Containment

Containment refers to the process of capturing, imprisoning, and exploiting Entities.

Summary

Containment is the desired end result when encountering Entities. Colonies can hold entities on a Holding spot or a Holding platform, the latter of which requires research and steel to build. Once contained, entities can be researched or regularly harvested for resources or power.

Only creature entities are placed on holding platforms. Item entities, such as the Cube, can be hauled around and placed in stockpiles - having an important stockpile dedicated to entities may be a good idea. Building entities, such as the Monolith, must be studied in their current location, as none of them are mobile. Be careful about integrating them into your base designs as they may be a source of risk down the road.

Containment strength

Any containment room is subject to containment breaches. The containment strength of the room can be viewed by clicking on the platform. It is affected by a broad number of factors:

• Wall/door integrity - The walls and doors that make up the containment room contribute to containment strength based on the combined average of their HP, with stronger structures having a higher contribution. Note that this relies on the structures' current HP, not their maximum HP, meaning that having damaged walls or doors will result in a lower containment strength. This effect only applies to fully enclosed rooms. If any door is held open too long, the room will no longer be considered enclosed. Holding Spots and Holding Platforms should be placed with a 1-tile gap from doors to prevent colonists from triggering spurious insufficient containment warnings by keeping doors open while studying void entities.
• Roof - Enclosing the containment room with a roof will increase its containment strength.
• Lighting - Ensuring that the light level around the entity is high enough will increase containment strength.
• Temperature - Some entities will be easier to contain in lower temperatures. This applies to:
  • Shamblers
  • Toughspikes^{[Verify and expand]}

The bonus is approximately 1% per degree Fahrenheit below freezing (32°F).^[Detail]

• Flooring - Using any amount of bioferrite plate floor will increase the room's containment strength. Flooring the entire room will provide the full effect.
• Containment facilities - Each containment facility has its own impact on containment strength. Some facilities exist solely to raise containment strength, while others exploit entities for resources while lowering containment strength. See below for more details.
• Number of platforms - Having multiple holding spots or platforms in the same room will reduce their effectiveness, even if they are unoccupied.

Larger and more dangerous entities generally require more containment strength. An entity can be held in a weak cell just fine in the short term, it simply increases the rate at which they will break out. As a general rule, the average frequency of breaches for entities that are sufficiently contained is measured in years, while the frequency of those insufficiently contained are measured in days. This is still likely to be enough time for an unprepared colony to quickly set up an adequate cell.

The size of the cell does not affect containment strength. Note that storing multiple entities in the same room will increase the required containment strength. This may still be worthwhile for harvesting certain resources more efficiently.

An entity incapable of moving will never breach. This includes entities with broken spines, or entities with destroyed legs and insufficient arm strength. Such entities can even be held outside in a holding spot without any risk, and are a useful resource to a colony.

Containment facilities

There are a handful of facilities that can be constructed alongside holding spots or platforms. Some facilities help to make entities easier to contain, while others allow you to exploit entities for resources.

Building	Research	Cost	Limit	Effects
Electric inhibitor	Entity containment	2 Components,  25 Steel	- 6 per holding platform - Max distance: 4 - Min distance: 1 - Must be pointed at platform - Requires line-of-sight	- +10 containment strength
Shard inhibitor	Entity containment	15 Steel,  1 Shard	- 1 per holding platform - Max distance: 5.9	- +20 containment strength
Bioferrite harvester	Bioferrite harvesting	50 Steel,  1 Component	- 1 per holding platform - Max distance: 5.9 - Requires line-of-sight	- −15 containment strength - Produces bioferrite
Electroharvester	Electroharvester	1 Component,  25 Bioferrite,  50 Steel	- 1 per holding platform - Max distance: 5.9 - Requires line-of-sight	- −25 containment strength - ×50% entity study rate - Periodically applies electrical burns to entities - Produces up to 2000W of power

Analysis

A good starting cell would include the strongest walls available, a steel or stone door, a light source, a ceiling, and a holding spot. In a pinch, a walk-in freezer serves as an excellent holding location for a range of reasons - they tend to have strong walls, double doors, entities will ignore the stored food, and the low temperature actually provides a small containment strength bonus. Another option is to integrate existing veins of metal into the wall. The extremely high HP of compacted steel - or better yet, plasteel - will cause the containment strength of the cell to skyrocket. Endgame setups will vary depending on how many of each entity the colony has acquired.

Once your colony becomes more established and you are able to construct dedicated holding chambers, stone blocks make for a decent early-game building material. All stone blocks create walls that are stronger than steel and non-flammable, with granite blocks and limestone blocks being the fourth- and fifth-strongest wall materials in the game. However, natural rough or smooth stone walls are even stronger, with natural granite walls being the strongest player-accessible non-ore walls available.

If you manage to down a high-risk entity, but don't have anywhere safe to put it, you could consider storing it in a cryptosleep casket in the meantime. This will ensure that it does not bleed out or escape, though you won't be able to exploit it.