Reverse Engineering D&D

[GBDeluxe]

Ok, someone mentioned in another thread how they would like to see a book entitled "Reverse Engineering D&D". Here is my first stab at the basic mechanics of the game. I think it's pretty much stating the obvious, but here it is anyway.

The d20 system is based on a 20 sided dice.
The base armor class for a character is 10
Classless characters would have a bonus attack of +0.

What does this mean? That two unskilled characters fighting each other without armor on, would each have approximately a 50% chance of hitting each other every turn. (on a d20 = 1-9 miss / 10-20 hit). The more armor or skill you acquire (levels) the better you become at attacking / blocking.

Anyway, everyone knows this. But I think it's the core mechanic of the game.

-GB

 

[Grazzt]

...have approximately a 50% chance of hitting each other every turn. (on a d20 = 1-9 miss / 10-20 hit).

-GB

Wouldn't that be a 55% chance of hitting each other?

 

[GBDeluxe]

Thats why I said approximate. You couldn't have exact 50%. unless if when you matched someones AC you had to roll again and had a 50% chance of missing / hitting.

 

[Ridley's Cohort]

More stuff...

An unskilled person has an approximately 50% chance to succeed at an "average" task.

An "average" person (Commoner 1) has an approximately 50% chance to resist the weakest magics.

The average damage by a thrust of the dagger (d4 damage) is the same as the average "health" of an average person.

 

[Staffan]

Thats why I said approximate. You couldn't have exact 50%. unless if when you matched someones AC you had to roll again and had a 50% chance of missing / hitting.

Sure you could. Since there's an even number of possible values on a d20, you can dedicate half of them to "miss" and the other half to "hit". This would mean that the base AC should be 11 instead of 10.

 

[pensiv]

if you're going to go that far to say that base AC should be 11, you might as well just change the rule to say that one has to roll above AC to hit, not at or above. Then AC could stay at 10 and you truly get a 50% chance to hit.

 

[hong]

0.55 == 0.5, plus a margin of error.


Hong "trust me, I'm a statistician" Ooi

 

[Balsamic Dragon]

I think it is deliberate, not only to have a round number (10), but also to give a slight advantage to the attacker (55% chance to hit).

Some other basic concepts:

Most actions that are taken by a character require a d20 roll. This roll will almost always by modified by a bonus/penalty that is derived from one of the character's six core statistics. The average commoner has a score of 10 in every statistic, which yields a bonus of +0. Once a statistic is tied to a certain type of roll, it will always be used for that roll. Game balance must be preserved by ensuring that each statistic is used in an equally important number of types of rolls.

d20 rolls, in addition to statistics, may also be modified by other abilities. These abilities are gained by achieving levels in classes. Each class offers some abilities that all characters of that class receive, and allows the player to choose other abilities from a designated list.

As a character gains levels, he or she also receives abilities based on character level, not class level. These abilities may also include increases in statistics.

Balsamic Dragon

 

[alsih2o]

i am not a mathemetician, but here is my take...

d20 stands for 'dollars, 20' and is the base price used for any product. hidden deep in the upc code on the back is how many and what fraction of a 20 dollar bill it will take to buy any given d20 product.

as any particular gamers collection of material grows, he stands a higher statistical chance of releasing more d20's to various companies. when enuf d20's have been spent the d can change into a symbol for Divorce, Debt collection, Dork or may others, probably 20 in all

 

[Ridley's Cohort]

I think it is deliberate, not only to have a round number (10), but also to give a slight advantage to the attacker (55% chance to hit).

I think it is deliberate to pick nice round numbers. Don't you think that standard DCs of 5, 10, 15, 20, are easier to work with than 6, 11, 16, 21?

That top end is important. They wanted a DC of 20 to be a standard number because it gives an unskilled person a small but realy chance of success. That is logical.

I also think that saying the AC starts at 10 has superficial similarity to 1e/2e, making the 3e more likely to be accepted.

Maybe the designers prefer 55% to 50% as you said. But methinks it is more likely these other issues were the deciding factor.