Of Dice and Men

In my last post I talked about my first steps into Ryzom's world of Atys. Sadly I have not logged into Ryzom since last I wrote so I don't have the follow-up I said I would write. Instead I spent the weekend and Monday working and researching on project WOTAN. To blow off steam I played myself a rare game of Civilization 4 on a huge ring map on Prince difficulty ... and got stomped. I never was all that good at Civ, but oh well I still love that game.

What I want to talk about in this post is the dice system I have finalized for project WOTAN. While putting the finishing touches on the character system, I became highly unsatisfied with how the  DnD/GURPS hybrid I was creating was turning out in regard to stat progression and potential inflation. I am also now free to more finely develop the roll system for the dice.

Rolls and Skills

First, if you haven't read my previous posts on WOTAN or I wasn't clear (happens a lot), let me talk about the original system. It was based heavily on a GURPS-like 3d6 roll-under mechanic for use with a character system that ... I'm not sure that it is based on anything, the character sheet is sort of growing on its own accord, ameoba-like ... is based around unlimited skills and roughly 14 stats which are also determined with a 3d6.

So, for instance, your character (we'll call him Fang) has Strength of 15 and needs to move a large boulder. The boulder is pretty big but nothing amazing, so we'll set the difficulty at -3. This means to move the boulder Fang must roll at or below a 12 (15-3) on 3d6.

This is fine and all, and I could work controls into the character system to make sure point distribution is not abused (i.e. trying to roll initial 18s on as many stats as possible), but somehow for me it feels inelegant. And that might not be the best way to put it, but in trying to come up with proper skills in my system I was running into a brick wall.

Do I make a skill a modifier to a stat roll? Example: If Fang has a weightlifting skill of 2, then in the previous example he would need to roll 14 (15+2-3) 0r under. That would be the common-sense way to handle it. But then what about skill skills? If Fang also has a Dexterity of 17 but no sleight-of-hand skill (i.e. +0), could he still pull off a pick-pocket?

It doesn't seem logical as tricks, lock-picking or pick-pocketing are all greatly benefited from high Dexterity but require practice and instruction. Anyone can still basically move a big rock with no training if their physical muscle allows it, but can't necessarily pick a lock just because they have good hand-eye coordination.

I am at a loss somewhat because one thing I am very much set against is using modifiers based on stat levels. The old "12-13 +1, 14-15 +2, 16-17 +3, 18 -19 +4," et cetera. When I act uptight about using modifiers, this is what is causing it - I basically just dislike those for reasons which largely come down to personal preference and opinion.

image from Wikipedia

There are also some technical reasons for my not wanting to use this. For one I want to shy away from the use of signed operators (the + and -) in the code just because that is me. It's not a big deal and there will be some, I would prefer to not have to scale difficulty with ever-expanding negative-levels.

Also, and more importantly, I would like to avoid having to add in a special logical check to see if Fang has the skill needed to perform an action in the first place. This is not a huge deal, but it seems like there could be a more elegant way of handling it. But maybe not, this is something I am not confident I can avoid.

Probability Curves

While the six-sided die is the most common and can be found everywhere and the math of a 3d6 system is not that hard, at higher levels I think it becomes less easily-intuitive. For a computer this is not a problem, but sadly I suck at math and I am the one who is going to have to figure it out for the computer to run it in the first place.

The aspect of the 3d6 dice system that I want to preserve is the basic distribution of results -- a bell curve. Here you can see it plotted out on the AnyDice Calculator. Why is this important? You should read this article on dice systems - it helped me really refine my ideas and come up with the new system. You will see on that page that the outcomes for a dice roll on a linear system like a d20 will be more evenly distributed. In other words you have a much better chance of rolling a 20 on a d20 than you do of rolling an 18 on 3d6.

To me, at least, this makes the job of implementing both criticals and rare loot and random occurrences easier. If you want an item or occurrance or outcome to be "common" then assign the difficulty to the middle range, if "rare" then assign it to the fringes. The basic dice probability of the bell curve takes care of the rest.

Jumping in the Dice Pool

So I am basically satisfied with the 3d6 system as it stands except for two considerations:

1. I do not like how character stats are initially determined.
2. Character skills become more complex to implement.
3. I do not like the basic difficulty qualifier system as it stands.

