User:EliDupree

Favorite complex constructions

Fully Automatic Instant Drowning Chamber

This is my current favored entranceway. The easiest way to get the basic idea across is with a side view:

 Key:
 
 ▲ = Ramp
 _ = Floor hatch
 ^ = Pressure plate
 % = Natural wall
 O = Constructed wall (this wall goes perpendicular to the view, blocking above-ground traffic)
 . = Floor/ground
 7 = Water, connected to a reservoir (there is also water on the upper hatch)
 
 Map:
      
  .. ...O... ..
  %%▲ %777% ▲%%
  %%%▲ %_% ▲%%%
  %%%%▲_^_▲%%%%
  %%%%% % %%%%%
  %%%%%%%%%%%%%

(This is a simple one to go under my wall around the world. This was for my first fortress, before I was ready to embark with any challenges/limitations :-) )

The pressure plate is linked to all three hatches. Whenever any enemy steps on the pressure plate, the tunnel floods - and the enemy can't move forwards or backwards either, because there are now un-covered channels in the way! (This pressure-plate/hatch/channel trick seems to be the simplest way to make a corridor that non-flying enemies simply cannot walk down.)

The water is connected to a reservoir whose maximum height doesn't go above the ground. The whole contraption floods almost instantly, but never to a higher water level than this:

  .. ...O... ..
  %%▲ %777% ▲%%
  %%%77%7%77%%%
  %%%%77777%%%%
  %%%%%7%7%%%%%
  %%%%%%%%%%%%%

(This is why you really need the ramps going up, even if you build this entirely underground or above ground. They're what allows me to build a drowning chamber without doors.)

The pressure plate is also linked to a gear box that turns off the pump (in the third dimension) that puts the water back up into the reservoir. This linkage isn't actually necessary, but it helps keep the framerate from dropping too much due to the constant pumping back and forth of water. If you have a constant supply of lots of water, you can use a drain instead of a pump. (In fact, if you build only diagonal passages to the drain, you never have to turn it off - the pressure will flood the area much faster than the drain drains.) I built this entirely underground so that the reservoir would never freeze (I was on a map that froze during a bit of the winter.)

With the pump/drain, the sequence goes like this when an enemy comes:

• Enemy steps on pressure plate. Hatches open. Room floods.
• Enemy stands still until it drowns. When it dies, it is no longer a unit and thus stops triggering the pressure plate.
• 100 rounds later, the pressure plate resets. The hatches close. With no more water coming in, the drain/pump clears the area, returning it to its original state. (Hence "Fully Automatic.")

Modifying the design to allow a three-tile-wide passage (for trade wagons), or to allow safe collection of the killed creatures' bodies and items, or to is left as an exercise to the reader.

A note on having a pressurized reservoir: In order to take advantage of the game's pressure rules, you need to have 7/7 water with more water on top of it. Here's some side views of reservoirs as examples:

 %3333333333%%
 %7777777777%%
 %%%%%%%%%%-%%
 %%%%%%%%% f %
 %%%%%%%%%%%%%
 
 With this much water, if the hatch ("-") suddenly opens, the area marked "f" will flood almost instantly (with the water from the "3" tiles).

 %          %%
 %7777777777%%
 %%%%%%%%%%-%%
 %%%%%%%%% f %
 %%%%%%%%%%%%%
 
 But here, the water will only flow slowly, without acting pressurized - even though, realistically, this should work the same way except with linearly less water.

Another REALLY weird effect is that in a wide reservoir, the northernmost water will fall through first, even if the hatch is at the south end. (You might want to build a reservoir no bigger than it needs to be - having the south water creep back to the north half can axe your framerate.) Yet another is the possibility of building a screw pump that forces water directly to its own source. (I haven't actually built that - I wonder how it would behave...)