Taking cover

Marines have the ability to take cover behind, generally, anything that can actually protect them. Such as level geometry and props. They will take cover behind things that obstruct their waist/hips, but not their eyes. They can also do things such as take cover on top of a ledge, if their target is under said ledge, i.e they can take cover on top of rooftops to fire at enemies below.

When taking cover behind blocking props, they will only take cover behind props large enough to actually cover most or all of their hitbox. If the prop in question can actually be destroyed, they will also only take cover behind it if it's got over 30 health, so they also won't take cover behind very weak breakable objects like chairs.

Locating cover

Marines will opportunistically hide behind anything that meets the conditions above. But they will also check 256 map units to their left and right for any valid cover, and go to the closest cover they find, if any. For example, if a blocking prop is 66MU to their left, and another is 136MU to their right, they will hide behind the prop to their left.

In-cover mechanics

Marines already behind cover:

• Stay behind cover to reload and dodge.
• Stay after throwing a grenade instead of making any attempt to run away.
• Take 20% less damage.
• Are more accurate when firing, and also not affected by the recoil of full auto firing.

Leaving cover

If already behind cover, marines will only leave if:

• They haven't seen any living enemies in a few seconds.
• If their target has come really close to their cover or is straight up behind it.
• If they are near a sufficiently dangerous hazard.
• If the cover is compromised, such as if a destructible prop they were behind broke or is very low on health, if a sector lowered. Or if it's a flying monster that is so high over them now that their hip level is no longer covered.