What should I use: D20 vs D100, for my game?

[Renfield]

I have a homebrew modern magical mystery setting and I want to use BRP for the rules. 

I have played the older versions of Call of Cthulhu, and as of recently, bought and run several one-shot games of Pendragon.  

I am more used to percentiles in game rules, but my players are more used to D&D  d20 rules. 

Now I am writing this mostly for me to enjoy running, but Pendragon was very fun to run too.  So... now I am not so sure which to pick.

 

What do you prefer, D20 or Percentile? 

What do you think the future of BRP games is going to use, just D20s now?

 

Cheers!

[Nick Brooke]

Chaosium’s BRP family of games has used D100 since the year dot (which, for these purposes, is 1978: RuneQuest First Edition). One BRP-derived game, King Arthur Pendragon, uses a D20 instead. It came out 38 years ago, since when no other Chaosium BRP games have swapped to use D20s. (And now I feel old.)

You should use whichever dice you prefer, of course. If you plan to publish, make sure you aren’t incorporating any text you don’t have the rights to use in your ruleset. The ORC license lets you use text from the new edition of BRP (2023), and there’s an older BRP OGL that covers some bits of the Big Gold Book (2008) - see the SRD for details.

(It’s a Chaosium OGL, so don’t worry about asshole lawyers retrospectively revoking it: we aren’t Hasbro.)

Edited January 9 by Nick Brooke
technical quibble from the peanut gallery

[g33k]

17 minutes ago, Nick Brooke said:

... One BRP-derived game, King Arthur Pendragon, uses a D20 instead. It came out 38 years ago, since when no other BRP games have swapped to use D20s. (And now I feel old.)

*cough*cough*Dragonbane*cough*cough*
Do you feel younger now?   🤡

 

17 minutes ago, Nick Brooke said:

... there’s an older BRP OGL that covers text from the Big Gold Book (2008).

Please double-check that, Nick!
I'm pretty sure the (2020?) BRP OGL only covers the (quite brief) SRD included in that release ... and NOT the full BGB rulebook!

TYVM.

 

 

6 hours ago, Renfield said:

What do you prefer, D20 or Percentile? 

I  prefer d100
While the d20 is identical to 5%-slice's of d100, I really like the fraction-of-skill for critical/special/fumble, which slices much finer than 5% increments!

Quote

... I am more used to percentiles in game rules, but my players are more used to D&D  d20 rules ...

I don't *think* the Pendragon-style roll-under-skill is very akin to D&D's class-based roll-over, despite both using d20's.
I wouldn't expect to see greater acceptance from the group because of the shared d20...
But then, I'm me, and I'm none of the players in your group!  You're the one most-likely to know if they'll prefer the system rolling-low on d20's instead of rolling-low on d100's ...
 

6 hours ago, Renfield said:

...
What do you think the future of BRP games is going to use, just D20s now?

As Nick points out, very VERY few BRP variants use the d20 in place of the d100' there is absolutely no indication that BRP games, broadly, will move to d20's.

Edited January 9 by g33k

[Mugen]

In general, I prefer d20.

But d100 in BRP works well with various degrees of success mechanisms, based on fractions of the chances of success. Critical success on a 1 or a 20 (or your skill value in Pendragon, for skills <20 ) on a d20 means it's just luck, and completely disconnected from your skill.

Basically, rolling a d20 under 13 or a d100 under any number between 63 and 67 won't make the game very different. But if you need to roll under 1 or any number between 3 and 7, it's a completely different story.

In order to have chances similar to critical success on 1/20th of your skill with a d20, you can ask for a confirmation roll if you roll 1 or 20, like in D&D3, or old French game Légendes. But for some reason this kind of rule is more and more rare. 

But if you want to do the same with classical "crit under 1/20th and special under 1/5th", "crit under 1/10th" or "crit on a double", you'd find that a d100 is better.

[smiorgan]

12 hours ago, Renfield said:

What do you prefer, D20 or Percentile? 

I generally prefer percentile, for immediate transparency and for granularity (you can have those 01 crits and 00 fumbles). That said, I'm fine that Pendragon is D20 and I might be tempted to use D20 for certain settings (e.g. Middle Earth) where it seems aesthetically fitting.

