"Roll Under" mechanic

[Brian Stanfield]

Just out of curiosity, I'm wondering what the history is of the "roll under" mechanic found in HERO System (and GURPS). This isn't a complaint on my part, but the "roll under" to succeed and "roll over" to tally damage is rather unique, and was intentionally chosen early on. It's second nature for me, but is sometimes challenging to explain to others since I don't know the rationale for the mechanic. This is in no way a criticism. I love HERO, so this isn't a "dump on HERO System" thread. I'm just curious what those reasons are. Does anyone know? 

 

[Hyper-Man]

I don't know all the history but hasn't AC and To Hit rolls in D&D fluctuated over the years?

[Brian Stanfield]

Yes, I believe so. I barely understand D&D 5e at this point. But again, this isn't really about comparing systems (HERO is the best ), it's just more about curiosity as to why that choice was made. I may not get an answer, but I know that HERO and GURPS grew up together and some interaction was there, so there wasn't just "coincidence" that they both use the same device. So there must be a "good reason" why that mechanic was chosen. I'm curious what it was.

[Hyper-Man]

My guess is that it provides for a rather simple subtraction system that still allows for making a roll by 'half'. I don't know how that could work in roll over.

[Brian Stanfield]

I think rolling over on 10 + DCV - OCV would yield the same result. But then "bonuses" and "deductions" would have to be made on the die roll, not the target number unless they were inverted (bonuses would actually have to make the target number lower while deductions would make it higher). 

 

I think I may have jut answered my own question right there. The problem with D&D and the THACO method was that as the skill got greater you rolled over at a lesser number while as the armor class got lower you rolled over a higher number. It sorta bent my mind out of shape when I was learning it as a kid, and that THACO chart was the only way I could make sense out of it.

 

HERO System just makes more intuitive sense: if you roll under a target number, bonuses make that number higher, so the roll is easier.

 

Incidentally, I've been playing a lot of Car Wars lately (another Steve Jackson game), and it's a roll over system with the modifications being applied to the die roll rather than the target number, which has suddenly become completely backwards and impossible for me to think about on the fly!

[mrinku]

As far as i know it originated with Melee in 1977, one of Steve Jackson's earliest games and the ultimate ancestor of GURPS. Melee was joined by Wizard (1978) and later expanded into a more complete system in The Fantasy Trip (1980). Acknowledged as a major influence on Champions; another part of it that carries over to Champions and GURPS is using hexes to regulate combat. Building a character out of a points total comes from here as well.

 

https://en.wikipedia.org/wiki/Melee_(game)

 

That's almost certainly where the 3d6 roll comes from, too. Traveller used 2d6 (as well as an "or more" mechanic) and most other games copied D&D in using d20 or d100. 

 

Rolls based on d100 are a "roll under" mechanic, however, and those pre-date RPGs. But for the exact thing that HERO uses, it's  Melee.

 

As a historical note, Runequest and its Basic Roleplaying family also use "roll under" to hit (usually with d100, but d20 versions such as Pendragon exist) and damage dice. But it post-dates Melee, being a 1978 release.

[zslane]

For d100, "roll under" makes intuitive sense. If, for example, you have a 64% "skill rating", then you succeed by rolling 64 or less because that's the most direct and intuitive route to "succeed 64% of the time" using percentile dice. Rolling 3d6 under a target number is the same system just with the "percentages to succeed" falling into less granular, step-wise bins.

 

If you want to increase your chances to succeed in a d100 system, you just add a certain % to the target value and try to roll under it as usual. Simple and intuitive, right? Similarly, if you want to increase your chances to succeed in a 3d6 system, you just add a modifier to the target number and try to roll under it as usual. The only reason the natural intuitiveness of this approach isn't quite so obvious with 3d6 is because 3d6 doesn't look like a percentile system to most folks, even though it is equivalent to one. The same could really be said for any "roll under target value" system, regardless of the dice involved.

[Tom Cowan]

Also if you have a set of... um 'HOT' dice that always 'roll good' you um lose a bit with this system. 

[assault]

I just checked Superhero: 2044, the other big influence on Champions. Its mechanics were famously wonky and inconsistent, but there is a system that uses d100 roll under.

 

There's also a 1" = 2m ground scale, and point based character construction.

[mrinku]

It'd be interesting to see if there was any cross-influence between Superhero:2044 and Melee since they're both 1977 releases. I'd tend to think not... outside the points building thing there's not much similarity (and that is very basic in Melee... 8 points to add between the two characteristics of Strength and Dexterity, which start at 8.)

 

I was already used to 3d6 vs target number or less from The Fantasy Trip when I encountered Champions in 1985. Of course, by then I was also across 2d6 vs a target number or more (Traveller), d20 against a target number or more (D&D) and d100 vs percentage target or less (Runequest).

 

And as a bonus historical note, Tunnels & Trolls (1975) is the origin of "exploding dice". That uses a 2d6 plus base value mechanic, with doubles giving you a bonus roll to add (which is open ended. Keep rolling doubles and you keep rolling). But I'm fairly sure I hadn't played T&T before Champions.

[Hyper-Man]

There is a frequent visitor to HERO threads over on RPGnet that states his house rules for Superhero: 2044 were one of the big influences on the 1st edition of Champions.  I can't remember his profile name right now.

[assault]

I don't know his profile name, but that would be Wayne Shaw. His contribution has been acknowledged in every edition, although I can't find it in Champions Complete. It might have fallen victim to the cutting process there.

[Hyper-Man]

3 minutes ago, assault said:

I don't know his profile name, but that would be Wayne Shaw. His contribution was acknowledged in the early editions.

 

It's SuperG or Strange Visitor. I can never remember who is who.