Mike's Law of Minimum Encounter Area

[mhensley]

In a game I ran a couple of nights ago, I felt that the big fight of the evening was somewhat spoiled by the room size being too small. It featured a group of 5 pc's fighting against 4 large monsters in a 40' x 55' dungeon room. Now that sounds like a decent sized room and it looked decent sized on the graph paper when I drew it up, but it felt very cramped in actual play and greatly hindered the monsters' options. So, in order to avoid this happening again, I sat down and tried to figure out a simple formula that would produce the minimum area needed for a good encounter. Here it is:

Take the number of squares that the pc's cover and multiple that times their average speed in squares. Example- in my game there were 4 medium sized pc's and 1 large pc (cleric who is almost always enlarged). They take up 8 squares and have an average speed of 6 squares so by themselves they need 48 squares.

Now do the same for their opponents in the encounter. Example- for the fight above, there were 4 large devils (4 squares each) with a speed of 8 so they need 16 x 8 = 128 squares to live in.

128 + 48 = 176 squares total encounter space. A 13 x 14 room will do nicely (182 squares) and would have played much better than the 8 x 11 room I actually used.

So in summary: Minimum Encounter Area = (Area of PC's x PC Speed) + (Area of NPC's x NPC Speed)

 

[Doug McCrae]

So Eberron's idea of Xendrik, a continent of adventure filled with ruins built by large/huge giants, is a good one?

 

[MonkeyDragon]

I use (PC Area + NPC Area) x4. Made bigger or smaller as the situation dictates. Some things need more space to be effective, and sometimes a cramped room adds to the challenge.

 

[carborundum]

I know the problem but I never thought to use a formula.

/hands in nerd status

 

[blargney the second]

That's a handy guideline! I like that it takes speed into account.

 

[mhensley]

I know the problem but I never thought to use a formula.

/hands in nerd status

Heh, I'm a programmer so I think in formulas.

 

[mhensley]

I use (PC Area + NPC Area) x4. Made bigger or smaller as the situation dictates. Some things need more space to be effective, and sometimes a cramped room adds to the challenge.

Yeah, depending on the monsters used or the situation you might want more cramped quarters. And for things that fly or teleport, you might even want larger areas.

 

[mhensley]

So Eberron's idea of Xendrik, a continent of adventure filled with ruins built by large/huge giants, is a good one?

Sounds like it. I think we'll see larger encounter areas in 4e adventures.

 

[Celebrim]

Or a 10 x 18 room might just be the minimum for two teams of five to have some minimal tactical intrigue. Though that might seem a little cramped and limit your options. Might be some shoving going on near the goals.

 

[Hrothgar Rannúlfr]

When we ran a certain section of The Shackled City, one of my players often complained about the size of the rooms and hallways. He said they were too small and it felt too cramped. No room to manuever, at all. And, the first characters into the fights were just about the only ones that could particiapate due to the cramped quarters.

I like the idea of the minimum encounter area, but at the same time, I believe that sometimes cramped quarters are necessary to the story. In that section of The Shackled City, I felt the size of the areas was just right based upon the history of the location and who built the structure.

What I did to compensate was to run groups of rooms and hallways at once. In the fights, the dungeon denizens would backtrakc through various passages in attempt to surround the PC's and cut off their exit to the surface. They would also try to cut the PC's off from one another, too. The monsters would also use horns, drums, gongs, etc... to warn as much of the dungeon as possible about the intruders. It had a very epic feel to it in the way that it played out. This was well before Mearls suggested that encounters in 4e might be designed as groups of rooms rather than single room encounters.