From Colonial Marines Wiki
The Queen, the Hivelord and the Drone all share the ability of secreting resin in a manner which allows them to create structures. This ability is incredibly important, as this allows them to create Hives, big resin chambers in which Xenomorphs can live, recover, gather hosts and protect Larvas. This environment hostile to non-Xenomorphs can also be used as a defensive position, allowing Xenomorphs to shape the battle to their will as they get pushed back.
All resin structures, outside of the Resin Sac, must be built on existing resin weeds. This means that building Hives is a methodical process, where weeds are first planted to accommodate local structures, and those weeds then serve as the foundation for other, more complex structures.
Resin is relatively tough, able to sustain some punishment from firearms, explosive shockwaves and sharp weapons before falling apart. It is however notably vulnerable to fire. Resin structures can only be placed on a stable surface without existing foliage. Artificial flooring and sand are two notable examples of surfaces that can be used. Grass and any tiles containing water are notable surfaces that won't be usable.
Only one resin structure may inhabit a chosen tile, not counting Resin Sacs. As such, it is impossible to stack a nest and sticky resin, or a door and sticky resin. If a structure is getting in the way, you can simply tear it down.
- All Hive structures cost 75 Plasma to create.
While it is easy to throw down resin, it is important to try and plan ahead for what you want to do with the space you are using. Are you simply weeding the terrain ? Are you planning to supplement existing structures with doors and walls ? Are you making a full Hive chamber ? Is it going to be a defensive chamber, a nest, maybe a storage chamber for Larvas and dead bodies ?
Not planning ahead can lead to serious errors, and once a Hive is well underway, it is extremely time-consuming to tear it down to try again. Be careful about the space available to you.
Some common tips to help you build a Hive worthy of your Xenomorph Hive:
- As time goes on, any area that isn't weeded and can be, should be. Weeds are the life and blood of the Hive, and as the Resin Weeds spread and extend through the colony, the area where Marines can safely navigate shrinks proportionally. In the event of combat, even the smallest patch of weeds can be used to rest and recover plasma and health, which is critical for staying power. A fight far from weeds can only last until either is running dry.
- An average chamber should be fully sealed with Resin Walls and Resin Doors. Of course, using existing structures as walls is perfectly normal. It is recommended to make doorways two or three tiles wide to make maneuvering easier, and to always provide multiple exits to ensure Xenomorphs never get cornered if humans are walking on the Hive
- An arrangement of Resin Walls and Resin Doors in a line is the most basic defensive setup possible. While it can be pierced through with concentrated fire, it allows Xenomorphs to fight during stand-offs and to ambush rushing humans. More complex layouts can involve stacking walls, or creating more complex arrangements like small Resin Walls posts for Xenos to hide behind, or labyrinth-like stacked walls to force Marines to waste all their ammunition.
- Nests, if you have the time and space, are best placed in a special layout, commonly called the "Checkerboard Nest". As its name implies, it consists of a Resin Nest surrounded in all four cardinal directions by Resin Doors, and those Doors surrounded in all cardinal directions by Resin Nests. This has a lot of benefits. It is the best trade-off between space used and safety, isolating hosts in individual chambers without taking too much space. They are extremely hard to navigate for humans, in and out, but easy to guard as you know where all the hosts are and they will not know where you are. They also allow you to immediately ambush and re-nest any host that manages to un-nest themselves, relatively safely as you can literally engage from any direction, preventing them from pre-aiming the entrance. Should they escape anyways, it will be a slow, grueling process for them to make it all the way out of the nest, and they will probably not empty the nest and save other hosts along the way.
- As mentioned before, Sticky Resin is an extremely useful tool to hamper mobility for humans inside the Hive, with its only cost being that you can't place anything else there. If used properly, you can make your Hive hellish to assault head-on, forcing Marines to either gun the entire lot down into crumbs or set everything on fire. If they are stupid enough to engage through Sticky Resin anyways, they will have trouble moving in and out to dodge your counter-attacks, especially if it's stacked along the way.
- Membranes are usually only useful to help Xenomorphs find their way deep inside complex Hives. They have no place inside defensive positions as they make obvious weak points for Marines to progress, and sometimes an open space is just better as it allows easy navigation along with seeing through.
Check My Badass Hive Guide for information on building good Hives and visual examples.