Editing Siege engine

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A '''siege engine''' in ''Dwarf Fortress'' is half building, half heavy weapon, and includes both the '''catapult''' and the '''ballista'''.  Both are capable of launching hazardous projectiles at a tremendous range (more than a screen-width, around 80 to 100 tiles for a catapult and between 130 and 200 tiles for a ballista).  A [[ballista arrow]] can kill or injure each creature in its path indiscriminate of friend or foe, but a stone launched from a catapult cannot harm [[dwarf|dwarves]] or [[animal trainer|tamed animals]].

Ballistae require specially-made [[ammo]] – [[ballista arrow]]s, made from [[wood]]en [[log]]s at the [[siege workshop]] (and optionally tipped with [[metal]] [[ballista arrowhead]]s that have been made at a [[forge]] by a [[weaponsmith]]). Catapults use simple [[stone]] as ammunition. Catapults respect [[economic stone]] restrictions and cannot fire [[clay]] at all.

 

In order to build a siege engine, you first need to produce (at least) three catapult or ballista parts in the [[siege workshop]]; catapults are made from any 3 '''catapult parts''', and ballistae are made from any 3 '''ballista parts'''. All parts are made from any type of wood at the siege workshop. Beyond that, "parts" are generic - there are no particular "sub-types" of parts beyond the distinction between those for the two different engine types. The quality of the parts determines the overall rate of fire (and maybe accuracy) of the engine - the best are made with 3 masterwork parts{{verify}}. This won't make up for an untrained siege operator, but every little bit helps. Siege engine parts are stored in Furniture stockpiles.

Once you have the parts, you may then build the respective siege engine like any other building, selecting the parts that you wish to construct that particular engine with.  It is not known whether the skill of the dwarf assembling the siege engine has any effect, but the quality of the parts certainly has: siege engines put together from [[quality|masterwork]] parts have a much higher rate of fire.{{verify}}

The assembled siege engine is, effectively, a 3x3 building. It cannot be moved about, other than by taking it down and re-assembling it at the new site. Siege engines do not impede movement, though, so you don't have to worry about building them in a corridor.

*Prepare to Fire:  Siege operators will load the engine and remain stationed for further commands.

*Fire at Will:  Siege operators will fire and load normally.

* Both catapults and ballistae have narrow fields of fire – they will only shoot at creatures directly "in front" of them, and so cannot target anything off at an angle.  They can be turned 90 degrees, but that often will not solve the problem. Unskilled operators have trouble aiming perfectly straight, and their shots will randomly veer off to either side, resulting in a field of fire roughly 19 degrees across. Highly skilled operators fire their shots perfectly straight, restricting their field of fire to a straight line facing directly north/south/east/west.

* Both catapults and ballistae aim and fire only along one z-level.  While ammo from both may drop down z-levels, they do no damage to creatures there. This also means that no "head room" is necessary – ammo only flies out, never up.

* Catapults have a minimum range – at least 30 tiles.

* [[Siege operator]]s are civilians and, as such, will run in fear if enemy units come too close to them. "Too close" varies somewhat, but may be as far as 10 tiles.

 

 

'''Ballistae can and will kill anything in their path!'''  Ballista arrows may hit any units in any square that the head passes through.  They are moderately dangerous weapons, and should never be used with friendlies anywhere in their cone of fire, including the space the ballista arrowhead occupies when loaded on the engine.  Always designate a [[traffic|restricted traffic area]] for a lot of tiles along the firing arc and keep dwarves out of the area or, better, wall off anything in front of them with fortifications to prevent all friendly traffic, or both.  The shots appear to travel until they hit a wall or fly off the screen; the maximum range is about 150 tiles for an ordinary ballista. If the bolt passes through any part of a [[tree]], the tree will disappear, presumably reduced to toothpicks.{{cite rev|210835}}

Siege engines can almost only shoot at targets right in front of them on the same Z-level. The target may deviate only slightly, as the field of fire is about 10-20 degrees wide. Because of the huge blind spots, it is advisable to [[Security_design#Siege_Engines|prepare the position]] so that the enemy will be channeled through the field of fire.

Siege operators are civilians! They may cease firing and run if the enemy comes too close, which is around 20 tiles. You should therefore place the engines behind a [[moat]] or a wall of [[fortification]]s that will keep the enemy at a safe distance, or shield access to their location in some other fashion.

Siege engines can shoot through [[fortification]]s, just like any other projectile weapon. As fortifications appear to provide some protection against incoming [[bolt]]s and [[arrow]]s, it's usually a good idea to protect the siege engine in that way. The siege engine can shoot through any tile thickness of fortification. Fortifications further on in the path of the shot will not hinder it either.

