Tutorials/Mob farm

Mob Farms are structures built to acquire drops from mobs more easily and more quickly than standard combat. A mob farm is typically a large dark room in which mobs will spawn and which contains a system to funnel the mobs to a central location. It is usually accompanied by a mob grinder to kill the mobs quickly and efficiently.

Locations
The rules that Minecraft applies to spawning mobs make choosing a location for the mob farm a fundamental decision.

Surface
Mob farms built on the surface can provide good drop rates during the day when they contain some of the few areas of ground without light, but they have a sharp drop in effectiveness during nighttime when the entire surface is dark enough to support mob spawning.

Underground
Mob farms built underground can remain within your personal spawn range for hostiles when you go mining, but their effectiveness, rather than being dependent on sunlight, is dependent on the amount of unlit caverns in your vicinity which provide alternative places for mobs to spawn.

Sky
Mob farms floating high in the sky can achieve record spawn rates in both night and day because they contain the only viable spawn ground within your spawn range. However, building one in Survival could result in your death from fall damage unless it is built over water that is deep enough to cushion you if you fall, and due to their altitude they will not spawn mobs when you descend underground to mine resources. For them to produce loot, you have to stay at the height of the farm.

Superflat
Superflat worlds will provide higher spawn rates than other worlds, as the missing air pockets underground reduce the amount of parasitic dark places.

The Nether
Farming is difficult in The Nether because water evaporates there, and all mobs that spawn there are immune to fire. This reduces the amount of functioning farm designs. Lava can be used instead of water for transporting mobs, but lava destroys the loot. The mobs can be funneled through Nether Portals to circumvent the restrictions.

Drops
The drops that a mob farm produces depend on the farm's location and the type of grinder used to kill the mobs. Automatic killing via mob grinders will not produce rare drops or experience orbs but is safer as the player is not required to be near the mobs. Manual killing can be facilitated by injuring the mobs in a grinder so that their health is low enough for the player to kill them with minimal effort and danger. Below is a table listing mobs that can be effectively farmed, their usual drops, and their drops that can only appear when they are killed manually. Experience orbs can also only appear when a monster is killed manually.

Designs
The most efficient size of a mob farm depends on where the player plans to be in relation to the farm. The player's spawn radii form invisible concentric spheres that move with the player and are always centered on the player's coordinates. If you plan to be directly beneath the center of the farm's spawning floor(s), waiting for the drops, then the radius of the horizontal circle at the altitude of the floor where mobs would spawn can be used to calculate the maximum horizontal dimensions for that floor:

Spawn_Floor_Radius = floor( sqrt( 1024 - (Y_coordinate_of_Spawn_Floor - Y_coordinate_of_Player's_Floor)^2 ))

Note that a square floor whose side lengths are twice that radius, thus fully enclosing the spawn circle for that floor's particular altitude, is not the most efficient square floor for that altitude. In the corners of the square that extend beyond the circle, mobs stop moving and can despawn randomly. Similarly, the parts of the floor within a different radius closer to the player do not spawn mobs at all. Finding the most efficient square floor for a particular altitude requires much more complex calculations. However, its side lengths are always between the inner, non-spawning diameter and the outer, despawning diameter for that altitude above or below the player.

If you plan to spend your time in a less-defined position, it might be easier to stack a simple design several times, ensuring that at least some areas remain in your spawn range while limiting complexity.

Sinkhole
The easiest possible design consists of a large, empty area of simple shape with one or more holes in the ground through which mobs can fall. The edge of each hole must be lined with signs or opened trapdoors to trick the mobs' AI into believing the hole to be solid ground. With approximately 0.542 wood per sign, they are the more economic choice over the trapdoors at 0.75 wood each. However, trapdoors can be controlled with redstone, so the farm's output could be disabled by closing the holes remotely.

The whole room is covered by a roof to create minimal light levels. A roof height of 3 allows Endermen to spawn, while a roof height of 1 would restrict the farm to spiders.

