Friday, June 11, 2010

Real World Distances

TRAVEL TIME AND DISTANCE

Ah, D&D travel. I remember plotting out how many 24 mile days my character could cover back in the day. Not very realistic if you've ever done much rucking in the real world in rough terrain. Anyone that has ever done any walking knows that this is a lot of ground to cover. That's why I think my hexploration movement rates are fairly realistic. They are generally geared to allow characters on foot to cover 4 (perhaps +/- up to 3) hexes per time period with perhaps 6 hexes for light horse.

DW and I recently covered ~35 miles on foot over three days. We hiked the Resurrection Pass North trail. We had excellent weather, good trail conditions, and it is of moderate elevation. We were hiking with full packs; I estimate that I had around 3-4 stone in my pack + 1 stone of rifle and other misc gear and DW had ~2 stone plus 1/3 stone of shotgun. We are both 20 somethings in good health and decent shape, although we are definitely not super athletic by any means. We also had the benefit of excellent boots, synthetic fabrics, and good modern packs.

My formula would say that we could cover four hexes each day. Going to the day-by-day scale and we get hexes which are two leagues across. Over each day we should have been able to cover four hexes which is 24 miles (eight leagues). That means over three days we should cover around 72 miles. We only did half that on our trip. Is the formula bad, or should we have applied modifiers to ourselves?

REDUCTIONS TO MOVEMENT ALLOWANCE

I think it is the latter. The first modifier would be anything that reduces our movement allowance.

First, DW walks slower than me even unencumbered. Her normal move might be only three hexes, not four. Nothing about male vs. female here, but maybe she took some sort of flaw at character creation to get build points for musical talents or something, setting her base move to three.

Another factor would be encumbrance. With a four stone pack plus a 2/3 stone carried rifle in my hands I am definitely encumbered to some degree -- probably enough to lower my move. If my normal enc limit is average (4 stones) then carrying 5 stones of gear would drop my move by some amount. Likewise, DW is not very strong by self admission (she must have also dumped STR at char creation) so she might be encumbered with more than 2 stone of gear.

On day two we dropped packs for a few hours and went ahead with daypacks only. That might have earned up an extra MP but we were already fatigued and possibly moving slower anyways.

TERRAIN MODIFIERS

We were in hilly terrain with mixed growth (forest to taiga) but we were going up a pass so the elevation gain was pretty moderate. As a side note, if we were bush whacking, it would have been MUCH slower going. Going on a trail is much faster, at least twice as fast. I think this illustrates the importance of trails and how they should affect terrain modifiers.

Anyways, say each hex normally costs 1 MP to enter. The dense growth would have added +1 MP. Our gentle elevation gain might have merited 0.5 MP extra but certainly not a whole extra MP (it didn't slow our speed THAT much). The trail definitely mitigated the undergrowth penalty. So I think a cost of 1-2 MP per hex is probably about right.

One neat idea that crossed my head was to use contour lines as a way of assessing extra cost for elevation change. Rather than saying, "All hill hexes cost an extra MP to enter" you can say, "It costs an extra MP to cross any contour line." Some old school maps already have these (think of B2's map). It allows for a much more natural depiction of topography and doesn't limit you to static "Hill" and "Mountain" terrain, although it can make map drawing a LITTLE harder if you don't "get" topography. I'm comfortable with topo maps so I don't mind it much. The trick is just setting the major contour interval appropriately.

On our scale with 2 league hexes an appropriate interval would probably be around 500-1000', just as a WAG. Charge one extra MPs for going up and 1/2 MP for each line crossed going down (50% to lose a MP perhaps). Anyone that thinks going down is super easy is wrong, it is really tough on your knees and feet, especially when carrying a load.



PUT IT ALL TOGETHER

What you end up with is a base speed of 3 hexes due to encumbrance, and a move cost of 1 MP per hex with perhaps 3 extra MP sucked up for crossing contour lines. So going with that we should have covered 3 * 3 -3 (for elevation) two-league hexes over three days: 6 total. That's 36 miles: which is exactly what we hiked, real world. If the DM had been generous and given us an extra hex for a half day of light load with daypacks then we'd still be close, but I spent my extra hex of move bushwhacking off trail a bit to explore rather than covering distance.