12 hours ago, Renfield said:

What do you think the future of BRP games is going to use, just D20s now?

 I'm pretty confident most BRP games will continue to use the d100. The newest Chaosium game "Rivers of London" is d100, the new edition of generic BRP UGE fresh from the presses is d100. Two BRP games in development (Lords of the Middle Sea, Mythic Iceland) are d100 too. There are two main "dialects" of d100 BRP: the Cthulhu dialect and the RuneQuest/ UGE dialect. My bet is that most Chaosium games will continue to use variants of these two. D20 has been used for Pendragon and for the licensed Pendragon-derived Paladin.

Outside Chaosium, most BRP-inspired games use d100 (e.g. Mythras, OpenQuest, Jackals, Delta Green). One notable exception is the Swedish game Drakar och Demoner, now published in English as "Dragonbane", which switched many years ago to D20. 

12 hours ago, Renfield said:

I have a homebrew modern magical mystery setting and I want to use BRP for the rules. 

You could either base it on the generic BRP UGE ruleset (which has plenty of rules for magic and a lot of support for modern era weapons and stuff) or you could try to adapt the new Rivers of London Game or the old Nephilim game (still available in PDF). Both are modern "urban fantasy" games, with very different styles. All these options are d100. 

 

     

[Questbird]

On 1/9/2024 at 4:52 PM, g33k said:

As Nick points out, very VERY few BRP variants use the d20 in place of the d100' there is absolutely no indication that BRP games, broadly, will move to d20's.

 

There's an excellent free BRP variant called Fire and Sword, available right here on BRP Central. It's by Ray Turney, one of the original creators of Runequest. It uses roll-under d20 mechanism (you can use d10 for super easy tasks and d30 for super hard ones). Ray's design notes are fantastic too, explaining his d20 choice among other game design decisions.

 

[Renfield]

I do want to publish, and I am using this SRD 1.0.2 document I have as a guideline.   (is there a bookmarked version?)

For the most part, I don't see any issues with that.  

Though...These parts of the SRD are quite vague, so they are a little worrying in case we choose to use a similar mechanic = What exactly does this mean?  Other than using the term "Glory" or "Push", which are very generic, the mechanic is fairly easy to write in my own game's context. So what would be an example of "substantially similar" ?

Quote

Glory: If substantially similar to the King Arthur Pendragon rules.
Passions: If substantially similar to the King Arthur Pendragon and/or the RuneQuest: Roleplaying in Glorantha rules.
Personality Traits: If substantially similar to the King Arthur Pendragon rules.
Pushing: If substantially similar to the Call of Cthulhu rules.
 

 

I will stick with the D100 rules I was thinking of using, so thank you everyone for letting me know about the typical use of D100.  🙂

 

Some other ideas I was not sure about how well folks have play-tested them, or seen them implemented in other BRP games with more or less success:

- How do most folks feel about negative modifiers to a players' roll?   (i.e. the house you are escaping is on fire, and falling apart.  It will be a -20% to get through the room safely.

- How do folks feel about rolls with consequences?  (the house you are escaping is on fire, and falling apart.  It will be a -20% to get through the room safely.  If you fail, you still get out, but you take damage.)

- How do folks feel about splitting out "soft specialty skills" into a sub-section of a character sheet.  (i.e. Language: English, French, German. and Lore: Occult, Religion, Fables.  Instead of having all of these listed in the main skill list, they are in a side section for "specialties" or "knowledges" or some such.

 

p.s.

sorry for long delay, I can only post once a day at this time.

[g33k]

2 hours ago, Renfield said:

I do want to publish, and I am using this SRD 1.0.2 document I have as a guideline.   (is there a bookmarked version?)

...

Are you referring to this:
https://www.chaosium.com/brp-system-reference-document/

???

Honestly, as of mid-early 2023, I would refer you to:
https://www.chaosium.com/basic-roleplaying-universal-game-engine-pdf/

This uses the (IMO far superior) ORC license.

