spring the trap. It's not like you can just wander around that 5 ft square all day searching and never spring the trap.

So consider the case of a trap that isn't going to be sprung - for example a trap on a door that doesn't go off until the door is opened. I think in this case it's reasonable that repeated searches of the same area would not produce a different result - for the same reason that a people get _other_ people to proofread their papers when it's important. A rogue that has looked for a trap in an area and missed an important clue is more likely to miss the same clue a second-time around than another rogue with a fresh pair of eyes.

So in the case of repeated searches of an area, I would probably take the original diceroll and perhaps give a +2 circumstance bonus. If that doesn't find the trap, then you can assume that the rogue is just having a bad day.

AuraSeer said:

This is exactly what the "take 20" rule was designed to avoid in the first place. Rolling dice is fun, but rolling a die a dozen times just to accomplish one task is tremendously boring-- especially for the other players, who have to just sit there and watch.

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Unless, of course, that task is killing something?

If you want to make searching for traps more random, you can use a "take approximately 20" house rule, where searching for 2 minutes allows a roll of 1d8+15. This is not nearly as sure an option as the automatic max, but it still averages much higher than a straight d20 roll.

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I like this idea in principle, although I note that it allows you to roll a "natural 23"!


RC

Raven Crowking said:

Unless, of course, that task is killing something?

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If the single action is "kill something", then I stand by my statement. If the party fighter is stepping on an ordinary bug, or putting a dying ally out of his misery, I don't want to twiddle my thumbs while he rolls fifteen attack rolls. Just tell me that the target is dead, or that something special happened, and we can move on.

Note that this is why we have rules for CDG, the combat equivalent of taking 20.

I like this idea in principle, although I note that it allows you to roll a "natural 23"!

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Yep, that's intentional, because the OP wants to increase randomness. By the book, when some Joe Rogue takes 20 he will always find a trap with DC 25 but will always miss a trap with DC 26, with no variation ever. The house rule I posted is intended to make both those events uncertain.

If I didn't allow for rolls above 20, it would let him miss the easy trap without making it possible to find the harder trap. That'd clearly introduce a disadvantage without any corresponding benefit, and I try not to do that in my house rules. If you prefer to limit the roll to no more than 20, go ahead and use 16+1d4 or 14+1d6 or whatever else feels right to you.

AuraSeer said:

Yep, that's intentional, because the OP wants to increase randomness. By the book, when some Joe Rogue takes 20 he will always find a trap with DC 25 but will always miss a trap with DC 26, with no variation ever. The house rule I posted is intended to make both those events uncertain.

If I didn't allow for rolls above 20, it would let him miss the easy trap without making it possible to find the harder trap. That'd clearly introduce a disadvantage without any corresponding benefit, and I try not to do that in my house rules. If you prefer to limit the roll to no more than 20, go ahead and use 16+1d4 or 14+1d6 or whatever else feels right to you.

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I was giving some thought to this, and the idea that "Take 20" means essentially "the best you can do under the circumstances" allows for variable circumstances, and hence variable results. I also agree with you that the variable rolls maxing out at 20 serve only to disadvdantage the player taking 20...making her more likely to simply keep rolling. Your system gives some chance for a specific benefit that cannot be gained in any other way (making it more attractive to players), as well as adding a random element (making it attractive to DMs).

In other words, yoink!

RC

I don't allow pcs to take 20 if there's a trap- there is a consequence of failure.

Usually, they'll trigger a trap that way.

Staffan said:

One thing occured to me while I was reading the latest of the old-school threads, and the first post mentioned traps. Finding traps in D&D is rather non-random - either you have a good enough Search skill to find it, or you don't. The easy fix for this is to disallow taking 20 on traps - however, the problem with this is that the traps in the system are designed to allow taking 20 (which is why the DCs for finding them is infernally high - 20 or higher).

The easy fix for THAT is to drop the DC of traps. However, that leads to another issue - it SHOULD be easier to find traps if you take your time doing it.

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Have you ever thought of creating more difficult and challenging traps for the players?

This is one of the things that I don't like about the game mechanics. With things like traps, magical doors, and other such things that should take some certain cunning to get around are resolved with a simple roll of the die. Even if you didn't want to do that, you could impliment more magical traps.

Silmarillius

I have another solution: traps are usually boring, lame, and don't really make any logical sense. Use less of them.

There was a recent gameday game in Detroit where a random sewer grate (that the PCs happened to want to go through) was trapped with a deadly magical trap that reset itself. It was potentially a TPK and it made absolutely no sense why it should even be there. I wasn't in that game, but I overheard it, and I got a full report later from a friend of mine who was. :\

I'm not a big fan of traps. Having some at certain points in the adventure where it really makes sense is fine, but IMO, traps are way overused in D&D in general. Putting traps in places where you can't take 20 is more of an adventure design rather than a rules fix, but it also addresses your issue, and if you use less traps, it's also an elegant solution. Otherwise, if traps are used less, I think the rules to cover them are fine.