The Impossible Dream

Resolution Mechanics I

by Hunter Logan
Mar 11,2003

Resolution Mechanics I
The Impossible Dream Installment #4
by Hunter Logan

Intro

Thus far, I have talked about play flow, balance of power, and player goals. This time, I want to move on and talk about something near and dear to most every designer's heart: Resolution mechanics.

Resolution mechanics are the means for getting things done in the game. When a character searches a room, attempts to run the gauntlet, or negotiate a contract, resolution mechanics determine what happens. This is a monster topic, so I will present it in two parts. The first part will cover the Three Means of Resolution.

The Three Means of Resolution

The Three Means of Resolution are loosely based on Jonathan Tweet's three means of resolution as presented in the Everway RPG and as modified by Ron Edwards in his many RPG theory discussions. Tweet's terms are Drama, Fortune and Karma. Edwards also uses them, though he applies slightly different meanings. I mention Tweet's terms as reference, but I've got my own take on them. To avoid the great onus and inertia of history, I'm not using them. I'm using the terms Chance, Ability and Intent. This is the way I conceptualize the Three Means.

Chance is random determination of what happens. Roll dice, draw cards, flip coins, and look at the results. They are random and subject to the laws of statistics. Dice are a common and popular method of generating random results in RPGs. I like dice because all dice have similar characteristics in the way they generate numbers. Here are some examples.

• A single die generates a linear curve. Roll a d20 and you have a flat 5% chance of rolling any particular number. You have the same chance of rolling a 1 as you do a 10 or a 20. When you change the number of sides on the die, you change the flat percentage chance and the range. Roll a d12 and you get a range from 1 to 12 with an 8% chance of getting a particular result. Roll a d10 and the range is 1 to 10 (or 0 to 9) with a 10% chance of getting a given result. Roll a d8 and the range is 1 to 8 with a 12-1/2% chance of getting a given result and so on.
• If you roll several dice and evaluate the result on each die independently, the curve for each die is still linear.
• Rolling a pair of dice and adding the results generates a bell curve. For example, you may roll two 6-sided dice and add the results. This produces a range of results from 2 to 12. At the extremes, the player has about a 6% chance of getting a 2 or a 12. In the middle, he has about 17% chance of rolling a 7. The actual result is random, but the player has a 28% chance of rolling 2 to 5, a 44% chance of rolling a result from 6 to 8, and a 28% chance of rolling 9 to 12. Clearly, the middle is favored.
• Rolling a pair of unequal dice also generates a bell curve. Rolling a d6 and a d4 and adding the results produces a range from 2 to 10. At the extremes, the player has about an 8% chance of rolling a 2 or a 10. In the middle, he has about 20% chance of rolling a 6. He has about a 23% chance of rolling 3 to 4, a 54% chance of rolling a result from 5 to 7, and a 23% chance of rolling an 8 to 10. Again, the middle is favored.
• As you roll more dice and add the results, the bell curve becomes flatter at the top with a greater chance of generating an average value and a far smaller chance of generating an extreme value. Rolling 3d4, for instance, produces a range from 3 to 12. A player has about a 3% chance of rolling either a 3 or a 12, a 15 % chance of rolling 3 to 5, a 69 % chance of rolling from 6 to 10, and a 15 % chance of rolling 10 to 12. Again the middle is strongly favored with a 1-in-3 likelihood that the player will roll either a 7 or an 8.


• Dice can be manipulated to tailor their function.



• Curved Results: The player rolls dice, but the actual result is curved. For example, the designer may have the players roll a single d10, but the die roll may actually produce results from ö3 to +3. Here's one way it could work.
  
  

  Curved Results

  Die Roll	Result
  1	-3
  2	-2
  3-4	-1
  5-6	0
  7-8	+1
  9	+2
  0 (10)	+3



• Exploding Die Roll: The player rolls the dice and rolls again on a designated result. The result of the next die roll is added to the first. For example, the player rolls a d6. On a 6, the die "explodes." The player rolls the d6 again and adds the result to his total. So, the player could roll a 6 then roll a 4 to get 10.
  
  If the die roll is open-ended, this goes on as long as the player's die rolls meet the condition for explosion. A player might roll 6, 6, 6, 6, 2 and get 26 off the die roll.
  
  If the die roll is closed, the player gets a fixed number of additional rolls (usually just one). This way, a player might roll a 6 and another 6. He gets 12.
  
