Hello All,

I am working on a Descent variant that would be closer to an RPG lite game then it is to the current dungeon crawl. i want to add in lots of character options and actions so that it feels somewhat like D&D, but with far less prep work

That being said, I need some help with dice probabilities. it has been many moons since I took a statistics class and I am just having trouble wrapping my brain around this. This is crucial for setting up proper defense and attack dice values at each level of monster.

Goal: Get the percentage chance of X hits occuring when rolling Y dice.

Example: What is the % chance of rolling 3 hits on a White and Yellow dice? What about on a White, Yellow, and Black? Etc...

Any help would be greatly appreciated,

Korvanus

What do you mean by "hit"? By the Descent definition, any attack with enough range and no "X" results is usually a hit, so if range isn't a factor, it's just based on the number of dice with "X" sides, and the number of "X"s per die. Broadening the search to common dice system terminology, a "hit" often refers to any single die whose result comes up greater than or equal to some threshold, as in, for example, Shadowrun's dice system. But I'm guessing you don't mean either of those, since the first is pretty trivial and the second doesn't make sense with Descent's special dice.

Regardless, most of the calculations you care about are probably very tedious to do by hand, so you'll probably find this spreadsheet to be a useful tool; it's got macros that will calculate the average number of attacks needed to slay a given foe with a given set of dice (and special abilities), plus a list of possible individual with probabilities for each, and it's designed to be fairly customizable. If you just want a probability table for all damage results for a given attack, you can simply match that attack against a high-health, zero-armor foe and check the cell comment after calculating. I created it for balancing monster and weapon stats in The Enduring Evil , and I think it did its job admirably. It may be of limited helpfulness if you're making fundamental changes to Descent's combat system, though, unless you're up to the task of reprogramming the macros.

Thanks for the quick reply Antistone. I will investigate your excel sheet, see if I can figure out how to adapt it to my purpose.

I guess I used the wrong terms in my previous post, let me elaborate a bit. I am looking to change the way the dice work for this RPG lite version of the game. The numbers on the dice represent accuracy (or to-hit), the hearts represent damage, surges will act similar to the way they do now, and the X will be used to determine critical hits (counts as 0 accuracy when calculating). All players and creatures will have a defense value that determines if they get hit (think armor class in D&D). If your accuracy is greater than or equal to you opponets defense your attack hits, dealing X damage (where X is the number of hearts). Essentially this performs both the attack and damage rolls at the same time.

The data I need to gather is the percent chance of hitting a target with X defense while rolling Y dice. Each cell would contain a number as the header column and a dice combination as the row header. Then the grid would be the % chance to hit given the dice rolled.

Example: When rolling one white dice you have an 83% chance to hit against Defense 1, 50% chance against Defense 2, and a 33% chance against Defense 3.

Example: When rolling one white and one yellow dice you have a 100% chance to hit Defense 1, 97% chance against Defense 2, 83% chance against Defense 3, 58% chance against Defense 4, 33% chance against Defense 5, and a 11% chance against Defense 6.

Hope this makes more sense,

Korvanus

Not the direction I would go if I were going to overhaul the Descent combat mechanics, but OK, here's what I suggest:

• Go to the "dice" sheet of the Excel file; this has tables listing the possible results for each die type and the probability of each. Replace the "X"s with zeroes; this will cause the macros to treat the X's as blanks, instead of making the entire attack miss (or enter in whatever bonus damage/surges an attack would normally get for rolling an X).
• Use the "Deflection" row (row 6) to input the target's AC; Deflection is an ability from The Enduring Evil that reduces the range on the attack (causing it to miss if it doesn't have enough range), so it basically already does what you want. However, the spreadsheet assumes that you're 1 square away, and thus already need a range of 1 in order to hit, so you should actually enter in one less than the target's AC, or you should give all attacks a +1 range bonus (or it's a one-line change to adjust the macro, if you prefer).

The spreadsheet should now effectively follow your combat mechanics, using "range" as accuracy and "deflection" as AC to determine whether attacks hit or miss. You can enter in whatever weapon and monster stats you want and see how much punishment they can take; if you mouse-over a cell after calculating it, it will tell you the probability of a miss, and the probability of inflicting each possible amount of damage.

If you'd really rather see the abstract probability distribution of different range results spread out across multiple cells, create a series of monsters with 1 health and an AC of 0, 1, 2, 3, etc. Calculate the results, which will tell you the average number of attacks you need to make before you score a hit (make sure the attack always inflicts at least 1 damage). Then, take the reciprocal of each cell (divide 1 by the cell's value) to convert that into a probability of a given attack being a hit (e.g. if it reports 1 attack required on average, that means a 100% chance of a hit, 1.5 attacks = 67% chance of a hit, 2 attacks = 50% chance of a hit, etc.).

Thanks Antistone this helps a lot!

I am curious, when a black/silver/gold dice rolls a 1/h, what does it count it as? range first, then damage? I was planing on using the 1/h as both range and damage. How would that affect the system?

Thanks,

Korvanus

If you want power enhancements to count as both range and damage, just edit the dice tables so that power dice have a "1 range and 1 damage" side instead of a power enhancement side. The macros get all their dice information from those tables, so anything you enter there will affect the calculations. (Just don't try inputing probabilities that don't add up to 100%.)

The macros will get range until they have the minimum needed to actually hit, then get damage (or in the case of surges, will spend them on piercing or whatever the attack's primary surge ability is set to). In some cases, you have the option of getting enough range either by spending surges or by spending power enhancements/sorcery, and calculating which is better is nontrivial, so the macros always spend surges last unless there's only one thing you can spend surges on.

After range, surges are spent on piercing (if possible) until the target's effective armor is zero, and then spent on the "main" surge effect defined for the attack (if any). You can define surge abilities like "1 surge for +1 damage AND +1 range", but you'll get weird results unless that's the only possible way to spend surges (if there's an option between spending surges on that or on Pierce, for example, the macro may get Pierce even if that causes the attack to miss due to range).

The macros will spend fractional surges if you allow it, so you can represent "1 surge for Pierce 2" by setting the surges-per-pierce cost to 0.5, and represent combinations like "1 surge for +1 damage or 2 surges for +3 damage" with "0.66 surges for +1 damage".

I made an RPG lite modification to Descent, but the combat system is something I left almost entire intact.

What I did add in was a class system with 5 classes (Warrior, Mage, Cleric, Ranger, and Rogue), and a Magic system that uses the fatigue for spellcasting. There's a a set of 20+ skills for each class and more than 20 spells for each spellcasting class.