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Call of Cthulhu 7 ed. Quickstart


fmitchell

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Backers of the 7th ed Kickstarter received a "Call of Cthulhu 7ed Quickstart" this weekend. Character generation has some major departures from standard BRP, but I kind of like them. Other parts, naturally, are extremely familiar.

Is there an implicit NDA for the Kickstarter backers? I was expecting the forums to blow up, and I'm bursting to talk about the rule changes. OTOH, I don't want to step on any toes.

Frank

"Welcome to the hottest and fastest-growing hobby of, er, 1977." -- The Laundry RPG
 
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Backers of the 7th ed Kickstarter received a "Call of Cthulhu 7ed Quickstart" this weekend. Character generation has some major departures from standard BRP, but I kind of like them. Other parts, naturally, are extremely familiar.

Is there an implicit NDA for the Kickstarter backers? I was expecting the forums to blow up, and I'm bursting to talk about the rule changes. OTOH, I don't want to step on any toes.

I don't believe there is any implicit NDA; there has been discussion over on RPGnet, and Paul Fricker has been answering some questions.

SDLeary

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I've only managed to skim the CoC 7E Quick-Start pdf very briefly...I have mixed views, but I have liked all the editions of Call of Cthulhu so far. These rules depart more than previous editions do from Sandy Petersen's original rules, and given that his original rules are over 30 yrs old then the changes with this edition is only minimal, it looks about reasonably compatible with the previous rules. This is great as none of the supplements suddenly become obsolete (not the case with many rpgs out there, esp the D&D line!). Interesting to note that Sandy Petersen was involved with this edition as well.

I don't mind that the core attributes are now expressed as %, it saves time rather than saying "roll your STR x 5%" etc. Its actually easier for newbies to grasp how to measure those traits, rather than saying STR 12, it is easier to understand STR 60% in the same way that you can grasp how good you are at Skills when they are expressed as a percentage. This would have been a great inclusion in the BRP BGB, and the inconsistency with the BGB is the main reason it won't feel right for many BRP GMs out there. I can understand this, given that the BGB is the guidebook toolset for BRP, and now CoC 7E has core attributes written very differently. However I was actually stating NPCs up like this for many moons to save me time during the gameplay, so the idea sure works for me.

I'm not sure if I can see any clear advantage for using the Bonus/Penalty Dice mechanics over the current BRP BGB rules for flat bonus/penalty modifiers. It's a big departure from the standard BRP way of doing things, I'm not sure what it achieves better than the current way of doing this. I suspect that it may feel more 'gamey' at the table, and it actually may be fun for playing a pulpy game, although its probably not an option I will bring to my current BRP games, for the sake of consistency. It does feel a bit too variable for me, but if I had new players I might give it a go though. In any case, this was one of those rules where I initially went 'Whattha?!", but it may have its place so I'ld need to see it during gameplay to get a feel for it.

The new idea of 'pushing' your roll has been is many a troupe's house rules for some time I expect, just expressed a little differently in different words. Not a bad addition to the core rulebook though.

If they were going for major changes I would actually got rid of the term 'Magic Points', and called it something like 'Conviction Points', based off POW or possibly POW+CHA perhaps. It could still be used for Spellcasting, but perhaps these points could have also been available to be used to add effects to certain mundane skills, which would provide a use for those points for non-magic using characters. Maybe you could 'Push' your skills for the cost of a Conviction Point, without having any disadvantage, I'm not sure. It could even be used to power an Advantage/Feats system in a pulpy setting perhaps. This kind of rule change, or something similar, would have been greatly appreciated (Note to authors: its not too late to use this idea, I certainly won't mind! ;))

I think I would have liked SANITY to be calculated from more base attributes than just POW, as mental coping is such a hard thing to define. Prior to the 1960s, Sanity was viewed as an intangible mental (and spiritual) aspect that was somehow related to one's 'Intellect and Nerves', so basing it off POW for a 1920s/1930s setting was okay. However now that we play Call of Cthulhu in later eras then this definition isn't really relevant and doesn't portray more current views of Sanity. From a more modern viewpoint, Sanity really comes down to emotional state, personality, willpower, biophysiology, culture & ethnicity, trauma exposure, social welfare, and even one's general physical health. Perhaps a more accurate (although convoluted) base calculation could be something like SANITY % = CHA+INT+CON +(POW x2), perhaps?

I would have even been open for an Allegiance style system for Sanity to keep some consistency with the BGB, having two opposing facets, 'Resilience' and 'Decompensation' perhaps.

