Editing v0.34:Silk farming

{{quality|Exceptional|19:18, 20 March 2013 (UTC)}}
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'''Silk farming''' is the process of havesting large quantities of silk from webslinging creatures like [[giant cave spider]]s. Several setups have been devised to farm silk quickly and safely, but successful silk farms have a few traits in common:

# The webslinging creature must be aggressive toward its bait.  Tame giant cave spiders are aggressive toward invaders, while wild spiders and [[forgotten beast|various other untamable creatures]] are aggressive toward most tame animals (with [[cat]]s being a notable exception). Tame spiders are not aggressive toward animals on restraints.
# The webslinging creature must not be able to reach its bait; if it can, the bait (or creature) will die and no further silk will be generated. Spiders can destroy wooden doors but not stone or metal doors. They cannot pass through forbidden doors or doors that have been "tightly closed". Other silk-spewing creatures can destroy all non-[[artifact]] doors, requiring drawbridges or walls for containment
# Web collection cannot occur in sight of wild webslingers or invaders serving as bait; either  will cause dwarves to interrupt collection.  Drawbridges work well to block line of sight in either case, as webs will not prevent them from raising.

==Simple silk farm==
{{diagram|spaces=yes|color=#888|\
╔═══════════╗
║+++++++++++║
║+++++++++++║
║+++++++++++╣
[#0FF][#088]X++++++[#080]╞[#080]═[#080]═[#080]═[#080]╡║
║++++++[#080]╥[#F00]╬[#F00]╬[#F00]╬[#F00]╬║
║++++++[#080]║[#F00]╬g[#F00]╬S║
║++++++[#080]╨[#F00]╬[#F00]╬[#F00]╬[#F00]╬║
[#0FF][#088]X++++++[#080]╞[#080]═[#080]═[#080]═[#080]╡║
║+++++++++++╣
║+++++++++++║
║+++++++++++║
╚═══════════╝
}}
# Dig out (and optionally smooth) a sufficiently large room (example shown is 11x11).
# Channel out the "S" square and the "g" square and build retracting bridges over the gaps. Link these bridges to a lever and place a cage trap underneath whichever square will eventually hold the hostile creature. Separate levers for each bridge may also be used. Do not use any creatures with a size of over 1,000,000 as bait! The weight of these creatures will jam the bridge in place. This step is optional, and allows a creature or corpse to be removed from the silk farm and either repositioned or recaptured without military involvement.
# [[Construction|Construct]] all of the red [[fortification]]s.
# Build the 3 green [[bridge]]s, all raising lengthwise to form long walls.
# Construct a [[lever]] somewhere convenient in your fortress and link it to the 3 bridges.
# Build one of the 2 [[floodgate]]s and link it to the lever. Pull the lever to open the floodgate and allow access to the room, then build the second floodgate and link it to the lever. Pull the lever until both floodgates are closed.
# Using a pit/pond [[activity zone]] on the Z-level above, drop a tame giant cave spider into the gray "S" square and a hostile creature (such as a goblin) into the gray "g" square. Alternatively, use a hostile spider and a tame creature - the main concern is that the spider must be hostile toward its target.

At this point, the spider will begin blasting the bait creature with webs, and most of the webs will fly through the fortifications and land on the floor to the left. Once enough webs have accumulated, pull the lever to open the chamber for collection and raise the 3 bridges. These bridges enclose both spider and bait, and while the spider will continue to web the bait this does not cause the same lag as the old door method.

Silk can be farmed just as easily from a wild spider with a few changes.  Domesticated [[pet]]s can be used in place of goblins for wild spider, but avoid [[grazer]]s; other animals may need to be replaced when they die of old age.  It's recommended that you place a backup [[cage trap]] to reposition the spider if your first design doesn't meet your needs, but remember that should any webbing fall on the cage trap, it will trap your dwarves as easily as it will the spider.  Wild spiders can be placed via [[lever]]-controlled deconstructing cage (which would have to be placed inside the chamber prior to building the fortifications), or [[Activity zone#Pit/Pond|pit]]ted from above.

Note that tame spiders are hostile to wild animals. This means that you can use a benign wild animal, such as a [[grasshopper man]] or a [[large rat]], as a bait animal, instead of a hostile creature like a [[goblin]]. Dwarves are not as frightened of wild animals as they are of hostiles, and this can make the shutter bridges and surrounding walls entirely unnecessary--the weaver can simply walk up to the webs as the spider shoots them. This may cause the occasional cancel spam when an errant web hits the weaver directly, but there is no real danger.

