Teach me. Seriously, I'm good at a lot in TTRPGs but my ability to run "dynamic" encounters - that is, encounters with traps, hazards, or unique conditions in the environment, are just lacking.
The party is APL 9 and terrain is usually Dungeon. We have a 1/2 elf u-monk 8 with a decent Perception and free Skill Focus (Perception) at creation. There's an elf u-rogue (scout)8, 120' Darkvision, a grippili bard (busker bard)6 cohort and the Trapspotter ability. We also have a 1/2 dwarf paladin 8 who brings his 1/2 orc cleric 6 cohort along everywhere and rounding out the party a human wizard (fire elementalist)8 with a pyrausta familiar on his shoulder; said dragon was allowed to improve to an "elder pyrausta" at level 7 to give it a fighting chance at higher level game play. This does mean however that the dragon has a 14 Wis, Perception as a class skill and the wizard has been sinking one of his own skill ranks into that skill every level, so the thing is a tertiary lookout.
My point is, unless the rogue and monk are both unconscious, they notice everything. They can use Free actions for a sentence or 2 in order to warn folks in combat where not to step so that triggers aren't set off, tripwires don't get pulled and so forth. The players are paranoid so unless there's a time crunch they scout ahead, occasionally use summoned monsters, or once in a great while interrogate their enemies.
Short of just GM fiat, how do I add traps or other static terrain elements that ACTUALLY impact encounters?
So they know where the pit traps are, that still limits how/where they can move about. Enemies can bull rush folks into pits or pressure plates.
Non-trap issues are good too, unstable or slippery floors/walkways, streams filled with piranha or leech swarms, fog that cuts visibility, pools of oil waiting to be ignited.
Smart enemies set up behind barricades (cover) with the approach a patchwork of caltrops and rubble.
A rope bridge that can be sundered from either end.
Some kinds of enemies will place enough traps and hazards around their lairs that even if the PCs detect them all, they'll still be at a disadvantage just navigating their way past them. It takes time to disarm a trap, or even just go around it, which gives the defenders more time to notice the intruders and start attacking (from range, with cover) or preparing other defenses. And some traps can be triggered remotely if the defenders know they're under attack.
Smaller races like kobolds, gnomes, derros, and gremlins can easily set a pressure plate to trigger when a larger creature steps on it, but ignore creatures their own size. Each entrance to their lair can be trapped in this way at little to no risk to the inhabitants.
And leading an enemy right into such a trap is a favorite tactic of such races.
The lowest CMD I've got to overcome is the paladin with a CMD 24. If the PCs happen upon a scene w/slippery floors, multiple levels, fast-flowing streams w/piranha and such, their foes have to work around these obstacles as well and I've got to incorporate them logically into my dungeon. Last session, I had a Grease spell on the ground trying to make it difficult for a monster to be flanked; the u-rogue managed a 21 Ref save alongside activating some boots for a grand total of 34 on an Acrobatics check to move through the monster's space w/no AoO as well as being unaffected by the Grease behind it.
The IDEA of obstacles or dynamic hazards in the terrain is good but in EXECUTION they never seem to work. Yeah, the paladin has a pretty low CMD; I could likely Bull Rush him into a dangerous square. Now I've got to line up a scenario where a foe survives long enough to get w/in Bull Rush range, sets up a perfect straight line to push the paladin back through to a threatened square, then ALSO rolls high enough to succeed against the PC.
Leading the party into a trap, thanks to trapspotter, means that first the players have to take the bait and rush off after their foes into the dungeon. Even if I pull that off, the group then has to have the rogue not be in a position where I'm rolling her a Perception +21 vs any trap she gets w/in 10' of. Her average check spots magic traps with level 6 spells or below and the majority of all pre-written mechanical traps.
Fake traps that obstruct the PCs but don't obstruct the monsters. Spooky fog rolling across the floor hides the traps, difficult ground, snakes and other clutter. Fire or acid when the monster is immune to it.
Spotting a trap doesn't tell you what it is, just that there's something iffy there. It could be that the "trap" is the place you need to stand to be safe, or to open or close the door. So a monster might deliberately trigger a trap the PCs avoid to hem them in or teleport out or fill the room with acid fog that the monster can easily resist.
And if the rogue does roll to see the trap? Then they're stuck on the wrong side of that trap getting shot at, or wasting time and resources disarming it or flying over it while getting shot at.
Fog Cloud, Ash Storm, Greater Darkness... do all of my fights now require specific monsters that are unaffected by such effects? I mean, a lot of my campaigns die off in low to mid levels, so I don't really get to explore tons of unique, high CR foes but there aren't a lot with the ability to see through mist and fog right?
Still I get the point you're making. If trapspotter is a thorn in my side, I should find a way to counter it once in a while. Getting around obstacles isn't a challenge for these PCs; high Dex and Acrobatics for some, levitate scrolls for another and a large sized mount as well. One of the cohorts also has a Climb speed and glider wings.
If anyone has any other tips or tricks please let me know. Thanks for all the help so far!
If you want to be really nasty cursed items aren’t technically traps but I’m sure you could find a way for one to act like a trap and yet be undetectable with trap sense.