If the authors were updating the rules, I feel that they should have taken the opportunity to place more emphasis on the relationship between Core Attributes and Skills, with Attributes having a larger impact on the base chances for Skills, like RQ6 does. Just a thought, no big criticism, but it would have been a good opportunity. I do like the quick previous experience system for skill calculation though, a bit like Magic World in this respect. You can have your skills allocated in no time, which is one of the drawbacks in the current BRP BGB. Perhaps there is an option in the full COC 7E rules for adding 1/5% Attribute Values to particular skills, that would probably be viable and simple. Have to wait and see I guess.

Regarding Skills, I actually couldn't find a Skill list in the Quick Start rules, not even an abridged list. I may have overlooked it, but I don't think it was included. For that fact this makes the Quick Start not a Quick Start rules at all really, more of a preview of the new rules for current players. Not a big issue for me, but its not like you can use these Quick Start rules for a game without having the full edition of CoC 7E. So the document would have been more aptly titled 'Call of Cthulhu 7E Preview' instead.

One thing I found unusual was that when a skill roll is halved, the authors have called it a 'Hard' roll, whereas in the BGB this is referred to as a 'Difficult' roll. I wish that consistency had been kept with the BGB where possible, especially if referring to the same thing. Just makes it a bit unusual from my point of view, plus players who are used to GMs saying "Make a Difficult roll!' will look perplexed when now requested to "Make a Hard roll!". I understand that RQ6 is different, but the Design Mechanism is a different company, fair enough. I think Chaosium should keep a little consistency where it can within their own publications however.

The new Build stat is interesting, but I'm a little unclear with it, I will need to clarify it better I think. Build does change the combat mechanics a bit, and I don't know how this sits with me yet, it may be too much of a departure for me, I will have to look at it further. This could be a sticking point, I will have to see how different the combat mechanics are with having Build involved. I must say I'm a tad concerned here...

I don't mind the basic damage chart, that's good for simplifying rules, and certainly good for Quick-Start rules.

I was surprised to see that Luck is a value akin to Sanity now, and recorded similarly in a tally. I wonder what the mechanic for this will be like, as it was not included in the Quick-Start rules. I suspect, given its prominence on the character sheet, that Luck will play a big feature now. Interesting to see that it is recorded in a tally, which alludes to the fact that it can be depleted, much like Sanity Points or Hit Points.

I think that Luck may even have variable rules according to the game flavour, perhaps you will be able to use it more in a pulpy setting rather than if playing in a gritty setting. I do know that the authors are looking at several types of gameplay styles, and high-end pulp does certainly have a place in a Lovecraftian rpg, given the success of Trail of Cthulhu and such, so it would be wise for the authors to provide this aspect of gaming as well to CoC 7E. I'm certain the Luck score will play a large role here.

Should be an intriguing edition when the full rules come out, and I'm glad there are a few changes here and there, although I would have liked a bit more of a 'rethink' on some things, given that the authors were open to altering several facets of the previous rules. Again I will have to hold judgement until I see the full edition, but I'm glad that the changes probably won't make my current library of CoC source books useless. This was a smart move, as the strength of BRP and CoC has been the fact you can pick up old scenarios and resources and use them with whatever core rules you are playing with. Glad to see that is hopefully still the case with this edition.

Well I guess its not too long for the full release now, I'm certain these forums will be a hive of activity once its out

Edited by Mankcam
grammar

" Sure it's fun, but it is also well known that a D20 roll and an AC is no match against a hefty swing of a D100% and a D20 Hit Location Table!"

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Was he? I have read otherwise.

He, like Lynn Willis, is credited as a coauthor - presumably on the basis that they're claiming continuity with all previous editions (IIRC Sandy wasn't consulted about the revisions in 5th edition, which is when the game started to be credited to both him and Lynn Willis).

Nick

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Whoops, my bad.

I saw Sandy Petersen's name first on the list under the heading '7th Edition Authors'. I thought there must of been some consultation with him. But upon further investigation I see at the bottom of the page they credit Sandy as the original author, and then also credit Lyn Willis. A little bit misleading, other editions have it written more clearly that the original edition was Sandy's work, but this one looked as though he had a prominent role in this edition. I will pay more attention next time. Now...I wonder what Sandy thinks of the changes with this edition?

" Sure it's fun, but it is also well known that a D20 roll and an AC is no match against a hefty swing of a D100% and a D20 Hit Location Table!"

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I think it looks just fine. The infamous "new rules" seem sound, and are not huge changes.

The one thing, that single thing, that makes me grind my teeth are the percentile attributes. Yes I realize that it's just 3d6x5, but I just don't like them! They're an eyesore.

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I think it looks just fine. The infamous "new rules" seem sound, and are not huge changes.

The one thing, that single thing, that makes me grind my teeth are the percentile attributes. Yes I realize that it's just 3d6x5, but I just don't like them! They're an eyesore.

The biggest issue with Percentile Attributes I think is going to be monsters. We are going to see some wildly large numbers in those stat blocks. And yes, it is an eyesore, makes things a bit more difficult to read IMHO.

