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| Jumping on Earth (left) and on the Moon (right) |
In order to give advice, I had to understand the rules, so I went through and read them (GURPS Basic Set, p. 350).
I quickly found them confusing, badly explained and broken. So in an effort to make them easier to understand and use (especially for newer players) I made some modifications.
The basic ideas are sound – tasks involving full-body co-ordination or judging ballistic arcs will be different than you expect, and stronger gravity will put strain on the heart and reduce blood flow to the brain. The issue is with the two advantages designed to mitigate these penalties: G-Experience and Improved G-Tolerance.
G-Experience assumes you can never adapt to a different gravity field fully. This is ridiculous! In even a few hours spent on the Moon, the Apollo astronauts figured out how to move more effectively and got used to bunny-hopping. Astronauts on the International Space Station adapt to microgravity so well they can fly gracefully through the air long before their six-month stay is over. The human brain is incredibly adaptable – at a rough guess I'd say you'd fully adapt to any gravity field within six months to a year of living in it.
Moreover, the two advantages overlap in weird and confusing ways. How far around your G-Experience can you tolerate? Is it one G-Increment? If so, does that mean you halve penalties in the 0.2G around it too? If you increase your G-Increment, does it affect your G-Experience?
The rules are messy, incomplete and confusing, so I made a replacement for the rules and the two advantages.
G-Increments and Attribute Penalties
The following rules replace those under the G-Increments and Attribute Penalties section in the Different Gravity box on B350.
Your G-Increment is your body's tolerance to different gravities. By default this is 0.2G.
DX: For every full G-Increment above or below your native gravity, you are at -1 DX. This applies only to activities that require bodily agility or judging trajectories; it affects Broadsword, Driving, and Guns, but not Beam Weapons, Surgery or Lockpicking. If you have Gravity Experience (see below), use the gravity that results in the lowest penalty. For working out DX penalties, Gravity Tolerance (below) has no effect – your G-Increment is always 0.2G.
IQ and HT: For every two full G-Increments above your native gravity, you are at -1 IQ and -1 HT, in addition to any effects on DX. Lower your FP score by the same amount. This is due to blood flow – your heart must work harder to pump blood around the body, especially upwards to the brain. Lower gravity has no effect. For figuring IQ and HT penalties, your G-Increment can be increased by taking Gravity Tolerance (below). See Temporary Attribute Penalties (B421) for how attribute penalties affect secondary characteristics and skills.
Example: A character is native to Earth (1G) and has spent several years working on the Moon, acquiring Gravity Experience (0.16G). The character is currently in 0.5G gravity. This is more than two G-Increments away from 1G, resulting in a penalty of -2 DX. But it's less than two G-Increments away from 0.16G, resulting in a penalty of -1 DX. The final penalty is the lower of the two: -1 DX.
Example: A character native to Mars (0.38G) is visiting Earth (1G). This is three G-Increments above their native level, so they take -1 to both IQ and HT. If this character had Gravity Tolerance (0.5G), then this would be only one G-Increment above and they would take no penalties.
New Advantages
These advantages replace G-Experience (B57) and Improved G-Tolerance (B60), respectively.
You have experience living and working in a gravity other than your native one. You suffer no DX penalty for that gravity, or within 0.2G of it. In situations where this gravity would make a task easier, you roll at normal DX, plus the bonus for the gravity, plus an extra +1. For instance, if a normal person would get +2 to catch a ball in low gravity, you would get +3. You can buy this advantage multiple times, representing experience with several different gravities. E.g. an Earth native who has lived on the Moon and Mars would buy Gravity Experience (0.16G) and Gravity Experience (0.38G). This has no effect on HT or IQ penalties for higher gravities – for that, buy Gravity Tolerance (below).
Your body is adapted to the rigours of higher gravity, giving you a larger G-Increment for the purposes of IQ and HT penalties only. A G-Increment of 0.3G costs 5 points, 0.5G costs 10 points, 1G costs 15 points, 5G costs 20 points, and 10G costs 25 points. Realistically, normal humans should be limited to the 10-point version; cybernetics or genetic engineering may increase this up to the 15-point version.
