Sunday, April 22, 2012

Sandbox Thoughts - Wither Shall I Wander?

Wandering encounter tables are the boon and bane of sandbox campaigns everywhere.  They can lead to exciting challenges for the PCs, and they can also lead to unexpected TPKs.  With a little planning, it's easy to make sure your encounter tables are more boon than bane (although no one can truly prevent a TPK in a sandbox wilderness ;)

The first thing to remember it is a "Wandering Encounter Table" and not a "Wandering Monster Table".  This isn't a dungeon stocked with nasties but a living, vibrant world (well, at least in most settings.  Your mileage may vary).  As such, although monsters and adversaries will make up part, or even most of the table, they shouldn't be the only things on it.

Additionally, you need to take into account not only the surroundings and environment, but whether or not the party is traveling on or off road.

You should be more likely to encounter other travelers or armed patrols on well used roads than orcs and highwaymen.  Less well used roads may leave one open to being robbed, and even encounters between honest folk may be strained ands suspicious.  As you can see, one table per general terrain type probably isn't enough.  You may need two (or more) but the payoff is worth it.

Now, before we can even go into the specifics of what goes on the table, we need to figure out the form of the table.  We can go with a single die (linear) or more than one die (giving a curve to the results, with the middle range being weighted more.  Keith Davies has a nice article on such, and advocates using 2 dice.  I'm going to go a step further, and go with three.  3d6.  This one roll will not only decide if there is an encounter, but what the encounter will be.

We know from years of gaming that 10 and 11 are the most common rolls on 3d6.

Here's the breakdown:

Score   Freq   Percentage
----- ---- ----------
3 1 0.463%
4 3 1.389%
5 6 2.778%
6 10 4.630%
7 15 6.944%
8 21 9.722%
9 25 11.574%
10 27 12.500%
11 27 12.500%
12 25 11.574%
13 21 9.722%
14 15 6.944%
15 10 4.630%
16 6 2.778%
17 3 1.389%
18 1 0.463%

So, if we want an encounter to happen 75% of the time (you decide the timeframe, but one encounter check every 6 or 12 hours is usual) a roll or 10 or 11 indicates no encounter.  Want the chance of an encounter to be around 55%?  A roll of 9-12 indicates no encounter.  This method also allows you to drop in that rare, overpowered "Holy Shit!  That's a Dragon!" by making it occur on a roll of 3, while the more common patrol or goblin raiding party may occur on a roll of 8 (nearly 1 in 10).

This method streamlines things a bit, and keeps the party from going "ah shit, he just rolled an encounter check and is now rolling a second time to see what we got!".  Everything is decided in one simple roll of the dice.

Alright, next in the series I'll actually put together an encounter table, building upon those presented in the HEX 000 series by Christian and using the 3D6 method I talk about above.

Owlbear by Keith Curtis


  1. An interesting approach, and I like things that streamline processes.

    However, isn't a 75% encounter rate really high? I seem to recall things like 1/6 per turn, up to 2/6 and maybe 3/6 in high-traffic areas. This might work if you wanted to have inconsequential encounters in the table as well, but 3d6 has only 16 distinct values and you've already ruled out a few of them.

    If I wanted to do this as a single roll, I'd use the 'which encounter' roll much as you have it (though 3d6 is a higher curve than I like -- I like not-quite-linear, rather than close-to-bell) and have the 'is there an encounter' roll be a separate die rolled at the same time.

    Just for fun, make it a d12. Want an encounter 1/6 of the time, it's on a 1-2, 1/4 is 1-3, 1/3 is 1-4, 1/2 is 1-6, 2/3 is 1-8, 3/4 is 1-9, 5/6 is 1-10. Simple, no slower, not observable (if you roll behind the screen), more flexible in applied frequency (frequency of encounter is linear, choice of encounter is not... though you could mess with that too by having a two-dimensional table of encounters, with the secondary die determining the column).

    Blank entries on the table to decide whether or not there's actually an encounter... interesting idea, but there are easier ways.

  2. I found a way to get to a potentially more interesting single roll result.

    Description at Random Encounter Tables: Second Thoughts, math to follow after I get home tonight (some 5.5 hours from now... probably post for tomorrow morning).

  3. I forgot to follow up here with the Heavy Lifting for the Second Thoughts post.


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