Indie Designer's Journal #8 Pondering Basic Dice Mechanics

In this episode we take a look a few common dice mechanics and how the can be applied to a design, including roll-over, roll-under, dice-pools, and more!
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[@Tysto]

The advantage Gary Gygax saw in a d20 for D&D is that it can simulate a percentile roll in chunky 5% increments. That way, small bonuses and penalties are meaningful, but the math remains easy. And a percentile roll is easy to control for the designer, because you always know that boosting the target by 1 makes it 5% harder to achieve. By contrast, if you try to add bonuses and penalties to multiple dice, like 3d6, you shift the bell curve, radically changing the player's chances of success.

[@Alkis05]

The problem is that investing in a skill shouldn't progress linearly. Investing more time and energy into developing a skill should have diminishing returns. They tried to make up for that by the first rank increase giving you +4 instead of +1, but that is not a very good solution. Anyway, for combat, which is what people is going to be doing most, it really doesn't matter because in the end, it turns into a bell curve, because you have to hit an opponent multiple times to kill him. Or you have multiple enemies to kill. You rarely make a single dice roll in a combat encounter.

[@SchizoidPersonoid]

Adding dice actually flattens the curve. 2 dice has the steepest peak.

[@jasonglover6615]

You are correct. That is because the number of outcomes increases. I think I was focused on how difficult the extremes would be to hit. Rolling all 5 dice and getting all ones would be extremely rare, but rolling two ones rolling 2d6 is hard, but happens fairly often. Thanks!

[@captainnolan5062]

At 5:09 Your roll of "6", when you were trying to "roll under" a strength of 3 to lift the rock was not a success, it was a failure.

[@matthew_thefallen]

I think you just converted me to the pool dice mechanic 😂 thank you for all the tips!

[@SchizoidPersonoid]

There are roll under systems that make you "more successful" the closer you roll to the target number (mainly used for opposed/contested rolls) with critical success for rolling the target number exactly. With bell curve systems like 3d6, you can make one of the dice a different color - or even all three dice different colors - and have the total value of the roll determine success or failure while the different color dice each represent some additional information, packing a lot of information into a single dice roll. The Savage Worlds roleplaying system has your attributes represented by die types (d4, d6, d8, etc.) where you improve the attribute by upgrading the die you roll for it while the target number is always 4.

[@jasonglover6615]

I am a big fan of using different color dice in a single roll. I used this in an earlier episode having the player roll 2d12 (each a different color). One die represented the hero and the other the enemy. If the hero die was higher, they dealt damage equal to the difference of the two die (+ modifiers) and the same was done if the enemy rolled higher. In addition the value on the representative die determined hit location. Lastly, you subtracted the two dice from each other to see if the enemy had a reaction (flee, rage, etc). It was a fun system from the designer's perspective, but honestly was just not super fun as a player... Different sided dice for different abilities is one I should have talked about. Maybe in a future episode. Thanks!

[@wishmeheaven]

Thank you very much for another great video, and for sharing your thoughts with us.... I feel a little bit guilty of not contributing some ideas of my own (..I don't have any..) but I really appreciate what your doing and I found your insights quite fuscinating and inspiring, and I'm truly appreciate it a lot. (Even if nothing will come out of it eventually, yet - Nothing is being taken for granted..)

[@goodjessehobbies]

Ive never had the bell curve broken down like that for me, so awesome.

[@thirdtake3770]

Do you have a longer video regarding dice system? This video was great! I am curious about other systems since I want to create a story driven game with dice mechanics.

[@galinor7]

Percentile dice games: Runequest, Pendragon, Warhammer, Call of Cthulhu, Chill. Most gamers I know use 2d10 of different colours, one for the tens and the other for the units. In every game for over twenty years my groups have always used Red for tens. Everybody knows the house rule and there is never any confusion. The dice are numbered 1 to 0.

[@GarthKauffman]

Great video. Just stumbled upon your video and plan to watch them all. Thanks!

[@Elric54]

"Talking about dice, I lose my mind a little bit." - I hear you, brother. lol

[@Alkis05]

ok, why I never heard of this subtracting one dice from the other thing and taking the absolute value? That is really useful. Thanx

[@MansMan42069]

I've been writing a wargame ruleset recreationally for nearly a decade and I had the most fun coming up with the dice mechanisms. I didn't like the maths that come in when numerical modifiers have to be added or subtracted after a roll, but I still needed a way for different situations to affect how likely someone is to succeed or fail at a task. I eventually settled on a roll under system where the die used changes with the difficulty of the task. The base is always a d10, with modifiers affecting the tier of difficulty and die sizes changing accordingly. With the maximum value of a stat being 5, the dice ranges would be the following: d4: Trivial. Impossible to fail if you're master at your craft (5) or really really good (4). Several factors have to come together to make a task trivial, almost stars aligning levels. d6 d8 d10 d12 d20 d%: Borderline impossible.