SDLeary

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The biggest issue with Percentile Attributes I think is going to be monsters. We are going to see some wildly large numbers in those stat blocks.

That was my big question. A few simplifications occur to me:

1. Adapting the "mastery" mechanic from HeroQuest, every superhuman creature has "automatic" levels of success over mere mortals.

2. A "scale" stat for extremely large creatures would add multiples of 100 or an equivalent to STR, CON, and SIZ.

3. Especially large or superhuman creatures don't have regular stats, just SIZ/scale, HP, AP, and attacks (damage, percentiles). Alternatively, Cthulhu or Abhoth isn't a creature but a series of environmental hazards and dodge-or-die mechanics (hence Luck).

All of these are very Lovecraftian, but not very BRP.

BTW, I may have been skimming too fast, but I didn't see how skills over 100 are supposed to work. The creature in the sample scenario -- do I have to worry about spoiling "The Haunting"? -- has an attribute over 100, and apart from higher chances of "hard" and "extreme" success it doesn't provide any real advantage.

Edited by fmitchell

Frank

"Welcome to the hottest and fastest-growing hobby of, er, 1977." -- The Laundry RPG
 
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The one thing, that single thing, that makes me grind my teeth are the percentile attributes. Yes I realize that it's just 3d6x5, but I just don't like them! They're an eyesore.

Depends on how the stat block looks

This is not an eyesore:

STR 60%

CON 65%

Sword Attack 45%

This IS an eyesore:

STR % 60/30/12

CON % 65/33/13

Sword Attack % 45/23/9...ugh!

How they have the sheets recording it is pretty cumbersome. I would have rather had the current attribute (ie 3d6 attribute) followed by the %, like this: STR 12/60% its a tad easier on the eye, and its easy to halve the percentile if you need to. I certainly don't like the character sheet looking cluttered, and at present I make my own so that the sheet isn't filled with all these listed but unused skills. Cluttering a character sheet is certainly not an advancement to my liking, its getting very rulesy for my tastes. One of the strengths of this system is that you can look at a skill at a glance and have a fair idea how good you are, given it is expressed as a percentage. Expressing it written down as xx/xx/xx doesn't have that same simplicity to it. It actually feels like a step backward rather than forwards unfortunately.

When it ain't broke, does it need a fixin'...?!!!

I will have to have a better look at the full rules, but from the outset its looking a little messy

Translating from the current stats to the new stats:

GYAA-YOTHN, Beasts of Burden

(Lesser Servitor Race)

STR % 135/68/27

CON % 70/35/14

SIZ % 150/75/30

INT % 35/18/7

POW % 55/28/11

DEX % 65/33/13

HP 22 AP 3

Build +4 DB +3d6

Bite A% 30/15/6 D 2d8

Claw A% 30/15/6 D 1d6+DB

Kick A% 40/20/8 D 1d6+DB

Sneak % 50/25/10

Sanity Loss 0/1d8

Not too bad...but still looking alot more cumbersome than the current stat block, there's no way I can quickly read the scores when everything is done in xx/xx/x format, and it just doesn't 'feel' like BRP to me...

Edited by Mankcam

" Sure it's fun, but it is also well known that a D20 roll and an AC is no match against a hefty swing of a D100% and a D20 Hit Location Table!"

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I think it looks just fine. The infamous "new rules" seem sound, and are not huge changes.

I disagree, although I have to see the rules in action yet. "Pushing" rolls and being able to use Luck poinst makes things more pulpy. Characters are no longer shipwrecked sailors in the sea of unknown, they are now heroes who are supposed to succeed in their mission.

Proud member of the Evil CompetitionTM

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Alternatively, Cthulhu or Abhoth isn't a creature but a series of environmental hazards and dodge-or-die mechanics (hence Luck).

All of these are very Lovecraftian, but not very BRP.

And with this I strongly disagree: in the short story that provides the title for the whole game, Cthulhu gets smashed to pieces by being overrun by a ship [i suppose I am spoilering no one here]. Not only is Cthulhu without hit points not very BRP, it is not very Lovecraftian, either!

I see Cthulhu monsters and their scariness as similar to the Kaiju in Pacific Rim: humanity's best weapons work on them... apparently! But mankind is still doomed, because you cannot really stop them, just hinder them a little bit. No matter how many times you drop Cthulhu with missiles and bombs: he will rise time and again, until everyone's SAN drops to zero and mankind is turned into his servitor race like the Deep Ones.

So no, no "environmental" Cthulhu can be faithful to the Lovecraft tradition.

