February 28, 2010

To Percentile or not

Filed under: Games — Tags: , , — bilbo @ 9:26 pm

One of the big things worrying me about Iridium Version 2 is that it is all standardized on percentile. So, unlike V1 where you had percentile for skills and d20 for combat/stats you now have percentile for everything. I am torn. I made the split originally as a sort of easy short hand. I saw no need for combat to have the % breakdown, steps in the 5% range were fine. However, I have had enough customers mention that they want a “standardized” system that uses one sort of dice, either d20s or %. For me, it had always been no biggie since conversion was easy enough. Now, some of the more refined pints might run into trouble with conversion back and forth. I really like how the system has been stream lined and is a very nice system with the conversion to % though out.

Still, I have to wonder, am I throwing the baby out with the bath water. Any thoughts?

Here is the V2 rules as they currently stand.


  1. I don’t get your objection, Bill. If you were going from percentiles to d20, then indeed some of the finer points might get lost – I had to deal with that in IHWSC – but going from a coarser to a finer scale, fine points don’t get lost.


    Comment by clash bowley — March 1, 2010 @ 9:11 am

  2. Let’s see if I can be clearer. If you design a system to have 3% gradation then convert to d20 scale then back again, you have lost that 3% gradation. You could just have independent systems sitting next to each other but then you run into problems with characters/NPCs/foes, any fixed object that utilizes a fixed format. Some folks would most likely not see it as a big deal but I do.

    Comment by bilbo — March 1, 2010 @ 12:25 pm

  3. I thought you were going only from d20 to d%, not the other way, Bill. There is away to fix this, but it adds a bit more complexity, of course! Roll a second d20. Each number on a d20 = 5%, so on the second d20, each gradation is 1/20 of 5%, or 0.25%. Notation would use a decimal between the dice – i.e first die.second die, so a roll of 7.4 = 36%. It’s actually a finer gradation – base 20 percentiles, as it were. You can translate any percentile into this notation.

    But it seems to me that since you are only translating d20 to percentile with Iridium V1, which has percentiles and d20, to Iridium V2, which has only percentiles, it shouldn’t matter.


    Comment by clash bowley — March 1, 2010 @ 12:51 pm

  4. Yeah, but if I were to offer a way of switching between the two it could become complicated. Not impossible, but complicated.

    Comment by bilbo — March 1, 2010 @ 1:12 pm

  5. Ah! OK – I didn’t catch that at all. I went through this with IHWSC and Commonwealth Space. The system has always been a framework system, designed to accommodate different task resolution mechanics, but I never had done a version where you could switch between mechanics before that. I had to abstract every occurrence of specific mechanics – i.e. “this gives you 1 bonus die.” to a mechanics neutral phrase – i.e. “this give you a Large bonus” – then define ‘Large bonus’ for each option – i.e “In StarPerc, a Large bonus or penalty is worth 10%” or “In StarPool, a Large bonus or penalty is worth 1 die.”, etc.

    It was a pain, but once it’s done you have a huge degree of freedom.


    Comment by clash bowley — March 1, 2010 @ 1:42 pm

  6. I think going 100% the percentages road is a good idea, in many ways, after the D20 splurge, D20 games engines have been demeaned and overdone, so going the percentage route (ala runequest) is a good move in my eyes

    Comment by alan hume — March 4, 2010 @ 4:36 am

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