Editing Defense structures

{{Image wanted|reason=Most images are from Beta 18, where deadfall/spike traps could be placed adjacent to each other.}}

Raids are frequent and numerous as enemies don't journey towards your base from their "camp" but just spawn on your map nor need to maintain their base like players do. So players must wisely consider protective measures while still taking everything else into account, whereas hostiles only attack.

Before laying blueprints, first inspect the [[map]] for natural features that can work as defenses, such as [[water]] or a [[mountain]].

 

Water or marsh tiles can be used as moats which will considerably slow down incoming [[Raiders]], giving you some time to shoot and soften the clash before engaging in melee [[combat]].

[[File:Moats.png|600px|thumb|center|Marsh used as moats to slow enemy advance, with little islands full of spike traps.]]

In maps with rivers or other bodies of water, you can build [[cover]], like [[sandbags]], on top of the water using a [[bridge]]. Funnelling enemies over the bridge can slow them down significantly while exposing them.

Mountains (in [[Small hills]] or [[Large hills]] maps) that align with each other can become part of your defensive walls by filling the gap in-between. Mountainous maps, however, are better used by [[Mining]] in tunnels and caves or walling out a section surrounded by mountains.

 

Pay attention when expanding towards the edges of the [[map]], as there's a boundary which your [[colonist]] can not build beyond that is only visible when the [[Structure]] tab is selected.

At the very beginning your most primitive [[security]] choices are [[spike trap]], [[sandbags]], and [[rock chunks]]. You will need to find a balance between these three to make the most out of the available materials without costing too much time. Analyze the terrain to find choke points, natural walls, and other features you can use to defend your colony.

=== Rock chunk manipulation ===

From the start, much time will be spent [[Hauling]] [[rock chunks]], either to build or to open a [[Growing zone]], while gathering raw materials into a [[stockpile zone]]. As you move rock chunks around, you might as well create a [[Dumping stockpile zone]] on the outside of your wall, covering its width and expanding it further. This is a little help as [[fire]] prevention, since stone chunks will slow the spread of fires by preventing grass growth, thus naturally removing any flammables below. Fires can spread up to 4 tiles away, so this won't completely stop fires unless you put a thick enough line.

Your speed in this matter is greatly affected by the number of haulers available. [[Taming]] and [[training]] animals with Advanced training capabilities, such as a [[Husky]], allows the animals to do the hauling, while your colonists can focus on building other defensive structures. Taming hauling animals is also time and food consuming so you will need to allocate resources carefully rather than getting 20 pets right away.

An essential [[Structure]] to keep threats out, so long as the base is self-sustainable inside. Walls alone can fend off early game raids if a colonist's [[Construction]] is high enough to keep the walls standing while enemies start to starve and become tired. Walls also protect from [[Carnivore]] attacks and a possible [[Manhunter pack]], which cannot reach colonists safely inside unless a colonist is seen passing through a [[door]], at which point the animal will attempt to break it down.

As raids become stronger, walls alone won't hold off raids, so prepare additional defenses behind them such as lines of [[Sandbags]], or funnel them through a chokepoint to engage in melee [[combat]].

Many layers can be raised as you expand. Initially it is faster to build with [[wood]] but later on, they should be made of stone like [[granite blocks]] or [[limestone blocks]].. Placing several doors 15 to 25 tiles between each other allows multiple exits and the ability to flank enemies.

Cover is vital for firefights as it can block projectiles, reducing the amount of [[damage]] received by your colonists. This is an essential defense as long as colonists or turrets are directly engaging.

[[Sandbags]] and [[barricades]] are very efficient when placed wisely. Their protection is inferior to walls ({{#expr: {{Q|Sandbags|Cover Effectiveness}}*100}}% vs 75% from walls), but are more effective against diagonal fire as they can be placed side by side. They are faster to build, and can be built from [[textiles]] (sandbags) or ordinary building material (barricades).

==== Rock chunks ====

[[Rock chunks]] are natural resources with 50% cover efficiency, weaker than constructed cover but still effective. Their placing is similar to sandbags only that it requires hauling to previously set dumping zone lines, instead of construction. Helpful if you have no one well skilled in [[construction]].

