Terrain

Maps are tile grids, and every tile has one terrain type. Terrain decides who can enter a tile, how fast ground vehicles cross it, whether a building can stand on it, and which shots can pass through it.

Terrain	Ground vehicles	Ships	Buildings	Notes
Grass, sand	✓	—	✓	The baseline.
Road	✓ 1.3× faster	—	✓	Lanes reward early map control, and a city base stands on its squares and streets. A road across water is a bridge; one that stops short of the far bank is a broken bridge, or a pier.
Bridge	✓ 1.3× faster	✓ Depends on water depth	✗	A steel truss bridge over a navigable channel. Vehicles cross above and ships pass below. All land units, including amphibious vehicles, enter and leave the deck through its ends connected to land; amphibious vehicles can also swim beneath it. The bridge is an overlay: the terrain underneath keeps its painted depth, including its effect on submarine surfacing. Paint Bridge in the map editor to keep both routes open; a crossing painted as Road still blocks ships.
Snow	✓ 0.82×	—	✓	Mild slowdown.
Ice	✓ 0.75×	✗	Offshore rigs on deposits	Sea ice, a frozen lake, a glacier: a road across the water for anything on tracks or wheels, and a wall to every hull. Ordinary buildings cannot stand on it; an offshore rig can work a deposit in the ice. A map with enough snow and ice underfoot gets snow for its weather.
Rubble	✓ 0.72×	—	✗	Collapsed urban ground: what is left where a town's blocks came down.
Mud	✓ 0.68×	—	✗	Punishes heavy columns.
Marsh	✓ 0.48×	—	✗	Heavy going.
Ford	✓ 0.5×	✗	Offshore rigs on deposits	Water a hand deep: a ford, a sandbar, a tidal flat. Vehicles wade it at half speed and throw a wake; a ship runs aground on it, so to a navy it is land. An amphibious vehicle crosses at its swimming speed. A shell into it throws up spray and leaves no crater.
Forest	✗	—	✗	Blocks vehicles; aircraft fly over.
City	✗	—	✗	A town's blocks: houses, terraces and flats wall to wall with their gardens and yards. Vehicles go through a town by its roads; aircraft fly over. Artillery, rockets, bombs and nukes knock its buildings down, scorched first and then to rubble; tank guns don't. A ruined block still blocks vehicles.
Mountain	✗	—	✗	Ranges and massifs, and the wall round a map: only aircraft cross them.
Cliff	✗	—	✗	A face of rock one or two rows tall, rimming a plateau. The ground behind it is high ground (below), reached through the gaps in the rim.
Props	✗	✗	✗	Telegraph poles and water towers on the hand-made maps, the desert's palms, tents, shelters and bunkers, and a freighter going down out at sea: scenery that blocks like a mountain, on land and on water alike. Thin-walled: force fire (Shift-click with attack armed) or any splash knocks one down and opens the ground (the sea takes the wreck), but no unit ever shoots one on its own.
Shallow water	✗	✓ 0.85×	Naval Yard on shore; Offshore Rig on deposits	The band off every shore, and the rivers and lakes. Ships make 0.85 of their speed over it, and a submarine cannot dive in it: it runs on the surface, seen and shot like any ship, until the water deepens.
Deep water	✗	✓	Naval Yard on shore; Offshore Rig on deposits	The open sea: full speed, and the only water a submarine can hide in. Here and there a coast drops straight into it, with no shallows but the surf line, and a Moray Infiltration Submarine can come in under the water to land a squad there.
Lava	✗	✗	✗	Impassable to everything but aircraft.

Aircraft ignore terrain entirely. Submarines follow ship rules, and cannot dive in shallow water. Land deposits take an Metal Extractor; deposits in water or ice take an Offshore Rig. Mines and deposit buildings are exempt from the headquarters build radius, while ordinary buildings still need it when the rule is enabled.

Forest, mountain and city tiles block direct fire between surface units. Units move around intervening cover to get an open shot; fixed turrets choose an unobstructed target. Arcing artillery, aircraft attacks and vertical cruise launches pass above it. A ruined City block still blocks direct fire; Rubble terrain is open.

Mountain and City tiles block ground visibility. Forests, cliffs and elevation do not obstruct sight. All Mountain and City tiles within the normal sight circle remain visible, including those behind other blockers. Other ground behind them needs a spotter on the other side, an aircraft, or powered radar. A ruined City tile still blocks sight; Rubble terrain does not. Allies share sightings.

High ground

Every cliff face has a low side and a high side, and the ground behind a ring of them is a plateau: a level above the ground in front. A mesa rimmed with a taller face is a level above a plateau, and a terrace with a plateau on it two levels above the shore. Elevation affects damage for buildings, ships and vehicles:

• Shots up a cliff do 25% less. A round fired from below the ground it lands on carries three quarters of its damage, and everything in its blast shares the cut. Nothing extra firing down.

Aircraft see the whole of their circle, and a shot at one or from one is never uphill. A powered Radar Station or Owl Radar Car also sees across mountains and city blocks. A unit on high ground wears a small peak beside its name in the selection panel; the minimap shows a plateau a shade lighter than the ground round it.

Using it

• Chokepoints. Ridge chains and forest walls turn open maps into a few lanes. Two cannon turrets in a lane do the work of six in the open.
• A town is a maze of lanes. Its blocks are walls to anything on tracks, so a column goes through by its streets and a junction is a crossfire. Aircraft and artillery reach over it.
• Roads cut both ways. They speed your reinforcements and the enemy's raid. Buggies on a road cross a map before a tank column has formed up.
• Slow ground is a kill zone. An army wading through marsh under artillery fire takes twice the shells before it reaches anything.
• A ford is a crossing and a dam. Tanks cross a river there at half speed, in the open; no gunboat gets up the river past it. Fords and ice are where a naval map joins its land, so the fight for one is a fight for both.
• Flank by air and sea. A Pelican Transport Helicopter or Landing Craft ignores every wall a tank has to drive around.
• Keep a fleet in the deep. Hulls crawl over a shelf and submarines have to come up on one, so fleets fight in the deep channels between islands, and a harbour is where a submarine is most exposed. A ship given a route picks the deep passage when that is quicker.
• Hold the rim, take the gate. Turrets and a Thunder Howitzer on a plateau cover its ramps and take less damage from uphill shots. Ground attackers use the gaps in the rim; aircraft can cross it.