Forked Thread: Help me make an encounter for an Instigator

[Noumenon]

Forked from: Help me make an encounter for an Instigator

I wish I could find the thread again, but somewhere there was a discussion about a formula for the optimal fighting area based on the number, size and types of creatures... The more the battleground shrinks, the less easier it will be for the PCs to stay close together, as a more efficient fighting machine.

30x30 is a single move from one end to the other. 60' depth is a double move for the spiders to get from the bottom to the top. With 'difficult' and balancing that might actually work out, but I would prefer a bit more space.

What is a good sized space for a battle? I don't know if the 3.5 DMG even mentions this issue other than saying that a 30x30 room, while huge in real life, makes a good size for a combat.