A new player arrives to play in your campaign. They are a big fan of Magic the Gathering. They do not have d20s with them but instead plan to use spindowns. Do you care or is this an issue in your mind?
A spin down die exaggerates results bias from manufacturing defects - on a regular d20, one side might be favored more than others, but that side has a mix of different numbers on it, so you will still get a range of different results. For a spin down, numbers are sequential, so that weighted side could result in clusters of similar numbers. In all likelihood, the actual effect on gameplay is probably fairly negligible.
That said, if someone shows up to my in-person game with a spin down, I am just going to lend them an extra full set of dice. As a bit of a dice dragon, I have plenty they can borrow and would rather they have a full set of every die they might require.
That said IRL i haven't played a game with a countdown, but I have tracked rolls with them to my content and haven't seen a big swing in rolls compared to a "regular" d20 what ever that is.
Personally as a DM I wouldn't die on this particular hill, and would go with the if it consistently rolls with a particular bias, then the die is not welcome at my table no matter its design or material.
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CENSORSHIP IS THE TOOL OF COWARDS and WANNA BE TYRANTS.
Agreed with Caerwyn_Glyndwr, though if for some reason I didn't have spare dice (I usually have 2-3 sets in my bag after a string of games I ran where I kept forgetting to pack dice), I'd probably allow it but make sure to bring extra dice in the future so the player can roll.
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Jander Sunstar is the thinking person's Drizzt, fight me.
Note that even a regular d20 is fairly easy to cheat with as long as you're hand rolling, and if you're using a dice tower or cup it won't make much difference.
Spindown dice are easier to roll in a way to give you consistently high or low results.
True, but most people don't have the necessary skill, and wouldn't think to try it anyway. IMO, it's not a big deal unless there's reason to suspect shenanigans.
Spindown dice are easier to roll in a way to give you consistently high or low results.
True, but most people don't have the necessary skill, and wouldn't think to try it anyway. IMO, it's not a big deal unless there's reason to suspect shenanigans.
A lot of people don't even know they're cheating, they just have a habit that has turned out well for them. If you don't roll dice pretty vigorously, they will be quite substantially non-random. If you just pick up your dice that may mean consistent patterns, if you habitually align your dice in a particular way in your hand it will be a consistent area of the die.
So the difference is that spindown has similar numbers next to each other rather than the more mixed normal d20?
In theory, I'd be fine with it. Random is random. However, in practice, it would feel pretty coincidental that they didn't have a normal d20, which are common, and had this special version that would be easy to cheat with. My regulars almost certainly would never do - accidentally or otherwise - so that would imply that this is a new person. That combination is sketchy as anything to me. While I wouldn't chalk it down to cheating, I'd hand them one of my sets, I pretty much always have at least five sets with me and normally only need two, so it's never a problem to lend couple of sets out.
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If you're not willing or able to to discuss in good faith, then don't be surprised if I don't respond, there are better things in life for me to do than humour you. This signature is that response.
I'd just give them a cup. I dunno if it's called a cup in English? You know, a little beaker you pop your dice in, and then throw it. Good enough.
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Blanket disclaimer: I only ever state opinion. But I can sound terribly dogmatic - so if you feel I'm trying to tell you what to think, I'm really not, I swear. I'm telling you what I think, that's all.
I'd just give them a cup. I dunno if it's called a cup in English? You know, a little beaker you pop your dice in, and then throw it. Good enough.
Yeah a dice cup.
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If you're not willing or able to to discuss in good faith, then don't be surprised if I don't respond, there are better things in life for me to do than humour you. This signature is that response.
Spindown dice are easier to roll in a way to give you consistently high or low results.
True, but most people don't have the necessary skill, and wouldn't think to try it anyway. IMO, it's not a big deal unless there's reason to suspect shenanigans.
A lot of people don't even know they're cheating, they just have a habit that has turned out well for them. If you don't roll dice pretty vigorously, they will be quite substantially non-random. If you just pick up your dice that may mean consistent patterns, if you habitually align your dice in a particular way in your hand it will be a consistent area of the die.
The mechanics needed to get consistently skewed results out of a spindown are way too deliberate to happen by accident.
So the difference is that spindown has similar numbers next to each other rather than the more mixed normal d20?
Yeah. Makes it easier to use as a life tracker in Magic.