=== Spike traps ===

The only initially available defense that deals damage, is single use and needs careful placement. Common locations are in the corners of your base where enemies will likely make turns as well as narrow areas even outside your base that receive frequent traffic. If it doesn't seem obvious to you at first, one way to find out is by carefully studying raids pathing from the map borders as they close in towards your base. Watch where they go through and starting laying blueprints but forbidding them (as you are currently being attacked).  

When building spike traps, you must also leave free areas so that your colonists and friendlies can pass harmlessly or else they are greatly slowed while trying to tiptoe through them, and may accidentally trigger one in the process. As such, putting them in a 1-wide corridor is not a good idea. A good way to harness this is a 2-wide corridor, with a spike trap, and then a fence next to it. friendlies will go over the fences, while enemies will walk through the traps.

Be aware that after subsequent game updates, you can no longer place spike traps adjacent to one another, as displayed below.  

File:Trap_choke_14.jpg|'''Trap and fence passage'''

[[File:Wildfire clearing.png|500px|thumb|right|Intentional burning of a tropical rainforest to reduce any cover that raiders might use.]]

Once your basics had been covered, it's time to make improvements. On maps where flora is dense, it's best to clear the surroundings so that enemies won't have cover to fight, totally exposed to your fire. From the [[Orders]] tab, use the "[[Cut plants]]" order to remove [[trees]] and "[[Haul]]" to haul rock chunks away, gaining [[berries]] and wood in the process, and hastening any jobs at the [[Stonecutter's table]].

Attackers will destroy [[furniture]] if no colonists are in sight, and will sometimes even stop to destroy furniture if it is between them and the nearest colonist. They may smash items or set flammable things on fire (particularly crop fields).

As a small added bonus, if your outdoor bait furniture consists of a table and stool, colonists completing work tasks far from your base may stop to eat there. This may help avoid the "Ate without table" negative [[thought]].

[[File:Cover_fire_wall.png|400px|thumb|right|Example of advanced cover using walls.<br> Colonists behind walls are enjoying full cover, with 75% of shots blocked. <br>Colonists behind sandbags are at half cover, with {{#expr: {{Q|Sandbags|Cover Effectiveness}}*100}}% of shots blocked.]]

While sandbags already give you an advantage over raiders in terms of cover (55% vs 50% for stone chunks), removing all sources of cover near your base is still very useful when dealing with ranged enemies as they will then have nowhere to hide.

Haul all stone chunks towards a dump behind your defensive lines so enemies can't use them. A [[sniper rifle]] has a [[range]] of 45 tiles, though most raiders can't shoot that far, so removing chunks around 30 tiles away from your defenses can deprive many enemies of suitable cover.

Watch out for your crop fields, as colonists tend to move and lay out chunks in straight lines when planting on [[Growing zone]] tiles, suitable for raiders to take cover behind.

* Cheap -- Wall materials are the only thing required to build a basic bunker, allowing for quick construction.

* Simple -- Four walls and a few sandbag/barricade firing positions is all it takes to build an effective early-game defensive structure.

* Upgrade-able and modular: Additional walls/rooms & defensive structures like turrets can improve the bunker’s capability.

* Full cover provides high defence for colonists.

** Full cover negates damage from explosions outside of the bunker, internal walls can negate explosives that enter the bunker.

 

* Static position: If not placed well, the bunker’s utility will be greatly decreased, and not all map types suit bunkers,.

* Continuous investment: In order for the bunker to remain useful into the mid and late-game, periodical upgrades will be required and will sap your resources unless you decide to abandon or repurpose the building.

* Hostile takeover: Enemies gaining control of your bunker(s) can prove dangerous as they can utilize the effective cover.

You can build flammable floors to set on fire, burning enemies. Once the floors are burnt, they leave behind burnt floors that apply a {{Bad|{{%|{{Q|Burned floor|Move Speed Factor}}}}}} movement factor, and will persist until removed.