Although, I’m not sure that you actually have a problem. Aren’t rogues supposed to find traps? I’m not sure why you would want to make one of the weakest classes even more ineffective.
Then again, perhaps I’ve misunderstood your intent and what you are looking for are obstacles rather than traps. This could be as simple as a dungeon filled one foot deep with mud. This counts as difficult terrain and requires a DC10 reflex save to stay upright in the slippery parts (like ramps). The native troglodytes are used to the swampy ground and can move through it unimpeded.
Since you're asking about traps in combat, the only thing you really have to be aware of is Trap Spotter. Anyone else, no matter their Perception, still has to stop and look for traps (and move at half speed, etc.). Any other time isn't at issue, traps are just a speed bump for this party. That's fine, it's what they've built for.
As for your grease trap not working on the rogue, of course it's not, it's a Reflex save against a rogue. It still might have hindered the others (or it might not have, they could have made their saves too with a lucky roll even if the odds were against them, which they aren't except maybe the wizard or a cohort).
If you absolutely need to have traps in combat, make a tactically interesting set up. If there's a 10 or 20 foot pit trap that crosses the corridor, either that isn't triggered by the defenders because of weight or more likely a lever thrown by a guard or sentry on the other side well back from the trap to lock it in place until they pass, combat will keep the PCs from just Taking 10, and stopping to disarm it will just be free shots while they're jamming the cover or whatever it takes to disable it.
The only one who would get a free chance to spot it if moving, running, or charging is the Trap Spotter, and that will only matter if they're in the lead or holding their action to run alongside the other leader in combat turn order. Even then, they'd either have to stop or continue their movement (possibly jumping it). But then, if you have another trap on the other side of the 10 or 15 or 20 foot gap they're jumping over (they might not know how big the pit is just because they sensed a trap, so they have to decide how far to jump or just whether they'll go as far as their roll allows), if there's a trap on the other side that they land on, the Trap Spotter can't do a thing about it, because it's over 10 feet away from the other trap or they're already flying through the air into/onto it.
Manual traps:
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Other traps can also be manually triggered by sentries and defenders. They can have triggers like tripwires or pressure plates, but you can also have levers or buttons or other manual triggers that can activate them from somewhere just outside of combat by an observer. They'd have to be traps that possibly affect an area or could hit a target that isn't specifically on the trigger itself. That would be like a 5 foot area with a pressure plate, but that drops a 10' x 10' net, so even if a PC sees or knows where the trigger is and avoids or steps around it, a ready defender can still just trigger it. Same for AoE spell traps or lines or even arrow or crossbow traps that would shoot down a hallway, but the automatic trigger is only at one spot, but the arrow could hit anyone along the path if triggered.
Just remember that defenders should know where traps are (and certain hazards), and can trigger them themselves even if they aren't set off by the PCs. If the rogue detects the trip wire that would drop a giant glass ball of acid on them or drop alchemist's fire on their heads, the defends could just adjust a ranged attack or two and shoot the orb themselves. The same is true for a patch of puffball mushrooms, yellow creeper plants, or just a poorly-shored up section of ceiling. They could shoot and cause a spore cloud or collapse (not blocking the whole tunnel or room). Similarly, caltrops or a whole cavern floor full of tiny sharpened stalagmites (which could function as caltrops) might not affect the defenders, say because they might be Small or Tiny (so small PCs might be okay) and maybe have safe trails that bigger footed creatures can't benefit from (or they have no feet, like a snake or serpent that just winds through them) can allow for some variation to a battlefield
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Hazards are also pretty pathetic just out in the wilderness. A party just wandering into an encounter with quicksand is still likely to be perfectly fine. In a tactical situation, it's much different. Most hazards aren't detected as traps and can't be disarmed (an unstable ceiling or a pocket of gas that just fills a small area). So if there's quicksand on the battlefield against creatures unaffected by it (because they fly or can swim or otherwise cross it, like snakes, or just don't have to because they're shooting at the PCs from the other side), that's a much better encounter. The same is true if the area the PC wizard is standing in contains some flammable gas (even if the gas isn't typically harmful or even noticeable in normal circumstances). They'd need to be using Survival or something to have detected it (and still might not know its area), but if the wizard launches a fire spell, they could trigger an explosion in the particular pocket of gas they're in (yes, still a Reflex save so unlikely to do much), just an example.
Finding and avoiding traps is what this party does, but even if the trap itself doesn't do its 'trap thing' like it would against a typical invader, its presence can still affect the PCs' actions in combat and thus make for a tactical or interesting encounter. Even if a pit or trap never goes off, the fact that it's blocking off or hindering a space on the battlefield can be effective. A covered pit that the PCs have to step around or circle around or prevents them from charging straight into the defenders is just as effective as an open pit just sitting there might be.
You could incorporate 4e style skill challenges into an encounter. Perhaps the party needs to disable a portal before something comes through: eg 3 successful Arcana checks before 2 failures, with a time limit. You can also have crossbow traps that need to be similarly disarmed in combat.
[EDIT] The key here is that failing the skill challenge doesn't make the combat impossible, just harder.
