Blindsided by Math

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I feel like total crap.

I could blame my sleep apnea, but the truth is, someone started talking about odds of rolling dice in a game and I went against my better judgement.

The premise involved permutations and custom dice and I tried to walk away from it...

So now that all of the hubbub is over, I can edit the post that was due earlier today.

Still. D12 dicepools are still enticing...

D20 + D10 Blurb

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Thanks to KJDavies for the link in his weekly roundup. Specifically, he linked to my mechanic for using roll under d20 + d10 for a skill check.

Here is a graph for your consideration:

I graphed the three mechanics mentioned in the post. Basically it shows that results above 21 begin to show diminishing returns. In other words, once a character achieves a score of 25, the benefit of pushing on to 30 is not so large an advantage.

One thing I haven't done yet is to look at this mechanic's effect on combat. Maybe it is tradition for me that I don't want to go into that direction. I'd like to say something at the beginning of Andras to the effect of this:

d4, d6, d8 and d10 are used for damage
d12 is used for initiative and surprise
d20 is used for combat
d20+d10 are used for non-weapon proficiency or special abilities. (Use a d30 if you prefer linear probabilities.)

Believe me when I tell you that if I could incorporate a d24, I would. 🙂

Next up, a crystal magic wielding rival for the Fire Primordials on their own plane and a look at the Water Primordials.

Odd Mechanic

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I was working on a random way to give my kids some very simple addition subtraction problems. I will admit that I am thinking a bit far in the future as we really haven't covered subtraction yet.

That being said, I am a fan of the d4-ized d6 featured at the Dice Creator store. I am saving up for one of these. I love the possibilities that come the fact that it has more than one number on its face.

When I first saw it, I realized that it could make a great randomizer simply by concatenating the numbers rolled. Last night, though, I had some crazy idea to combine the d4ized-d6 with a Fudge die and an LCR die. (It kept me awake for half the night.) The Fudge die would tell you to subtract, concatenate, or add. The LCR die would tell you what other number on the face to compute with. For example, if you rolled a 6 (meaning that the 6 is on the bottom), the Center number would be the upside-down 1 above the 6. The Left and Right numbers would vary, but let's say for the sake of argument that the Left number is a 2 and the Right number is a 5. Left+Add would produce 8. Right+Add would produce 11. Center+Add makes 7. Left+Subtract gives you 4, Center+Subtract gives you 5, Right+Subtract produces 1. Left+Concatenate makes 62. Center+Concatenate makes 61 and Right+Concatenate makes 65.

You get the idea.

Yes, you can get negative numbers. The range produced goes from -5 to 65. Believe it or not, the median roll is a 7. In a roll-under system, the chances of rolling a 7 or less are about 55%.

Here is the spreadsheet with my analysis.

If, by some odd stretch, someone decided to use this mechanic in a roll-under system. It does allow for a natural "diminishing returns" feature.

Say for example that a system has a skill system rated by points. A Skill score of zero still gives you a 16% chance of success. Once you get up to a 7, you have a better than 50-50 chance of success. You're above a seventy precent chance of success at 15. After that, though, it's slow going to get a lot of progress. You break an 80% chance of success at a score of 34. To get above a 90% chance happens at a skill score of 52.

Critical successes? Roll a -4 or -5. Critical Failure? 61 or better.

Would this work in an RPG? Maybe not. It requires some getting used to. I think it might be better for a sports simulation sim, like American Footbal, for example. These kind of fiddly rolls happened in Paydirt. The results can emulate all kinds of tables, like Second Season Football. (I own both of these, by the way.)

Anyway, there's my odd mechanic idea that kept me awake last night. Enjoy!