When I roll high in roll-high (see what i did there?), I announce "134" and actually do not know whether I suceeded or not. but I do know that everything over 100 is pretty good in standard cases. Whereas the reverse example...I do not know where to start.

As a player, I hate GMs who do roll-under, as they most of the time do not even care to modify die rolls at all. Personal, anecdotal, evidence.

I prefer roll-under.  d100 roll-over is just d20, and if I wanted to play d20, I'd play D&D.

Quote from: Settembrini;468901As a player, I hate GMs who do roll-under, as they most of the time do not even care to modify die rolls at all. Personal, anecdotal, evidence.

I've never had that problem -- either as a GM or as a player. My solution to it if I encountered it would be either to find a different GM or -- if the game was still a lot of fun anyway -- to just not care.  I would not see changing to roll over as a potential solution to poor GMing.  But then, I loathe rules changes to try to prevent poor GMing or poor playing.

Quote from: Settembrini;468901When I roll high in roll-high (see what i did there?), I announce "134" and actually do not know whether I suceeded or not. but I do know that everything over 100 is pretty good in standard cases. Whereas the reverse example...I do not know where to start.

As a player, I hate GMs who do roll-under, as they most of the time do not even care to modify die rolls at all. Personal, anecdotal, evidence.

Well, in fixed TN 100, you actually do know that you succeeded, barring opposed rolls or subsequently added modifiers. Fixed TN 100 is the case that is literally exactly the same as roll-under except that it has better inter-player communication.

Rolemaster is variable TN with roll-high. But if you fix the TN to 100, you get literally every single advantage of Roll-Under while still maintaining several of the roll-high advantages. So if we're going to be comparing Roll-high to Roll-low for d100, we're obviously going to be talking about the fixed TN 100 case.

Roll-under is very intuitive to design, since it is intuitively obvious that the numbers 01-57 represent 57% of the random number generator. But roll-high, fixed TN 100 has the same property. The numbers 43-99 also represent 57% of the RNG. So when you tell people that their skill is 57% and represents a 57% chance of success on an unmodified test, that stays the same. To the player, that advantage is held just as completely by roll-over-100 as it is by roll-under-skill. The designer had to do a little bit of math at the beginning to confirm the numerical identities, and that's why it doesn't get used much. But from the standpoint of the actual table, roll-over-100 is strictly superior in every way it isn't exactly the same.

-Frank

Quote from: FrankTrollman;468880In the Roll Over case, I've already given the GM the complete information. He just reduces 134 to 129 and says "Oh yeah, the floor is still greasy, so that's only a 29." But in the Blackjack setup he actually doesn't have complete information and has to ask more questions. "Oh yeah, the floor is still greasy, so you have an extra -5 penalty. Does a 62 still succeed?"

That's not how I see it come into play in a BRP game. It's rather :

GM : What are you doing?
Player: I play blackjack.
GM : Ok. Roll for it. The floor is still greasy though. That's a -5 penalty.
Player (looks at character sheet for blackjack skill) : 62. Success.

Perfect, now everybidy should be able to see it.

Quote from: Benoist;468955That's not how I see it come into play in a BRP game. It's rather :

GM : What are you doing?
Player: I play blackjack.
GM : Ok. Roll for it. The floor is still greasy though. That's a -5 penalty.
Player (looks at character sheet for blackjack skill) : 62. Success.

Blackjack is the system for generating degrees of success (DoS) in which the best roll is the highest number that still falls under your modified skill. It is not what BRP uses, but it is the best possible face that Roll-Under can put forward when resolving opposed rolls.

If you generate DoS in the blackjack method, and you have a 60% modified skill, then you have one number that generates a DoS of 59 (59) and one number that generates a DoS of 1 (01). If you generate DoS in the subtraction method, you still have one number that generates a DoS of 59 (01) and one number that generates a DoS of 1 (59). So it's mathematically the same. Blackjack proponents suggest it over roll-over because you are still able to figure your DoS with a comparison operation. Roll-under-skill with subtraction to determine DoS is obviously inferior to roll-over-100, because it's just subtracting double-digit numbers instead of adding them. The same mathematical operation, just slower and less accurate for human beings to do in real time.