In theory, I'd be fine with it. Random is random. However, in practice, it would feel pretty coincidental that they didn't have a normal d20, which are common, and had this special version that would be easy to cheat with. My regulars almost certainly would never do - accidentally or otherwise - so that would imply that this is a new person. That combination is sketchy as anything to me. While I wouldn't chalk it down to cheating, I'd hand them one of my sets, I pretty much always have at least five sets with me and normally only need two, so it's never a problem to lend couple of sets out.
If the new person is new to RPGs, why would they have a d20?
In practice, they'd have to be lent the rest of the dice. I'd only find it suspicious if they had a full set of dice with only spindown 20s. Also, if they were planning to cheat, why would they mention that their dice are spindowns? Who inspects their players' dice?
In my experience, a d20 Is one of the first things people get. It's the most ubiquitous dice. I've yet to have to lend my dice to anyone, despite introducing quite a few people to D&D and even TTRPGs in general. They just go out and buy them.
I've never even seen spindown dice, and had to Google them to find out what they were. I'd notice that the numbers were different if someone played with them. While I wouldn't be looking for it, I'd notice that the adjacent numbers were different.
As for skewing the dice...it wouldn't necessarily have to be accidental. My wife very frequently rolls that exact same number as the previous person did with the dice (we often share). I highly doubt it's intentional because it's not just the "good" numbers - if I roll a nat1, she's just as likely to roll a nat1, as she would a nat20 after I rolled one. The shape of her hands and technique as well as she picks up the die obviously lends itself to getting similar results to what the die displayed before picking it up. With a d20, the numbers next to each other are highly variable, so if it doesn't quite land on the same side, it'll be different (eg if it was a 20, it's likely to become a 2, 8 or a 14. Spindown dice are likely to become a 13, 16 or a 19).
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If you're not willing or able to to discuss in good faith, then don't be surprised if I don't respond, there are better things in life for me to do than humour you. This signature is that response.
While I wouldn't say I've spent a lot of my life thinking about dice, there are two periods where I did; my second year physics lab thesis where I built a machine to study real-world mechanical randomises (a machine that flips coins and rolls dice), and my dice making hobby. Finally, I work in an industry that handles not just probability a lot, but also things like volatility and other metrics of random number behaviour over large sets. As such, I have a fairly good grasp on the probabilistic theory of dice, as well as the practical aspect of their physical properties.
1. Perfect Dice
If we took two perfect twenty-sided dice, one a typical distribution and one a spindown distribution, and rolled them a gazillion times, we'd get the exact same distribution of values. Each number would have a 1/20 chance of coming up. Remember, we're talking about a purely theoretical, perfect dice. The distribution of the numbers across the face of the die will not influence which numbers come up because each face will come up an equal number of times.
2. Imperfect Dice
The next scenario is where we have the same two d20s, but they're not perfect dice but real, physical dice. They have slight variations in their surface, distribution of mass, micro bubbles, etc. These imperfections, as well as those of the environment the dice is being rolled in influence the outcome of the dice. However, the system is so chaotic that the influence is still largely random. But sometimes an imperfection or collection of imperfections can create a subtle bias towards a certain orientation. This is where the advantage of a standard distribution of face values comes into play.
Say you have two dice that both bias towards an orientation centered on the value 15. On a typical d20 the immediately adjacent values would likely be 7, 5, and 12. These values average out to 9.75 and give a fairly high volatility (range between high and low possible values on a given outcome). This means even if the die favours that orientation, there is still a range between 5 and 15 in terms of values, and the average is lower than the biased face.
However, a spindown is very different; the adjacent faces to 15 are 16, 14, and 6. This gives a higher average of 12.75 and while the volatility is still quite high at the min and max, it is skewed towards 14/15/16. A die biased towards this orientation would roll consistently higher than a standard layout. This issue only gets worse if you have a die biased towards the 20 orientation, with adjacent values of 13, 16, and 19, compared to 2, 8, and 14.
