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Old 03-30-2015, 02:11 AM   #1
vicky_molokh
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Default [P:ES] Smell: military advice vs. RAW distance penalties

Greetings, all!

Powers: Enhanced Senses makes Smell rolls take a penalty equal to the number of yards to the source of the smell, unless one takes superhuman smelling perks. However, I've encountered advice in several military primers to avoid smoking, because they make people detectable by smell at huge distances, as long as the detector is a non-smoker who spent significant time outdoors.

Wordings tend to be something like this:
Quote:
Cigarette smoke can be detected up to one-quarter of a mile away if the wind conditions are right. You can smell fish, garlic, and other foods being cooked for several hundred meters. You may be able to detect a person who has been using scented soap or eating specific foods from up to 100 meters away, thus discovering an ambush before walking into it.
Assuming this is even partially true (and I get the impression that it is), this means one of the following:
  • Cigarette smoke should have modifiers of something like up to +400 to everyone's smell rolls, depending on circumstances. Other scents may have somewhat smaller, but still enormous bonuses.
  • Humans should start with one level of Long-Range Smell for free, i.e. the default distance modifiers for smell should be as per SSRT, not -1/yard.
  • Humans can trivially purchase the Long-Range Smell perk with minimal training, i.e. the first level should count as a non-exotic trait.

So, which one should it be?

Thanks in advance!
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Old 03-30-2015, 02:54 AM   #2
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Default Re: [P:ES] Smell: military advice vs. RAW distance penalties

Another option: the right wind conditions and direction can alter effective range for scent by factors of 100 or more.
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Old 03-30-2015, 03:08 AM   #3
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Default Re: [P:ES] Smell: military advice vs. RAW distance penalties

As johndallman says: There is a huge difference in how smells carry depending on the wind conditions and wind direction.

Also there is a huge difference in human senses, smell included.

The military advice you speak about is in a way the same as much other military advice based on the understanding that Murphy is always involved in military operations and that way too many troops try to avoid using their head for thinking. Thus it is a combination of prepare for worst possible cases and your troops doing stupid things... So while in average situations you cannot smell things that far there are cases when you can and the troops are not going to know/think about when the risk is there so better to err on the side of safety.
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Old 03-30-2015, 05:05 AM   #4
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Default Re: [P:ES] Smell: military advice vs. RAW distance penalties

Quote:
Originally Posted by vicky_molokh View Post
So, which one should it be?
All passive senses (which includes stuff like vision and hearing too) described as having ranges are *physically wrong* playable approximations. A passive sense always has a range of zero, it can't detect anything that isn't in contact with the sensor. Any time it is described with one, you are looking at somebody's approximation of how far a typical signal remains above the detection threshold under some set of conditions. Nobody lists the range of vision is not 2.5 million light years, even though most people can see something (M31 in Andromeda) that far away in certain conditions (starting with it's dark and clear, so less than half the time....)

In this case it's a combination of a much stronger signal (you probably should get a fairly large bonus for smelling burning tobacco) and a focusing effect (being "downwind" means effective odor source distances are reduced by something like the ratio of the "normal" mixing rate (whatever that is, it isn't going to be anything related to diffusion that's ridiculously slow for odor molecules despite it being commonly cited in these sorts of discussions) to the wind speed.
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Old 03-30-2015, 06:58 AM   #5
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Default Re: [P:ES] Smell: military advice vs. RAW distance penalties

Reversing the roles, try and see if some military source can tell you by what range, as the detector, you should expect to have noticed the cigarette smoke. I'd expect a much smaller value.

It does seem like square root makes a more reasonable penalty, and if the wind is on your side, you could say square root of the width of the area the smell's been blankleted over by the time it reaches you.

By RAW, though, it seems like you're out of luck.
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Old 03-30-2015, 07:58 AM   #6
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Default Re: [P:ES] Smell: military advice vs. RAW distance penalties

Cigarette smoke is certainly detectable 1/4 mile or further away. On a kayak you can smell it coming from other boats or people on the shore for amazing distances. (Even stranger, you can use the smell of outboard motor exhaust to track a boat over open water in the dark).

I don't have a particularly good sense of smell -- in fact, my wife says it's pretty bad. But when I'm outside for awhile it seems to get very honed.

This might be more of an environmental awareness thing, rather than a skill or special ability. Maybe a Survival (Terrain) roll to notice something out of place for that locale would be a good way to model it.
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Old 03-30-2015, 11:21 AM   #7
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Default Re: [P:ES] Smell: military advice vs. RAW distance penalties

Smell is weird even by the standards of senses, because it's very slow, extremely directional, and has a significant persistence. That cigarette a quarter mile away might be something you can detect, but probably 5-15 minutes after it was actually smoked.
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Old 03-30-2015, 01:31 PM   #8
vicky_molokh
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Default Re: [P:ES] Smell: military advice vs. RAW distance penalties

Quote:
Originally Posted by johndallman View Post
Another option: the right wind conditions and direction can alter effective range for scent by factors of 100 or more.
Now I don't know how to react. On one hand, looks like you're onto something with this idea. On the other, it looks extremely unGURPSy.
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Old 03-30-2015, 01:32 PM   #9
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Default Re: [P:ES] Smell: military advice vs. RAW distance penalties

Quote:
Originally Posted by ArchonShiva View Post
Reversing the roles, try and see if some military source can tell you by what range, as the detector, you should expect to have noticed the cigarette smoke. I'd expect a much smaller value.

It does seem like square root makes a more reasonable penalty, and if the wind is on your side, you could say square root of the width of the area the smell's been blankleted over by the time it reaches you.

By RAW, though, it seems like you're out of luck.
Guy with some outdoor experience says that 50 yards is about how far 'will' replaces 'can'.
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Old 03-30-2015, 03:05 PM   #10
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Default Re: [P:ES] Smell: military advice vs. RAW distance penalties

Quote:
Originally Posted by weby View Post
As johndallman says: There is a huge difference in how smells carry depending on the wind conditions and wind direction.

Also there is a huge difference in human senses, smell included.
...
So true. Before my diabetes, I once smelled my cat's favorite outdoor "den" from over 100 feet. Now, I can smell cigarette smoke from that far, maybe.

Scents are unusual in that not all parts move at the same speed or last equally as long. They separate making identification much harder over time and disatance.
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