So showing that the Blackjack method is inferior communicatively, which I did, is sufficient to show roll-over-100's inherent superiority. Roll-under-skill with subtractive DoS isn't even worthy of consideration.

-Frank

Right. That's why CoC is such a horriblibad game, and so many people played it over so many years. And RuneQuest. And Stormbringer. And Hawkmoon. And Nephilim. Etc. Right.

Call me when you come back from theoretical la-la-land down to the real world where people play games, Frank.

Quote from: Benoist;469027Right. That's why CoC is such a horriblibad game, and so many people played it over so many years. And RuneQuest. And Stormbringer. And Hawkmoon. And Nephilim. Etc. Right.

Call me when you come back from theoretical la-la-land down to the real world where people play games, Frank.

THAC0

-Frank

Quote from: FrankTrollman;469029THAC0

I don't see anything inherently wrong with THAC0 either. Like the arguments about with ascending or descending AC is the one best way, I just don't get it. Both work well. Some people like one more than the other, but that does not make the one you prefer inherently the best for every game and every player.

Translation: Just like there is no "One True Way" to play D&D, there is no "One True Way" to design RPGs.

Arbitrarily changing things in a well-known RPG like RQ just to match some designer's vision of "the one true way" is just going alienate players. If the rights to RQ fell into my lap, I certainly would not change the system to D100 roll over any more than I'd change the system in Rolemaster to D100 roll under if the rights to Rolemaster fell into my lap.  Both would upset lots of players without any real need for the change other than to match someone's "design theory."

Quote from: FrankTrollman;469029THAC0

-Frank

As far as I know, Call of Cthulhu, Stormbringer, etc, don't use THAC0. Do they?

Quote from: Benoist;468876Rolemaster, BRP... I take both. They serve different purposes at the game table.

This. I've played and enjoyed both.

Holy crap are you kidding? THAC0 was completely annoying, especially if you started getting into negative ACs (and what was up with that?!) Descending AC was more difficult and counter-intuitive in a number of ways. And those same issues are why Frank is so clearly and obviously right about d100 roll-over that I find it hard to believe this thread has gone on this long.

1) Addition is easier than subtraction. Some people don't have this problem, but most people I have encountered do. I certainly do.

2) As English speakers (and as far as I know, most or many other languages) ascending = better is ingrained into our language and thought process at a deep level, top ten countdowns notwithstanding. Roll higher = roll better is fundamentally intuitive to the way we think. Roll high but not more than X is better than roll low, but it's still a little weird and counter-intuitive.

3) GMs make mistakes and have to apply modifiers to the roll after the fact all the time, at least in my experience. The easier this is to do the better. If >100 is always a success, then this is an improvement over any system which varies the TN from roll to roll.

I get that Blackjack or Roll-low might be preferable for sentimental or aesthetic reasons, but roll-over is clearly simpler, clearer, and more intuitive.

Quote from: FrankTrollman;468959Roll-under-skill with subtraction to determine DoS is obviously inferior to roll-over-100, because it's just subtracting double-digit numbers instead of adding them. The same mathematical operation, just slower and less accurate for human beings to do in real time.

-Frank

I'll argue against THAC0 quite happily, but getting rid of roll under for d100 is a mistake. The most frequent thing you'll be doing is checking binary success/failure. In this case the ability to make a simple comparison with no addition involves makes it objectively superior. Situations where you have a large group of people shooting at each other become trivial with roll under.

When you add in degree of success, it becomes a weighting problem, as addition is easier than subtraction. Is it worth losing comparison for simpler DoS? I still feel that roll under wins (because it is very natural to say "I make the roll... by 12").

As for opposed rolls, roll over is indeed more natural. However, it's still a bloody awful mechanic, and the very worst of the roll and adds. About the only thing I like less than d100 roll over (apart from THAC0) is adding dice pools with more than 5 dice. I'd really consider switching to a d20, as you've lost the main thing a percentage system has going for it.

Quote from: FrankTrollman;469029THAC0

-Frank

You'll find no love for 2nd ed from me, technically speaking. And TSR drove DnD pretty much into the wall by the end of the 90s. THAC0 for me is a reference in the DMG, in first edition, and I pretty much don't use it in play. So. Shrug.