[@mattgreenbean]

I can't point to a specific game, but I feel like there could be discussion on this mechanic; roll # of dice to see if you hit, roll # of dice to see how much damage. Commercial plumber? I'm a mechanical engineer. I'm one of those chair-sitters that never go in the field.

[@geoffreychance9770]

One of the most fun dice systems I've played with in an RPG is the one in Savage Worlds. It's a lot to explain but I'll give it a go. You roll two dice. One is always a d6, one varies d4, d6, d8, d10, or d12. This dice reflects your skill level or attribute score. You're typically aiming for some target number, say 5 or more, on one die. Beating the target by 4 (so 9) is then considered an excellent result. On top of this the dice "explode" meaning if you roll the highest result, you roll again and add to the result. This led to a character of mine acing a skill check they only had a d4 in by constantly rolling 4s. The total at the end was a 21, far exceeding the target number. This is the really exciting part of this dice system.

[@dougbass]

Jason, thank you for your videos. After watching this one, it occurred to me that I have played games combining the dice pool system with the roll-under system. For example, in some block war games like Richard III, a block with a strength of 4 would roll 4 dice and might hit on a 1 or 2. Another block, with a slightly lower strength (perhaps injured) but higher accuracy or skill, might only roll 3 dice but hits on a 1 - 3. I see you released several more videos in the past few days, I look forward to watching them, and thanks again!

[@jasonglover6615]

That sounds interesting. Great way to handle groups of troops or enemies. Thanks!

[@northernlight8857]

I am a little too fond of vids on dice mechanics. Is this my path to Carcosa?

[@kidneythief6227]

Great video. I like your systems 2d6 minus each other but I found my brain works 1/2 speed when subtracting.

[@CH-fp6gj]

There is a great free online dice probability calculator

[@torymiddlebrooks]

Which one are you referring to?

[@DiomedesRangue]

@@torymiddlebrooks Not him, but anydice is good.

[@BanjoSick]

A board is abstract and about using mechanics, while the theme is just veneer. RPGs are concrete and simulate reality, the mechanics are just a tool.

[@drcfungis2045]

J. The kid(17) and I are enjoying Banners. Good strategy game. I like when you battle longer , it gets harder to hit your enemy (energy level) depending on what weapon you use. I like your design and Spires end. It involves thinking. Skip an attack and recover energy. J, checkout Spires End.

[@jasonglover6615]

I have watched a few videos on spires end and I will likely be utilizing a bit of their combat system in Underquest.

[@justawhim]

But doesn't it also depend on how you read the results? Like how you can get a d100 by rolling 2d10s. Or a 1d12 with 2d6. Or a 1d4 with 2d6 by dividing the numbers into 4 equal groups

[@siriushelldog6771]

Welp, 2d6 gives a result between 2 and 12. And 2 dices will give you higher avg. result then 1d12

[@hachu3_hachu4]

clacking mouth noises. please stop them

[@andynonimuss6298]

As a society, we are already conditioned to higher numbers being better. Even in RPGs, higher attribute scores mean stronger attributes. Roll-under systems are therefore counter to our natural expectations toward higher rolls. If you told me a high skill score is GOOD and a low skill score is BAD... it then becomes counter when you are saying (in a roll-under system) a high number on my roll is BAD and a low roll is GOOD. Roll-under systems force counter psychology of GOOD and BAD. A roll-over is more natural as high attribute scores are GOOD and high dice rolls are GOOD. Most games, whether RPGs or board games, reward high rolls, not low. Gamers naturally associate high numbers with "positive" results. A d20 being static is a bad system, as it is too random over a high number range. This is why everyone calls the d20 "too swingy". A bell curve with three dice creates too strong of a bell curve. A subtract-the-results of a two-dice system creates uneasy math. Most people are better at adding than subtracting. Based on my extensive research of dice psychology, I disagree with every die system you like in this video.

[@jasonglover6615]

The point of the video was not exactly to state any system is better than the next. Some games use a few different systems. I think is a game that has the player grow slowly over a long period of time (D&D), that a roll-over makes sense, as players will slowly increase stats over time. I do like roll-under in board games or quicker games, because it often removes a target number. I can try to push open a wedged door by rolling under my strength with a static dice. No need for the door to have a target difficulty and you have to roll a die and ad your strength to it. I think both have their place. Roll-under does have its place. I really do like roll and subtract. I totally understand that people get addition much easier than subtraction. Rolling 2d6 and adding does create a nice bell curve and I do love it. I do not consider 2d6 and subtraction as creating uneasy math. Rolling a 1 is easier than rolling a 2, and rolling a 2 is easy than rolling a 3, etc. This creates a nice pyramid. Rolling doubles can be used for special effects or misses. I do completely understand what you are saying, and generally I am not a fan of static dice rolls. I do think that each system has their place.

