So, I've never really played around with incorporating traps into my dungeons before, and I feel like it's time to start. However, I find the trap designing section of the Core book to be kind of...confusing, at parts. I have several questions, but since I'm sleepy at the time of this posting, I'll keep it simple for now.
I've never been a mathematical expert, but when trying to determine the CR of the trap, the table indicates that the CR raises for every 10 points of average damage the trap can dole out. How does one determine the average damage when you're creating something from scratch?
I think they mean extra damage.
The damage will likely come from a weapon or spell.
If you go beyond that with respect to damage you will have to up the CR.
This is easier if you build a trap, and have us break it down for you.. :)
the average damage of 2d10s is 11
you basically look at all the possible rolls for a die, add them together and then divide by the die number.
d4 = 2.5
d6 = 3.5
d8 = 4.5
d10= 5.5
d12= 6.5
then just multiply by the number of dice, and tada average damage.