Friendly AI will always prefer to move through doors and avoid traps, while enemies will prefer to go around structures by entering open spaces and are unable to see traps. (Note: Recent updates have removed the ability for spike traps to be placed within 1 tile of each other in any of the four cardinal directions)

Because of that, trap chokepoints like this one are effective. Enemies will prefer to use the corridors rather than attempting to destroy doors as it would be more time consuming, and being unable to see the traps, they will trip them hopelessly. On the other hand, your colonists can safely pass using the door instead. Enemies cannot pass doors unless they destroy them first, or they are being held open.

This clever trap is simple to set up and hard-hitting when triggered. It can be considered a giant single-use spike trap.

You can build one surrounding your base, and divide the map into sections in order to control fires. You can also use them to separate crop fields such that a fire won't consume all your crops.

Keep in mind that building such amounts of floors usually requires huge amounts of building materials - if you have stone on hand it is better to build a perimeter wall out of stone instead, with the added advantage of fortifying defenses.

Turrets are automated defenses which shoot at enemies in range. There are three varieties; the [[mini-turret]], [[autocannon turret]] and [[uranium slug turret]] from 1.0 onwards, while in earlier versions there is only 1, the [[mini-turret]].

==== [[Mini-turret]] ====

==== [[Autocannon]] ====

==== [[Uranium slug turret]] ====

*Explosives deal immense damage to turrets. All forms of regular explosives wielded by raiders are capable of 1-hitting a steel mini-turret and leaving a plasteel one at less than half health.

*[[Smokepop pack]]s prevent turrets from locking onto targets within or behind smoke. An enemy equipped it can create a safe zone from turret harm.

Mortars can't fire at anyone within 30 tiles of it, so you will need to place the mortars deep inside your base for maximum coverage. It needs to be well-protected against intruders, for enemies that survive to come close to the mortars can wreak havoc on the helpless mortar crew, so you should pay attention and unassign the mortar crew to fight if necessary. It's best that you have your colonists standing guard outside, but if you need to you can always have a few pillboxes to defend the mortar base.

**They excel at dealing with [[shield belt]]s, instantly downing many at once. This can be helpful in preparing for a melee blocking or killbox defense.

**They can also shut down [[mech high-shield]]s {{RoyaltyIcon}} for 0.5 hours, giving you an window to send a barrage of high explosive shells to destroy whatever is inside.

1 IED trap can trigger other IED traps in its explosion radius. This may or may not be desirable depending on the situation; you can easily set off a chain reaction to destroy a whole incoming raider horde, but also use up much more resources. They also damage nearby structures, such as walls or spike traps, so don't put too many close to each other.

[[File:Killzone.png|500px|thumb|right|An example of a killbox. [[Fence]]s spaced 1-tile apart slow enemies down. Barricades near the entrance prevent enemies from standing on the corner. Traps and fences allow colonists to pass unimpeded, but enemies will walk through the traps. Doors can be closed in case of [[manhunter]]s.]]

It's always best to double-wall the "receiving" end of your killboxes as the sheer firepower raining on your enemies will inevitably destroy some of your own walls by accident, allowing raiders to flood in from another direction, bypassing traps and overwhelming your defenders. This is especially true if you use explosives such as frag grenades or IED traps to kill incoming enemies.

Entryways should be long, but not too long, corridors with [[sandbag]]s or [[barricade]]s every second tile to slow enemies. Do not place a continuous line of sandbags or barricades, as pawns only slow down when they are climbing on and off the two (similar to real life, as you can just run on the barricade after you climb on it). In between the spaces, spike traps can be placed to soften up the raiders (with doors adjacent to the sandbags so your colonists can replace them). At the end of the corridor, place a T-Shaped sandbag line (do not alternate with empty tiles like before), as pawns cannot stand on the sandbags and therefore are incapable of using the corridor exit walls as cover. [[IED trap]]s can be used, but should be used sparingly lest they blow up all the walls of the corridor.

<!-- File:Trap_tunnel.png|Same entryway but with spike traps. Deals heavy damage to incoming raids but costs a lot to build. -->

Different equipment is necessary in different situations.  