But does this matter? Typically, no, as dice very rarely have a meaningful orientation bias. What I mean by a meaningful orientation bias is a trend towards a certain orientation that will present itself in a statistically valid way over the reasonable course of a sample size. Let's say you only have a single d20 and you play D&D once a week, every week, no exceptions, for 50 years. Your session lasts 4 hours each week and you roll a d20 on average once every 3 minutes, or 20 times an hour. You will roll that die 208,000 times, which may seem like a lot, but in the scope of statistical analysis that's small potatoes. In my work, we run simulations in the order of tens of millions to get the minimum viable expectation values. You are simply not likely to roll a dice enough for a natural bias to meaningfully affect your D&D game
3. Weighted Dice
You're cheating at this point, all bets are off, be gone with ye!
A new player arrives to play in your campaign. They are a big fan of Magic the Gathering. They do not have d20s with them but instead plan to use spindowns. Do you care or is this an issue in your mind?
A spin down die exaggerates results bias from manufacturing defects - on a regular d20, one side might be favored more than others, but that side has a mix of different numbers on it, so you will still get a range of different results. For a spin down, numbers are sequential, so that weighted side could result in clusters of similar numbers. In all likelihood, the actual effect on gameplay is probably fairly negligible.
That said, if someone shows up to my in-person game with a spin down, I am just going to lend them an extra full set of dice. As a bit of a dice dragon, I have plenty they can borrow and would rather they have a full set of every die they might require.
Just loan or give them a d20 is my vote.
That said IRL i haven't played a game with a countdown, but I have tracked rolls with them to my content and haven't seen a big swing in rolls compared to a "regular" d20 what ever that is.
Personally as a DM I wouldn't die on this particular hill, and would go with the if it consistently rolls with a particular bias, then the die is not welcome at my table no matter its design or material.
CENSORSHIP IS THE TOOL OF COWARDS and WANNA BE TYRANTS.
Agreed with Caerwyn_Glyndwr, though if for some reason I didn't have spare dice (I usually have 2-3 sets in my bag after a string of games I ran where I kept forgetting to pack dice), I'd probably allow it but make sure to bring extra dice in the future so the player can roll.
Jander Sunstar is the thinking person's Drizzt, fight me.
Spindown dice are easier to roll in a way to give you consistently high or low results.
Find your own truth, choose your enemies carefully, and never deal with a dragon.
"Canon" is what's factual to D&D lore. "Cannon" is what you're going to be shot with if you keep getting the word wrong.
Decent explanation of spindown dice and their flaws: https://diceenvy.com/blogs/news/what-are-spindown-dice-what-makes-them-different-and-why-does-it-matter
Note that even a regular d20 is fairly easy to cheat with as long as you're hand rolling, and if you're using a dice tower or cup it won't make much difference.
True, but most people don't have the necessary skill, and wouldn't think to try it anyway. IMO, it's not a big deal unless there's reason to suspect shenanigans.
A lot of people don't even know they're cheating, they just have a habit that has turned out well for them. If you don't roll dice pretty vigorously, they will be quite substantially non-random. If you just pick up your dice that may mean consistent patterns, if you habitually align your dice in a particular way in your hand it will be a consistent area of the die.
I can not see why a normal die could not be configured just like a spin down die and still hold to the 20-1 rule.
I’m another vote for a loaner. Or a dice rolling app on their phone. There’s plenty of free ones.
So the difference is that spindown has similar numbers next to each other rather than the more mixed normal d20?
In theory, I'd be fine with it. Random is random. However, in practice, it would feel pretty coincidental that they didn't have a normal d20, which are common, and had this special version that would be easy to cheat with. My regulars almost certainly would never do - accidentally or otherwise - so that would imply that this is a new person. That combination is sketchy as anything to me. While I wouldn't chalk it down to cheating, I'd hand them one of my sets, I pretty much always have at least five sets with me and normally only need two, so it's never a problem to lend couple of sets out.
If you're not willing or able to to discuss in good faith, then don't be surprised if I don't respond, there are better things in life for me to do than humour you. This signature is that response.
I'd just give them a cup. I dunno if it's called a cup in English? You know, a little beaker you pop your dice in, and then throw it. Good enough.
Blanket disclaimer: I only ever state opinion. But I can sound terribly dogmatic - so if you feel I'm trying to tell you what to think, I'm really not, I swear. I'm telling you what I think, that's all.
Yeah a dice cup.
If you're not willing or able to to discuss in good faith, then don't be surprised if I don't respond, there are better things in life for me to do than humour you. This signature is that response.
The mechanics needed to get consistently skewed results out of a spindown are way too deliberate to happen by accident.
