Line of Light (LOS)
A military unit in civ VI can only attack an enemy if that enemy is visible. Equally units can only see a certain distance and it can be useful to know these. For example, can a barbarian scout see my capital from that hill 4 tiles away if my city is on a hill also?
The line of sight rules I find a little weird and have only found these through trial and error.
- LOS distance is the number of tiles to the target tile including the target tile but not including the source tile.
- Most units have a LOS distance of 2 tiles. Some units have a longer range (listed at the end of this document)
- You can always see hills and mountains at +1 LOS range if there is a clear LOS. Being on a hill or in a city centre does not increase your LOS range.
- Hill and mountain tiles have a height value that will block LOS when a unit is on a lower height value (flat ground and water can be considered height 0).
- Obstacles in a source tile do not block vision out of it nor do they hide units in the target tile. They do add to the height value of an intervening tile for vision purposes.
- A city centre or encampment is deemed to be a source tile height level increase for LOS but does not count for a height increase as a target or intervening tile. Forts and other districts do not gain elevation. A city/encampment bombard also gains the elevation advantage.
- You can always see all units and objects in a target tile if allowed to by LOS rules apart from a couple of exceptions below.
- You can always see the tile adjacent to your tile
- If source height is >= intervening height + Obstacle values, the target tile can be seen if within LOS range.
- For tiles at a distance of 2, lines drawn from 2 border points of the source tile to the target tile centre that do not touch any part of the source tile or edge of source tile and are not blocked by intervening tiles, allow the target tile to be seen
- For tiles at a distance of 3, lines drawn from 3 border points of the source tile to the target tile centre that do not touch any part of the source tile or edge of source tile and are not blocked by intervening tiles, allow the target tile to be seen. See the examples section.
- Air units on a tile are deemed grounded unless in flight. A fighter on patrol has fullvisibility over its LOS range
- Scouts have a promotion making them only visible if a unit is adjacent.
- Privateers cannot be seen by other units unless adjacent. The only exceptions to this are other privateers and destroyers can see them as per normal LOS.
- Indirect fire means a ranged unit capable of indirect fire can shoot a target within firing range without seeing it as long as a unit may be able to
- A drone is not an air unit but has full visibility over its range (5)
Example 1 – A unit with a visibility of 3 can see a hill at a distance of 4 because it can see hills and mountains at +1 distances. It cannot see an obstacle at 4 tiles.
Example 2 – A unit with a LOS range of 3 tiles;
Example 3 - A unit can have a visibility advantage where an intervening hill can block a height level 0 person from seeing another hill behind it but the unit on the target hill tile will be able to see them. This allows the unit on the hill to shoot the ground archer but not get shot at itself.
- Can see tile A at 4 tiles because it has a height value higher than any intervening tiles.
- Cannot see tile B at 4 tiles because sight is blocked by tile C that has a height of 2
- Can see Tile C can be seen over intervening terrain because it has a greater height value than any intervening tiles
- Tiles D and E cannot be seen because they have the same height value or less, of any intervening tiles.
Example 4 – It works the same as for example 3 but uses a city to become elevated. The unit in the city can shoot all 3 archers but only the lowest archer on the picture can shoot back because it has a clear LOS.
Example 5 – For tiles at a distance of 3, lines drawn from 3 points of the source tile to the target tile centre that do not touch any part of the source tile or edge of source tile and are not blocked by intervening tiles, allow the target tile to be seen. This is shown by the green lines while the red lines show 3 tiles that cannot be seen due to the red lines passing through blocking terrain.
Unit LOS other than a range of 2
Range 3 Spy, Naturalist, Settler, Varu, Caravel, Ironclad, Observation balloon, U-boat, Destroyer, Helicopter, Rocket Artillery, GDR, Missile Cruiser
Range 4 Biplane, Fighter, P51, Bomber
Range 5 Jet Fighter, Drone, Jet Bomber
Still to add promotions.
Thanks and links
Thanks to @chazzycat who made a clear set of rules on this when initially discussed.
Original post https://forums.civfanatics.com/threads/los-question.637933/
Civ VI - LOS
Line of Sight