 

==== Short-range killboxes ====

* [[Chain shotgun]]s inflict extreme pain at killbox range, surpassing the DPS of every other weapon at short range or less.

* [[Minigun]]s are excellent at attacking the bunched-up raiders inside a killbox, but require large amounts of resources to craft ({{Required Resources|Minigun}}).

* [[Charge rifle]]s and [[heavy SMG]]s are second-tier picks, being able to dish out hurt against closely grouped targets at close-mid ranges.

* Long range weapons are not optimal due to low DPS. Instead, use them to pick off survivors outside the killbox.

* Grenades are good if you can time them right. Throw them near the entrance where each explosion can hit a tight group of raiders, especially if they're slowed down with obstacles, but take care not to demolish your own walls.

==== Long-range killboxes ====

* [[Charge rifle]]s are the best weapon{{Check Tag|Arguable}} for this purpose, shooting 3 semi-accurate high damage charge shots. It also has a decent 26 tile range and an excellent 35 percent armor penetration, essential for killing targets late game, when your killbox is more developed.

* [[Heavy SMG]]s are excellent alternatives to charge rifles. Significantly cheaper but similarly skill friendly and with a solid DPS.  

* [[Assault rifle]]s are basically charge rifles with lower damage and armor penetration, but making it up for its longer range and higher accuracy. Higher skilled pawns are required to make use of their range however.  

* [[Minigun]]s, [[Chain shotgun]]s, and perhaps [[LMG]]s are second options, excelling at crowd control, especially against tribals.

* Explosive weapons are not advised, as raiders will be moving around the killbox frequently, and grenades have a delay between the grenade hitting the ground and the explosion of the grenade.

[[Centipede]]s with [[inferno cannon]]s can counter killboxes as the fire makes your colonists lose control and run out of cover, and the flames can destroy turrets easily. Having some [[firefoam popper]]s inside your box helps a lot with extinguishing fires and preventing future fires.

# "Shooting range" corridor, where enemies will be shot at from distance and will be forced to advance one behind another. It is also filled with stone chunks to slow them while they're being shot at (as chunks may be moved or destroyed during the attack, 1×1 [[stockpile zone]]s allowing only stone chunks should be placed, enabling their quick rearrangement).

#* Above, the "escape exit" corridor, filled with spike traps (doors allow replacing traps without having to walk on them).

# "Entrance to the base" (or at the part that enemies are planning to reach), with wall corners at the end to use as shooting positions (in case some enemies reach this part).

#* This can also be a place where corpses are burned, if it is preferred to butchering.

* Spike traps should be made out of [[steel]], as it has the best price-quality ratio for this device (nevertheless, steel is flammable in RimWorld, but here, traps are protected behind the walls and doors).

* Accurate weapons should be preferred for colonists: the narrow corridor will be damaged unnecessarily if explosives are used, or weapons like [[shotgun]]s or [[minigun]]s (not to speak of their reduced range).

* The hall should like an unobstructed path to enter the colony (i.e. no closed door between the outside and the inside of it), but the doors leading to it that will be used by colonists should be strong enough to deter attackers from trying to break them.

This is a powerful way to burn a massive [[infestation]] to a crisp. Provided that the infestation have no direct access to map edges and unroofed areas.  

To start, build a medium-sized room (approx. 5x5) with triple-thick stone walls, next to the infestation. Fill it with [[Straw matting]]s, and flammable objects such as wooden [[barricade]]s, it has good hp which means it will burn for longer and has high flammability, so it will catch fire quickly. Another alternative is to use tainted clothing.

After that, dig a 1-wide tunnel towards the infestation at night when the insects are sleeping. Finally, toss a Molotov into the room.  

Once the temperatures reach ({{Temperature|250}}), insects will begin to burn. They will attempt to dig out by rushing towards the purifier, but be set alight by the burning [[Straw matting]], making them unable to dig. Temperatures can rapidly reach {{Temperature|500}} or above, boiling both the insects and the hives. Even those that don't get set alight will eventually succumb to heatstroke.