The problem with the earlier SRD was IMO two-fold:  first, it was so minimal as to require a lot of extra work by creators to achieve a useful chassis for their RPG; it simply left out too much.  Second, Chaosium was (at the time) being very protective of their IP's.  It's sensible not to undercut their own "bread and butter" make-a-living products, but IMHO they went overboard.

In particular, I think you're right to worry about the term "substantially similar" -- notwithstanding the (AFAIK not well-tested in court) assertion that "rules cannot be copyrighted" the BRP-OGL referenced above relies upon contract law rather than copyright law:  you will be in violation of the license if you produce a rule or setting "substantially similar" to one of those Chaosium protected in their license.  You can violate that contract without violating (c).

[Susimetsa]

I definitely prefer D100. My first true RPGs (RPGs that we played for more than a few sessions) were Runequest and MERP, so I am perhaps indoctrinated to D100...

I don't see BRP games switching away from D100. What would be the point?

Addendum: people learn to crawl before they learn to walk. That doesn't mean that we design our spaces primarily for those who crawl. In short, learning D100 is not difficult.

Edited January 12 by Susimetsa

[Mugen]

On 1/10/2024 at 4:51 PM, Renfield said:

I do want to publish, and I am using this SRD 1.0.2 document I have as a guideline.   (is there a bookmarked version?)

As said above, there are actually 2 Basic Roleplaying "Open" licences a available. The SRD is attached to the Basic OGL, which is the older one. The other one being the BRP ORC licence, whose SRD is the "BRP Universal Game Engine" book.

The Basic OGL is more restrictive than the other, and although Chaosium has not cancelled it, it's almost dead now.

On 1/10/2024 at 4:51 PM, Renfield said:

- How do most folks feel about negative modifiers to a players' roll?   (i.e. the house you are escaping is on fire, and falling apart.  It will be a -20% to get through the room safely.

- How do folks feel about rolls with consequences?  (the house you are escaping is on fire, and falling apart.  It will be a -20% to get through the room safely.  If you fail, you still get out, but you take damage.)

I don't see how the game could work without those, to be honest.

On 1/10/2024 at 4:51 PM, Renfield said:

- How do folks feel about splitting out "soft specialty skills" into a sub-section of a character sheet.  (i.e. Language: English, French, German. and Lore: Occult, Religion, Fables.  Instead of having all of these listed in the main skill list, they are in a side section for "specialties" or "knowledges" or some such.

That's a good idea. I think a big problem for beginners with Call of Cthulhu is that the skill list doesn't clearly outlines which skills are important and which are for experts.

[Renfield]

Ok great! 

Got the big color book, so will dig into that here soon.  🙂

 

And thanks for the feedback on the rules ideas above.  I just wanted to double check that I was not doing crazy odd stuff for BRP fans. 

My own group likes this stuff, and they find the breakout of  "top 20 skills as per setting" on front of sheet , then "odd/specialty/uncommon  skills on back of sheet" very helpful as purly a design aspect.  So I wanted thoughts on that.  I will have a graphic designed character sheet here soon (anyone else start their game design with the character sheet too?)

Ok, so more odd mechanics questions...

* How does everyone feel about Characteristics being just  for base modifiers?  (i.e.  You only ever roll the x2 , x3, x4 mod on the Characteristic if you absolutely cannot find a skill that matches... but.... with that said, we are thinking of making a slightly more typical Skill that ties to each Characteristic which should catch 99% of all 'generic' uses of a Characteristic...) 

example:

- Instead of rolling Dexterity x2,  x3 for doing some odd jump tumble, balance move = we have a skill of "Acrobatics", and that is described as "Covers all non-athletic/martial-art style movements" in the way a generic Dex roll would cover.

- or instead of Strength x2, x3 for lifting, pushing, dragging, etc = we have a skill of "Brawn" and that is described as "Covers all acts of non-combat actions where weight matters" in the way a generic Str roll would cover.

Note that this functionally is the same as Characteristic xN,   but for my players it has eliminated the knee-jerk panic of mid-session maths.  And it lets me leverage the above mentioned Difficulty penalties instead of changing the multiplier  (that way its a rather standard mechanic/math for all actions in the game)

(and yes yes i know, some folks are ok with multiply/division mid-game.  But I have found in my experience, that if there is a clever way to not do it and get same results, it won't hurt the mechanics of the game at all, and eliminates all complaints to such.)

