Question Concerning 3.5 Trap CR & Cost

[Adept_Scholar]

I am attempting to design a two-part multiple dependent trap (total equalling CR 12), with the first part being a CR 8 trap (a modified pit trap). What CR would the second trap need to be (what is at the bottom of the pit) in order to make the encounter itself a CR 12? A CR 12 encounter is shown on page 38 in the 3.5 D.M. Guide as providing 3,600exp, so going by that, a CR 8 encounter at 2,400exp and a CR 4 encounter at 1,200exp would equal the 3,600exp of the CR 12, yet I know this is not how encounters are determined when handling creature encounters (a CR 12 encounter shown as a mixed pair is 11+9 via Table 3-1 on page 49 in the D.M. Guide). :smallconfused: In addition, under Mechanical Trap Cost on page 75 in the 3.5 D.M. Guide, it states the minimum cost for a mechanical trap is CRx100 gp (which would mean a CR 1 trap would cost 100gp), yet states in the paragraph above that the base cost of a mechanical trap is 1,000gp...Does this mean that the minimum extra cost for a mechanical trap is CRx100 plus the 1,000gp base cost? Any replies are appreciated. :smallcool:

[Jeraa]

Cost for a mechanical trap:

Base cost is 1000gp. Apply any modifiers from table 3-15 to that cost. That total is your modifier base cost.

Multiple the modified base cost by the CR of the trap, and add in any extra costs not covered on table 3-15. This is the traps total cost. The traps total cost must be at least 100gp x its CR. It will most likely be higher.

[Adept_Scholar]

Okay, I think I understand that part better. Any ideas on determining the 2nd part of the trap's CR?

[Jeraa]

Okay, I think I understand that part better. Any ideas on determining the 2nd part of the trap's CR?

You've already found that out. A CR 11 and a CR 9 combine to be roughly an Encounter level of 12. A CR 10 and a CR 8 would be an encounter level 11.

So a CR 8 combined with a CR 11 should roughly be an encounter level of between 11 and 12.

[Adept_Scholar]

Ahh, I see now. :smallwink: Thanks for the aid Jeraa. :smallcool: