Problems with making Traps

[Three_Haligonians]

Hey,

This isn't about character's making traps with the Craft skill. This is about designing them as the DM.

I was working out a few for an upcoming session when I started to think about what I was reading about triggers.

There are seven different types of triggers. It doesn't matter which one a DM chooses because it doesn't affect the CR. This is odd, because the triggers are very different. Let us say there is a door at the end of the hallway that is rigged with some kind of spell trap - scorching ray for example. If we say it is a touch trigger, then whoever touches the door gets targeted. If it is a visual trigger equipped with true seeing, then whoever stands in front of the door gets targeted, assumedly without getting a chance to search the door first. In fact, since the door has a sight range of 120ft with true seeing the poor target could be at the other end of the hallway. Heck, it could be dark and for whatever reason, the target might not even be able to see the door.

Technically, both types of traps have a CR based soley off the damage output of the scorching ray, regardless of the trigger used. Am I missing something? Doesn't the true seeing version seem a bit.. harder?

Then there is automatic reset. The DMG only says that these types of traps reset themselves, "either immediately or after a timed interval." Given the example above, that makes a big difference. The trap becomes a lot harder if it goes off every round rather than say, 1d4 rounds, or 1d4 minutes or whatever.

Am I thinking too hard? Is this something that the ad hoc XP system can handle, or do the rules on Trap CR calculation leave a little to be desired?


J from Three Haligonians

 

[HeavenShallBurn]

Trap CRs can be somewhat wonky.

Though I tend to use fewer traps than most this is a suggestion. Upper Krust did a comprehensive revision of the entire CR system where he broke it down into individual characteristics and figured out their CR.

It would probably work to use his CR system and calculate the trap CR as if it were a unique special ability or such. This would take a bit longer but would give a far more accurate idea of just how much XP it is worth.

The CR breakdown is on a PDF, I've seen it posted on these boards before in House Rules some time back. Otherwise you can get it from his website.

 

[The Grackle]

I think you add the highest level spell to the CR. So that would be True Seeing rather than Scorching Ray.

If it had a visual trigger w/o True Seeing it would be the same though, but then it could be fooled by darkness.

 

[Kerrick]

Check my sig, TH - I did a big netbook on traps. I think the traps system is really wonky too, so I sat down and rewrote the whole thing, although I have to admit, I think I missed adding a CR adjustment for things like the true seeing trap you mentioned.