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Old 03-20-2009, 11:38 PM   #41
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Default Re: Cthulhu in GURPS 4e

Quote:
Originally Posted by David Johnston2
Once you've got the Delusion, no better fate can be imagined.
Hmm... maybe... Perhaps it's the ones with a shred of sanity left that might try to run :/

"Poor blighters... Even men as corrupt as they don't deserve to die like that."
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Old 03-29-2009, 04:59 AM   #42
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Default Re: Cthulhu in GURPS 4e

I'm kind of enthused at the prospect of running CoC with GURPS, even though we haven't played yet. (Had to reschedule the game for next Friday.) I've been looking over the rules and I've typed up some notes. Nothing revolutionary here, but I figure I'll post them for anyone who's interested. I'll be using the rules in Cthulhu Lives!, with the following modifications. Some of these ideas were appropriated from other contributors to this thread, most notably Gollum. (Thanks!)

Character Creation:
Starting characters are 100 points. Advantages are limited according to Keeping It Real by Paul Blackwell on pg. 31 of issue 3/21 of Pyramid magazine. [This is to make suspense a little easier to maintain, while still allowing players a wide range of character creation options. But if you don't have that issue, don't worry about it. The impact is small, and some would prefer the pulp feel of the standard rules anyway.]

The Mythos Awareness Advantage from GURPS CthulhuPunk does not exist. [I don't think it fits the genre.] The Innsmouth Look Disadvantage is tricky to write up and I doubt anyone would want it, so I'll ignore it for now.

Fright Checks:
When making a Fright Check, refer to the sanity loss for a failed roll in the BRP system. The character receives a penalty equal to (maximum possible die roll)/2, provided the max roll is no more than 24. For higher rolls, the penalty is 10 + (Maximum possible die roll)/10. If a roll has a modifier (e.g., 1d6+1) then double the modifier for this purpose (so 1d6+1 becomes 1d6+2). If the Fright Check is due to a corpse or other mundane cause, however, use the standard GURPS modifiers instead.

The rules for Stress, Derangement, and therapy from GURPS Horror, pg. 141-146, will be used. (And naturally, GURPS Horror contains is lots of other good material for CoC campaigns as well!) For more realism, the "shell shock" options on pg. 34 of GURPS Tactical Shooting will be used for some Fright Checks, especially those caused by mundane horrors, rather than Sanity-Blasting Mythos effects. [But none of this is vital. You'll do fine with just the Basic Set, if that is all you have.]

Cthulhu Mythos Skill:
Oddly, Hidden Lore is an average skill in 4e, even though it seems to meet the criteria for a very hard skill on B168. I will use The Cthulhu Mythos skill from Cthulhu Lives! instead. This skill does not default to Occultism, as in CthulhuPunk, but some occultists do stumble upon Mythos lore and acquire the skill.

A Mythos tome allows the reader to increase Cthulhu Mythos skill by spending a maximum number of character points equal to half the percentage of skill increase it grants in BRP (round down, minimum 1). [If we assume 99% skill in BRP is equivalent to a skill of IQ+10 in GURPS, this works out about right.]

Whenever characters fail a Fright Check from an encounter with Mythos phenomena and gets a result of 13 or higher, they are entitled to spend one character point on Cthulhu Mythos. Otherwise, they cannot increase this skill without the help of a tome.

Magic:
Spells are IQ/H skills, or VH if they cost more than 12 magic points, and have no Default. They function as in BRP, but read POW as Will, Magic Points as FP+Energy Reserve, and "Resistance Table roll" as "Quick Contest". On a critical failure with a summon/bind spell, the creature appears, but is not bound.

Mythos Creatures:
Some excellent monster write-ups can be found here.

Converting characters from BRP:
The system in Cthulhu Lives! is good for monsters, but it lacks detail for humans. Here are some alternate rules for converting PCs and important NPCs.

Do not reduce IQ by two, as Cthulhu Lives! recommends. Instead, the difference between 10 and the level of any Attribute should be reduced by half, and the Attribute should then be rounded toward 10. This is to account for the facts that BRP Characteristics have less impact on play than GURPS Attributes, and are often quite high or low. (Ignore this rule if the character has a good reason to have an extreme Attribute.) Following are variant options for converting Attributes for humans:

GURPS: BRP
ST: (Str+Siz)/2 (Alternately, use Str for ST! and Siz for HP, if the disparity is small.)
DX: Dex
IQ: (Int+Edu-3)/2
HT: Con (But note that in BRP, "magic points" are based on POW. So to preserve magical power, adjust GURPS FP to equal BRP POW, or give the character Energy Reserve to make up the difference.)
Will: Pow
Per: This is composed of the Listen and Spot Hidden skills. You could average them, or use the lower one for PER and add Acute Sense to model the other. Or use the higher one for PER, and take a Disadvantage that impairs the other sense.

Skill Equivalents (Or, Further Evidence That I have Too Much Free Time):
The skill conversion system in Cthulhu Lives! gives fairly low scores on average (11), and makes skills higher than Attribute+4 impossible. Also, it converts percentages into scores of Att+x, even though Characteristics don't affect skills in BRP. This doesn't agree with me.

