This has confounded me since 4e came out.
If you use the idea that the trigger is in a square, and the player detects it with passive perception, but doesn't know what it does, every player will avoid that square. Now, it could be a set of squares, but in 4e, it's not so hard to get to other squares with the new diagonal movement method of walking, teleport powers, and jumping and climbing being rather easy. They simply bypass the square. Fun? I think not.
I do like the idea that when they enter a room their passive perception tells them something is amiss, and they have a chance to learn more by making a perception check, outlined by bganon above. But I came up with a method awhile back that adds a bit to that scenario. Lurker traps.
When I thought about it more, the thing that got to me about wotc's rules for traps is the placement of those traps in a specific square, or set of squares. Since those were generally outlined in sparse amounts I was like, well, I'm just going to make the triggering area "four strategically placed squares" to "10 strategically placed squares" and go digging for monsters that can use forced movement. But then I thought to myself: why do i have to plan on where the trigger square is? That meant it was a hassle for me to remember and keep track of of those squares (should the players not detect them). What if even *I* didn't know where the square was? However, I knew the *vicinity* of where the trap might go. That was easier.
The idea goes like this: choose an area on your battle map that makes sense where a trap might be located. Pick a square or squares in the middle of that area and call it the "vicinity square." Now, depending on how mean you want the trap to be, determine how big of a vicinity the trap will be laid. In most cases I would choose a burst 1, burst 2, or something like a line (get to that in a second). Now, the player walks in the room, and the passive perception says to them "there's a trap—or traps—laid somewhere in that area" and you mark an X in the vicinity square. The players might avoid it, sure, but they don't know how far out they should avoid, so it takes on a ticking bomb sort of feeling. Now, let's say it's a standard trap vicinity of burst 2. When a player (or i guess monster too, but more on that too in a second) enters a square within a burst 2 of the vicinity square, call for a perception check. Effectively, the player is trying to move through the trapped zone without stepping on the freaking trap. But the trap probably isn't like one wolf trap, it's probably several well hidden wolf traps with multiple lures and deceptions, so the player needs to watch where they're going. If they fail your DC, they trigger the trap, if they succeed the Perception check, then they can move through the entire trapped zone until the end of their turn. If they start their turn in a trapped zone, they have to make the check again (oops, that back step i took when i turned around, and clamp, there goes my foot).
The point here is to reward the players with the higher perception without giving away where the one or two squares on the board are that they should avoid. I don't know about you guys but my players can easily avoid 1-4 squares if they find out it they are trapped. But avoiding 3 burst 2 areas is harder, and they don't know if they are burst 2 or burst 4, so they're still walking on eggshells.
Few more details. Disabling the traps is easy: use a move action to make a thievery (or appropriate check) to disable 1 square in the vicinity, 4 vicinity squares disabled and the whole trap is disabled. Do they know where the vicinity squares are? No. That's the point. If they want to try disabling a square that isn't in the trapped zone, let them. If they succeed or fail in a square that is within the zone or not, they know if the square is within the trapped zone. The move action is worth at least that much. With deduction or bravery, the players will eventually learn what the trapped zone is. Failure to make the DC in the trapped zone does NOT set off the trap. Success on the DC may or may not (depending on the type of trap).
I don't like to have my monsters make the same perception checks as the pcs. Of course it all depends, but if they set the traps, then they know where not to walk. I typically make them immune, give them a circ bonus, or make them just as vulnerable to the traps as the players (if they are beasts, or mindless or something). Traps are supposed to be a challenge and stack the threat against the pcs, not become just as much a threat to the monsters as they are to the pcs. I've ruled before that, although moving into a square means they don't have to make the check, being forced into the zone means they do. Again up to the dm.
Also, the trapped zone need not be just a burst 1 or 2 or 3 or whatever, why not make it a line? or a zag? Make two vicinity squares in squares adjacent to two opposite walls and make the trapped zone all squares between them. Or put the vicinity squares in all the corners of the room and make the trapped zone any square adjacent to the walls. Heck, put down a vicinity square that is a fake trap to make them think they should be walking on eggshells. Tons of options, and you don't have to know exactly where the trapped squares are.
I have a ton more ideas about how this is a good tool to go by, but I think I've said enough. Let me know what you guys think.