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..."Pushing" rolls and being able to use Luck Points makes things more pulpy. Characters are no longer shipwrecked sailors in the sea of unknown, they are now heroes who are supposed to succeed in their mission.
Yes, very true. Having said that, I do love the Pulp genre and think it can be done well with Mythos games, but perhaps these pulp-orientated rules should be included in an Optional Rules chapter, designed to pulp things up a bit. I agree with you that the default setting should remain challenging and gritty, even with its high death count. It has worked well so far, over 30 years, and I think the system is better for it. This default setting should remain 'Mythos Horror', with 'Pulp Mythos' being an optional play style. I'm now starting to worry that changing the format too much may be the death of a good thing...

" Sure it's fun, but it is also well known that a D20 roll and an AC is no match against a hefty swing of a D100% and a D20 Hit Location Table!"

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I'm not sure on the percentile stats, although admittedly I haven't reviewed the playtest document. But with the BGB, if I know a monster has a STR of 50, I can use the SIZ chart to roughly figure out how much it can lift and get a vague idea of what that strength level means. If the same STR is listed as 250%, I don't know what to compare it to to figure out what it means (other than "a whole lot stronger than my PC").

While I, like Mankcam, love pulp adventure, changing the default toughness of the player-characters will have a profound effect on the nature of the game. Call of Cthulhu characters have traditionally been rather fragile compared to, say, Justice, Inc./Pulp Hero characters, who are intended to be action heroes. While both ways can be fun, there's a big difference between playing Professor Bert Philby, anthropologist, and playing Dr. Wisconsin Smythe, two-fisted archeologist with a bolas. Both characters may have similar academic skills, but their combat skills, outlook and general hardiness will be quite a bit different. Philby is cautiously watching his back, alert for cultists and seeking to avoid confrontation until he thinks he is ready. Smythe, on the other hand, polishes off a quartet of thugs as part of his usual breakfast routine and is ready to face anything (he thinks).

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And with this I strongly disagree: in the short story that provides the title for the whole game, Cthulhu gets smashed to pieces by being overrun by a ship [i suppose I am spoilering no one here]. Not only is Cthulhu without hit points not very BRP, it is not very Lovecraftian, either!

I doubt Lovecraft was thinking about hit points when writing that scene, or even force and momentum. It was "big thing crashing into other big thing". A scale mechanic might cover that situation ... or a GM saying "yeah, that might work". In most stories, though, it's humans with human-scale weapons (if that) trying to get out alive.

In retrospect, I suspect my supposed "simplifications" really aren't much better than CoC7 Characteristic = CoC6 Characteristic x 5%. Going by the rules available, stat of 500% is essentially a > 95% chance of an "extreme" success. (I hope a skill > 100% reduces fumble chances.) In a way, that might combat stat inflation, which is one of my pet peeves.

Frank

"Welcome to the hottest and fastest-growing hobby of, er, 1977." -- The Laundry RPG
 
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I disagree, although I have to see the rules in action yet. "Pushing" rolls and being able to use Luck poinst makes things more pulpy.

I agree with you that the default setting should remain challenging and gritty, even with its high death count. It has worked well so far, over 30 years, and I think the system is better for it. ... I'm now starting to worry that changing the format too much may be the death of a good thing...

I'll reserve judgement until I see what the opposition looks like. Using the resistance table, STR 15 vs STR 10 has the same chance as STR 25 vs. STR 20. Using opposed rolls in the current rules, STR 125% and STR 100% are a little more evenly matched, and STR 275% vs STR 250% is far more dependent on luck. I suspect creatures will have more tricks in their tentacles than just high stats ... enough perhaps to require pushing rolls and Luck points. (Pushing rolls has an explicit if GM-dependent cost, and I suspect spending luck will be more painful than blowing a few luck rolls.)

Frank

"Welcome to the hottest and fastest-growing hobby of, er, 1977." -- The Laundry RPG
 
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This evening I wrote a Ruby program to calculate probabilities in CoC7. I can post it for peer review, after I do a little cleanup and retesting, but for now, this looks right:


|  A\R  ||    10 |    20 |    30 |    40 |    50 |    60 |    70 |    80 |    90 |   100 |   110 |   120 |

|------:||------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|

|   10  || 50.00 | 12.74 | 11.99 | 11.24 | 10.49 |  9.74 |  8.99 |  8.24 |  7.49 |  7.09 |  7.04 |  6.99 |

|   20  || 87.26 | 50.00 | 19.18 | 17.66 | 16.14 | 14.62 | 13.10 | 11.58 | 10.06 |  9.24 |  9.12 |  9.00 |

|   30  || 88.01 | 80.82 | 50.00 | 24.08 | 21.79 | 19.50 | 17.21 | 14.92 | 12.63 | 11.39 | 11.20 | 11.01 |

|   40  || 88.76 | 82.34 | 75.92 | 50.00 | 27.44 | 24.38 | 21.32 | 18.26 | 15.20 | 13.54 | 13.28 | 13.02 |

