D&D 5E Introducing the COUNTDOWN DICE Mechanic!

[Dausuul]

Those match what I got for 6 and 10. What did you use to get them? (I'm going to feel silly if I did matrix stuff for nothing ).

I threw together a Google Sheet which did the calculations for a given dice pool. For each round, I calculate the probability that you've hit zero, one, two, etc. dice on that round, based on the probabilities for the previous round. I ran it out to 100 rounds, which seemed good enough.

The probability formula involved is ugly. Your code looks a whole lot cleaner -- I'm not a statistician, I just play one on the Internet.

 

[Cadence]

I threw together a Google Sheet which did the calculations for a given dice pool. For each round, I calculate the probability that you've hit zero, one, two, etc. dice on that round, based on the probabilities for the previous round. I ran it out to 100 rounds, which seemed good enough.

The probability formula involved is ugly. Your code looks a whole lot cleaner -- I'm not a statistician, I just play one on the Internet.

In any case, it made me feel good that our numbers agreed

 

[Morrus]

Here's the average number of rounds and standard deviation for dice pools from 1 to 10:

DICE	AVG ROUNDS	STD DEV
1	6.00	5.46
2	8.73	6.13
3	10.56	6.39
4	11.93	6.54
5	13.02	6.63
6	13.94	6.69
7	14.72	6.74
8	15.41	6.77
9	16.02	6.80
10	16.56	6.82

Note that the standard deviation is very high, indicating a very wide spread. If you use this mechanic, be prepared for a lot of variation in your results.

Of course you can also play with different die sizes for faster and slower countdowns too.

 

[John R Davis]

Sounds just like the 'usage dice' ( which I'm a big fan off and have used in my publications).

 

[UngeheuerLich]

It is also called exponential decay. We use that to simulate radioactivity (I don't know all the correct English words).

The average remaining dice can be calculated with the formula:

Remaining-dice = Starting-number-of-dice * (5/6)^turns

Note, that with this formula you will never approach zero, as it uses a continuum instead of discrete numbers.

You can use the formula for the half-life-time and say: after 10 half-life times you are close to zero.

You can also use a treshold and say: if you get below < 0.5 you are done and use logarithm to estimate the rounds.

You can probably just look up a formula on the internet too.

 

[Cadence]

Of course you can also play with different die sizes for faster and slower countdowns too.

I think these are the results for mean and sd of number of turns using one to ten d4:

ndice mean standard deviation
[1,] 4.000000 3.464102
[2,] 5.714286 3.896623
[3,] 6.872587 4.065951
[4,] 7.741776 4.157531
[5,] 8.437008 4.215216
[6,] 9.016347 4.254849
[7,] 9.512926 4.283732
[8,] 9.947433 4.305713
[9,] 10.333662 4.323000
[10,] 10.681268 4.336953

 

[Clint_L]

It occurs to me that a jenga tower would work exceedingly well for this purpose as well, as in Dread. And adds the visual tension of watching the tower become more and more precarious. Plus some player skill, so it would be it's own mini-game.

 

[Stormonu]

It may make it a bit less dramatic though if the party jumps out of the tomb landing as a pile of bodies covered in spiderweb only to have enough time to get up and clean themselves off, rearrange their gear, and take a few potions and a 10 minute heal before the dungeon finally collapses.

Well, in that case you just assume that the round after the party jumps out that you rolled all 6's on the timer, ending it and having the dramatic collapse. Maybe the unused dice give the players extra XP or other benefits by expending them this way, giving them a bonus for being quick, decisive and a bit lucky or cautious.

 

[Charlaquin]

That’s really neat! I use a dice pool mechanic for tracking time and building tension, but it counts up in dice instead of down. But yours definitely seems better as a countdown to a specific event.

 

[Stalker0]

I have used this heavily in my current A5e game and have found it an excellent mechanic. I have often used it for threats over long period of time. For example, my current game involves a number of fey lords. Because their sense of time is very capricious, their activities are often random in time. Recently the party greatly angered one of them, so I set up a doom clock for retaliation. The fey lord is coming, but will it be next week....or 3 months from now? The clock adds that fun tension.

I also like the countdown clock combined with A5e's "Doomed Condition". Doomed is a status condition where the person is going to die, and simple "clerical healing" is not sufficient to save them. Now the core condition is "this person is going to die, no matter what" but what I have found more effective in my game is to add some plot way to save them, and attach a doom clock.

So the party must get the magical flower X to save this person, and the doom clock triggers once every day. Will the party get back in time to save the person.....we will find out!