Gravity Adaptation Time
This isn't so much a rule as guidance for how long it takes characters to learn how to adapt to new levels of gravity. Basic Set tells us that each character point is equivalent to 200 hours of learning. Given that time spent in a new environment is constant, it feels appropriate to count every hour spent awake (sixteen hours) as time towards learning it. That said, it should also count as self-teaching, which halves the effective number of hours. So this gives you eight hours of learning per day.
The most basic level of adaptation to zero gravity is the point at which you can get where want to go without bouncing uncontrollably, going in the wrong direction, spinning hopelessly, or wanging your head on doorways. You're still nowhere near as good at moving around as you are on Earth, however. This is Free Fall DX-1 and costs one point, or 200 hours of learning. This takes 25 days, a little less than a month.
The next level is being able to do basic motion in zero gravity as easily as walking on Earth. Moving around is routine and you no longer lose objects because you forgot to attach them to something or forget to anchor yourself when using tools, though you wouldn't be able to fire a gun as easily as you could on Earth. This is Free Fall DX and costs two points, or 400 hours of learning. This takes 50 days, about seven weeks.
Once you have mastered zero gravity, you can move as easily and fluidly as you could on Earth. Your brain has totally adapted your sense of motion, ballistics and co-ordination to zero gravity and you can perform almost any task at no penalty. This is Free Fall DX+5 and costs twenty points, or 4,000 hours of learning. This takes 500 days, or about a year and a half.
Adapting to a new gravity requires adjusting your co-ordination and sense of motion. It takes longer to achieve than basic competency in zero gravity because it removes all penalties, representing it feeling natural. But its faster than mastery of zero gravity because it represents only a change in the way you judge motion, whereas zero gravity requires a total overhaul of your understanding of how to move. This is Gravity Experience (above) and costs five points, or 1,000 hours of learning. This takes 125 days, or a little over four months.
The Free Fall values fit in pretty well with what I've heard of astronauts on both Mir and the ISS, and the Gravity Experience value is in the same ballpark as my initial guess, so these seem like sound assumptions!
Example: A character is native to Earth (1G) and has spent several years working on the Moon, acquiring Gravity Experience (0.16G). The character is currently in 0.5G gravity. This is more than two G-Increments away from 1G, resulting in a penalty of -2 DX. But it's less than two G-Increments away from 0.16G, resulting in a penalty of -1 DX. The final penalty is the lower of the two: -1 DX.
Example: A character native to Mars (0.38G) is visiting Earth (1G). This is three G-Increments above their native level, so they take -1 to both IQ and HT. If this character had Gravity Tolerance (0.5G), then this would be only one G-Increment above and they would take no penalties.
New Advantages
These advantages replace G-Experience (B57) and Improved G-Tolerance (B60), respectively.
Gravity Experience
5 points/level
You have experience living and working in a gravity other than your native one. You suffer no DX penalty for that gravity, or within 0.2G of it. In situations where this gravity would make a task easier, you roll at normal DX, plus the bonus for the gravity, plus an extra +1. For instance, if a normal person would get +2 to catch a ball in low gravity, you would get +3. You can buy this advantage multiple times, representing experience with several different gravities. E.g. an Earth native who has lived on the Moon and Mars would buy Gravity Experience (0.16G) and Gravity Experience (0.38G). This has no effect on HT or IQ penalties for higher gravities – for that, buy Gravity Tolerance (below).
Gravity Tolerance
5 to 25 points
Your body is adapted to the rigours of higher gravity, giving you a larger G-Increment for the purposes of IQ and HT penalties only. A G-Increment of 0.3G costs 5 points, 0.5G costs 10 points, 1G costs 15 points, 5G costs 20 points, and 10G costs 25 points. Realistically, normal humans should be limited to the 10-point version; cybernetics or genetic engineering may increase this up to the 15-point version.