In BRP, 50% is the level at which a character can make a living with his skill, and has the maximum chance of succeeding at an easy task. This is probably equivalent to skill 12 or better in GURPS. A character with human maximum skill still fails often in difficult conditions, so no one seems to have a very masterful level of skill in BRP. So 99% should represent 19 or, at best, 20.

Therefore, if we just use the Probability of Success table on B171 (rounding to the nearest whole number), and add 2 or 3 to the scores, we can get reasonable skill levels. If the BRP skill falls between the listed percentages, count it as the lower one. A BRP score of 99% is one level above the top score on the table. For 100%, assign any value you like - this is only used for beings with superhuman abilities.

If the listed level of GURPS skill is lower than a character would have if they spent 1 character point on it, or if no skill points were spent on it in BRP, then they do not have the skill.

Here is the table, using the more generous +3 modifier. This is mainly for PCs and major villains, so I figure we can cut them some slack:

BRP: GURPS
100%: 21+
99%: 20
98%: 19
95%: 18
91%: 17
84%: 16
74%: 15
63%: 14
50%: 13
38%: 12
26%: 11
16%: 10, or what the character would have if he spent 1 cp on the skill, if that would be less.
9%: 9, or a Dabbler Perk for Default +2, if that would be less.
5% or less: Default

I thought about making a conversion from the "How Good Am I?" table on pp.177 of the CoC Keeper's Companion I, but I find it hard to harmonize with the CoC core book, much less GURPS. Still, that table and mine seem to be in the same ball park, at least in part. It equates 35-40% with a bachelor's degree, 40-50% with a master's, and 50-59% with a master's plus practical experience. (And then we go to Fantasy Island, where a Ph.D has a minimum of 60% right out of grad school, with no upper limit. Which is the same as a pro athlete. Right...)

If we ignore the inflated numbers for a Ph.D, I think my table corresponds in a generous but believable manner, as intended. If we subtract 1 from the GURPS skill lvls on my table, and cut the Ph.Ds down to a more plausible 50-65%, I think the correspondence is more realistic.

Last edited by GodlessRose; 07-11-2017 at 11:26 AM.
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Old 03-29-2009, 08:35 AM   #43
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Default Re: Cthulhu in GURPS 4e

Quote:
Originally Posted by GodlessRose
Some of these ideas were appropriated from other contributors to this thread, most notably Gollum. (Thanks!)
Don't mention it! Most of "my" ideas were clarified thanks to the discussion with you. I used them, of course, but not in a such formal manner: it was more intuitive and approximative.

Quote:
Originally Posted by GodlessRose
Nothing revolutionary here, but I figure I'll post them for anyone who's interested.
This is a great work! Thank for writing it clearly and posting it. It will help a lot of players.

I would only correct one thing:

The sentence: "If a roll has a modifier (e.g., 1d6+1) then double the modifier for this purpose (so 1d6+1 becomes 1d6+2)." could be replaced by: "If a roll has an odd modifier (e.g., 1d6+1), round up." It gives the same result but, to my mind, it is more easy to understand.
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Old 03-30-2009, 06:01 AM   #44
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Default Re: Cthulhu in GURPS 4e

Quote:
Originally Posted by Gollum
The sentence: "If a roll has a modifier (e.g., 1d6+1) then double the modifier for this purpose (so 1d6+1 becomes 1d6+2)." could be replaced by: "If a roll has an odd modifier (e.g., 1d6+1), round up." It gives the same result but, to my mind, it is more easy to understand.
My purpose in that rule was to make sure the Fright Check penalty keeps pace with the average sanity loss in BRP. So any whole-number modifier would need to be doubled. If there were a 1d8+2 sanity loss, it would need to become 1d8+4. So just rounding up wouldn't work in all cases.

Of course, there may not be any +2 modifiers, in which case your version would be perfect. But I don't know the game well enough to be sure there aren't.

I do tend to over-think things, though...
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Old 03-30-2009, 07:57 AM   #45
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Default Re: Cthulhu in GURPS 4e

Quote:
Originally Posted by GodlessRose
My purpose in that rule was to make sure the Fright Check penalty keeps pace with the average sanity loss in BRP. So any whole-number modifier would need to be doubled. If there were a 1d8+2 sanity loss, it would need to become 1d8+4. So just rounding up wouldn't work in all cases.
OK. I didn't understand... Sorry.
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Old 05-13-2009, 04:50 AM   #46
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Default Re: Cthulhu in GURPS 4e

I will start a new Cthulhu campaign in a couple of weeks and I found this thread invaluable.
I agree with almost everything in GodlessRose's conclusion, so let's see what I disagree with:
(any feedback on my ideas would be greatly appreciated)

Mythos skill default.
I find it logical to use the CthulhuPunk-rule that Mythos skill defaults to Occult - 12.
If you read Lovecraft's works you notice that the mythos tomes are very rare, but definitely not unknown - so a person with high a value in the occult should probably have heard of Necronomicon for example.
I also like the idea that every time the mythos skill increases you have to roll a fright check with the new skill level as negative modifier.

