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Old 10-19-2013, 03:26 PM   #1
Peter Knutsen
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Join Date: Oct 2007
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Default Trouble with Night Vision/Colour Vision model in Sagatafl

I have a model for Night Vision and Colour Vision, in Sagatafl. It's better than nothing, but not by much. And that bothers me.

So I'm wondering if a few of you want to read my description of how Sense rolls work, and see if you can think of a different implementation from the one I use for regular Senses (including Vision), where everything works fine.



Sense rolls use the normal Sagatafl roll mechanic, with the added tweak that all Sense rolls use the Safe Roll rule, meaning that they can't Fumble. No matter how badly you roll, you can't do worse than failure, the absence of detection-of-stimuli. (Some other rolls can also be Safe Rolls, usually at the GM's call, as per his sense of realism, or sometimes the rules will probably say outright that certain rolls should be Safe.)

You roll a number of twelve-siders equal to the stat rolled for, the attribute or skill or sub-attribute or "derived", or in this case the Sense.

Each one that equals or exceeds the Roll Difficulty (RD) is a Success. More Successes are usually better, and of course they are more desirable in an Opposed Roll (e.g. Hearing vs Stealth Skill). If you get no Successes then you have a failure, or possibly a Fumble, except Sense rolls are Safe Roll so it's always just a failure (no "Ow! I sprained my nostrils!").

An average Human has a Perception of 3, with about 16% of the population being Perception 4, and much fewer being better than that, and the maximum being Perception 9, making you one-in-a-billion in world demographic terms, and of course exemplified by Sherlock Holmes. Below-average Perception can also occur in Human biological variety, about 7% are Perception 2, and about 0.15% are Perception 1, with lower values being rare.

Characters can have different Perception values for different Senses; this fuctioning as a sort of sub-Attribute, for instance one character can be very inclined to vision, so he's Perception 4 but Vision 5. I'm either slightly inclined to Hearing or slightly disinclined to Vision, so either Perception 4 and Vision 3, or more likely Perception 3 and Hearing 4.

It'd be quite reasonable to say that Leonardo da Vinci, in addition to being Intelligence 9, also was Vision 8 or even 9, in spite of not having quite such an extreme overall Perception value (maybe only 6 or perhaps 7). He really, really cared about that Sense.

Different Sense values represent fixed permanent inclinations, possible due to neuro-structure, or formative experiences in early childhood. You can't train Attributes or sub-Attributes, or Senses.

Sensory acuity is handled via a different mechanic:
permanent modifiers to the Roll Difficulty of the roll.

Normal Humans have an RD modifier of +0 for each Sense (this means the baseline is Humans - it's not like Humans have a poor Sense of smell and dogs have a decent Sense of smell, but rather Humans as the norm have a decent Sense of smell and dogs then have a fantastically amazing Sense of smell), but individual Human specimens may have an RD bonus of -1, or in extreme cases even -2. It's quite common for some people to have one Sense that's more acute than average, and I've read once that the test pilot Chuck Yeager had really sharp vision, so that could be an example of -2.

Impaired Senses are of course also possible, a penalty of +1 or higher, potentially much higher. Another possibility again is that a Sense is completely absent, as in Blind, Deaf or Anosmic. In this way there's a distiction between actually Blind and Legally Blind: The former sucks more.

The standard "adventuring" RD is 8, the equivalent of an unmodified roll in most roll-under systems (such as GURPS or Hero System). For everyday routine things you use a lower - easier - RD, even very low for the really easy. It's hard not to notice it if there's an elephant in the room. Everybody has in fact noticed it. They just pretend they haven't.

Rolling twelve-siders, you can't beat an RD of 13 or higher, meaning that for normal Humans, RD 13 is not perceivable ever, no matter how hard they try, how much they focus, how many time they roll. None of the twelve-siders you're rolling are ever going to come up 13.

(For Skills, you can Take Extra Time to lower the RD, and maybe with some other stat rolls too, but that doesn't work with Sense rolls.)

But of course individual Humans may have a -1 RD bonus to the relevant Sense, or in rarer cases a -2 RD bonus. Anything beyond that is superHuman, although Charles Darwin doesn't care about that. Lots of animals have superHuman Senses, with bonuses as high as -5 or -6, maybe even -7 or -8. A normal dog might be Smell -5 RD and a blood hound Smell -6 RD (most animals species also have an average Perception of 4, slightly higher than the 3 of Humans), while a cat would be Smell -4 RD I think. Dogs being a very scent-based species, they also probably have a raised average Perception (Smell) value of 5 (and possibly 6 for blood hounds, although that sounds a bit extreme to me), whereas cats are only Perception 4.