Gravity Adaptation Time
This isn't so much a rule as guidance for how long it takes characters to learn how to adapt to new levels of gravity. Basic Set tells us that each character point is equivalent to 200 hours of learning. Given that time spent in a new environment is constant, it feels appropriate to count every hour spent awake (sixteen hours) as time towards learning it. That said, it should also count as self-teaching, which halves the effective number of hours. So this gives you eight hours of learning per day.
The most basic level of adaptation to zero gravity is the point at which you can get where want to go without bouncing uncontrollably, going in the wrong direction, spinning hopelessly, or wanging your head on doorways. You're still nowhere near as good at moving around as you are on Earth, however. This is Free Fall DX-1 and costs one point, or 200 hours of learning. This takes 25 days, a little less than a month.
The next level is being able to do basic motion in zero gravity as easily as walking on Earth. Moving around is routine and you no longer lose objects because you forgot to attach them to something or forget to anchor yourself when using tools, though you wouldn't be able to fire a gun as easily as you could on Earth. This is Free Fall DX and costs two points, or 400 hours of learning. This takes 50 days, about seven weeks.
Once you have mastered zero gravity, you can move as easily and fluidly as you could on Earth. Your brain has totally adapted your sense of motion, ballistics and co-ordination to zero gravity and you can perform almost any task at no penalty. This is Free Fall DX+5 and costs twenty points, or 4,000 hours of learning. This takes 500 days, or about a year and a half.
Adapting to a new gravity requires adjusting your co-ordination and sense of motion. It takes longer to achieve than basic competency in zero gravity because it removes all penalties, representing it feeling natural. But its faster than mastery of zero gravity because it represents only a change in the way you judge motion, whereas zero gravity requires a total overhaul of your understanding of how to move. This is Gravity Experience (above) and costs five points, or 1,000 hours of learning. This takes 125 days, or a little over four months.
The Free Fall values fit in pretty well with what I've heard of astronauts on both Mir and the ISS, and the Gravity Experience value is in the same ballpark as my initial guess, so these seem like sound assumptions!
Two thoughts: There's two situations in which gravity will come up. The first is where people spend a lot of time in different gravity fields (Star Trek, with characters hopping from world to world), or where characters spend most of their time in a single, non-earth-like gravity field (astronauts in orbit, colonists on mars). I'm not sure the current system really covers either well. I'll give your system a closer look when I dig into Heroes of the Galactic Frontier
ReplyDeleteThe second is that it seems like your fumbling towards familiarity penalties. Isn't it enough to say that particular gravity fields had the equivalent to familiarity penalties? For example does it really matter if you're in 0.8 gs or 0.2 gs when firing a gun? Your shot is going to be off in both, and once you've seen how much its off, it'll take the same amount time to compensate
"The second is that it seems like your fumbling towards familiarity penalties. Isn't it enough to say that particular gravity fields had the equivalent to familiarity penalties? For example does it really matter if you're in 0.8 gs or 0.2 gs when firing a gun? Your shot is going to be off in both, and once you've seen how much its off, it'll take the same amount time to compensate"
ReplyDeleteThe idea of familiarity penalties had crossed my mind but I think the size of the difference in gravity *does* matter. The main reason is that we're using the standard definition of "adventuring situations". If you're making your Climbing roll in a climbing centre on the Moon in your downtime, no big deal, you can adjust for the local gravity. But if you're climbing the outside of a dronetruck combing the lunar regolith for He-3 while being pursed by terrorists, you're not in a clear enough mind to calmly judge how much the local gravity varies before making that leap.
The scale of the DX penalty is to do with how far away local gravity is from your instinctive understanding of movement, which is what you use in "adventuring situations".
The other problem I can see with familiarities is that you'd have to have a separate one for *every* skill affected by gravity. Keeping track of that would be a headache!
Something I included in my Pyramid article, Free Falling (you might want to check it out, since its intent was to update and consolodate all 3e and 4e microgravity rules on one spot), was a No Nuisance (Free Falling) perk to help everyone avoid making those rules. There are some other useful perks in there you might like to use, too.
ReplyDeleteAlso, I like that you split out DX penalties and HT penalties for the purposes of G Experience and Improved G Tolerance. I'm making a note to do that in the future.