[Squaredeal Sten]

On 1/10/2024 at 9:51 AM, Renfield said:

l

- How do most folks feel about negative modifiers to a players' roll?   (i.e. the house you are escaping is on fire, and falling apart.  It will be a -20% to get through the room safely.

- How do folks feel about splitting out "soft specialty skills" into a sub-section of a character sheet.  (i.e. Language: English, French, German. and Lore: Occult, Religion, Fables.  Instead of having all of these listed in the main skill list, they are in a side section for "specialties" or "knowledges" or some s....

About negative modifiers: Ihave used them while GMing, and have also used fractional modifiers, that is "roll against half your skill".  My difficulty with negatives is that low skill characters have NO chance of success, while with fraction al modifiers they have some chance.

About splitting out specialty skills: If your game is going to have a great variety of those then that is a great idea.  But if you use RQ's category modifiers you need to make it easy to reference those in play, else players may forget to use them.  

[Ravenheart87]

1 hour ago, Renfield said:

* How does everyone feel about Characteristics being just  for base modifiers?  (i.e.  You only ever roll the x2 , x3, x4 mod on the Characteristic if you absolutely cannot find a skill that matches... but.... with that said, we are thinking of making a slightly more typical Skill that ties to each Characteristic which should catch 99% of all 'generic' uses of a Characteristic...) 

example:

- Instead of rolling Dexterity x2,  x3 for doing some odd jump tumble, balance move = we have a skill of "Acrobatics", and that is described as "Covers all non-athletic/martial-art style movements" in the way a generic Dex roll would cover.

- or instead of Strength x2, x3 for lifting, pushing, dragging, etc = we have a skill of "Brawn" and that is described as "Covers all acts of non-combat actions where weight matters" in the way a generic Str roll would cover.

Note that this functionally is the same as Characteristic xN,   but for my players it has eliminated the knee-jerk panic of mid-session maths.  And it lets me leverage the above mentioned Difficulty penalties instead of changing the multiplier  (that way its a rather standard mechanic/math for all actions in the game)

(and yes yes i know, some folks are ok with multiply/division mid-game.  But I have found in my experience, that if there is a clever way to not do it and get same results, it won't hurt the mechanics of the game at all, and eliminates all complaints to such.)

There are already characteristic rolls with char x 5% value (Effort, Stamina, etc.), so you are one step away from turning them into a skill. Mythras, OpenQuest also turned them into skills (e.g. Brawn, Athletics). In both games every test is a skill test, they don't use characteristic rolls or resitance matrices.

[Nozbat]

As @Ravenheart87 has said a lot of the BRP derivatives already use Common skills and Specialist/ Professional skills split. The Common skills are all on the character sheet and the Specialist column is left blank to allow players to construct their own lists. New specialist skills not allocated through character creation have to be learnt from a teacher or through study (if you have a literate milieu). I do think its useful to have all the skills on the front of the sheet but that's my personal choice.

They also calculate the base chance by adding characteristics (Athletics is STR+DEX; Insight is INT+POW etc) which I like as there is a different combination for each type of skill. It means that none of the characteristics is redundant and players can benefit from a high characteristic.

I'm mostly playing online at the moment and as a GM I need to know how strong the characters are and what their skill level is when designing opposition for game play. I did design a fillable character sheet as one of the many tasks needed to start the game. The players can then upload their character sheets to a Cloud Drive which I can check when working out how strong to set the GMCs. 

I think the great thing about BRP is you can do what you and your players want. There is no right or wrong way. If the RAW or houserules don't work for the group, have a discussion after the game and change them. Its all about maximum game fun.

[Renfield]

What implementation of BRP rules does everyone think created the "biggest sin"?

That is to say, if there was a rule or mechanic that you think deviated to such a degree as to be un-fun or overly clunky = what was it?  

Or maybe to say, is there a mechanic or rule that a majority of folks just kinda wish would go away/ be replaced by some better implementation?