If you use the idea that the trigger is in a square, and the player detects it with passive perception, but doesn't know what it does, every player will avoid that square. Now, it could be a set of squares, but in 4e, it's not so hard to get to other squares with the new diagonal movement method of walking, teleport powers, and jumping and climbing being rather easy. They simply bypass the square. Fun? I think not.
I do like the idea that when they enter a room their passive perception tells them something is amiss, and they have a chance to learn more by making a perception check, outlined by bganon above. But I came up with a method awhile back that adds a bit to that scenario. Lurker traps.
When I thought about it more, the thing that got to me about wotc's rules for traps is the placement of those traps in a specific square, or set of squares. Since those were generally outlined in sparse amounts I was like, well, I'm just going to make the triggering area "four strategically placed squares" to "10 strategically placed squares" and go digging for monsters that can use forced movement. But then I thought to myself: why do i have to plan on where the trigger square is? That meant it was a hassle for me to remember and keep track of of those squares (should the players not detect them). What if even *I* didn't know where the square was? However, I knew the *vicinity* of where the trap might go. That was easier.
The idea goes like this: choose an area on your battle map that makes sense where a trap might be located. Pick a square or squares in the middle of that area and call it the "vicinity square." Now, depending on how mean you want the trap to be, determine how big of a vicinity the trap will be laid. In most cases I would choose a burst 1, burst 2, or something like a line (get to that in a second). Now, the player walks in the room, and the passive perception says to them "there's a trap—or traps—laid somewhere in that area" and you mark an X in the vicinity square. The players might avoid it, sure, but they don't know how far out they should avoid, so it takes on a ticking bomb sort of feeling. Now, let's say it's a standard trap vicinity of burst 2. When a player (or i guess monster too, but more on that too in a second) enters a square within a burst 2 of the vicinity square, call for a perception check. Effectively, the player is trying to move through the trapped zone without stepping on the freaking trap. But the trap probably isn't like one wolf trap, it's probably several well hidden wolf traps with multiple lures and deceptions, so the player needs to watch where they're going. If they fail your DC, they trigger the trap, if they succeed the Perception check, then they can move through the entire trapped zone until the end of their turn. If they start their turn in a trapped zone, they have to make the check again (oops, that back step i took when i turned around, and clamp, there goes my foot).
The point here is to reward the players with the higher perception without giving away where the one or two squares on the board are that they should avoid. I don't know about you guys but my players can easily avoid 1-4 squares if they find out it they are trapped. But avoiding 3 burst 2 areas is harder, and they don't know if they are burst 2 or burst 4, so they're still walking on eggshells.
Few more details. Disabling the traps is easy: use a move action to make a thievery (or appropriate check) to disable 1 square in the vicinity, 4 vicinity squares disabled and the whole trap is disabled. Do they know where the vicinity squares are? No. That's the point. If they want to try disabling a square that isn't in the trapped zone, let them. If they succeed or fail in a square that is within the zone or not, they know if the square is within the trapped zone. The move action is worth at least that much. With deduction or bravery, the players will eventually learn what the trapped zone is. Failure to make the DC in the trapped zone does NOT set off the trap. Success on the DC may or may not (depending on the type of trap).
I don't like to have my monsters make the same perception checks as the pcs. Of course it all depends, but if they set the traps, then they know where not to walk. I typically make them immune, give them a circ bonus, or make them just as vulnerable to the traps as the players (if they are beasts, or mindless or something). Traps are supposed to be a challenge and stack the threat against the pcs, not become just as much a threat to the monsters as they are to the pcs. I've ruled before that, although moving into a square means they don't have to make the check, being forced into the zone means they do. Again up to the dm.
Also, the trapped zone need not be just a burst 1 or 2 or 3 or whatever, why not make it a line? or a zag? Make two vicinity squares in squares adjacent to two opposite walls and make the trapped zone all squares between them. Or put the vicinity squares in all the corners of the room and make the trapped zone any square adjacent to the walls. Heck, put down a vicinity square that is a fake trap to make them think they should be walking on eggshells. Tons of options, and you don't have to know exactly where the trapped squares are.
I have a ton more ideas about how this is a good tool to go by, but I think I've said enough. Let me know what you guys think.
