D&D 3E/3.5 Help converting a fire trap from 3E to 4E.

[the-golem]

I'm prepping for the next leg of my campaign, and there's a fire trap I'd like to convert. First the text of the 3E version.

Fire Trap (CR2)
Alchemist's Fire causes 4d6 fire damage in the first round, then causes 1d6 fire damage each round after until 10 rounds pass; Reflex save each round halves damage first round, and negates damage after first round (DC23), no saves needed after first successful save; Search DC 23; Disable device DC 23; takes 2d4 rounds.

Now, I've a fair guess on how to do the basic bits.:

Fire Trap
Attack: +?? vs Reflex
Hit: 4d6 fire and 5 ongoing (save ends)
Miss: Half-damage and no ongoing damage.

The original trap calls for a pretty high reflex save, so I'm unsure how to rule that.

Plus, I'm not exactly sure how traps work. Do they attack like monsters? Should I give the trap 2 attack powers? One for the first attack, and then a less powerfull attack for the others?

What do you all think? I sure could use some help. Thanks.

 

[Keenberg]

It would help to know your party level. This will help figuring appropriate DCs, damage, and attack rolls (by the way, traps do attack like monsters.)

The DM's Guide has a whole chapter devoted to building traps, with many examples. In fact, on page 90, there is a "Flame Jet" trap which looks like a converted "Fire Trap" from 3E. It's built for a level 8 party.

 

[the-golem]

To answer your questions, Its a party of 7 characters, all level 3.

The trap is triggered when someone opens the door, spraying any squares in a close burst 3 surrounding the door.

The door is essentially fake, as the only thing in the room is the trap equipment and a counterweight that shuts the door after 2 rounds.

There isn't a way to disable the trap on the outside; all the mechanisms are inside the room.

The spouts are 10 feet above the floor, and are carefully worked into the stonework (Search DC18 3e to see them)


Going by the trap section in the book, I'm looking at an Immediate Reaction Attack for 4d6, and Standard Attacks at 1d6 following initiative.

Disable Traps is supposed to take 2d4 rounds, I could make this a simple skill challenge, requireing 4 successes before 3 failures.

The trap also allows for salvaging the materials, which would take 2 hours of tedious alchemy work, allowing for 2d4 vials of alchemists fire flasks.

 

[Primitive Screwhead]

.. posting later now that EnWorld is back online..

Some traps act almost exactly like monsters.. the suggestion below does pretty much just that. Other traps are one-shot tools..
One of the paradigms with traps is that, generally speaking, the PCs should know there is a trap.. the fun question is what to do about it. Try avoiding the older paradigm of a 'hit point tax' kind of trap that doesn't enhance the encounter.


What level? Assuming 2nd I would de-level a sample Blaster from the DMG

So something like:

Alchemical Flame Thowers Level 2 Blaster
Trap XP 125
Two jets of Alchemal Fire spray at passing creatures when they enter the burst 3 in from of either jet.

Trap: When the trap is triggered, two hidden nozzles in the
walls attack each round on their initiative.
Perception
✦ DC 16: The character notices the nozzles.
✦ DC 20: The character notices the control panel on the far
side of the room.
Initiative +2
Trigger
When a character enters the traps area of one of the flame
jets, it makes its first attack as an immediate reaction. It
then rolls initiative, it can make one attack as an immediate reaction against the closest creature in the traps area each round.

Attack
Immediate Reaction
Targets: Triggering creature in blast
Attack: +11 vs. Reflex
Hit: 1D10+3 fire damage and ongoing 5 fire damage (save
ends).
Countermeasures
✦ An adjacent character can disable one flame jet with a DC
20 Thievery check.
✦ A character can engage in a skill challenge to deactivate
the control panel. DC 24 Thievery. Complexity 1 (4
successes before 2 failures). Success disables the trap.
Failure causes the control panel to explode (close blast
3, 1D10+3 damage to all creatures in blast) and the trap
remains active.
Upgrade to Elite (300 XP)
✦ Increase the Perception and Thievery checks by 2.
✦ Increase the number of nozzles to 4


But, traps should be designed as part of an encounter. This one is a good plug-n-play, giving the PC's a tactical choice in pushing enemies into the traps area.

 

[the-golem]

I'm guessing you tried to post that earlier, but for some reason couldn't.
Regardless, I answered everything in my last post. ;-)

A few minutes and I'll post a complete write-up attempt.

 

[Primitive Screwhead]

I did try to post that earlier the other day, but EnWorld was down for maintenance... and I didn't have too much time to repost it later in the day so I didn't check very well if my question had been answered.

The numbers would still work for 3rd level characters, but if this is a stand-alone trap there are a couple of questions raised:

- Why is the trap there {metagame}?
If the door doesn't lead anywhere and the Perception is too high, it becomes a hp tax ala 'Ha Ha, you get hurt'. If the door doesn't lead anywhere and the perception is low enough for the trap to notice, its still a hp tax, but with an added '....sucker!'

Perhaps the PC's need or can use the harvested alchemist fire for a later encounter and you want a more interesting way of dropping it for them?

- Why is the trap there {in character}?
Traps tend to be to keep people away from something precious, not randomly sprinkled on side doors to nowhere.

- How can this trap be used in a challenging encounter?
Does the trap have strategic or tactical value, enhancing the storyline?

Personally, if I can't answer these questions I don't bother with the trap.

 

[the-golem]

When the door is pulled open, a counterweight mechanism pumps burning alchemis's fire from the spouts, dousing any creature standing within a close burst 3 of the door. The trap makes its first attack as an immediate reaction. It then rolls initiative, and makes a standard attack each round on its initiative. After the door is opened, the counterweight pulls the door shut in 2 rounds. Fast thinking characters can jam it open to inspect the small room behind it. The only contents of the trap room are the counterweight mechanism, piping for the alchemist's fire, and two almost empty copper drums containing about 20 gallons of reagents for alchemist's fire (the liquids are mixed then sprayed out, as alchemist's fire ignites on contact with air). Piping runs out through small channels to the southeast and southwest to the spouts overlooking the killing zone.