Yeah. Makes it easier to use as a life tracker in Magic.
If the new person is new to RPGs, why would they have a d20?
In practice, they'd have to be lent the rest of the dice. I'd only find it suspicious if they had a full set of dice with only spindown 20s. Also, if they were planning to cheat, why would they mention that their dice are spindowns? Who inspects their players' dice?
In my experience, a d20 Is one of the first things people get. It's the most ubiquitous dice. I've yet to have to lend my dice to anyone, despite introducing quite a few people to D&D and even TTRPGs in general. They just go out and buy them.
I've never even seen spindown dice, and had to Google them to find out what they were. I'd notice that the numbers were different if someone played with them. While I wouldn't be looking for it, I'd notice that the adjacent numbers were different.
As for skewing the dice...it wouldn't necessarily have to be accidental. My wife very frequently rolls that exact same number as the previous person did with the dice (we often share). I highly doubt it's intentional because it's not just the "good" numbers - if I roll a nat1, she's just as likely to roll a nat1, as she would a nat20 after I rolled one. The shape of her hands and technique as well as she picks up the die obviously lends itself to getting similar results to what the die displayed before picking it up. With a d20, the numbers next to each other are highly variable, so if it doesn't quite land on the same side, it'll be different (eg if it was a 20, it's likely to become a 2, 8 or a 14. Spindown dice are likely to become a 13, 16 or a 19).
If you're not willing or able to to discuss in good faith, then don't be surprised if I don't respond, there are better things in life for me to do than humour you. This signature is that response.
While I wouldn't say I've spent a lot of my life thinking about dice, there are two periods where I did; my second year physics lab thesis where I built a machine to study real-world mechanical randomises (a machine that flips coins and rolls dice), and my dice making hobby. Finally, I work in an industry that handles not just probability a lot, but also things like volatility and other metrics of random number behaviour over large sets. As such, I have a fairly good grasp on the probabilistic theory of dice, as well as the practical aspect of their physical properties.
1. Perfect Dice
If we took two perfect twenty-sided dice, one a typical distribution and one a spindown distribution, and rolled them a gazillion times, we'd get the exact same distribution of values. Each number would have a 1/20 chance of coming up. Remember, we're talking about a purely theoretical, perfect dice. The distribution of the numbers across the face of the die will not influence which numbers come up because each face will come up an equal number of times.
2. Imperfect Dice
The next scenario is where we have the same two d20s, but they're not perfect dice but real, physical dice. They have slight variations in their surface, distribution of mass, micro bubbles, etc. These imperfections, as well as those of the environment the dice is being rolled in influence the outcome of the dice. However, the system is so chaotic that the influence is still largely random. But sometimes an imperfection or collection of imperfections can create a subtle bias towards a certain orientation. This is where the advantage of a standard distribution of face values comes into play.
Say you have two dice that both bias towards an orientation centered on the value 15. On a typical d20 the immediately adjacent values would likely be 7, 5, and 12. These values average out to 9.75 and give a fairly high volatility (range between high and low possible values on a given outcome). This means even if the die favours that orientation, there is still a range between 5 and 15 in terms of values, and the average is lower than the biased face.
However, a spindown is very different; the adjacent faces to 15 are 16, 14, and 6. This gives a higher average of 12.75 and while the volatility is still quite high at the min and max, it is skewed towards 14/15/16. A die biased towards this orientation would roll consistently higher than a standard layout. This issue only gets worse if you have a die biased towards the 20 orientation, with adjacent values of 13, 16, and 19, compared to 2, 8, and 14.
But does this matter? Typically, no, as dice very rarely have a meaningful orientation bias. What I mean by a meaningful orientation bias is a trend towards a certain orientation that will present itself in a statistically valid way over the reasonable course of a sample size. Let's say you only have a single d20 and you play D&D once a week, every week, no exceptions, for 50 years. Your session lasts 4 hours each week and you roll a d20 on average once every 3 minutes, or 20 times an hour. You will roll that die 208,000 times, which may seem like a lot, but in the scope of statistical analysis that's small potatoes. In my work, we run simulations in the order of tens of millions to get the minimum viable expectation values. You are simply not likely to roll a dice enough for a natural bias to meaningfully affect your D&D game
3. Weighted Dice
You're cheating at this point, all bets are off, be gone with ye!
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