Design Spotlight: d100 Systems

Design Spotlight: d100 Systems
D100 Systems are everywhere. Some big names like Call of Cthulhu (the original Chaosium version) and (one of my personal favorites) Dark Heresy utilize a d100 (or 0-99) dice system for the core of their game.While the d20 system is generally more popular, this week's Design Focus is on d100 systems (aka "d-Percentile Systems")


The How To...
Generally you roll 2d10 with one representing the tens column and one representing the ones column. D100's exist, but generally you can use those two dice for other things. (Like skill/statistic rolls) Dark Heresy even inverts the numbers to determine what part of the body is hit!


"It's Fuzzy Math See?"
D100 systems have a very unique advantage over other dice sizes used for systems. They directly represent percents. Sometimes this is a boon when you are trying to design a system. Instead of relying on an average roll of 4/6 on a d6 to represent the odds "50%/50%" you can actually roll 50% on these dice.

It's nice for both you (the designer) and your players to be able to do quick math (or even no math at all) to figure out your percent chance of success or failure in a given situation. Since This generally makes it easier for younger players/inexperienced people to pick up a system quickly. 100 is easily divisible and most of the population can figured out fractions from 100. This is something d6 systems have a problem with. (For example; the average roll of 2d6 results in a total added value of 7)


Verity in Your Diet
2d10 can generate 100 numbers. (As most D10 have a 0-9 listed) I know this might be a little obvious but it is a overlooked factor. This is generally the highest you can get on today's commonly sold dice. (2d20 would be the highest... but a d40 system would be... unique.) What this means is you have a wider range to assign results. (Don't go crazy with this! It's a double edged sword!) For example: I hear a lot of d20 players complaining about critical misses on a d20 roll of 1. (It's a 1/20 chance to epically both whatever it is you are doing!) Some games fix this with a "confirmation" roll but d100s don't necessarily need that confirmation.


The Flip-Side
-Percents: When someone sees that they only have "33% Strength" it tends to be somewhat of a turn off because they know percents so well. (You might want to phrase it as, "33 Strength Points" or something similar.)
-Fuzzy Math: Sometimes ambiguity is a good thing! The fact that the average player doesn't know you're average damage for 23+6d6 is 44 is sometimes a good thing. They know it's "high" but they generally can't guess even in the ballpark!
-Verity: This is a double edged sword. Adding TOO MUCH can confused players. Keep in mind "Just because you CAN doesn't mean you SHOULD."
-Over 99: A common issue is rolling results (with modifiers normally) over 99%. Sometimes this doesn't make sense to players mind even though your math does. Anything "automatic" tends to be a VERY big deterrent to players. (They like to be engaged!)

Start Your Dice

Intro

Standard d-percentile (Players roll 10 sided dice. One is the tens column and the other is the one) system. You have stats (caped at below 50%) and your goal is to roll below your stat to hit.

Design Note: This system is similar to the one seen in Warhammer 40k’s “Dark Heresy” game only that you have to roll below your stat with a d100. I'm a big fan of this system due to the speed and flexibility of this little novelty. Thumbs up to them!

Dealing Damage

Your goal is to roll as low as you can. The amount you roll below your stat is the amount of damage you do. Weapons and other equipment provide a bonus to their related stats. (So a sword might add 10% to your melee stat.) While your stats are capped at 50%, your totals after equipment is not limited (until 90%). A hit scored causes your opponent to have to avoid damage.

Taking Damage

My goal in this game is to not use HP in the traditional sense. My attempts prior to this resulted in very deadly games but I think the system “Eldritch RPG” did it well. Players will be provided with a set of “Defense Options”. (Parry, Dodge, or Armor) A player accumulates uses of these based on their equipment (a sword might give you +2 Parry and your heavy armor might give you +5 Armor but -2 Dodge) The last use it to “take it”. This is a 50/50 chance to fall and a 10% chance to die. While I initially wanted the players to immediately die, I wanted them to have a feeling of dread when they roll that dice. (Observation: Any time a player has control over something they are generally more engaged. Taking away control removes them from the game a little bit.)

Design Note: Equipment is the focus of the game.

Defense Options

Parry- You parry an incoming blow. Next attack, if you attack them back you receive a +10% to your Melee stat.

Dodge- You dodge an incoming blow by motion. You move yourself 1 square as a result. (Utilizing a hex map so those pesky diagonals don’t get in the way!)

Armor- You take the damage against your armor, hopefully allowing you to get away unscratched. (Design Note: This is generally meant to be the most widely available.)

"Take It"- You take it like a little bitch, meekly attempting to shrug-off the damage as nothing more than a flesh wound. When you “take it” you roll a percentile. If you get 50% or lower you go unconscious. If you get 10% or less you die. Every turn you are unconscious you roll again, although death is at 25%.

Design Notes: The Defense Options was inspired in part by Eldritch RPG.

Options

Advancement: Universal Defense Pool

Each level you get 1 point to your “defense pool”. This means you can use it to do any form of defense once per day.

Design Notes: I am not sure if I want to add this. It may be a little too close to “HP” for me.

Advancement: Class-Specific Defense Pool

Each level you get 1 point to a predestine pool depending on your class.

Design Notes: You’ll lean quick I don’t like class systems in general. They are USEFUL but I really don’t like them.

Plot Hook

All Things Start Somewhere...
They say an artist should practice several hours a day every day so on this site that's what I plan to do. In the twisted bowels, hidden away in this little corner of the internet you will find my freak game gallery where I attempt to put up a game-a-week.


The PC's Hook
I LOOOOVE game mechanics.
I LOVE balance.
I LOVE the stench of min-maxing in the morning.
I LOVE hybridizing roles.
I LOVE taking a new take on an old concept. (Screw HP...)
I LOVE watching people play the games I make and smile.
I LOVE it even more when they don't notice a mechanic or a little bit of balance or it just flows so naturally that it is just "assumed".

SO!
That being said, I try to work as much as an artist every week to put out SOMETHING. Consider this little fragment of webspace my gallery. Every week I will put out something. In general this will be SOME form of game. It could be a design doc for a mechanics system. It could be some interesting new take on a situation utilizing Lore. Hell, once I sink my teeth into it, I might even put out an entire game systems!

Additionally I've played WAY to many games. WAY to many...
Questions, comments, flame wars, whatever... they are all welcome here so long as it's civil.


You seem to be a trustworthy fellow...
Well, I do happen to be a trustworthy and roguishly handsome fellow... but I am also currently a junior (ish) at the University of Advancing Technology in sunny Tempe Arizona and enrolled in their Game Design major. I have over 5 years DMing experience in various systems (including some of my own) and my passion is in game mechanics. I have lead various projects at my school (with various degrees of success...) and enjoy talking shop whenever possible.

Happy Gaming!
-Scott