==Automated silk farm==

{{diagram|spaces=yes|color=#888|\
      z             z-1        z-2  
 ╔═══════┼══╗   ╔═════╗      ╔═════╗ 
 ║[#080]╔[#080]═[#080]═[#080]═[#080]╗+++++║   ║[#0AA]╔[#0AA]═[#0AA]═[#0AA]═[#0AA]╗┼      ║+++++┼ 
 ║[#080]║[#080]+[#080]+[#080]+[#080]║+++║[#0F0]^║   ║[#0AA]║[#0AA]+[#0AA]+[#0AA]+[#0AA]║╠═┼╗   ║+++++║ 
 ║[#080]║[#080]+[#080]+[#080]+[#080]║+..[#F00]╬[#888]┼╣   ║[#0AA]║[#0AA]+[#0AA]+[#0AA]+[#0AA]║║++║   ║+++++║ 
 ║[#080]║[#080]+[#080]+[#080]+[#080]║+.[#FF0]H[#F00]╬[#CCC]S║   ║[#0AA]║[#0AA]+[#0AA]+[#0AA]+[#0AA]║║++║   ║+++++║ 
 ║[#080]║[#080]+[#080]+[#080]+[#080]║+..[#F00]╬═╝   ║[#0AA]║[#0AA]+[#0AA]+[#0AA]+[#0AA]║║++║   ║+++++║ 
 ║[#080]║[#080]+[#080]+[#080]+[#080]║+++║     ║[#0AA]║[#0AA]+[#0AA]+[#0AA]+[#0AA]║╠══╝   ║+++++║ 
 ║[#080]╚[#080]═[#080]═[#080]═[#080]╝+++║     ║[#0AA]╚[#0AA]═[#0AA]═[#0AA]═[#0AA]╝║      ║+++++║ 
 ╚════════╝     ╚═════╝      ╚═════╝ 

}}

# Dig out the three chambers as shown.
# Smooth and carve the red [[fortification]]s.
# [[Channel]] out the areas in green and cyan, linking all three levels
# Build the large green [[bridge]] (retracting) and large cyan bridge (retracting)
# Construct a [[pressure plate]] in a well-traveled area (or a [[repeater]]) and link it to the green bridge
# Build a [[lever]] and link it to the cyan bridge
# Build a [[cage]] containing an *untamed* spider at the gray "S", and link it to a lever
# Build a '''non-wooden''' [[door]] above the spider cage, and mark it forbidden and pet-inaccessible
# Channel the yellow "H", build a [[hatch cover]] there, and link it to a lever. This will allow you to remove the bait and stop production.
# Channel the tiles around the yellow "H", and remove the ramps below
# Recommended: build a [[cage trap]] on the green "^" to recapture your spider later
# Evacuate the upper two chambers and forbid their entrance doors
# Pull the lever linked to the cage to release the spider
# Pit a *tame* *non-grazing* *hostile* bait animal (such as a dog) onto the yellow hatch from the level above
# The spider will blast the bait with webs. When the green bridge automatically retracts, the webs will fall and stack on the cyan bridge
# Pull the lever linked to the cyan bridge to drop the stacked webs to the bottom level for collection
# Sit back and enjoy your (mostly) automated supply of new silk socks

Note that a simple pit in the harvesting chamber will not work--the bridge is required to cause the "web objects" to drop to the next level (and stack). Because falling items are deadly (a falling web managed to break the spine of one of my aspiring weavers), it is necessary to collect the webs on the "holding" bridge and only drop them into the collection chamber when your weavers are clear. Also, webs "tossed" by the retracting bridge can injure anything they hit, so your bait animal may require occasional replacement. One spider can easily keep several weavers busy, and collecting all the webs provides a great opportunity for [[cross-training]].

==Notes on exotic webslingers==

Farming silk from other [[forgotten beast|procedurally]] [[titan|generated]] creatures is somewhat more difficult and less rewarding. As level 2 [[building destroyer]]s, these creatures can only be contained by [[bridge]]s or [[artifact]] [[door]]ways. They are also immune to [[trap]]s, making positioning in the farm rather more complicated. Finally, without a value modifier, the collected silk will be equivalent in [[value]] to common [[cave spider]] silk. They do still provide a nearly-inexhaustible source of silk thread, and with some effort their webs can also be used to [[cage trap|cage]] other trap immune creatures.