|   50  || 89.51 | 83.86 | 78.21 | 72.56 | 50.00 | 29.26 | 25.43 | 21.60 | 17.77 | 15.69 | 15.36 | 15.03 |

|   60  || 90.26 | 85.38 | 80.50 | 75.62 | 70.74 | 50.00 | 29.54 | 24.94 | 20.34 | 17.84 | 17.44 | 17.04 |

|   70  || 91.01 | 86.90 | 82.79 | 78.68 | 74.57 | 70.46 | 50.00 | 28.28 | 22.91 | 19.99 | 19.52 | 19.05 |

|   80  || 91.76 | 88.42 | 85.08 | 81.74 | 78.40 | 75.06 | 71.72 | 50.00 | 25.48 | 22.14 | 21.60 | 21.06 |

|   90  || 92.51 | 89.94 | 87.37 | 84.80 | 82.23 | 79.66 | 77.09 | 74.52 | 50.00 | 24.29 | 23.68 | 23.07 |

|  100  || 92.91 | 90.76 | 88.61 | 86.46 | 84.31 | 82.16 | 80.01 | 77.86 | 75.71 | 50.00 | 25.76 | 25.08 |

|  110  || 92.96 | 90.88 | 88.80 | 86.72 | 84.64 | 82.56 | 80.48 | 78.40 | 76.32 | 74.24 | 50.00 | 27.09 |

|  120  || 93.01 | 91.00 | 88.99 | 86.98 | 84.97 | 82.96 | 80.95 | 78.94 | 76.93 | 74.92 | 72.91 | 50.00 |

Equal percentiles are 50/50, as in the old Resistance Table. Low percentiles still have a slight chance, probably based on the straight 5% fumble. Note, though, how chances for the less skillful party fall off faster, even in the 190 vs 200 case; I suspect this is due to the "higher skill wins" rule.

EDIT: Apparently my probability math is off, because I'm getting weird numbers beyond 200. Among other things I'm not limiting hard and critical successes by the "fumble" limit. I've removed columns beyond 120, and even then the numbers might not be exactly right.

Edited by fmitchell

Frank

"Welcome to the hottest and fastest-growing hobby of, er, 1977." -- The Laundry RPG
 
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OK, here's the revised table, extended to 200. I'm pretty confident about this one, since I get the same numbers with two separate algorithms.



CoC7 Opposed Rolls Probability, from 10 to 200

--------------------------------------------------


|  A\R  ||    10 |    20 |    30 |    40 |    50 |    60 |    70 |    80 |    90 |   100 |   110 |   120 |   130 |   140 |   150 |   160 |   170 |   180 |   190 |   200 |

|------:||------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|------:|

|   10  || 50.00 | 12.90 | 12.23 | 11.56 | 10.89 | 10.22 |  9.55 |  8.88 |  8.21 |  7.79 |  7.62 |  7.45 |  7.28 |  7.11 |  6.94 |  6.77 |  6.60 |  6.43 |  6.26 |  6.24 |

|   20  || 87.10 | 50.00 | 19.66 | 18.30 | 16.94 | 15.58 | 14.22 | 12.86 | 11.50 | 10.64 | 10.28 |  9.92 |  9.56 |  9.20 |  8.84 |  8.48 |  8.12 |  7.76 |  7.40 |  7.34 |

|   30  || 87.77 | 80.34 | 50.00 | 25.04 | 22.99 | 20.94 | 18.89 | 16.84 | 14.79 | 13.49 | 12.94 | 12.39 | 11.84 | 11.29 | 10.74 | 10.19 |  9.64 |  9.09 |  8.54 |  8.44 |

|   40  || 88.44 | 81.70 | 74.96 | 50.00 | 29.04 | 26.30 | 23.56 | 20.82 | 18.08 | 16.34 | 15.60 | 14.86 | 14.12 | 13.38 | 12.64 | 11.90 | 11.16 | 10.42 |  9.68 |  9.54 |

|   50  || 89.11 | 83.06 | 77.01 | 70.96 | 50.00 | 31.66 | 28.23 | 24.80 | 21.37 | 19.19 | 18.26 | 17.33 | 16.40 | 15.47 | 14.54 | 13.61 | 12.68 | 11.75 | 10.82 | 10.64 |

|   60  || 89.78 | 84.42 | 79.06 | 73.70 | 68.34 | 50.00 | 32.90 | 28.78 | 24.66 | 22.04 | 20.92 | 19.80 | 18.68 | 17.56 | 16.44 | 15.32 | 14.20 | 13.08 | 11.96 | 11.74 |

|   70  || 90.45 | 85.78 | 81.11 | 76.44 | 71.77 | 67.10 | 50.00 | 32.76 | 27.95 | 24.89 | 23.58 | 22.27 | 20.96 | 19.65 | 18.34 | 17.03 | 15.72 | 14.41 | 13.10 | 12.84 |

