(Psi)SeveredHead
Adventurer
D20 Modern has neat rules for hazards, so long as the hazards do hit point damage. For instance, an electric floor that does 8d6 damage per round would have a hazard CR of 11. If the players can't figure out how to shut the trap down, they just might be able to survive dashing across the floor. (That's when you include the motion detector-water sprinkler trap. 
)
Now let's suppose a GM is running a World War I campaign.
In one mission, the players are exposed to mustard gas. They can wrap things over their noses as makeshift gas masks (+2 to +4 to their saves).
But what is the CR of mustard gas, if used as a hazard?
I wouldn't actually try to use the stats of the poison as listed in D20 Modern. I'd rather have a slightly more flexible system, where you could increase the save DC or even ability damage at the cost of raising CR.
According to my probably wildly inaccurate calculations, I figure the hazard CR of mustard gas, if it had a save DC of 16 and did 1d4 Con damage per round (primary and secondary) would be 12.
I figure this from using the rules from Iron Heroes (to figure out the approximate CR - I think an 11th-level character can make a poison that does 1d4 Con damage, then I reduced the CR by two because that Iron Heroes character would have other abilities).
I increased the CR by 3 because it's exposure over time, rather than one round (so CR 9 for one whiff).
Finally, the save DC came from a chart I use (level 9 opponents could make a Fort save DC 16 half the time, which might not be particularly accurate at all - the DC here is low for CR 12 because the players have to breathe the stuff every round).
Sheesh! Does anyone have an easier way?
Spycraft 1.0 has a knock-out gas trap. It does 1d6 Strength or Dex as primary damage and unconsciousness 1d3 hours as secondary damage (Fort DC 18 negates). The CR is listed as ... 2. Much lower than a much less deadly radiation trap. Spycraft was no help here. Even in Spycraft, 2nd-level PCs have a real hard time making saves against that, especially since the medic might be too busy dodging automated cannon fire to try to treat the poison, or something along those lines.
)Now let's suppose a GM is running a World War I campaign.
In one mission, the players are exposed to mustard gas. They can wrap things over their noses as makeshift gas masks (+2 to +4 to their saves).
But what is the CR of mustard gas, if used as a hazard?
I wouldn't actually try to use the stats of the poison as listed in D20 Modern. I'd rather have a slightly more flexible system, where you could increase the save DC or even ability damage at the cost of raising CR.
According to my probably wildly inaccurate calculations, I figure the hazard CR of mustard gas, if it had a save DC of 16 and did 1d4 Con damage per round (primary and secondary) would be 12.
I figure this from using the rules from Iron Heroes (to figure out the approximate CR - I think an 11th-level character can make a poison that does 1d4 Con damage, then I reduced the CR by two because that Iron Heroes character would have other abilities).
I increased the CR by 3 because it's exposure over time, rather than one round (so CR 9 for one whiff).
Finally, the save DC came from a chart I use (level 9 opponents could make a Fort save DC 16 half the time, which might not be particularly accurate at all - the DC here is low for CR 12 because the players have to breathe the stuff every round).
Sheesh! Does anyone have an easier way?
Spycraft 1.0 has a knock-out gas trap. It does 1d6 Strength or Dex as primary damage and unconsciousness 1d3 hours as secondary damage (Fort DC 18 negates). The CR is listed as ... 2. Much lower than a much less deadly radiation trap. Spycraft was no help here. Even in Spycraft, 2nd-level PCs have a real hard time making saves against that, especially since the medic might be too busy dodging automated cannon fire to try to treat the poison, or something along those lines.