Sinkhole farms are naturally not very effective, as the chance for a mob to wander into a hole is small and becomes zero when the player is so far away that the mobs stop moving. But they can be built quickly and cheaply and will work in The Nether.

Canal-style


To force mobs to fall into holes and to transport mobs after they fall, canals filled with flowing water can be added, leading to a central hole or gathering area. The canals are lined with signs to trick the mobs into falling in, and the water transports them into the grinders. Such a design requires a bit of planning to ensure that there is no stationary water in which the mobs might get stuck, thus reducing effectiveness.

Since the system uses water to transport mobs, it will fail to capture Endermen because they teleport away when they touch water. Therefore, the roof of each spawning room should be 2 blocks above its floor to prevent griefing of your farm by Endermen taking or placing blocks. For sufficient farm designs, see Tutorials/Enderman Trap.

Compact canal design


This design consists of a 20x20 area with a floor of opaque blocks and four canals that are at least two blocks below the spawn floor to prevent mobs from jumping out of the canal, two blocks wide to accommodate spiders, and exactly eight blocks long so that the water stops exactly at the edges of the central 2x2 hole. It uses two water source blocks at the starting edge of each channel to fill the canals with water flowing toward the hole. Signs or open trapdoors are affixed to the inner walls of the canals to trick the mobs' AI into believing there is solid ground over the canals. The design can be easily stacked or placed next to each other to increase its effectiveness.

The floor area can be larger or smaller than 20x20 as long as the canals remain eight blocks long, at least two blocks wide, at least two blocks deep, and are lined with signs or trapdoors on their inner walls.

Minimal canal design


If there is not enough space for larger designs, this might be used. Its small inner area of 10x10 allows it to be incorporated into more compact construction projects. It uses four water source blocks, one in each corner, with the water flowing around four 3x3 platforms to the central hole. The one-block-wide canals between the platforms and the walls are covered to provide more spawning area. Canals that are one block wide are not useful because they cannot easily accommodate spiders. They would be useful only if spiders can be prevented from spawning.

Large canal design


If there is enough space for larger designs, this might be used. Its large size of 102x102 takes advantage of the way mobs spawn within 128 blocks of the player, allowing for more drops by attempting to transport mobs to where the player waits at the center of the farm quickly enough so that the mobs do not despawn from being over 32 blocks away from the player. Note that the portions of this design that are further than 32 blocks from the player are ineffective unless active systems are in place to push mobs into the canals. Smaller portions of this design may also be used for smaller farms.

Active mob displacement
Canal-style designs still suffer from the mobs not moving when outside a 32-block spherical radius around the player and thus not falling into the canals. Active systems can correct that problem by using redstone and dispensers filled with a bucket of water to flood the spawning floors repeatedly, flushing all mobs into the canals to be transported to the grinders. Alternatively, pistons could be used to hold back water from water source blocks until the pistons' redstone signal is disabled, retracting the pistons and allowing water to flow onto the spawning floors. Mob farms with active systems provide a viable area for mobs to spawn but do not rely on mob movement to get them into the grinder. With active systems, passive designs can omit the signs or trapdoors lining the canals or holes.

An example of this kind of farm can be seen in the following video, stacking the same basic design several times and using fall damage as grinder.

Other designs
Instead of using water to transport mobs, there are various other methods to make them move towards the grinder, all of which may work better with certain mobs, but can have higher resource requirements or lower gathering rates.

Sky-high mob farm
A sky-high mob farm is a structure built at a high altitude in order to generate large quantities of mob drops. This particular design is distinguished by its location far from other monster-spawnable areas. Its design is very similar to the compact mob farm discussed earlier on this page. It is an enclosed box typically 20x20x6 in exterior size and varies in:


 * Materials used in its construction: cobblestone, etc.
 * Platform construction: may or may not contain spider-spawnable ground
 * Number of water canals: 1 or 2, depending on whether platforms permit spider spawning
 * Internal height: permitting Endermen (Note, however, that water cannot be used for transporting Endermen because they teleport on contact with it.)

The procedure for constructing this mob farm is outlined here:


 * 1) Pool: Build a small pool of water 2x2 directly below where the intended opening of the farm will be. This pool has nothing to do with the finished mob farm as it is only for making constructing the farm easier. The pool will be removed when the farm is completed.
 * 2) Column climbing: Pile any unessential block off one end of the pool-rim upward by placing these blocks below the player as he jumps up and continue building this pile into the air no higher than an altitude of 250 but more than 140 blocks away from any monster spawnable area. This pile will also be removed when the farm is complete, and is only for gaining access to the intended location of the finished farm.
 * 3) Hole: At the top of this pile, begin building off the sides the exit port of the farm a hole 2x2 in size. This is where the monsters will fall out of the farm.
 * 4) Canals: From each of the four sides of this exit, build off of the sides away from the exit 8 blocks away for a total of 9 blocks including the exit rim, or 10 blocks including the exit space. These will serve as the water canals where the monsters will be directed toward the exit. These canals will be filled with water later.
 * 5) Floor: Build platforms 9x9 between each of these canals 1 block higher than the level of the canal. The end blocks furthest away from the exit of the farm will not serve as a spawnable platform for the monsters but instead serve to support the walls that surround the structure. There should now be one platform between every two canals for a total of 4 canals and 4 platforms.
 * 6) Light: Before the walls and roof are constructed, the platforms should be well lit as monsters may now spawn if at any moment the player accidentally falls through the exit or builds far enough away in a corner of the roof of the farm.
 * 7) Canals' starting edge wall: Build a 2 block high wall around the end of the farm structure by dropping the preferred block material on top of the edges of the 9th platform end blocks.
 * 8) Walls: After all the 2 block high walls surrounding the structure are placed, continue again building the walls 2 blocks higher than before for a total wall height of 4 blocks high. The fourth block will be used to attach the roof of the structure.
 * 9) Roof: Begin building above this highest block with half block material of choice. The placement of the slab material must be correct in order to ensure maximum output of the farm. The slab material must be placed above a full block of any kind, this position ensures that monsters will not spawn above the mob farm. If it is placed against the side of the top of the wall, this area becomes a spawnable area for monsters which reduces the efficiency of the mob farm.
 * 10) Go inside: After all of the roof is completed, dig through the roof and fall onto one of the platforms. Cover up the roof from inside with the same slab material.
 * 11) Water: Fill each block end of each of the four canals with a source block of water. The player may opt to build an infinite water source on one of the platforms in order to have a place from which to fill all of these water canals before beginning to fill each canal. The infinite water pool built on the platform should be removed before leaving the mob farm area.
 * 12) Check the water: After each water canal has 2 water source blocks placed on their respective 8th block positions, the water will flow toward the mob farm exit but will not overflow out of the exit. If this is not the case, the water source block should be stopped and the measurements should be rechecked in order to ensure that the mob farm will work correctly. If the water is not reaching the farm exit hole, the canals may have been constructed more than 8 blocks away. If the water overflows out of the farm exit, the canals may have been constructed too short or the water source block may have been placed on top of another block making its flow longer.
 * 13) Darken, descend, and build a platform: Collect all of the torches inside the completed mob farm and leave the mob farm through the exit on top of the pile of material used to build upward initially. Dig downward 50 blocks and begin to build a platform more than 10x10 around. This is a fall-damage grinder and will be the collection platform where the monsters' drops will be collected. If the roof is 3 blocks above the floor and water is not used for transportation, it is important the this platform be more than 45 blocks below the farm to ensure that Endermen will be killed. It is important that the platform be wide enough to ensure the player doesn't fall off the edge since falling skeletons may shoot the player causing knockback of the player.
 * 14) A ladder may be built against the remaining pile of material for ease of access to the platform catcher, and the player may jump into the pool at ground level in order to build his ladder from ground up toward the catcher.

One-way doors
Relying on the random movement of mobs, one-way door designs prevent the mobs from wandering backwards by using doors or pistons. Making several sets of doors can increase the speed with which the mobs move towards the hole.

The easiest configuration consists of a wall of doors (Iron on Hard difficulty to prevent Zombies from smashing them, Wood on other difficulties) with a row of pressure plates in front of them. When the mobs walk onto the trapdoors, the door opens, letting them through, but once on the other side, they can't open the door since there is no switch.

With Pistons, the arrangement is reversed, with the pressure plates on the desired side, and the pistons pointing upwards, so that they block the path of the mobs when extended. This design only work with a 2-block high roof to prevent the mobs from jumping, and even then might fail on spiders. However, it requires considerably more common ingredients than the iron door variant.

Such systems can also be used to "store" mobs after gathering them from the farm, so that they later can be killed for the rare drops and experience.

Transporting Mobs
After collecting the mobs from the farm, it might be beneficial to transport them to a different location before grinding them, so that you can access the items more easily while remaining at a close-to optimal position for the spawning of your farms.

Horizontal Transportation
Horizontal Transportation can be done easily using flowing water, with a drop of 1 block vertically for every 8 block traveled horizontally. Build a tunnel with a height of 3 blocks and a width equal to the size of your gathering holes (usually 2). Mine forward to a length of 8 Blocks, so that water placed at the start ends exactly at the drop. Repeat, but one block lower, so that the mobs fall from one funnel part to the next. Mine out the roof at the higher level for 2 or 3 more block to prevent spider clinging to the walls from clogging up the funnel.

Alternatively, one can use a cactus to grind the spiders immediately. To do this, make the first funnel part only 7 block long and place only one water source block instead of two. Place a sand block and a cactus on top on the same side as the source block. The place the cactus, you have to mine out the block next to it. To ensure the water flow on the next part, mine out the wall block next to the sand and add the water sources there and next to the sand, where there would usually be one.

Downward transportation
Transporting mobs and items downward is trivial, simply let them drop down a chute with a water brake at the bottom. Or omit the water brake when you want the mobs to die from fall damage.

Upward transportation
Upward transportation uses the fact that nearly all mobs will attempt to swim in water, moving upwards. Therefore, to get the mobs using upwards, one has to provide only a column of water with enough air holes to prevent them from drowning. This can be done by arranging signs or ladders and water source blocks in the following vertical configuration:

This can be repeated indefinitely in any direction for a mob elevator. When arriving at the right height, flowing water on top of the topmost ladder is enough to dislodge them.

However, one should remember that Slimes do not swim, and neither do Items. These things will instead float downwards to the bottom, which can be used to separate items or slimes from other mobs.

Grinding
The last part of a mob farm is to kill the gathered mobs and collect their items. This can be done in different ways, using the variety of damage available in Minecraft, like falling, suffocating, drowning, burning, sunlight (for undead), touching cacti or simply player-applied damage from weapons/potions of harming or healing

Passive systems
Passive systems do not change to kill the mobs, they rely on constantly available damage sources. The most common mob grinders, the "Lava Blade" and "Drowning Trap" fall in this category.

Active systems
Active systems have to change configuration to actually kill mobs, usually in the form of redstone devices. The most known might be the "Piston Grinder", which applies suffocation damage by pushing an opaque block into the head of the mob. While possibly faster than passive systems in killing, active systems usually have a limited capacity, and higher amounts of mobs might clog or even jam the system.

Experience farms
Experience farms (EXP farms) are systems that capture and soften up the mobs, but rely on the player to deliver the killing blow, so that the rare drops and experience can be gathered. An example would be a nearly-lethal falling height which would reduce the majority of mobs to half a heart, easily killed even without a weapon. However, such systems are only as good as the player using them, and in constant danger of being destroyed by Creepers if not built out of obsidian.

Video
With a hopper, it becomes easy to collect the dropped items, even without player interference. Place a Double Chest under the hopper which will funnel the drops into it and save you going into your trap every time. This makes fully automatic mob farms possible where the loot will be deposited in a chest for easy accessibility.

Anleitungen/Mob-Farm Tutoriels/Exploiter les créatures Мобофермы 教程/刷怪塔