|   80  || 91.12 | 87.14 | 83.16 | 79.18 | 75.20 | 71.22 | 67.24 | 50.00 | 31.24 | 27.74 | 26.24 | 24.74 | 23.24 | 21.74 | 20.24 | 18.74 | 17.24 | 15.74 | 14.24 | 13.94 |

|   90  || 91.79 | 88.50 | 85.21 | 81.92 | 78.63 | 75.34 | 72.05 | 68.76 | 50.00 | 30.59 | 28.90 | 27.21 | 25.52 | 23.83 | 22.14 | 20.45 | 18.76 | 17.07 | 15.38 | 15.04 |

|  100  || 92.21 | 89.36 | 86.51 | 83.66 | 80.81 | 77.96 | 75.11 | 72.26 | 69.41 | 50.00 | 31.56 | 29.68 | 27.80 | 25.92 | 24.04 | 22.16 | 20.28 | 18.40 | 16.52 | 16.14 |

|  110  || 92.38 | 89.72 | 87.06 | 84.40 | 81.74 | 79.08 | 76.42 | 73.76 | 71.10 | 68.44 | 50.00 | 32.15 | 30.08 | 28.01 | 25.94 | 23.87 | 21.80 | 19.73 | 17.66 | 17.24 |

|  120  || 92.55 | 90.08 | 87.61 | 85.14 | 82.67 | 80.20 | 77.73 | 75.26 | 72.79 | 70.32 | 67.85 | 50.00 | 32.36 | 30.10 | 27.84 | 25.58 | 23.32 | 21.06 | 18.80 | 18.34 |

|  130  || 92.72 | 90.44 | 88.16 | 85.88 | 83.60 | 81.32 | 79.04 | 76.76 | 74.48 | 72.20 | 69.92 | 67.64 | 50.00 | 32.19 | 29.74 | 27.29 | 24.84 | 22.39 | 19.94 | 19.44 |

|  140  || 92.89 | 90.80 | 88.71 | 86.62 | 84.53 | 82.44 | 80.35 | 78.26 | 76.17 | 74.08 | 71.99 | 69.90 | 67.81 | 50.00 | 31.64 | 29.00 | 26.36 | 23.72 | 21.08 | 20.54 |

|  150  || 93.06 | 91.16 | 89.26 | 87.36 | 85.46 | 83.56 | 81.66 | 79.76 | 77.86 | 75.96 | 74.06 | 72.16 | 70.26 | 68.36 | 50.00 | 30.71 | 27.88 | 25.05 | 22.22 | 21.64 |

|  160  || 93.23 | 91.52 | 89.81 | 88.10 | 86.39 | 84.68 | 82.97 | 81.26 | 79.55 | 77.84 | 76.13 | 74.42 | 72.71 | 71.00 | 69.29 | 50.00 | 29.40 | 26.38 | 23.36 | 22.74 |

|  170  || 93.40 | 91.88 | 90.36 | 88.84 | 87.32 | 85.80 | 84.28 | 82.76 | 81.24 | 79.72 | 78.20 | 76.68 | 75.16 | 73.64 | 72.12 | 70.60 | 50.00 | 27.71 | 24.50 | 23.84 |

|  180  || 93.57 | 92.24 | 90.91 | 89.58 | 88.25 | 86.92 | 85.59 | 84.26 | 82.93 | 81.60 | 80.27 | 78.94 | 77.61 | 76.28 | 74.95 | 73.62 | 72.29 | 50.00 | 25.64 | 24.94 |

|  190  || 93.74 | 92.60 | 91.46 | 90.32 | 89.18 | 88.04 | 86.90 | 85.76 | 84.62 | 83.48 | 82.34 | 81.20 | 80.06 | 78.92 | 77.78 | 76.64 | 75.50 | 74.36 | 50.00 | 26.04 |

|  200  || 93.76 | 92.66 | 91.56 | 90.46 | 89.36 | 88.26 | 87.16 | 86.06 | 84.96 | 83.86 | 82.76 | 81.66 | 80.56 | 79.46 | 78.36 | 77.26 | 76.16 | 75.06 | 73.96 | 50.00 |

I'll provide the Ruby script in a following post, so other programmers can check my assumptions. I'd check it into the download section, but it's probably not interesting to many people.

Frank

"Welcome to the hottest and fastest-growing hobby of, er, 1977." -- The Laundry RPG
 
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It's a long one, since I wanted to make it as user-friendly as possible. I called it coc7rt.rb.


