The Global Defense Initiative utilizes powerful and efficient technologies in their arsenal. Their presence on the ground is unmatched in terms of armour and raw firepower, but their high-tier units are slow and expensive. Their main weaknesses are the lack of a proper artillery unit and the fragility of their aircraft.
Structures
Construction Yard
Cost: $2500 (MCV) | Power: 0 | Prerequisites: none
The heart of every base is the Construction Yard. This structure is responsible for the creation of all other buildings in your base, from simple walls to the technologically-advanced Upgrade Centers and superweapons. Because this building controls your ability to expand your base and acquire new technologies, the wise commander protects it at all costs and at all times. In many missions, you will start with a Construction Yard already in place, while in others you will begin with an MCV and must deploy it to begin building.
Power Plant
Cost: $300 | Power: +100 | Prerequisites: none
Power Plants provide power for base structures and are critical to keeping base defenses online. GDI Power Plants can be upgraded with up to two additional power turbines. Each will increase the power output of the structure by 50% compared to a non-upgraded power plant.
Power Turbine
Cost: $100 | Power: +50 | Prerequisites: Power Plant
Up to two of these power turbines can be added to a Power Plant to increase power output. The output of each turbine is less than that of a new Power Plant, but the cost is much lower.
Tiberium Refinery
Cost: $2000 | Power: -30 | Prerequisites: Power Plant
The refinery converts the harvester loads of Tiberium into credits for the player. It also stores a certain amount of Tiberium. Once a Refinery is full, Tiberium Silos must be created in order to store excess Tiberium. If there is no available storage capacity at a Refinery or Silos, excess Tiberium will be lost. Each Tiberium Refinery comes with a free Harvester.
Barracks
Cost: $300 | Power: -20 | Prerequisites: Power Plant
The barracks allows infantry units to be trained. It also a prerequisite for basic defensive structures.
War Factory
Cost: $2000 | Power: -30 | Prerequisites: Tiberium Refinery, Barracks
This structure allows for the construction of vehicles and mechs. Certain advanced vehicles require additional structures before they can built by a War Factory.
Radar
Cost: $1000 | Power: -40 | Prerequisites: Tiberium Refinery
A Radar station allows commanders to view the battlefield and the relative locations of friendly and enemy units. In order for the radar view to remain active, the Radar station must be constantly powered.
Service Depot
Cost: $1200 | Power: -30 | Prerequisites: War Factory
During the course of a battle, your vehicles and aircraft will become damaged. Moving a damaged vehicle or aicraft into a Service Depot begins the repair process. Repairing damaged units costs credits, with the cost being proportional to the severity of the damage the unit suffered. The damaged unit can also be sold here, and a percentage of its purchase value will be returned to the owner.
Helipad
Cost: $500 | Power: -10 | Prerequisites: Radar
The Helipad allows for the construction and rearming of aircraft. Without the Helipad, aircraft cannot be constructed and cannot be rearmed when returning to attack. One pad can only host one aircraft at a time, but aircraft can land on open ground.
Tech Center
Cost: $1500 | Power: -200 | Prerequisites: War Factory, Radar
The Tech Center is where GDI conducts its advanced weapons research. This structure is required prior to the construction of certain high-tech units and structures.
Upgrade Center
Cost: $1000 | Power: -150 | Prerequisites: Tiberium Refinery, Tech Center
The Upgrade Center is used to communicate with various advanced units and structures on the battlefield. Upgrade Centers have two available upgrade pads and can accept the following upgrades: Ion Cannon Uplink or Seeker Control.
Hunter-Seeker Control
Cost: $1000 | Power: -50 | Prerequisites: Upgrade Center
This upgrade to an Upgrade Center allows communication with a Hunter-Seeker Droid, allowing it to acquire enemy targets and navigate to it. This upgrade is required in order to build and release Hunter-Seeker Droids. It deactivates if the base’s power is low.
Ion Cannon Control Uplink
Cost: $1000 | Power: -100 | Prerequisites: Upgrade Center
This upgrade to an Upgrade Center that allows targeting control of GDI’s orbital ion cannon weapon. It deactivates if the base’s power is low.
Support structures
Pavement
Cost: $75 | Power: 0 | Prerequisites: Barracks
Pavement is designed to protect your base from burrowing units as well as prevent heavy weapons fire and explosions from making craters in your base. Certain units like Harvesters will move faster on pavement than on normal terrain. Pavements also prevent spreading of Tiberium, but not Tiberium veins.