Here's a rough table of ROT's:

Average Unencumbered Move: 4 hexes on foot / 6 hexes mounted
  • Light Encumbrance: 3 hexes
  • Moderate Encumbrance: 2 hexes
  • Heavy Encumbrance: 1 hex
Base Cost to Enter Hex: 1
  • Light cover (tall grasses, light undergrowth): +1
  • Moderate cover/rough terrain (dense forest): +2
  • Heavy cover/rugged Terrain (dense swampy forest with alder thickets): +3 (use rarely)
  • Extremely Rugged Terrain (you're on the friggin' moon, and there is a swamp with alder thickets there somehow): +4 or more (use rarely)
  • Crossing contour line (uphill): Costs one MP
  • Crossing contour line (downhill): Costs 1/2 MP (roll D6, 1-3 = lose a MP)
  • Using trail: Negate effects of cover if on foot; some sort of bonus to fatigue checks?
  • Using path: Negate effects of cover if on foot or mounted; some sort of bonus to fatigue checks?
  • Using road: Negate effects of cover if on foot or mounted or with wheeled vehicle; some sort of bonus to fatigue checks?
This basically lets you use trails to negate penalties for heavy cover (with an obvious channeling effect), and it also makes using them even in non-cover a smart idea to avoid fatigue. Or you could just say that most off-trail areas except for wide open plains have even light cover, which is fairly realistic.
Even people on the great plains used roads and trails, especially for vehicles. A more complex (but less usable) table might have a column for each terrain assigning a cost for on foot, mounted, and wheeled traffic with trails/roads being especially important for the latter options. That represents the advantage of foot travel in rough terrain. It also allows you to say things like, "Mules are treated as foot in rough terrain" to make mules cooler than horses in some situations.

Another way to tackle it would be having two short tables:
COVER: None (+0), Light (+1), Heavy (+2), Legendary (+3)
FOOTING: Good (+1), Rugged (+1), Poor (+2), Legendary (+3)

So, the savannah (good footing) with tall grass (light cover) might be 2 MP to enter each hex. Up here, an alder forest (+1 or +2) growing on rocky rugged ground (+1) would be 3-4 MPs; if it is also a swamp (not uncommong) then it might be 4-5 MPs per square, which means the average guy would spend a whole day bushwhacking to go two leagues... Or find a trail in a hurry!!!

OTHER NOTES

As a side note we did some packing with horses too for a few hours recently and they do appreciate trails too. They also don't go a whole lot faster than people do most of the time. I just want a game mechanic to represent the idea that light infantry r0xors in rough trackless terrain. The trail/paths/road mechanic does that, I think. A vast forest with only trails is a great place for elves to hang out. If human knights want to travel there then they better start hacking paths for themselves, which will also have the effect of neatly channeling all those said horses into predictable areas most of the time. Otherwise, a horse (6 MP, costs 3 MP to enter every non-path hex) will move slower than a light infantry (4 MP, costs 1 MP to enter trail-ed hexes), and then why bother bringing horses? If dwarves want to roll through with big wagons then they'll need an actual road, or else it will be painful hauling through the woods (probably 3-4 MP with costing 3 MP to enter each hex...).

If you don't have enough MPs to enter a hex then a few things could happen. First you could just forbid it; this is simplest. You could also allow it with a random check: say 1 MP is left and 2 MP are required to enter; you spend the MP and have a 50/50 shot of actually moving. You could also require the extra MPs to be spent with some sort of consumable resource ("forced march") and/or check. We basically forced march the last few miles on the first day; a good way to represent that would have been needing 1 MP to move a hex and 1 MP to cross a countour line and only having 1 MP left. We fatigued ourselves and it was dicey whether we'd make it to our site or just give up and set up camp where we were, so maybe we expended some willpower or emotional HP too.