Wednesday, February 6, 2013

An abstract fatigue model for travelers


In the Palantir Commission campaign, there will be a lot of travelling, some of which will be into the wild. The Palantir commission is a gritty campaign: where everything will try to wear the characters down, not just swords and Owl bear claws. It is, in fact, an important aspect in some part of the campaign. The original MERP module had a bit of a nutty way to model that (calculators and lots of floating point tables to look at). I want to create a realistic model which isn't going to slow the game down, but will encourage the players to be thoughtful about their travels. Carrying a tent and a bedroll in one's backpack isn't going to be enough!

I see FPs as a short term concept: most players can recover from depleted FPs in 1-2 hours. I don't want to change this. In our campaign, we are also using AP (Cole D, The last Gasp, Pyramid#3/44), which I see as "anaerobic FP", which works in the minute scale. I'm proposing here a mechanics to deal with day-scale fatigue, which uses an exhaustion illness, and some guidelines on abstractly figuring out the character's starting FP at the beginning of an encounter.

What do we know about Fatigue from GURPS's basic

GURPS's rules are pretty good to model all sorts of factors in the short term: not sleeping enough, skipping meals, exposure to cold while wearing a bathing suit, this is all in the Basics book. In the end, however, an hour of rest with a meal brings back 7 FP, let alone a full night of sleep. There seems to be no way to wear travelers down at all for as long as they can rest every now and then.

  1. Sleep : Everyone needs 8 hours of sleep
    1. Staying up late costs 1FP + 1FP/4 hours of missed sleep
    2. Waking up early : cost twice as much sleep time for the following night.
  2. Food : Everyone needs 3 meals a day
    1. Each skipped meal costs 1 FP, must be recovered by eating, not resting.
  3. Water : Everyone needs X per day.
    1. ...
  4. Hiking : Encumbrance dictates the FP cost of each hour
    1. 1FP (None), 2 FP (light), 3FP (medium), ...
    2. Terrain and weather affect the distance covered.
      1. Limited by the weakest link.
      2. Mitigated by Leadership.
  5. Exposure : Exposure to cold really burns through FP at a high rate!
Reader interested in other interesting thoughts about Fatigue should Read "The Last Gasp", from the Pyramid #3/44. I don't want to change the FP recovery-based mechanics, so I created an illness called exhaustion to model long term exhaustion.

Principle of a recordskeeping-light long term exhaustion

  • A travel routine is determined in the form of a schedule.
  • The accumulated FP at any point of the day can be determined just before an encounter.
  • Long-term effect of exhaustion is an illness, and slows down the recovery of FP.


Setup a travelling routine

Here is a simple example for a sustainable, full day of travel:
  • Sleeping : 8 hours (10PM -6AM) [FP reset]
  • Eat : 1 hour (6AM-7AM)
  • Travel : 4 hours (7AM-11AM) [see below]
  • Eat, rest, graze : 1 hour (11AM-12PM) [regain 7 FPs, 4 FP (exhaustion), 2FP (exhaustion II), ...]
  • Travel : 4 hours (12PM- 4PM) [see below]
  • Encamp, graze : 1 hour ( 4PM - 5PM ) [no FP gained]
  • Eat : 1 hour (5PM-6PM) [regain 7 FPs, 4 FP (exhaustion), 2FP (exhaustion II), ...]
  • Free time: 4 hours (6PM - 10 PM) [Ideal for long-tasks, or catching up on sleep.]

New (or modified) rules on Fatigue

  1. Horseback riding : Let's assume that horseback riding is a FP neutral activity: yes, it is tiresome, but yet again, the characters are sitting all the way through and cannot get themselves reeling just by riding on a mount. Medium Encumbered expend at the rate of 1FP/2h, Heavy Enc. 2FP/2hr
  2. Exposure: GURPS rules on cold exposure are harsh if considered in the long term. They are also onerous to keep track of. Again, the rate of FP loss is tempered by the small and regular pause that PC will take to manage fatigue. The consequence of this is dealth with in term of distance traveled in the Hiking rules. At the end of a riding period (or at least halfway through), apply the following: -1FP/4h is raining/snowing, -1FP/4h if slightly outside of the temperature comfort range. 
  3. Shitty food: Whoever cooks must roll a survival check. On a failure, the bonus 1 FP recovered when eating and resting is negated.
  4. Night watches: Thoses who stay up late lose 2 FP, those waking up early will need to recover during the free time slot or lose 2 FP. Middle of the night watches count as staying up late.