  There is a fault with this method of rolling dice: Some numbers may drop out. In the preceding example, it's actually impossible to get 6, 12, 18, 24, and so on with an unmodified die roll. The counting goes ·4, 5, 7, 8· It's possible to mechanically work around that, but I think the d10 provides a more elegant solution. The d10 is numbered 0 to 9. If you count the 0 as 0 and 9 as the maximum value, your numerical progression will always be very smooth. If a player made an open-ended d10 roll, he could possibly roll 9, 9, 9, and 0 to get 27.



• Counting Victories: The player rolls one or more dice. Each die is evaluated separately to generate a number of victories. The more victories the player gets, the better the outcome of the character's action. For example, a player might roll 4d6 and evaluate the results against a target number. Say the target is 2. If the player rolled 1,3,5,and 2, the player would get 3 successes. If the target number had been 4, the player would have only 1 success.



• Mass on Target: The player again rolls one or more dice. This time, the results are tallied to produce a really big number. Well, the player hopes it's a big number. The device is usually die roll vs. target. For example, the player might roll 3d10. If the player rolled 3, 5, and 8, his result would be 16. Of course, rolling dice this way greatly increases the chance of getting a mid-range value.



• Many More Possibilities: I am the first to admit that the examples and ideas I've presented here barely scratch the surface of what you can do with dice, but I think these are the basic building blocks. You can mix and match these methods to your heart's content.



• A Good Article: As it turns out, Shannon Appelcline recently wrote a very good article about the nature of random chance.

Ability is deliberate determination of what happens based on the capabilities of the character. If the character has the skill, if the character has a resource such as hero points, or if the character has a built-in capability that allows him to do certain things, the player can use this Ability to resolve an event.

• Using skill to resolve an event: Skill is usually based on character attributes or skills. Frequently, a character with a low attribute or skill will only be able to do simple, little things with that attribute or skill. A character with a high attribute or skill will be able to do amazing things. If the character's attribute or skill is too weak, the character will fail. If the character's attribute or skill is sufficient, the character will succeed. It's that simple.
  
  For example, a character has a skill, Fencing 5, where '0' is untrained and '10' is the best on the planet. The character gets in a duel with an opponent who has Fencing 7. Using ability alone, the character with Fencing 5 will lose every single time.
• Using a resource to resolve an event: Resources are expendable units of success that the player can spend during play. They are finite. Once used, they're gone, though the player may have the opportunity to earn more. A resource like Hero Points may temporarily improve character skill to ensure success. The player spends the points to get the desired result. A resource like Victory Cards may provide the character with instant victory. The player plays a single card and gets the desired results. For more thoughts on this, I refer you to Eric Brennan's wonderful article about Hero Points.
• Using a built-in capability: Capabilities often work with no muss or fuss because the rules say so. A character may have the ability to cast certain spells or to do certain things without any chance of failure. The player says the character is doing it and the character does it thanks to Ability.

Intent is resolution based on what a player wants to happen in the game. The player makes a declaration. The declaration becomes a mechanical device for resolving events.

For example, a group of characters surrounded by enemies, running low on ammunition may make their last stand. Before the end, a player declares, "·And the cavalry arrives in the nick of time, distracting the enemy and giving us the chance we need to escape." The GM allows this to happen because it's in the spirit of the game. But nothing is free, so the GM replies, "The cavalry assault breaks the enemy line, but they take very heavy casualties. It will be a long time before they can help you again."

Using Chance, Ability, and Intent

The three methods of resolution are seldom used in isolation. A resolution mechanic is rarely Chance, Ability, or Intent alone. The process for resolving events almost always includes a combination of Chance, Ability, and Intent, especially Chance and Ability.

Consider this common resolution mechanic:

• Player declares character action.
• Chance and Ability: Player generates a die result using Attribute + Skill + Die Roll vs. Target Number. The player must roll over the TN for the character to succeed.

Here, Intent is a qualifier. If the GM determines the player wants the character to do something easy, the TN will be low. If the GM determines the player wants the character to do something really difficult, the TN will be much higher. Then, the die result is a combination of Chance and Ability. The character's attribute and skill are both Ability. Small numbers mean the character has little ability. Large numbers mean the character has lots of Ability. Naturally, the die roll is Chance. I have a lot more to say about all this, but that will fill the next installment. As always, thanks for reading.