The quality of the siege engine parts affects the engine's reload time (and possibly accuracy).{{verify}} It is not known whether the siege engine itself also can be of a certain quality. The quality and material of the ammunition (in case of ballista arrows) affects the damage and possibly accuracy as well.

The operator skill affects reload time and accuracy. It will take a whole month for an unskilled dwarf to load a catapult; a Legendary operator with nearby ammo will get several shots at a running enemy.

Operators are best trained by firing into a nearby pit (to conserve ammo and ensure that it remains near the engine). It is recommended to have multiple skilled operators for each engine, since, as civilians, they cannot be compelled into action if they've decided to take a rest. Dwarves that have increased their strength statistic load engines much more rapidly than others, making them good candidates for operator duty (experienced operators can be [[cross-training|cross-trained]] for strength). You should start training early: it can take one year for an operator to become Proficient, and two more years until he finally reaches Legendary level; by then he will have spent 300 rounds.  

An alternative approach is [[cross-training]] any highly skilled dwarves who aren't doing anything useful at the moment.  With a couple levels each in strength and agility, a free siege engine, and an ample supply of ammunition nearby, a dwarf can become a Legendary siege operator within a few seasons at most, giving more flexibility in defense and several more levels for the fortunate dwarf.  Rotating legendary [[miner]]s out to siege-operation and then to stone-hauling duties sets up an efficient cycle.

Catapults are generally less effective in battle situations than ballistae.  The launched rocks will often glance off mail armor, making them poorly suited for killing even [[goblin]]s; they are also very inaccurate.  Their ammo is easily replenished, making them ideal for target practice and very cheap to make and use.

Ballista arrows tipped with softer materials (such as wood) can glance off ordinary clothes, making the choice of arrowhead significant.  However, the arrows may hit multiple targets in a single launch.  This makes ballistae many times more efficient than catapults, which fire in an arc that hits only a few tiles per shot and is nearly useless against anything larger than smaller, poorly-armored foes.  Ballista arrows fired through too many successive targets will be lost or destroyed; the limit seems to be roughly 5-6 goblin-sized targets hit before the arrow is lost.  Adding a channel to the end of the arrow's trajectory will allow expensive bolts to be recovered after the attackers are dealt with.

  Entrance++++++++++++▼    ╬  ╬▐▀\◄═«  (~ammo~)

  Entrance++++++++++++▼    ╬▐▀\◄═«▐▄/

  Entrance++++++++++++▼    ╬◄═«▐▄/ (~ammo~)

  ══════════════════════════╣▐▄/ (~ammo~)

 

:*<tt>＋</tt> - floor

Ammo storage can be on the same level, or via [[stairs]] or [[ramp]]s on another [[z-level]]. Expand the room as desired for more storage.  Also note that ballista arrows are stored in [[Stockpile#Furniture_Storage|furniture stockpiles]], not ammo stockpiles.

An alternate strategy could be to place a [[floodgate]] or retracting [[bridge]] in the center of the 3x3 hallway, and activate it during times of crisis so that the Goblins are forced to fight in two separate 1x1 corridors rather than a single 3x3 corridor. If the corridors are further lined with spike traps and weapon traps, this combined defense can assure your dwarves that any attempts to assault your base will be very, very bloody.

A drawbridge can be combined with the channeled area to provide a practice area, as discussed above.  The channels would be accessible from the battery area via a staircase, keeping the dwarves below/behind the lines of fire at all times.

When a catapult throws a stone, that stone is destroyed upon landing, unless it falls a z-level, where it lands harmlessly.  That means that if you can arrange it so ammo hits a wall (or door, or raised bridge), and there is empty space immediately under that, the stone arrives at that point.  If the ammo reaches its maximum range, again, it falls harmlessly.  Even with a single, no-quality catapult and an untrained crew, this is massively faster than hauling stone by hand.  Ammo that hits [[stairs]] is destroyed, even if it can fall a z-level. Stones falling one z-level onto a floor with empty space under it will also be destroyed, make sure there is a wall under the tile where the ammo ultimately lands on.

This involves a catapult, a garbage dump [[activity zone]], and a legendary siege operator. Set up your catapult where you'd like it to be used, then place a garbage dump zone in the middle of the catapult and dump a sufficient number of stones there. Reclaim the ammo using {{k|d}}-{{k|b}}-{{k|c}} (making sure that you don't have any stone [[stockpile]]s that permit the stone you used) and you're good to go. With a sufficiently strong/agile siege operator (and a lack of distractions), you can easily manage 2-3 stones flying at once per catapult.

:*[[cross-training#Artillery proving ground (siege operator)|Army corps of engineers]]