#!/usr/bin/env ruby


##

## Routines and a command-line program to calculate probabilities of success

## for opposed tests in _Call of Cthulhu_ 7th edition.

##


require 'rational'


FUMBLE = -1

FAILURE = 0

SUCCESS = 1

HARD_SUCCESS = 2

EXTREME_SUCCESS = 3

CRITICAL_SUCCESS = 5


# Calculate opposed success chances

def coc7_opposed_success(a, r, bf=false)

  bf ? coc7_opposed_success_bf(a, r) : coc7_opposed_success_p(a, r)

end


# Calculate opposed success chances w/ brute force (counting all possible outcomes)

def coc7_opposed_success_bf(a, r)

  total = Rational(0,1)

  incr = Rational(1,10000)


  1.upto(100) do |ar|

    as = success_level(a, ar)

    1.upto(100) do |rr|

      rs = success_level(r, rr)

      if as > rs then

        total += incr

      elsif as == rs then

        if a > r then

          total += incr

        elsif a == r then

          total += incr/2

        end

      end

    end

  end

  return total;

end


def success_level(target, actual)

  if actual > 95 then

    FUMBLE

  elsif actual == 1 then

    CRITICAL_SUCCESS

  elsif actual > target then

    FAILURE

  else

    if actual <= target/5 then

      EXTREME_SUCCESS

    elsif actual <= target/2 then

      HARD_SUCCESS

    else

      SUCCESS

    end

  end

end


# Calculate opposed success chances w/ probability calculations

def coc7_opposed_success_p(a, r)

  result = 

    p_critical(a)          * (1 - p_critical(r)) + 

    p_extreme_only(a)      * (1 - p_extreme(r)) +

    p_hard_only(a)         * (1 - p_hard(r)) + 

    p_ordinary_only(a)     * p_failure(r) + 

    p_failure_no_fumble(a) * p_fumble(r)


  # In cases of a tie, success goes to the higher percentile

  if (a > r) then

    result += p_tied(a, r)

  elsif (a == r) then

    # coin toss, essentially

    result += p_tied(a, r) / 2

  end


  return result

end


# Converts integers to probabilities (0..1)

def pct(p)

  if (p >= 100) then

    Rational(1)

  elsif (p < 0) then

    Rational(0)

  else

    Rational(p,100)

  end

end


# Probability of a CoC7 fumble

def p_fumble(p)

  pct(5)

end


# Probability of a CoC7 critical success

def p_critical(p)

  pct(1)

end


# Probability of a CoC7 ordinary success or better

def p_success(p)

  max = pct(100) - p_fumble(p)

  result = pct(p)

  ### Success never more than 100 - fumble ###

  return (result > max) ? max : result;

end


# Probability of a CoC7 extreme success or better

def p_extreme(p)

  p_success(p/5)

end


# Probability of a CoC7 extreme success only

def p_extreme_only(p)

  p_extreme(p) - p_critical(p)

end


# Probability of a CoC7 hard success or better

def p_hard(p)

  p_success(p/2)

end


# Probability of a CoC7 extreme success only

def p_hard_only(p)

  p_hard(p) - p_extreme(p)

end


# Probability of a CoC7 ordinary success only

def p_ordinary_only(p)

  p_success(p) - p_hard(p)

end


# Probability of a CoC7 ordinary failure or worse

def p_failure(p)

  pct(100) - p_success(p)

end


def p_failure_no_fumble(p)

  p_failure(p) - p_fumble(p)

end


# Probability of tied success levels

def p_tied(a, r)

   p_critical(a)          * p_critical(r) + 

   p_extreme_only(a)      * p_extreme_only(r) + 

   p_hard_only(a)         * p_hard_only(r) + 

   p_ordinary_only(a)     * p_ordinary_only(r) + 

   p_failure_no_fumble(a) * p_failure_no_fumble(r) + 

   p_fumble(a)            * p_fumble(r)

end



### Print out probability table

def print_coc7_rt(min=10, max=100, step=10, bf=false)

  mind = (min/step).to_i

  maxd = (max/step).to_i


  puts("")

  printf("CoC7 Opposed Rolls Probability, from %d to %d\n", mind * 10, maxd * 10)

  puts('-'*50)

  puts("")


  puts("(brute force method)\n\n") if bf


  printf('| %4s  |', 'A\\R')

  mind.upto(maxd) do |rd|

    r = rd * step

    printf('| %5d ', r)

  end

  puts("|")


  printf('|------:|')

  mind.upto(maxd) do |rd|

    printf('|------:')

  end

  puts("|")


  mind.upto(maxd) do |ad|

    a = ad * step

    printf('| %4d  |', a)

    mind.upto(maxd) do |rd|

      r = rd * step

      p = coc7_opposed_success(a, r, bf)

      printf('| %5.2f ', p.to_f * 100.0)

    end

    puts("|")

  end

  puts("")

end


###### COMMAND LINE ##########


def run!