What I have done is tweak the system more to my liking, and in the process changed to dice system, which I will call Xd10. The X is an integral part of my tweaking both afore-mentioned issues of mine, it stands for the fact I am now using a Dice Pool system. And if you didn't read the Darkshire link above or are not already familiar with dice mechanics, that means the number of dice rolled is a variable. A situation might require a d10 roll or even a 8d10 roll.

The reason I chose the d10 (it could have been Xd6 after all) is mainly out of mental laziness on my part - honestly, a decimal system is just far more intuitive to me than base-6. It is also has a higher granularity of outcomes - a 3d6 has 16 outcomes with 216 combinations while a 3d10 has 28 outcomes with 1,000 combinations.

The reason I have decided upon a dice pool system is primarily due to its easy and elegant ability to scale a character to a situation. The difficulty of an action is determined by number of dice in the pool. And therefore it also allows me to start every stat and skill at ZERO.

This also allows me to keep to one of my initial design principles which was to use as few modifiers as possible. A skill can be looked at as a specialized stat, in that while it might have a modifier it does not itself modify anything. This is a concept I want but am not wedded to.

What the dice pool difficulty scaling means for the character is that his stats and skills will grow organically over his or her life and I will be able to refine the leveling process to a fine degree. It will make it easier to make (i.e.) d10-level mobs and loot or 8d10-level versions of the same. I will likely address from the character's standpoint by dividing levels into tiers, where the tier level is the same as the number of dice the character will mainly encounter.

For progression, what I am planning at the moment (very basically) is that every character will start off with X stat points and X skill points, to be assigned as they wish - stats will begin at one and skills begin at zero. Lets say we give fang 20 stat points and 10 skill points, he now distributes his 20 stat points between 10 stats and if he is wise he will now have all stats in the range of 1-10 with a few key stats close to 10, a few non-essential ones near 1 and others somewhere in the middle - remember, he has 30 stat points total as all stats start at one. When he gains a level he will be presented with X new stat points (depending on whether I want lots of high levels or low levels) to distribute as he sees fit.

When designing obstacles for Fang, I will now keep in mind that a level 1 character is going to have 30 stat points, so I will design most of them as d10 difficulty with a few really hard ones at 2d10. This means that most of his stats are going to be between 1-10 and most rolls are going to need between 1-10 or less. A few will require between 2-100 or less, making the roll improbable but not impossible. And help Fang out a bit if he put all his points in one stat and has been having an extremely hard go at everything else not related to that one super stat.

Skills work in a similar way, except that they start at zero and you choose them for the character, where the stats are pre-determined standards for all. This also allows for easier customization on the GM end. It's just as easy to have either an archery skill, a laser rifle skill or both at the same time. Stat modifiers influence skills through the use of two skill levels:actual and virtual.  A skill's v-level is equal to the average of its actual level (the points you have put into it) and a governing stat. So if you are Archery level 5 and Dexterity level 15, your Archery v-level is 10. Likewise at later levels, if you are Archery level 50 but you neglected to build Dexterity and it is only level 10, your Archery v-level will only be 30. For almost all instances of skill rolling, the v-level will be what you are rolling on, so it will be important to define the key stats for your character and stick with them as he/she progresses.

A drawback of the system at this point is that a master archer could not shoot a rifle at all if he had never bothered to take an initial point in the skill. This arbitrariness and the skill/stat interaction are the current weak links in the system, but I'll be revisiting them when I am at the stage really fleshing out the various roll types. I am afraid I still may have to end up using a logical check for every single obstacle. Maybe that's not such a big deal and I'm just being anal.

To overcome the skill-exists logic check, I may have to define characters as already having every skill in game, but starting at level 0, which would effectively nullify "knowing" them all. So to specialize your character, rather than selecting skills to learn then upgrading them through points, you merely upgrade skills on a universal skill list. The end result would be mechanically identical but it would alter the player experience a bit. And if a game utilizes 100 or more skills, that could get too unwieldy.

Anyway, it's a cold rainy day here. Perhaps when I get a spare free hour I will revisit Ryzom. However, if I am going to make my January deadline, I suppose I should get in every minute of work I can.