Mythos skill-level is GM-domain.
In CoC BRP the Cthulhu Mythos skill actually works differently than all other skills, as you never get skill checks in it.
In CoC d20 Cthulhu Mythos also works different as it is the only skill using %.
So I think that it is only logical that only the GM, not the players, can decide when the Mythos skill raises.
The only way a player can control their mythos skill is by raising their occult skill.

Mythos skill - sanity relationship.
In CoC BRP max SAN = 99 - Cthulhu Mythos.
In GURPS this should mean that a Cthulhu fright check fail if you roll (20 - mythos skill) or higher.
The game logic is actually not that a high mythos skill turn you insane (even if that could be true too), but that knowledge makes fright checks even more horrifying; it's horrible to find a dead mutilated body, but it's even more horrifying to when you realize that the body is a close relative!
Remember that the fright check rule of 14 is still in play, so the new rule will not kick in until the mythos skill rises above 7.

Successful fright checks.
In the original CoC BRP rules a monsters sanity loss value could be something like 1/1d6 or 1d10/1d100.
The value after the slash is of course the sanity points lost after a failed SAN-roll, but the value before is actually the number of points lost when you SUCCEED!
In GURPS this should mean that you actually can go insane even if you succeed with the fright check.
So: for cthulhu mythos fright checks in GURPS (not for ordinary fright checks) you roll on the fright check table even if your fright check succeed, but the margin of success is a negative modifier.
So basically you roll 3d and then deduct your effective will to get the modifier for the 3d-roll on the fright table.
This could be simplified by rolling (6d - effective will) directly on the fright check table.

Sanity modifier on fright checks
I like the simplicity in taking max SAN loss in CoC BRP and divide by 2 to get the fright check modifier in GURPS.
I also understand GodlessRose's idea with doubling CoC-modifiers, but I have a simpler solution:
Instead of half max, use average and round down - and the problem with modifiers is automatically solved.
When the average increases above 12 use 10 + average/5 instead (still max -20).

Unsolved problems...
In CoC you lose SAN when you are using magic/psionics. There is no SAN roll involved - you just lose SAN.
The human mind is not supposed to handle magic/psionics so therefore you lose your sanity by using them.
I haven't found a good way to emulate this in GURPS yet.
I'm thinking of using Threshold-Limited Magic from GURPS Thaumatology p76;
Of course magic still costs FP, but it ALSO cost tally:
Halve the threshold, double the recovery time and use the fright table instead of the calamity table.
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Old 05-13-2009, 04:36 PM   #47
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Default Re: Cthulhu in GURPS 4e

Long time CoC player. Adapted the Genre heavily into Fantasy Campaigns struggling hopelessly against the ultimate uncaring powers of the mythos. Running/writing a steampunk fantasy post-apocalyptic campaign for over a decade now, just now getting into GURPS and converting my campaign.

My company web page <below> is based on programming this into a PC game. free GURPS netbooks based on this campaign are a by-product of this endeavor. I don't have any content up for it yet but we will soon.

That being said i've never come across a way of translating the CoC sanity system to my satisfaction without completely transplanting the CoC sanity rules. IMHO the gurps fright check system is mediocore at best for anything other than occasional randomness.
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Old 05-13-2009, 04:43 PM   #48
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Default Re: Cthulhu in GURPS 4e

Quote:
Originally Posted by rcarter
That being said i've never come across a way of translating the CoC sanity system to my satisfaction without completely transplanting the CoC sanity rules. IMHO the gurps fright check system is mediocore at best for anything other than occasional randomness.
There was some posted rules someone came up with for dealing with genres with lots of fright checks, CoC-style. I'll see if I can find it.

EDIT: Here, courtesy of everyone's second-or-third-favorite Canadian.
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Old 05-13-2009, 04:47 PM   #49
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Default Re: Cthulhu in GURPS 4e

Quote:
Originally Posted by Anth
Unsolved problems...
In CoC you lose SAN when you are using magic/psionics. There is no SAN roll involved - you just lose SAN.
The human mind is not supposed to handle magic/psionics so therefore you lose your sanity by using them.
I haven't found a good way to emulate this in GURPS yet.
I'm thinking of using Threshold-Limited Magic from GURPS Thaumatology p76;
Of course magic still costs FP, but it ALSO cost tally:
Halve the threshold, double the recovery time and use the fright table instead of the calamity table.
Have you looked into contractual magic and taint? I thought of CoC when reading it.
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Old 05-18-2009, 12:46 PM   #50
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Default Re: Cthulhu in GURPS 4e

Quote:
Originally Posted by Crakkerjakk
Have you looked into contractual magic and taint? I thought of CoC when reading it.
I think I know what you mean from other RPGs, but I have no memory of contractual magic nor taint in GURPS.
The closest that I have found is Spirit magic with spiritual distortion in GURPS Thaumatology p90.
Did you mean something else?
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