(just making sure I don't wander down mechanics path that is already a tried and tested failure/frustration, lol )

 

As a side note, I am not really looking to do anything radical with my implementation of BRP rules.  So really, this is largely a sanity check since this is my first time making a full game from the ground up.  🙂

[Nozbat]

The simple answer is that if there was a rule like that we’d all ignore it. 
 

Having said that..sorcery has always been difficult to conceptualise and to get mechanics right without over-complicating it. I’m probably in the minority if I said I liked RQ3 sorcery. There will be a future new RQG version coming and we’ll have to wait to see how that works. 

[Atgxtg]

4 hours ago, Renfield said:

What implementation of BRP rules does everyone think created the "biggest sin"?

 

Oh, that's like tossing a grenade into the room. I doubt you'll get a consensus. MRQ1 maybe? And that mostly for how they bungled the Gloranthan cults. Orlanth with the Chaos rune because TPB didn't understand that Gloranthan Chaos wasn't the same as D&D Chaotic. 

4 hours ago, Renfield said:

That is to say, if there was a rule or mechanic that you think deviated to such a degree as to be un-fun or overly clunky = what was it?  

Well most people didn't like the fatigue rules from RQ3. Ticking off a fatigue point every round and appling an increasing peanlty to roll, in 1% increments. Probably the winner for " un-fun or overly clunky"

4 hours ago, Renfield said:

Or maybe to say, is there a mechanic or rule that a majority of folks just kinda wish would go away/ be replaced by some better implementation?

Yeah, that was probably fatigue points. Not that there aren't other things here and there that people don't like, but Fatigue Points probably topped most peole lists.

4 hours ago, Renfield said:

(just making sure I don't wander down mechanics path that is already a tried and tested failure/frustration, lol )

Oh, it's not that bad. It's just pesky micro-managing bookeeping.

4 hours ago, Renfield said:

 

As a side note, I am not really looking to do anything radical with my implementation of BRP rules.  So really, this is largely a sanity check since this is my first time making a full game from the ground up.  🙂

Good Luck! From the ground up can be a bit tricky. Be sure to playtest stuff. It's surprising just how consistently another pair of eyes can spot something in ten seconds that the designers somehow could miss repeatedly for months. 

[Nozbat]

37 minutes ago, Atgxtg said:

Well most people didn't like the fatigue rules from RQ3.

LOl...I'd forgotten about the RQ3 fatigue rules... but I also ignored them until a fight went on a bit then I'd deduct some percentiles

[Mugen]

10 hours ago, Renfield said:

Or maybe to say, is there a mechanic or rule that a majority of folks just kinda wish would go away/ be replaced by some better implementation?

First, I prefer to use the sum of 2 characteristics as a base for skills, instead of a fixed value (or a fixed value plus skill category modifier). For instance, all Melee Weapon skills could start with (STR+DEX), and all Perception skills with INT+POW or INTx2.

I also think the game could benefit from a rule similar to Revolution D100, where there are very few skills, and specialties add a bonus to this base skill. That is, a Sword fighter could have a Melee skill of 40 and a Sword specialty of +30, and when he fights with a Sword, his effective skill is 70.

BRP is also lacking a good skills opposition rule. Simply comparing levels of success results in too many ties. And a tie, in a lot of situations, is in fact a success for one of the protagonists. For instance, if someone is hiding from another character, that person is alright if nothing happens. Even a solution like the one in Pendragon/Mythras system where you compare the d100/d20 results to break ties have flaws : it's counter-intuitive (as you have to roll low to get better success levels, but have to roll high to break ties) and still produce a lot of ties (as skill failure versus skill failure is not covered). A simple solution is to use the formula behind the Resistance Table : 50+active skill-passive skill.

[Mugen]

5 hours ago, Atgxtg said:

Well most people didn't like the fatigue rules from RQ3. Ticking off a fatigue point every round and appling an increasing peanlty to roll, in 1% increments. Probably the winner for " un-fun or overly clunky"

Yeah, that was probably fatigue points. Not that there aren't other things here and there that people don't like, but Fatigue Points probably topped most peole lists.