[@andreazanon5995]

Interesting. What die system would you recommend then, Andy?

[@andynonimuss6298]

​@@andreazanon5995 In dice psychology people are drawn toward dice feel. Most prefer a less sharp die to roll, so a sharper die like a d4 and d8 are the two dice people disfavor the most. There's also the rolling time to consider. A longer rolling time helps increase the anticipation and excitement level. Again people disfavor a d4 and d8, because the rolling time is too short. A d6 is an ok die, but a d10 and a d20 have longer rolling times. A d20 by itself is too swingy. The best dice with good roll times and non sharp edges are the d10 and d20. The best die system, to replace a d20 is 2d10.

[@andreazanon5995]

@@andynonimuss6298 I came to some of the same conclusions while pondering dice mechanics for an RPG I am writing, but yours is still some great insight, so thank you a lot. You speak like you have studied the subject academically, where can I read more about dice psychology?

[@andynonimuss6298]

@@andreazanon5995 Unfortunately, there is no single good source for Dice Psychology. It's only what I have read, collected, and experienced myself over 35 years of RPG gaming. Writing a game system is a very challenging task. I've been writing my own system now for a few years and of course, using 2d10.. he he! Set aside time to write a little every day and you'll be there before you know it. Best to you in your writing and system journey!

[@antonioroldan3707]

First, a nice tool to have in case you want to pin it in the description: a Dice probability calculator: anydice.com/ Second: thanks for this great content! Third, some thoights on dice mechanics: they are great! And manipulating the number of dice too. Let's say you have 3 ability; that can mean you use 3D6, or 1D6 + 3, or 3D6 + 3, or that you need 7-3 = 4 or higher on 1D6 (like in Warhammer 40k), or you get 3D6 - enemy's stat Y and the enemy has XD6 - 3... Another interesting one for the enemy: a level 3 enemy will throw 3D6 on the first attach, 2D6 on the second, 1D6 on the 3rd and onwards, because they are getting tired. This can also use modifiers: 3D6 + 3, 2D6 + 2, 1D6 + 1, then 1D6 + 0 if still standing, for example; the hero will receive a great hit first but later they can better manager their resources (energy, strength, will...) if the combat gets long Tying it with dice-pool mechanics: ability of 3 = throw 3 dice, and you need at least 7-3=4 -> so a higer ability has 2 rewards: 1 more die, and also 1 more result that works (as an ability of 4 lets you throw 4 dice, needing 3). This can be useful for an ability that is very hard to improve (high cost, high reward) while other abilites just let you modify a +1 on a die, or recover 1 more health or whatever (low cost, low reward). Maybe leveling up (to compare it to Iton Helm: completing a level+defeating the boss) grants you +1 on this great ability, while minor stuff (getting a new Skill will trigger an extra reward)

[@SchizoidPersonoid]

I tried to mention anydice but youtube kept autodeleting my comments. Is it because I didn't include https?

[@jasonglover6615]

Great stuff! I especially like the part where you mention the enemy getting weaker (tired) as the battle moves on. I will have to think on that a bit. Currently, I am using the d6-d6 system that I love so much and used in the past. This time it works quite a bit differently. An enemy will have 6 different reactions on their turn ranked 0-5). You roll 2d6 and subtract the results. In this way rolling a 5 will be quite difficult and rare and likely result in the player getting hit hard (strong physical attack or a nasty magical effect). Rolling a 1 will be common and likely a weaker attack. Rolling doubles will cause the enemy to "power up". You will place a skull token on them. At a certain threshold (maybe three skulls for a particular enemy) they will unleash a super devastating attack or other effect depending on the enemy (they could simply attempt to flee). I think it will be a fun system. I could have enemies have ranks (1-3 or something). Level 1 enemies would add add 1 to their first attack, while level 3 would add 3. This modifier could decrease by one each round like you mentioned. Hmmmm I will think on that. Player characters will work the same, but the weapon they are using (Sword, Wand, Bow, etc.) will determine the outcome of their d6-d6 result. Right now I have weapons having a prerequisite to use them (a Long Sword might require 2 Brawn and a lightning wand may require 4 Mind). However, I could scrap that and simply have the player add their ability score their roll results during combat. So a character with 2 Brawn swinging a Sword will get to add 2 to their dice results (example: Player rolls 2d6 with results of a 2 and 3 for an outcome of 1. They get to add their ability score to the result 1+2=3). I will have to think on this some more. Thanks for the great comment.