Role-playing game help

[hunterjwizzard]

So I'm not sure if I am posting in the right place, but I am designing a tabletop role-playing game, and am looking for some assistance with a to-hit mechanic. If you're familiar with Dungeons and Dragons, it's like that, wherein you roll dice to add some random elements. I've been through several iterations so far and am hitting a wall in terms of a mechanic that scales appropriately with level and keeps the character's stats relevant. Essentially, I need to find a balance between "entirely random" and "the dice are completely meaningless".

The core mechanic of the game centers around using percentage dice(two ten-sided dice that when rolled give you a number between 0 and 99), then adding a bonus to the role derived from various values assigned to the characters. This is then compared to a static "defense" value, if it's higher, the attack hits. This system needs to scale with character level as the character gains bonuses and things.

I would like attacks to be successful around 70% of the time. Unfortunately, math has never been one of my strengths, so inventing a system that works right but also scales has been extremely challenging. I'm hoping I can get a few ideas.

Thanks in advance!

 

[lev888]

A few examples would help. Different levels, etc.

 

[Cubist]

Sounds like an interesting project!

I recommend having a go at writing down an equation for the probability of winning an attack. Keep it simple initially (see * below). To help with this you can start off by stating your variables, for example...

Let "d" be the random dice throw, range 00 to 99

Situation variables...
Let "a" be the player's attack ability, range 0 (useless) to 100 (Chuck Norris)
Let "e" be the enemy's defense ability, range...

Output...
"p" is the probability of winning a single attack, range 0 to 1

etc

Then write down some simple aims in bullet points
- p should be approx 0.7 for the scenario when a=e (since in these games the hero usually meets stronger enemies just after getting a power up)

Then write your equation p=<whatever!> and check it (maybe come up with some test scenarios, each with different values for your input variables?).

* - Later on you can break your variables down into more detail, eg. "a" is made up from a function of weapons "a_w", skills "a_s", current health "a_h" - with their own defined ranges. You could write a function a=f(a_w, a_s, a_h) - and if "a" still keeps its original range then your top level equation can remain unchanged/ correct.

 

[Cubist]

I recommend having a go at writing down an equation for the probability of winning an attack. Keep it simple initially (see * below). To help with this you can start off by stating your variables, for example...

A hint to help you calculate "p", consider the range of values of "d" that would result in the player winning versus the full range of "d"

 

[krimzondeleeuw]

A hint to help you calculate "p", consider the range of values of "d" that would result in the player winning versus the full range of "d"

Yeah, that sounds like a good plan to me.

 

[hunterjwizzard]

So sorry for orphaning this thread! Wildfire season, am I right?

Anyway, here's the basics of what's going on:

A player-character has a series of stats and skills that provide various types of bonuses to roles. Whenever they want to do something(attack an enemy, open a lock, etc) they roll percentage dice, then add the appropriate bonuses.

To play around with this, I rolled percentage 100 times and mapped it on a spreadsheet, then ran some equations on it. What I came up with is that the total bonuses need to add up to about 40 in order to ensure that, at least 70% of the time, the player is successful. There was probably an easier way to figure that out, though.

I'm still fine-tuning the bonuses. The reach challenge is the system has to scale as the character levels, but not allow for broken min/maxing at the start.

Thank you all, I've got a good start!