I think it also completely missed the mark, as wounds you suffered or what actions you performed in a round didn't have any impact on your Fatigue.

[Atgxtg]

21 minutes ago, Mugen said:

I think it also completely missed the mark,

Not really. The "mark" as it were was to handle encumbrance. THe fatquie system was made as a replacement to the encumbrance rules of RQ2. 

21 minutes ago, Mugen said:

as wounds you suffered or what actions you performed in a round didn't have any impact on your Fatigue.

True, but wouldn't probably shouldn't have impacted fatigue. In combat you get an adrenaline dump and don't usually feel fatigue until later, when it all wears off and you crash. Of course that should apply to all fatigue though, not just encumbrance.

 

I think most people's objects to the fatigue system were three fold:

1.  You can to mark off a point every round.
2. You had to subtract 1% per point into negative from everything.
3. It made high stats much more important in terms of what armor you could fight in while still having some skill, and for what length of time.

 

 

 

[Kloster]

3 hours ago, Mugen said:

A simple solution is to use the formula behind the Resistance Table : 50+active skill-passive skill.

We use a very simple rule since years: the better success win, and in case of a tie, the larger margin of success (or in case of dual failure, the lower margin of failure) wins.

[Mugen]

2 hours ago, Kloster said:

We use a very simple rule since years: the better success win, and in case of a tie, the larger margin of success (or in case of dual failure, the lower margin of failure) wins.

As far as I know, Warhammer 4th edition uses a similar method. And the various versions of French Légendes, too.

It works, and is not counter-intuitive, but requires two more subtraction than the "black jack" method, for exactly the same result (providing you don't consider failure versus failure as a tie in Black jack).

 

[Joerg]

On 1/10/2024 at 4:51 PM, Renfield said:

- How do most folks feel about negative modifiers to a players' roll?   (i.e. the house you are escaping is on fire, and falling apart.  It will be a -20% to get through the room safely.

I apply them when I deem them sensible, but the same or a similar statistical effect can be gained by having them to roll twice, giving them two chances to suffer damage on a fail, or even requiring help while stuck for another roll.

 

On 1/10/2024 at 4:51 PM, Renfield said:

- How do folks feel about rolls with consequences?  (the house you are escaping is on fire, and falling apart.  It will be a -20% to get through the room safely.  If you fail, you still get out, but you take damage.)

You can incur some form of attrition by taking light damage on a success, worse damage on a failure - not necessarily hit points, maybe movement rate, strength, or some other trait temporarily or possibly long term inhibited or even lost.

 

On 1/10/2024 at 4:51 PM, Renfield said:

- How do folks feel about splitting out "soft specialty skills" into a sub-section of a character sheet.  (i.e. Language: English, French, German. and Lore: Occult, Religion, Fables.  Instead of having all of these listed in the main skill list, they are in a side section for "specialties" or "knowledges" or some such.

Retrospectively, I think the RQ2 option to train up skill category modifiers (as expensive broad skills) makes sense, although with technical or scientifical abilities a lot of cross-over knowledge would be available.

I probably would reduce the number of skills to a much smaller set of broader skills (up to RQ3 skill categories) and then allow specialisations as well as un-specialisation - maybe someone's STEM skill gets better for chemistry but worse for botanics and electronics.

Broad skills would be harder to raise, and may meet hardness ceilings which alter the cost and chance to overcome, while specializations (and possibly sub-specialisations) are easier to perfect.

Automatic augments (and possibly automatic demerits) might be applied to a skill, too.

 

What dice to roll is up to personal preference - I use 2 D20 for my percentile rolls as I distrust those non-Euklidean bodies abilities to roll.

A single d10 roll for the tens would be sufficient half of the time, with the second D10 for the ones rolled afterwards only when it might make a difference. A single d20 roll followed by a D5, D10 or D20 for granularity when required works just as well.

 

[Kloster]

5 hours ago, Mugen said:

As far as I know, Warhammer 4th edition uses a similar method. And the various versions of French Légendes, too.

It works, and is not counter-intuitive, but requires two more subtraction than the "black jack" method, for exactly the same result (providing you don't consider failure versus failure as a tie in Black jack).

 

Correct.