Concrete Walls
Cost: $100 | Power: 0 | Prerequisites: Barracks
Walls are a passive defence system designed to stop enemy infantry and vehicles. Up to 4 pieces of wall section can be placed at once if near an existing wall section for quick building.
Note: Multi-piece wall construction introduced in patch 1.13.
Gate
Cost: $250 | Power: 0 | Prerequisites: Barracks
Gates prevent enemy units and Tiberium growth from entering a base. They automatically open to allow friendly units to pass, but will not open for enemy units.
Tiberium Silo
Cost: $150 | Power: -10 | Prerequisites: Tiberium Refinery
Tiberium Silos store excess Tiberium once Tiberium Refineries are at maximum capacity. If a Tiberium Refinery is filled to capacity and there are no empty Silos available, excess Tiberium from a Harvester will be lost.
Component Tower
Cost: $200 | Power: -10 | Prerequisites: Barracks
Based on a modular construction principle, the Component Tower serves as the foundation for all GDI base defenses. Component Towers can be built as individual structures or as a part of a wall. One of three weapons can be mounted on a component tower: a Vulcan Cannon, RPG launcher, or SAM launcher.
Vulcan Cannon Upgrade
Cost: $150 | Power: -20 | Prerequisites: Component Tower, Barracks
The Vulcan cannon component consists of two mini-guns firing 50mm projectiles at high speed. The cannon is primarily intended for use against infantry, but it can be used less effectively against vehicles.
Rocket-Propelled Grenade (RPG) Upgrade
Cost: $600 | Power: -20 | Prerequisites: Component Tower, Barracks
The rocket-propelled grenade (RPG) upgrade component launches grenades at enemy units. The RPG is designed for use against vehicles but can be used against infantry as well. Its explosive charge ensures splash damage to any other units caught around its target.
Surface-to-Air Missile (SAM) Upgrade
Cost: $300 | Power: -30 | Prerequisites: Component Tower, Radar
Surface-to-air missiles (SAM) are GDI’s anti-aircraft defense. SAMs can only be used against flying units.
Electro-Magnetic Pulse (EMP) Cannon
Cost: $1000 | Power: -150 | Prerequisites: Radar
The EMP Cannon can fire a high-powered blast of electro-magnetic energy that renders any mechanized unit (including cyborgs) or structure inoperative for a short period. It deactivates if the base’s power is low.
Firestorm Generator
Cost: $2000 | Power: -200 | Prerequisites: Tech Center
The Firestorm Generator creates an infinitely strong force field. Once the generator is constructed, special Firestorm Wall sections must be placed on the perimeter of an area to be defended, just like a wall. When activated, the force field that results from these emitters is impenetrable by any unit, and even any missile (except support powers). The Firestorm Generator consumes massive amounts of power and can only be active for a short period before it needs to recharge. The shield can be turned on and off at will when ready. It deactivates if the base’s power is low.
Firestorm Wall
Cost: $50 | Power: -2 per tile | Prerequisites: Firestorm Generator
Used in conjunction with the Firestorm Generator, these emitters are placed like a wall and control the placement of the Firestorm defense shield. These emitters can be used to completely encircle a base or can be used at key defensive positions. Up to 4 pieces of wall section can be placed at once if near an existing wall section for quick building.
Note: Multi-piece wall construction introduced in patch 1.13.
Support powers
Electro-Magnetic Pulse (EMP)
Cost: free | Cooldown: 4:30 | Prerequisites: EMP Cannon
Fires a high-powered blast of electro-magnetic energy that renders any mechanized unit (including cyborgs) or structure fully inoperative for a short period.
Hunter-Seeker Release
Cost: free | Cooldown: 12:00 | Prerequisites: Hunter-Seeker Control
Releases the Hunter-Seeker Droid, a lighting-fast drone that is deployed to “clean up” the battlefield. Hunter-Seeker Droids randomly search out an enemy unit or structure and ram it. The unit cannot be controlled and will automatically seek prey when released.
Ion Cannon
Cost: free | Cooldown: 8:30 | Prerequisites: Ion Cannon Control Uplink
Orders the Ion Cannon, GDI’s massive orbital weapon, to fire at the selected area, causing considerable damage.
Firestorm Defense
Cost: free | Cooldown: 3:00 | Prerequisites: Firestorm Generator, at least one Firestorm Wall tile
Activates the Firestorm defense system, which causes all Firestorm walls to start emitting energy that does not allow any unit or missile (except support powers) cross them. When activated, this defense is online only for a period of time, and can be manually deactivated at any time.