rune math

Discussion of the RGS
Forum rules
No cyber-bullying, no racism, no spam! Keep discussions civil and respectful or you will be banned!
Post Reply
User avatar
raleel
Posts: 976
Joined: Sun Oct 20, 2013 11:53 pm

rune math

Post by raleel »

So, got a little bored.

https://docs.google.com/spreadsheets/d/ ... sp=sharing

a spreadhseet that shows the odds of getting a number of runes and morphing same colored ones. it wasn't quite as clear cut as a straight combinatorics thing, thanks to morphing, but not too bad
User avatar
raleel
Posts: 976
Joined: Sun Oct 20, 2013 11:53 pm

Re: rune math

Post by raleel »

Updated. Now includes the probability of success at wyrding 2-8 runes.

Short of it - it is REALLY worth it to get to wyrd 3. eliminates chances of failure. an even number of runes has a VERY high probability of getting (# of runes)/2 successes - over 1/3 on 8 runes, and increase chances as you get lower. going up from an even to an odd number shifts you up quite a bit.

Partially doing this because I want to be able to arbitrarily say a number of successes required and have a good idea of how well the PCs are going to do.
User avatar
andrew
Posts: 1250
Joined: Thu Apr 25, 2013 10:39 am
Contact:

Re: rune math

Post by andrew »

Nice work. Helpful for Norns who need to assess a challenge for their players.

Do you account for rune payments made for conditions like Shroud or Taunt? 1/4 runes played is extra punitive at 3 Destiny. I had a similar exercise done back in 2005 to make sure it's somewhat linear with some spikes at certain values. But the rules were also constructed with punitive elements at those spikes as well.
User avatar
raleel
Posts: 976
Joined: Sun Oct 20, 2013 11:53 pm

Re: rune math

Post by raleel »

Nope. Not currently. But it's still growing. I spent half an hour or so on it last night putting together the probabilities. It also doesn't take into account the void rune.

It also doesn't take into account the distribution of the rune colors in your pile. It assumes you have enough of the success color to be able to cover every option there - essentially, you have essence equal to 3x your destiny (enough of any color to draw your destiny in that color completely). Once this is adjusted for (downward, in most cases) it makes setting The difficulty at Destiny/2 a reasonably hard challenge for A lot of dwellers. Skill will matter, allowing just enough of a shift to compensate for a lack of natural ability (rune color distribution)

The rune morphing rules have an interesting effect of really impacting the floor on the number of successes. It pretty much eliminates it and reinforces the average strongly.
User avatar
raleel
Posts: 976
Joined: Sun Oct 20, 2013 11:53 pm

Re: rune math

Post by raleel »

Updated with the notion of an "advantage" mechanic as an experiment.

in 5e D&D, they have "advantage", which essentially means you roll 2d20 and take the highest. My thinking on a FOTN version would be "a second color gets you successes at the normal rate". In the case of my spreadsheet, red is what I pick for the normal success, and blue is the advantage ones. The effect ends up shifting the average number of successes up by 1-2 without changing the upper and lower bounds. This number increases as the number of runes you pull goes up. It also shifts the odds rather dramatically up... your chances of getting minimal successes is very small. This mirrors what it does in D&D, and right now I like it (doesn't mean that won't change)

to be done: disadvantage. Logically, this means "no color gives you successes, you must morph". This gives a very flat curve... essentially you get success equal to wyrd/2, round down, with a little alteration if you are at wyrd 3 and draw one of each. That seems a little predictable to me, though pretty easy to toss out there. I am not convinced I like that as much.

Another possible option is to cap the number of successes you can get from the declared color
User avatar
raleel
Posts: 976
Joined: Sun Oct 20, 2013 11:53 pm

Re: rune math

Post by raleel »

andrew wrote:Do you account for rune payments made for conditions like Shroud or Taunt? 1/4 runes played is extra punitive at 3 Destiny..
So, I added a column to the min/max/avg sheet to show the difference in averages. You are quite correct, shroud and taunt are quite punitive at 3 destiny. You lose half a rune worth of average there versus the other levels which is more like just a bit. Granted, this is less applicable, since you are not wyrding for successes against shroud and taunt (in my experience).

That 1/4 round up really impacts pretty fierce at anything less than wyrd % 4 = 0 (that % is the modulus operator for you non-CS people - it gives you the remainder). essentially, your "punitive spikes" are more frequent, because of that round up. It impacts 3 numbers per 4-rune set instead of 1 more strongly. If I come up with anything that I think is smoother in there, I'll move the conversation to house rules
Post Reply