Quote from: B.T.;469175What I'm saying is that why would I bother adding large numbers to get a three digit number when I could just roll 1d20 and have the same results?  If I have 1d20 + 10, it's the same as 1d100 + 50, but the numbers are smaller and thus faster to compute, making gameplay quicker and easier.

Granularity. If you have played Rolemaster, MERP, or HARP (is there any other 1d100 roll-over system?), you can have a +53, or a +82. Sure, a d20 roll-over system is fine, just like a d20 roll-under system is fine too. Why would I want to play an 1d100 roll-under system, when I could play Pendragon (1d20 roll-under system)?

QuoteOn a side note, people arguing about how 1d100 roll under is better than 1d100 roll over are retarded:

Well, I'm not one of them. I like both roll-under and roll-over.

Quoteroll over is superior in almost every way, as Frank has repeatedly explained.  My personal preference is roll under, but that doesn't mean that roll over isn't the superior system in terms of mathematical ease and intuitiveness.

And I have repeatedly explained that that's not the case, that none of them is superior, it's just a question of taste.

Addition is quicker and easier than subtraction, but simple comparison is easier yet. So I find it difficult to say anything more decisive than "roll-over is better as long as you are habitually adding modifiers to skill rolls, often enough to offset the advantage of comparison vs. addition."

For me, roll over is tempting, but in practice I do not often modify skill rolls when I am GMing BRP. If a task is more difficult, I can have the PC apply the modifier by adding it to his roll, and if the raw roll is higher than the skill %, the addition can even be skipped. If the task is a markedly easy one, I would tend to ask myself if a roll is needed to begin with. I do not have a problem, by the way, with just telling the PC the modifier ahead of time and letting that influence his risk assessment. For something like Spot Hidden where the PC wouldn't know the modifier, I am going to be making the roll myself as GM anyway.

If I do add modifiers, I don't really see the point off modifying in less than 10% increments for situational modifiers to begin with. That kind of granularity can come in handy for fixed modifiers that have been figured in beforehand, advancement, etc., but on the fly I wouldn't bother with a 5% modifier. So it's really only a 1 digit of addition to begin with.

One place where roll-over seems clearly better is opposed rolls, rather than consulting a chart.

At least at a table I am personally running, I think I'd still see more overall benefit from roll-under comparison, but I might test out roll-over addition for the next BRP game I end up running. I wouldn't personally have a problem with using mostly roll-under comparison but calling for roll-over addition in certain circumstances (e.g. opposed rolls) as I saw fit, since they are basically equivalent, but I can see how you might want to pick one or the other for printed rules. I could see defaulting to roll-over and allowing a sidebar that offers comparison as a dirty trick for unmodfified checks, though.

Quote from: Imperator;469112Critical success calculations are just a breeze, as it is the use of modifiers.

How do you do critical successes?  5% or 10%?

Quote from: Imperator;469112In the first round we forgot many modifiers due to darkness and such, but we could easily add them because at my table dice rolls stand until next round in case we need to look them back.

If that's the rule, they would still be there in the case of roll-under too, right?

Quote from: Imperator;469112Actually, one of my players said that he saw no reason to go back rolling under, because he hated to re-calculate special success chances due to modifiers (as if you have Gun 60% you make a special success with 01-12, but if something modifies your % you need to re-calculate it again).

If you are using the Harn 0/5 method, you could use that for roll-under as well and not need to recalculate.

Quote from: Imperator;469112Also, several of us are hardcore MERP players One of them said we could use open rolls like in old MERP times

Most of my players are RM/MERP aware at the least, and we've switched to roll-over for Dark Heresy (with a switch to d20 roll-over sometimes to allow for a fist full of auto-fire dice ).

I'll try it for RQ, if the players go "Holy Shit! This is objectively and demonstrably superior!", we'll switch.  If they say "Meh, whatever.", we probably won't.

What about both? Roll under your skill and over a set difficulty. Kind of like blackjack.

Quote from: CRKrueger;469678How do you do critical successes?  5% or 10%?

