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Author Topic: Trap design- guaranteed-kill resetting fall trap?  (Read 1440 times)

Niyazov

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Trap design- guaranteed-kill resetting fall trap?
« on: May 25, 2012, 09:46:23 pm »

I have a very specific problem so I'm turning to the vast knowledge of the Bay 12 community for help.

I am experimenting with self-sustaining fortresses that can persist for years without the player entering any commands and have identified clothing decay as a major limiting factor.

Without scripts, there is no way to have an infinite source of clothing in a hermetically sealed fortress, so it has to come from outside.

My first crack at the solution is to have an fortress entrance containing an automatic trap that kills invading goblins and dumps their bodies somewhere where their clothes are accessible but the haulers are never subject to attack.

My first test involved a corridor of ten training spear vertical spikes in a row hooked to a lever set to pull on repeat. On either side are 15-z-level drops onto upright spikes. In a hands-off fort the dwarves spend most of their time idling so the trap will always be running; I guess that I could hook it to a repeater, but they aren't fast enough. A second enclosed spike corridor with real metal spikes follows the drop corridor; this for killing fliers and any other creature that fails to dodge to its death. Both corridors are forbidden to dwarves using burrows, but the bottom of the drop is accessible so that dwarves can retrieve clothing.

I thought that this design would force all invaders, up to and including titans, to dodge into the empty space and fall to their deaths. It does-eventually. The problem is that it is too slow; in my test with a goblin ambushers, all of the invaders got promoted to elite warrior status through the danger room effect before they started to dodge and fall to their deaths.

So the current design is not a satisfactory solution because I had to lock and then unlock the main door to achieve this effect, an option that won't be available to me in a handsoff fort. The goblins would've run right in if I hadn't locked the door.

So what I really need is a trap design that will:

  • kill every invader
  • harvest as many goblins as possible without scaring them off
  • drop their bodies somewhere safe where dwarves can access them
  • require no special labors (e.g. mechanic) to be enabled on any dwarf

Any suggestions?

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WCG

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Re: Trap design- guaranteed-kill resetting fall trap?
« Reply #1 on: May 25, 2012, 10:03:27 pm »

Can you do the same thing using water to knock them off a high ledge?

I've thought about this, but never done it. You'd need a narrow ledge with a wall of vertical bars or grates along one side (fortifications might slow the water, I don't know). Then put a pressure plate to trip a retractable bridge so you can dump a massive amount of water all at once, knocking creatures off the ledge.

The whole thing would reset when weight came off the pressure plate (probably because the flow of water would slow up after the initial flood). But you might have to mess with it to get it to reset quickly.

I don't know. Just a thought.

PS. I did use some pressure plates and a long series of trapdoors to dump invaders to their deaths. That took some tricky designing to always give them a way to attack, so they'd step off the first pressure plate and loop around to the beginning again. (I used doors and floodgates, which close at different speeds, and a restrained dog (which they could never quite reach) for a lure.

But that's been a couple of years ago, and I gave up that fortress before I was fully able to test it.
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Niyazov

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Re: Trap design- guaranteed-kill resetting fall trap?
« Reply #2 on: May 25, 2012, 10:15:01 pm »

Can you do the same thing using water to knock them off a high ledge?

I've thought about this, but never done it. You'd need a narrow ledge with a wall of vertical bars or grates along one side (fortifications might slow the water, I don't know). Then put a pressure plate to trip a retractable bridge so you can dump a massive amount of water all at once, knocking creatures off the ledge.

The whole thing would reset when weight came off the pressure plate (probably because the flow of water would slow up after the initial flood). But you might have to mess with it to get it to reset quickly.

I don't know. Just a thought.

PS. I did use some pressure plates and a long series of trapdoors to dump invaders to their deaths. That took some tricky designing to always give them a way to attack, so they'd step off the first pressure plate and loop around to the beginning again. (I used doors and floodgates, which close at different speeds, and a restrained dog (which they could never quite reach) for a lure.

But that's been a couple of years ago, and I gave up that fortress before I was fully able to test it.

Water is a good suggestion. Dumping it from above is probably safest since building destroyers will take out bars, grates, floodgates, etc. The corridor will have to be placed below the aquifer level; I can use a map-edge fortification to drain away the water without needing to pierce the caverns. My current fort is toast- super elite danger room goblins can apparently survive 15-z falls, and I didn't have the spikes rigged up at the bottom- but I'll try this in the next fort.

One potential problem is that water sometimes pushes creatures and items through fortifications and grates, so I'll need to figure out some way to ensure that the corpses don't get washed out of reach.

