How to create dice rolls for multi-attacks in a custom tabletop RPG system

I’m working on a simple tabletop RPG based in a sci-fi universe. The rule set is very basic, since I’ll be playing with players with little experience and general tabletop know-how.

Most of it appears to be working fine, based on a test session. The only problem I’m having are attacks that hit multiple times.

Unlike most fantasy RPGs, you can wield weapons that fire e.g. 10 bullets in a single attack. For example, with an assault rifle, you can do a single shot, a short burst or hold down the trigger for fully automatic fire. Single shot is of course the most accurate, burst is less accurate and fully automatic is only accurate for the first few bullets.

I want to know how many bullets hit before calculating the damage. A normal attack roll is a normal 1d20 roll with modifiers against a DC (default 20), e.g. 1d20 + x has to be higher than 20. Afterwards, a damage dice is added for every bullet that hits, e.g. 1d6 for a single bullet, 2d6 for 2 hits, and so on. Characters can wear bullet proof vests that reduce the damage of every bullet, not for the full attack.

On one hand, I could add a "burst damage" and a "full auto damage" stat to the weapons, e.g. a weapon does 1d6 damage single shot, 2d6 burst or 5d6 full auto, but that makes full auto always the superior option, outside of the ammunition/reload mechanics.

I could roll every bullet separately, but that would result in a lot of rolls and/or calculations if I add modifiers to every roll. I thought about reversing it and making the DC DC - modifiers, and just rolling a d20 for every bullet, then counting all that are above the modified DC, but that also favors attacks with lots of bullets, unless I increase the DC for attacks with more bullets by some amount, though what should be the modifiers to achieve the expected result?

My current solution is to have players make a normal attack roll with the weapon specific maximum amount of bullets shot per attack type as negative modifier, and for every point above the DC, one bullet hits, up to the weapon specific number of bullets per attack type. For example, with a normal attack modifier of 10, a roll of 15 and a maximum of 3 bullets to hit with, the player could roll 2d6 for damage (15 (1d20 roll) + 10 (modifier) - 3 (max burst bullets) - 20 (DC) = 2 hits). This works, but it’s fairly clumsy and still favors full auto. I thought about increasing the DC of burst to 21 and full auto to 22, to reduce the effectiveness, but it still feels clumsy.

My intention is for single shot to be a safe and reliable choice, burst to be common and full auto to be high risk, high reward. How can I transform that into dice roll rules with a small amount of individual rolls?

Ideally:

  • With a high modifier (>15), full auto should have the highest expected damage per attack.
  • With a medium modifier (10-15), burst should have the highest expected damage per attack.
  • With a low modifier (<10), single shot should have the highest expected damage per attack.

Answers that use math to model the expected damage would be preferred. You can use 1d6 as damage per bullet, 3 bullets per burst and 6 bullets per full auto attack.

If a player rolls 33-34 on the wild magic table (maximize damage), what happens if they miss the target on the damaging attack?

On the Wild Magic Sorcerer’s Wild Magic Table, (PHB p.104), getting a roll of 33-34 results in:

Maximize the damage of the next damaging spell you cast within the next minute.

What happens if the sorcerer casts an attack roll spell that deals damage, and misses the target? I am being confused by the term "damaging." Is a "Damaging Spell" a hidden category of spell that can be cast, and thus means casting the spell ends this effect? or does the spell need to apply damage in order to be damaging, and would therefore need to hit for the effect to happen?

Can a Divination wizard in the Border Ethereal use the Portent feature to influence rolls of creatures on the Material Plane?

A particular School of Divination wizard is native to the Ethereal Plane (he was created by a wish spell replicating simulacrum cast on that plane).

While this wizard is in the Border Ethereal, can he use his Portent feature to affect the rolls of creatures on the Material Plane?

How can I add a seperate damage dice to my hombrew magic item so that it rolls two separate dice on beyond’s new dice roller?

Got curious for when my paladin reaches lvl 11/2 warlock and gets a permanent 1d8 divine smite all the time. My main weapon is magical gifted by my patron so im looking to see if it’s possible to add the extra dice as a feature so it’s properly displayed and usable in dnd beyonds dice roller feature. I can’t figure out the right combo in the magic item creation page.