This means that Sherlock Holmes with his Perception 9 cannot notice an RD 13 scent, or an RD 13 sound, or an RD 13 visual stimuli, ever, whereas if he had a dog companion, a Familiar or something, it would have a fairly high probability of noticing even an RD 14 or 15 scent or sound, even if it has a Perception as low as 5 (or more appropriately for a pet of Holmes, 6).

Another Human with a keen Sense of smell (-1 RD bonus) might notice the RD 13 scent, but it's not likely, and he'd never notice the RD 14 scent.

Strength of stimuli also raises RD, of course, e.g. distiance for most Senses.

One further rule is that all characers have a Casual Perception modifier, which is applied to all Perception rolls when the character isn't being attentive, hasn't got any reason to be attentive (meaning you're always attentive while in the dungeon, obviously, but if you're in your home, or you're at a school or work place where you're comfortable, then you're not).

Normally this modifier is -2, meaning that most Humans have a Perception of 3 but a Casual Perception of only 1 (meaning fairly low odds of Casually noticing an RD 12 sniper on a roof). A few Humans, with some odd brain fault, may have a worse modifier (maybe if you're Absent-Minded it becomes -3?). You can reduce this modifier by 1 with a specific inborn Genius Trait, and by another 1 with a particular kind of training regimen (many scout/spy/investigator-type characters get this during training, or learn it on the job later). Sherlock Holmes, of course, would have both.

The Casual Perception modifier is ignored if it is zero. If not, then it applies to all Sense rolls.
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Old 10-19-2013, 03:27 PM   #2
Peter Knutsen
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Default Re: Trouble with Night Vision/Colour Vision model in Sagatafl

Okay, so far so good.

I've got Sense values for Vision, Hearing, Taste, Smell and Touch. Exotic beings may also have different Senses, such as the Life Sense of many (if not all) Undead, and Danger Sense is (or can/should be viewed as) a Sense. Same with Senes Holy/unHoly.

That works fine. Strength of stimuli, you determine final RD, then you roll to see whether X is noticed or not.

The problem is, I've opted to have Night Vision and Colour Vision as separate Senses. And that's not too elegant. It means that normall you roll for the Sense of Vision, but in low-light conditions you roll for Night Vision instead. If you for some reason need to tell certain colours apart, e.g. determine whether a particular clothes item for sale is or is not your girlfriend's favourite colour, then you roll for Colour Vision.

Also, the Colour Vision Sense value affects the character's Aptitude for some Skills, e.g. many artistic Skills. Better Colour Vision means they're easier to learn, worse Colour Vision means they're harder to learn. Some scientific Skills are also influenced, such as Chemistry (and Physics, but not very much), and of course Alchemy, and ideally Blacksmithing and certain other metalworking Skills to. (Night Vision doesn't currently affect any Skill Aptitudes, and I see no particular reason to change that.)

Colour Vision is abstract. We don't know which colours it is someone with a +1 RD penalty to Colour Vision can't discern between. It's probably red and green, but we don't know, and we don't need to know. If it's a +2 RD or +3 RD penalty then it's probably something fairly exotic, and if it's much higher than that then it's effectively complete Colour Blindness. likewise, a -1 RD bonus is probably tetrachromaticism but maybe it's something else, and -2 RD (if possible for Humans - jury is still out on that one...) could be something like pentachromatism, or could be something else.

I don't much like the Colour/Night Vision as separate Senses thing, but I find it hard to come up with a better mechanic.

I think the way forward might be some kind of secondary modifier that modifies the primary modifier, but that sounds completely horrible to me. I like to have as much as possible pre-calculated before game start, so that in-play resolution can be lightning fast, and I find it difficult to envision a subsystem where a modifier modifies another modifier that won't slow down play by a lot. Something multi-layered is fine when it's handled by the spreadsheet during character creation, and printed in ready-to-use form on the character sheet. But during play it's a huge cost to search-and-handling and should be avoided when possible.
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Old 10-19-2013, 04:03 PM   #3
johndallman
 
Join Date: Oct 2010
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Default Re: Trouble with Night Vision/Colour Vision model in Sagatafl

Quote:
Originally Posted by Peter Knutsen View Post
... Sense rolls are Safe Roll so it's always just a failure (no "Ow! I sprained my nostrils!").
Humans with poor senses may not sprain their eyeballs, but they definitely can see things that aren't there through miss- or over-interpretation of poor-quality data. Optical illusions can cause these effects for normal senses, and people are used to the idea of ignoring or discarding information from those. People with poor senses get those effects from things that aren't designed to trick them.
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Old 10-19-2013, 06:08 PM   #4
Peter Knutsen
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Default Re: Trouble with Night Vision/Colour Vision model in Sagatafl

Quote:
Originally Posted by johndallman View Post
Humans with poor senses may not sprain their eyeballs, but they definitely can see things that aren't there through miss- or over-interpretation of poor-quality data. Optical illusions can cause these effects for normal senses, and people are used to the idea of ignoring or discarding information from those. People with poor senses get those effects from things that aren't designed to trick them.
That's true. I've just opted to ignore that, because I can't see a way to simulate it objectively. It'd have to be the kind of rules subsystem that the GM can choose to invoke when he wants to hose the players or their characters, and can choose to "forget" to invoke when he doesn't want to.