A metal spike killbox will still be needed after the water hazard to kill thieves, fliers, and wildlife that is too small to trigger pressure plates.
« Last Edit: May 25, 2012, 10:17:27 pm by Niyazov »
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bluefox

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Re: Trap design- guaranteed-kill resetting fall trap?
« Reply #3 on: May 26, 2012, 12:56:55 am »

I suggest a variation on the Grand Goblin Melter:
http://mkv25.net/dfma/movie-2424-grandgoblinmelterdemo

Instead of magma, use water. Once the water reaches 7/7 on the far side of the trap, the bridges retract, letting the drowning goblins fall however many z-levels you like. The water can get filtered from the goblins using grates (so the water falls further, and the goblins smash on the grates), the water gets pumped back up to trap-level, and the corpses and clothing are available for pickup.

This might be safer than any other fall trap design, because the fall isn't available to fliers if they don't trip the pressure plates.

Note also the rows upon rows of weapon traps on the far side of the fall trap, for those who are fast enough to trigger the trap but not get caught in it.
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i2amroy

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Re: Trap design- guaranteed-kill resetting fall trap?
« Reply #4 on: May 26, 2012, 01:10:39 am »

A good idea, though I would like to point out two objections:
1)Fliers do trigger pressure plates if they walk over them, so you might end up with a floating goblin bowman riding a giant eagle or something like that.
2)Any sufficiently large creature that could breathe underwater (such as many titans) will gum up the system. If you planned on doing something like that, it would be best to have an earlier trap that filtered out both of these categories and dealt with them separately before any type of drop trap to deal with the goblin and troll invaders.
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backora900

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Re: Trap design- guaranteed-kill resetting fall trap?
« Reply #5 on: May 26, 2012, 04:20:28 am »

Maybe you can use water trap I tested if you have river or aquifier.
Code: [Select]
WWWW>>>WWWWW
W...fffFPp_W
W...fffFPp_W
W...lllFPp_W
W...fffFPp_W
W...fffFPp_W
WWWW>>>WWGWW

W-wall, .-open space (drop), f-floor, F-fortification, l-pressure plate, >>>-ramps (don't flood your fort)
Pp_-pump (east to west), G-gear assembly connected to pressure plates - or better make it above solid part of one of these pumps
Make this unit as long as you need.

I tested this design in .34.04. From puppy, cat dog, sheep, dwarf (+child), yak bull; everything was washed to the abyss. Problem was with cat I think because it didn't trigger plates.
Also make this pumps take water from a reservoir and not endless source (2-4 water push the most). Mine was 2 tiles (below pump) + 2 tiles (pump level - on picture) + 1 tile (above pump leve).
For trap avoiding beasts connect gear assembly to a lever for manual operating.

It creates first wave 7/7 water which ussually stops creatures or persuade their pathfinding to go closer to the edge (maybe submerging fliers also helps - didn't tested). Then when you deplete reservoir, it pupmps like 2-3 water which makes the final pushing of the edge. Another bonus is that this trap should work on ambushers as well.

At the bottom make some fortification drainage to the aquifier. Also they are falling with water so I don't know if they actually survive the fall. I only tested it on 1-2 level drop.

Make this corridor only 1 level wide -> enemy is always pushed in the right direction.

Combine with standard weapon/cage trap setup for more efficiency

Use MAGMA if you are brave enough ;D
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Tirion

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Re: Trap design- guaranteed-kill resetting fall trap?
« Reply #6 on: May 26, 2012, 05:49:10 am »

Titans are building destroyers and don't bring clothes, neither do trolls (well they do but large clothes are useless), you could build a wooden armor stand surrounded by a field of 10x menacing steel spikes linked to a lever set to repeat to deal with them someplace before the bridge. For non-trapavoid creatures, you might want to combine the goblin grinder design with the dodge trap, so that even if they run across the traps they automatically turn back as they step on a pressure plate and their way in is suddenly blocked.
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Niyazov

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Re: Trap design- guaranteed-kill resetting fall trap?
« Reply #7 on: May 26, 2012, 09:01:39 am »

I suggest a variation on the Grand Goblin Melter:
http://mkv25.net/dfma/movie-2424-grandgoblinmelterdemo

Instead of magma, use water. Once the water reaches 7/7 on the far side of the trap, the bridges retract, letting the drowning goblins fall however many z-levels you like. The water can get filtered from the goblins using grates (so the water falls further, and the goblins smash on the grates), the water gets pumped back up to trap-level, and the corpses and clothing are available for pickup.

This might be safer than any other fall trap design, because the fall isn't available to fliers if they don't trip the pressure plates.

Note also the rows upon rows of weapon traps on the far side of the fall trap, for those who are fast enough to trigger the trap but not get caught in it.

this is a good suggestion and I'm going to try to implement it. Won't falling goblins smash through grates, though?

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