Structures: 6 Core Buildings · OpenFront Intel

All 6 Structures

Name	Cost / Formula	HP	Damage	Build	Upgrade	Role / Notes
Port	125,000 min(1,000,000, 2^n × 125,000), n = existing ports/factories	—	—	50t	✓ Upgradable	Naval hub: spawn base for trade ships, transports, and warships. Higher level = better trade ship spawn rate and revenue Can be captured; ownership transfers to the new occupier
Missile Silo	1,000,000 Fixed 1,000,000	—	—	100t	✓ Upgradable	Core infrastructure for launching nuclear weapons. Upgrades reduce reload time AI nukes avoid SAM-covered targets
Defense Post	50,000 min(250,000, (n+1) × 50,000)	—	—	50t	—	Land defense tower: significantly boosts defense within 30 tiles. Defense zone mag ×5, speed ×3 Range 30 tiles
SAM Launcher	1,500,000 min(3,000,000, (n+1) × 1,500,000)	—	—	300t	✓ Upgradable	Anti-air installation intercepting atom and hydrogen bombs. Cooldown 90 ticks Range scales 70 → 150 tiles by level Cannot intercept MIRV
City	125,000 min(1,000,000, 2^n × 125,000)	—	—	20t	✓ Upgradable	Raises population cap and participates in train trade. +250,000 troop cap per level Buildable even without a port (v24) Acts as a train station
Factory	125,000 min(1,000,000, 2^n × 125,000) (shares n with Port)	—	—	20t	✓ Upgradable	Spawns trains; combines with railways and cities to form a trade network. Train spawn rate (factories+10) × 15 ticks Builds railway loops

City — Population Factory

Each level +250,000 troop cap, max 4 levels = +1,000,000.
v24: no longer requires port first, can place anywhere (including inland).
Also serves as train station, defining railway network topology.

✦ City Build Order

Priority: 1st City > Port > 2nd City > DefensePost > 3rd City > Missile Silo. 4th city onward has diminishing returns—upgrade existing cities instead.

Port — Naval Hub

Enables trade ships, transport ships, warship spawning.
Higher level = better trade ship spawn rate and per-ship revenue.
Shares 2^n × 125k cost counter with Factory; build order determines which hits 6-figure costs first.

Factory — Train Production

Spawns trains and unlocks railways (max 120 tiles).
Train spawn rate: (numFactories + 10) × 15 ticks. More factories = denser train traffic.
Upgrades improve train throughput, but city count matters more for train economy.

DefensePost — Chokepoint Guardian

30 tiles range: mag ×5 / speed ×3.
Cost: min(250k, (n+1)×50k): posts 1-4 cost 50k → 100k → 150k → 200k, 5th+ capped at 250k.
Build time 50 ticks (5 seconds), can emergency-fill defensive gaps.

SAM Launcher — Nuclear Shield

Only intercepts AtomBomb and HydrogenBomb, cannot hit MIRV.
Range: 150 − 480/(level+5): default 70 → level 5 ≈ 140, approaching cap of 150.
Build time 300 ticks (30 seconds), cooldown 90 ticks.
v24: AI nukes actively avoid SAM coverage, so first SAM provides deterrence value.

Missile Silo — Offensive Arsenal

Nuclear launch platform, build time 100 ticks.
Upgrades improve reload speed (shorter salvo intervals).
Multiple Silos required for simultaneous volleys.

⚠ Buildings Can Be Captured

When territory is captured, buildings transfer to new owner (including SAM and Silo). Late-game attacks on enemy core cities can strip their nuclear shield—a critical strike target.