The "Base" are strategic objectives in both the Siege and Assault game types.
In this mode each team has a radar outpost that they must defend. These bases can take up to 21,000 damage but have a -100 armor value so all splash damage weapons actually do double their displayed damage. This means it takes a team effort or a specifically built mav to destroy the base.
The base structure in Siege is a connected complex of one and two story structures with a massive multistory tall radar dish on the top of the structure. It is suggested to target this dish as it is possible to shoot through the base structure and miss the instillation.
The radar outpost is a Siege objective and if it is destroyed that team automatically loses the match, also if the match time runs out the team with the most damaged base will lose.
There is a visual effect to show the base's remaining health, when the base's health drops below 75% remaining it will start smoking and the effect grows more prominent with more fire and smoke at the 50% health remaining and 25% health remaining marks.
In this game type only one team has a base to defend while the other is purely offensive. The base itself is composed of a large dominating structure surrounded by multiple smaller auxiliary structures which each has to be destroyed in order for the attacking team to win. Surrounding these structures is a complex of minor buildings, walls, fuel storage containers, and other miscellaneous buildings to shield the base from direct fire except at close ranges.
There has been three different concept art designs portrayed for use but nothing is definite except that the main structure itself will be extremely durable requiring a dedicated effort to bring down that could span across multiple battles. The auxiliary buildings are scattered randomly nearby to decrease the effectiveness of long range attacks without any additional forms of intelligence or just leveling the whole area.