So to my mind it's better to leave it out.

Besides, Sense rolls are relatively passive in nature, compared to Skill rolls, yet a fair amount of Sense rolls can be called for during a typical adventuring campaign (dungeoncrawl, espionage, et cetera), so there could be a rather large amount of Fumbles cropping up, which the GM is then forced to deal with even if he doesn't want to. Especially if his inclination is to say that 95% of those Fumbles aren't Fumbles after all, then he'll still have to devote brainpower to determining which of the ones those are.

Attribute averages, including Perception and Sense values, also tend to be a bit lower than Skill averages. Even if the average adventuring PC has a higher Perception that the 3 of an average person (and a spy, rogue, detective or assassin could very reasonably be 5 or 6), his skills are likely to be much higher still (Stealth of 8, 9 or even 10, e.g.). And during adventuring you'll occasionally face some really hairy Sense rolls RD, like 11 and even 12, which if they are all Safe Rolls constitute opportunities to get "early warning" about approaching danger, e.g. first an RD 11 roll to notice the slimy goblinoid shadowing you down in the Mines, then an hour later an RD 10 roll, then an RD 9 roll, as more and more of the Fellowship become aware of it.

If all those rolls are not Safe Rolls, then you'll end up with a lot of sprained eyeballs and nostrils and ears. Or a lot of cases of the GM needing to override the roll mechanic outcome. Me, I'm lazy. I'd like to avoid having to perform that kind of work, as a GM.

Of course it would be desirable to be able to have Sense Fumbles. Characters with strong prejudices or outright mental disorders (like the female thief character from the TV show "Leverage", who's extremely afraid of horses) ought to occasionally perceive all sorts of things that aren't there. Black-skinned youths who look like they might be carrying concealed knives or even guns. Women who look like they might enjoy being grabbed, pulled into a dark alley, and ravished. Cats who look like they're secretly trying to cast a Dark spell on you.

Misperceptions are also more likely to occur in a stimuli-rich enviroment or situation. If that black-skinned youth is stark raving naked, and is smiling and looking like he's madly in love with the entire world, because he's high on one of a particular category of recreational happy-drugs, then you'd have to be extremely racist to truly suspect that maybe he's got a tiny weapon stashed away in his rectum, and that he's going to pull it out and use it to murder you, if you fail to maintain vigilance.

On the other hand, if you're in a dungeon, afraid and wounded, and there are all sorts of noises from geology, dripping water, creaking rocks due to a nearby semi-dormant volcano, and everybdoy is carrying torches throwing wild shadows everywhere, and nobody has had a bath for the last 4-5 days, wearing clothes filthy with blood and slime and worse, then it's fairly easy to start imagining that you're percieving all sorts of things that aren't there.

There's no tweakable "noise" factor in Sagatafl's roll mechanic. If you raise the RD, you increase the chance of failure and of Fumble, and decrease the chance of Success, or if you lower the RD, you increase the chance of Success and lower the chance of failure and of Fumble.

It's not like in GURPS, where as a house rule, you could sometimes roll 2d9 or 1d20-1 or 4d4+2, or 6d3, instead of 3d6, if you want some rolls to be "more chaotic" and other rolls to be "more reliable". Or in FUDGE where you can (and I believe the text actually mentions that as a possibility) sometimes roll 3dF or 5dF instead of the recommended norm which IIRC is 4dF, to tailor the variance to the situation.
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Old 10-19-2013, 06:29 PM   #5
Anthony
 
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Default Re: Trouble with Night Vision/Colour Vision model in Sagatafl

The real problem with critical failures resulting in seeing things that aren't there is that most of the time the GM is only calling for a roll when something actually is there, and you can see things that aren't there when there really isn't anything.
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Old 10-19-2013, 06:34 PM   #6
Peter Knutsen
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Default Re: Trouble with Night Vision/Colour Vision model in Sagatafl

Quote:
Originally Posted by Anthony View Post
The real problem with critical failures resulting in seeing things that aren't there is that most of the time the GM is only calling for a roll when something actually is there, and you can see things that aren't there when there really isn't anything.
That is certainly a big problem. Good point!
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