Inferring FPs just before an encounter begins

Example: A group of travelers are interrupted in their progress around 10AM. The temperature is 5C, low wind, and it is raining. Player A took the first watch and missed the first half of the night's worth of sleep. Player B took the second watch. Because of the rain, they decided to skip breakfast in hope of finding shelter on time for lunch.
  • Three hours of riding light : 0 FP.
  • Three hours, 5C, low wind, wet clothes : 1 FP (rain)
  • Meal skipped 1 FP
  • Player A : 2FP (staying up late)
  • Total : -4 FP (Player A), -2 FP (Player B)
At the time that an Encounter begins, if a character is at FP/3 or less, then he/she must check for exhaustion.

Are we there yet?

In the situation where a lot of distance is covered in an abstract way. Get all character to roll a HT+3. The positive margin (minimum of 1) will be the number of days that a well managed travel routine can be maintained before a character must take a half day or more of rest. Adjust the check to account for various factors that matter. In a group setting, the weakest margin dictates the timing to rest for everyone. If, for any reason, travel must go on passed some of the character's margin, they will end their travel after completing as many checks vs. exhaustion as there are days of forced travel. 

Example: A company of 5 are hurrying to get back to town. They all have HT of 10 (for simplicity), the margin on HT+3 for each of them is PC1:+3, PC2:+5, PC3:+2, PC4:+6, PC5:+4. After two days, it is determined that it will take another two days to complete the trip.  They press on. PC3 will have to check twice against exhaustion, potentially getting as much as Exhaustion II, PC1 will check once. The company should let PC1 and PC3 get over their exhaustion. All other PCs are ending the trip with nothing more than a sore derriere.


  1. One thing I've contemplated, and this would make an interesting Pyramid article, I think, is to actually break down FP costs for metabolic activities. Say you burn something like (um) X FP every two hours just by living. Eating a meal gives you Y FP back, making FP a proxy for calories consumed or burned.

    Then, activity, from walking around to combat to lifting things, always has a FP cost.

    It's quite similar to what you're trying to do - force the players to care about travel, food, and rest via a game-mechanical outcome.

    1. This implies a redefinition of the FP as something that model fatigue on the day scale. I think that, based on your article "The last Gasp", you tend to think of FP as such. Your model changes this to a day-like scale. It took me forever to accept a recovery rate of 1FP per 10min from Basic, but I think that I do now. I'm trying something a little different where the hour-scale fatigue can be altered by levels of exhaustion: someone on top of their game will recover from a blast of efforts quick, while someone who is run down won't, and may start getting other ailment in the process.

      Your sketch of a metabolism model essentially parallels a caloric tracker. The couter-balance to this is that people can draw from their own body seemingly any amount of energy if they have the stamina. More robust people (HT high) will be able to sustain fatigue better than low HT people. Unless you want to simulate at a fine grain level, it only matters to know how tired the characters are when an important scene, or encounter begins. Just as an encounter begins, you need to figure out how much of the total FP is tied down into recent strain. This smells to me like a HT check of some kind, modified by recent strain maybe. In the end, I think that we only want to set the stage to reflect the situation (how much FP you've got), and emphasize on the story being told.

      Just thoughts. Thanks for yours.

  2. Nice! Give it a nice layer of polish, and it would be pyramid-worthy IMHO

    Also, a minor nitpick, Cooking is the skill for cooking fancy things 8the kind of skill you can expect a Le Cordon Blue chef. Housekeeping (when in an urban environment) and Survival (when in the wilderness) are the skills to use for non-fancy cooking

    1. Good point about Cooking.

      I want to come up with wilderness navigation rules and lightweight travel distances and I think that it may make a nice story, maybe general enough for pyramid with some work. Thanks!