In CoC, special successes are 1/5 of your %.

QuoteIf that's the rule, they would still be there in the case of roll-under too, right?

Guess so.

QuoteIf you are using the Harn 0/5 method, you could use that for roll-under as well and not need to recalculate.

Which method is that?

QuoteI'll try it for RQ, if the players go "Holy Shit! This is objectively and demonstrably superior!", we'll switch.  If they say "Meh, whatever.", we probably won't.

That is what we did, too. We decided to give it a couple sessions as a try, and this far we're very pleased.

Quote from: Imperator;469683In CoC, special successes are 1/5 of your %.

Are there also critical successes, or is that just BRP?

Quote from: Imperator;469683Which method is that?

It's the one you're using.  If a special success is defined as 20% of your normal success rate, then any success that ends in 0 or 5 is a special success.  As far as I know, that 0/5 method originated in Harnmaster.  It could be used for either over or under.

I think it really depends on the design of a game system as a whole. Roll-under and roll-over are just 2 tools a game designers arsenal. Roll-under puts some constraints on your numbers, but if your design fits within those parameters or has good reason to implement those constraints, you can have a very concise and intuitive game. Roll-over easily allows infinite escalation but it takes a more intricate framework of exceptions to contain.


D100 roll under is generally easier in practice. CoC is one of the simplest games ever to play. Characters are presumed to be within human standards of maximum aptitude. Their skills read as a % of the maximum. Resolution is supposed to be realistic and quick. The roll under system works wonders there by keeping the game simpler then it would be with a mathematically equivalent roll over system. As a whole it is very simple, intuitive and provides interesting games.

Some games do percentile bad. Like the FFG Warhammer 40k line. You need to add 20% to a skill when it is of 'average' difficulty. They want you to remember to add a number to your skill for the Majority of your rolls! That's pretty idiotic game design, even for a game made to simulate the oppressive universe of WH40k.

I haven't played any D100 roll-over games, none of the popular ones are appealing to me. I've read some version of Rolemaster and the massive list of tables turned me off completely.

With percentile, I prefer roll under. It's very easy to and quick to adjudicate. Same with most roll under systems actually. One quick comparison and your done. However, I would agree that roll-over is conceptually superior to roll-under. However, when  you throw a D100 before it, then you lose me. For a roll-over game to adequately take advantage of a D100 as it's core mechanic, it would need to be very petty and granular with the divvying up of bonuses and penalties. That's just something I'd rather not deal with.

Quote from: KrakaJak;469688Some games do percentile bad. Like the FFG Warhammer 40k line. You need to add 20% to a skill when it is of 'average' difficulty. They want you to remember to add a number to your skill for the Majority of your rolls! That's pretty idiotic game design, even for a game made to simulate the oppressive universe of WH40k.

This made me smile. The potential implication that someone out there designed an "oppressive universe" game to itself be oppressive, in play (for greater realism, don't ya know), is quite amusing.

And, like you, I've only played d100 as roll under. There doesn't appear to be anything fundamentally wrong with it, from the point of view of actual play. It could be that I'm missing out on some theory cred, mind you.

Quote from: CRKrueger;469687Are there also critical successes, or is that just BRP?

The distinction between critical and special success comes from RQ, if I'm not mistaken.

QuoteIt's the one you're using.  If a special success is defined as 20% of your normal success rate, then any success that ends in 0 or 5 is a special success.  As far as I know, that 0/5 method originated in Harnmaster.  It could be used for either over or under.

Oh, definitely. For me, the main advantage of using roll-over is the ease of doing opposed - rolls, which I like to use a lot.

I'm not in favour of roll-over with percentile dice, since I like to know instantly the results when I roll the dice. It's okay to have addition and chart-consulting and so on, so long as they're before the dice-rolling. The dice-roll needs to be the money shot, once it happens it's all over, pass to the next player.

I tried the "roll dice, add modifiers, consult chart" for some years with Rolemaster, it got tedious. By the time we figured out if we'd lived or died we no longer cared.