A player rolls four 20-sided dice, takes the lowest value, ignores the rest. What is the probability of this value at least 7?

I’m designing a tabletop game, and I need to figure out how to calculate a few probabilities:

  1. Roll 3 20-sided dice, take the highest value. What is the probability of it being 7 or higher? 15 or higher?
    1. Roll 4 20-sided dice, take the highest value. What is the probability of it being 7 or higher? 15 or higher?
    1. Roll 3 20-sided dice, take the lowest value. What is the probability of it being 7 or higher? 15 or higher?
    1. Roll 4 20-sided dice, take the lowest value. What is the probability of it being 7 or higher? 15 or higher?

How can I do this? Could you explain to me how this works, or even better – give me a simple formula?

AnyDice — efficiency of code calculating rolls hitting a target with mixed pools; hitting the 5 second barrier

I have some code that is hitting the 5 second barrier;

function: target N:n of A:s B:s C:s {     result: [count {1..N, 1..(N/2)} in [sort {A, B, C}]] } output [target 7 of 4d12 0d20 0d8] output [target 7 of 4d12 2d20 0d8] output [target 7 of 4d12 4d20 0d8] 

Even if I remove the final output line, it still fails.

I believe the code does what I want it to – calculate the number of dice rolling at or under the target from mixed pools (it runs when using other pools: d20s seem to be a problem).

Is there anyway I can improve it so that at least the first two of these output lines will run (or better yet, all three of them)?

N.b. from my perspective these were some of the simplest pools I wanted to look at.

How do I determine the proper bonuses for my attack and damage rolls? [closed]

I am a half orc monk at level 14. I am using a homebrew gun called the demon of powder, which has 6 charges that it expends instead of regular bullets as ammo. My stats are 14 20 14 8 15 10 in order. in the description of the weapon it says i get +5 to both hit and damage rolls, but on dndbeyond it says i have +6 to hit and 2d8+6 for damage. My DM said that the regular damage for this is 2d8. I’m very confused where dndbeyond is getting the 6s from. Additionally, should i manually add in the +5 to hit from the description or is it already included?

Thanks!

Are lore rolls to detect magic automatic?

I know from reading the volume 1 rule book, that the presence of magic such as with trap-wards and ghosts (examples used as they are cited in the book), can be detected by a magic user rolling well on lore – however, I’m not sure on if the roll is supposed to be automatic or not? According to the rules of the system.

As in, if there is something like a magical trap set or a non-visible ghost present: by the rules, is the GM be supposed to automatically call for magic-users to roll lore to detect magic, or do the players have to decide themselves if they want to make a roll to check an area?

I’ve perhaps missed something somewhere in the book clarifying this.

How to model opposed rolls in Anydice?

I’ve seen there are quite a lot of brilliant people on this board answering questions about Anydice. I am hoping somebody will be kind enough to answer this one too.

I want to use anydice to figure out the probability of success with opposing dice rolls. For example, 1d6+1d8 (test roll) vs 1d10+1d4 (challenge roll). The challenge roll determines the target number. If the test roll meets or exceeds the challenge roll, the attempt succeeds.

How do I set that up in Anydice?

For anydice.com, is there a way to set a total number for three rolls?

I am very, very new to writing code and working on designing a RPG. As part of that, I am trying to do a simulation of three weighted dice rolls, ranging from 1-12 where I set the limit of how much the total of all three rolls can be. Meaning, I want to limit the total that any set of three rolls can give me to 12.

I am interested in the actual results of the dice and not just their sum so 3/3/3 is different from 4/4/1.

If the sum of the dice would be above 12 then the die making it go above 12 would be rerolled until this is not the case.

As an example:

  • If you rolled 5/5 on the first two dice, the third die would be rolled until it was either a 1 or 2.
  • If you rolled 1/1 on the first two dice, the third die would be rolled until it was a number 1-10.

I have the dice weighted according to the percentages I need. I just have no idea how to do the language to limit the total.

Here’s what I have thus far:

W: {  1:12,  2:14,  3:18,  4:18,  5:17,  6:8,  7:8,  8:1,  9:1,  10:1,  11:1,  12:1 } output dW 

Any help would be GREATLY appreciated!