In several games, both new and old, are chance rolls. Typically, I've seen these handled with a d6 (there's a 2 in 6 chance of an ambush) or d% (there's a 50% chance that your spell fails).

Out of simplicity and streamlining, I'm thinking of just handling this with a d20 (close enough to a percentile, more "granular" than a d6).

Have any of you done something similar, assuming that you were not wholly satisfied with either the d6 or d% options?

Old editions of CoC gave me the idea to use Luck rolls.  In many of my d20 games, I treat Luck as an attribute, right after Str, Int, Wis, Dex, Con, Char.  I usually do a point buy system for character generation, so players can decide if they are going to be lucky or unlucky.

Comes up in all sorts of situations.  "Do I have a flashlight in the trunk of my car?"  Make a luck roll.  "Who does the troll attack first?"  Make a luck roll.  "Is my night uneventful so that I can study that artifact?"  and so on.  Obviously, every instance does not use luck.  Once that troll picks a character to attack, the throes of battle take over . . . a luck roll is not rolled to decide who would be attacked each round.

For my style of play, these kinds of rolls come up frequently enough.  

Sometimes a player wants a challenge and would like his character to be unlucky.  Had a blues musician in d20 CoC with a Luck of 4 I think.  It was great.

Yes, I've used sometimes mathematics to substitute one dice for another.

Quote from: Vic99;808004Old editions of CoC gave me the idea to use Luck rolls.  In many of my d20 games, I treat Luck as an attribute, right after Str, Int, Wis, Dex, Con, Char.  I usually do a point buy system for character generation, so players can decide if they are going to be lucky or unlucky.

Comes up in all sorts of situations.  "Do I have a flashlight in the trunk of my car?"  Make a luck roll.  "Who does the troll attack first?"  Make a luck roll.  "Is my night uneventful so that I can study that artifact?"  and so on.  Obviously, every instance does not use luck.  Once that troll picks a character to attack, the throes of battle take over . . . a luck roll is not rolled to decide who would be attacked each round.

For my style of play, these kinds of rolls come up frequently enough.  

Sometimes a player wants a challenge and would like his character to be unlucky.  Had a blues musician in d20 CoC with a Luck of 4 I think.  It was great.

Being Lucky in CoC is indeed great. Whenever there's a choice who'll be eaten/attacked first, I use it.

Quote from: Rincewind1;808009Yes, I've used sometimes mathematics to substitute one dice for another.

Har har. I'll rephrase in an attempt to prompt better discussion.

I've never seen luck rolls handled by anything except a d6 or d100. Is there a reason why, in D&D for example, they don't just use the predominantly-used die, the D20, for this? Am I missing something?

In a perfect world, I'd only use the other dice (d6, d8 etc...) for damage and for random tables.

5e DnD uses the d20 for wandering critter checks, if that is what you mean.

Come up with whatever odds are appropriate for the situation and roll a d20.  Is there something more you are looking for?

Quote from: Old One Eye;808040Come up with whatever odds are appropriate for the situation and roll a d20.  Is there something more you are looking for?

No I guess not. If it is indeed that simple, then I guess that I'm overthinking this.

Quote from: Necrozius;808050No I guess not. If it is indeed that simple, then I guess that I'm overthinking this.

You are, I'm afraid - the "2 in 6" chance is simply 1/3. So for thirds, D6 is best. And yes, you can easily emulate that with d100 or D20 rather than d6, even if in one case you loose 0,(3)% and in another, you add 2% or loose 5%. But anyone who'd seriously bitch about that should be congratulated for leaving their room to interact with other human beings any way.

Yeah I'm not sure what you are looking for either... are you trying to make luck rolls more granular by using d20 over d6? But even then you mentioned d100 and it doesn't get much more granular than that in my game world.

If you are looking for an idea of a luck mechanic applied across the game I would point you to DCC. It has a rolled luck score for each character which is applied to various mechanics depending upon class. And then the luck score is used as your every day crazy stuff happens and an optional award system (if the GM desires).

Quote from: Necrozius;807955Out of simplicity and streamlining, I'm thinking of just handling this with a d20 (close enough to a percentile, more "granular" than a d6).

Have any of you done something similar, assuming that you were not wholly satisfied with either the d6 or d% options?

One reason in favor of the d6 is the coarser granularity; always at least a 1/6 chance of failing or of success (otherwise you wouldn't be rolling), versus 5% or 1% with d20 or d100. I didn't care for d% where all of the odds and bonuses were multiples of 5% (e.g., most thief skills in early D&D).

I tend to use a completely off-the-cuff percentage only as a last resort if I can't see how any other game mechanics would apply. Still comes up reasonably often I suppose, particularly if it relates to setting micro-details I haven't worked out ahead of time, like a shop having X in inventory or whatever.

I tend to like luck rolls where I can get an amount of success as well as just yes/no if I need it e.g. Storyteller I guess with its '5 dice, count successes'. It was good because the result could be converted back to use on other rolls too, like rolling to find out how many successes the PCs would need to do something.

I do quite like DCC's "Luck" attribute; but in other versions of D&D when it's something that's completely a question of luck I just roll, as GM, some kind of probability based on what I think that luck would be; usually on a D6.