My New Dice Probability Calculator

My favorite pen and paper RPG system is Silhouette by Dream Pod 9, which powers what happens to be my favorite RPG world, Heavy Gear. It’s a fast-paced, mostly elegant and rather gritty system, which is flexible in all the right ways.

Unfortunately Dream Pod 9 has been reeling for the last few years, and their last release of this system, SilCORE from 2005, isn’t exactly the shining beacon of perfection it should have been, suffering as it does from complexity issues and a severe editorial malnutrition.

Steve Jackson Games and DP9 are allegedly working together on a fourth version of Heavy Gear, but to my knowledge, nothing has come of this yet, and so Silhouette flounders.

However, the core system is still solid, and I just for kicks I like to play around with it in my sparetime. To do that, because of the way the system works, a probability matrix for the resolution mechanics is a must-have tool. I plotted around with the official one and found it to have some rather odd curves here and there.

So I built my own simulation system, SilProb and created my own damn matrices!

And good thing I did, as the official numbers on all the cinematic reality distortion levels have apparently been calculated using a broken bonus system.

Also, I’ll be lucky if anyone has read this far. It’ll be a downright miracle if anyone but myself finds this even remotely interesting.

PS: You may get ‘script slowdown’ issues in your browser. I’ll fix it if I can.

PPS: I would re remiss if I didn’t mention Morten Heiberg, who was kind enough to write me a small program a while back which allowed me to take the first meager steps into the wonderful world of probability simulations. But he’ll have to talk to my lawyer about that…

Update: – Nov. 8th, ’09 I’ve ripped out the brute force method from the JS and replaced it with an exhaustive trip through all possible combinations instead. It’s much faster and perfectly precise.

Update 2 – Nov. 11th, ’09: I’ve redesigned the results to make more sense as a tool for figuring out what it takes to hit a given target threshold.

Update 3 – Nov. 12th, ’09: SilProb v4.

7 Responses to “My New Dice Probability Calculator”


  • >Also, I’ll be lucky if anyone has read this far. It’ll be a downright miracle if anyone but myself finds this even remotely interesting.

    Oh, come on, you know I’m always one for obscure game mechanics and probability :-)

  • It’s all for you Løffetronics :)

  • I have no idea what you did – I’m just impressed that you made a simple form look so darn good.

  • Me too. On both accounts… :|

  • I expect this is all in preparation for a grand retort against my favouring D20+skill bonus rather than roll many, take highest?

    Bring IT!

  • Check mate bitch!

    Actually, it was in some way also born from that, but also I wanted to try and solve a few of the problems Silhouette have as well as understand it better. I concede that 1D20+mods is a very understandable and flexible solution; but there’s something beautiful about D6’s :)

    Anyway, it’s given me a taste for playing around with making a system of my own. Principally I would prefer to use Silhouette, if it wasn’t, if not broken, then at least chipped, in certain areas, and left for dead by its creators.

  • For those interested, I’ve updated SilProb to make it faster, better, stronger and tastier.

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