  require 'optparse'


  min = 40

  max = 80

  step = 10

  bf = false

  lookup = false


  opts = OptionParser.new do |opts|

    opts.banner = "Usage: coc7rt.rb [options] [-l active resist]"


    opts.on("-b", "--[no-]brute-force", "Use brute force method") do |v|

      bf = v

    end


    opts.on("-l", "--[no-]lookup", "Lookup a specific entry") do |v|

      lookup = v

    end


    opts.on("-n", "--min [INTEGER]", "Set minimum percentile in table") do |v|

      min = v.to_i

    end


    opts.on("-s", "--step [INTEGER]", "Set step between rows/columns") do |v|

      step = v.to_i

      step = 5 if step < 5

    end


    opts.on("-x", "--max [INTEGER]", "Set maximum percentile in table") do |v|

      max = v.to_i

    end

  end.parse!


  if (lookup) then

    if (ARGV.size == 2) then

      a = ARGV[0].to_i

      r = ARGV[1].to_i


      p = coc7_opposed_success(a, r, bf)


      printf("\n%d vs %d: %5.2f%% \n", a, r, p.to_f * 100)

    else

      opts.usage

      exit(1)

    end

  else

    print_coc7_rt(min, max, step, bf)

  end

end


run! if __FILE__ == $0


Frank

"Welcome to the hottest and fastest-growing hobby of, er, 1977." -- The Laundry RPG
 
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BTW, the practical limit for any creature's STR, DEX, etc. is 480% (or old-school 96). At that point it has a straight 94.31% chance of success against all opponents except ones with an equal opposing score (50%) or higher (5.69%).

EDIT: I should say 475% / 238 / 95. At that point, all rolls are either criticals, extreme successes, or fumbles.

Edited by fmitchell

Frank

"Welcome to the hottest and fastest-growing hobby of, er, 1977." -- The Laundry RPG
 
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Percentile stats are still eyesores.

I'd like to know what funky colour their skies were when they decided that SIZ 65(percent! I haven't seen the sheet yet. They are percentages, not just numbers?) is easier to relate to than SIZ 13. As they've managed to put in the exceptionally unsightly Luck-stat, it sure wasn't to streamline anything?

The same with the renaming of the successes. No more Critical, it's Extreme.. Not only is it a(nother) completely unnecessary break-off from the parent system, it's the audio-version of an eyesore.

The other tweaks; opposed rolls, combat, healing,pushing rolls, and (even) spending luckpoints are very nice. They add something new to the game, and are easily ignored if you don't want them.

For all it's niceness, the new tweaks still don't make up for a goof equivalent of a 5-wheeled Audi.

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Percentile stats are still eyesores.

I'd like to know what funky colour their skies were when they decided that SIZ 65(percent! I haven't seen the sheet yet. They are percentages, not just numbers?) is easier to relate to than SIZ 13.

When they decided to retire the Resistance Table, converting to percentile characteristics made more sense. Not only can you directly oppose a skill with a characteristic (or vice versa), you render Stamina %, Idea %, Know %, and so forth superfluous. As a side effect, INT, EDU, and SIZ are on the same scale as the other stats. (The 3d6 vs 2d6+6 vs 3d6+3 always rankled a bit, even though I understand the reasoning.) I'm not sure how this compares to the MRQ solution of adding parallel skills -- Brawn, Endurance, Persistence, Evade -- but I'm willing to give it a try.

BTW, the character sheet has three boxes for each characteristic or skill: percentile, half percentile (hard success), and 1/5 percentile (extreme success / old-style characteristic). The latter two are half-size and stacked atop each other.

Frank

"Welcome to the hottest and fastest-growing hobby of, er, 1977." -- The Laundry RPG
 
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When they decided to retire the Resistance Table, converting to percentile characteristics made more sense. Not only can you directly oppose a skill with a characteristic (or vice versa), you render Stamina %, Idea %, Know %, and so forth superfluous.

Sorry. The derived percentile values already do exactly the same, only simpler. I can see the reasoning behind this change, it's just that it is poor reasoning.

As a side effect, INT, EDU, and SIZ are on the same scale as the other stats. (The 3d6 vs 2d6+6 vs 3d6+3 always rankled a bit, even though I understand the reasoning.)

And in the process breaking away of the established attribute-formulas of coreBRP. I already look forward to the new SIZ-dicussions:p And again; does the sheet state "SIZ 65%" as opposed to just SIZ 65?

I'm not sure how this compares to the MRQ solution of adding parallel skills -- Brawn, Endurance, Persistence, Evade -- but I'm willing to give it a try.

Yeah, I'll guess I'll try it as well.

BTW, the character sheet has three boxes for each characteristic or skill: percentile, half percentile (hard success), and 1/5 percentile (extreme success / old-style characteristic). The latter two are half-size and stacked atop each other.

And I fail to see the improvement. I only see clutter.

Edited by Baragei
correcting, correcting...
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