Survival Gametype (L4D)

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This article includes basic instructions for creating a Survival mode map for Left 4 Dead.

Starting Survival

Survival rounds begin by triggering any form of panic event.
Any entity capable of telling the Director to force a Panic Event will work. Such as func_button, func_button_timed, trigger_finale, trigger_once, prop_car_alarm or even that one song on the Jukebox.
This is set up in the same method as starting a finale or crescendo event.

Navmesh

All Survival mode maps rely on using the "Finale" or "Battlefield" and the optional "Battlestation" attribute on your navigation mesh to define the play space for the Survival mode. Setting up the Nav mesh works differently based on whether your map is exclusively for survival, or if it adds survival mode to maps already used for campaigns.

Pure Survival Maps

If your map is only meant for survival, select the starting area navmesh In Nav edit mode and use the command "mark Player_start". to mark it as starting location.
Afterwards use the console command "nav_select_radius 1000000000" to select the entire navmesh and mark it using the command "mark finale".
Also, the "Battlestation" attribute can be used to define good holdout spots for the Survivor Bots, which will then prefer to stick to that area. This is set up in the same way as finales or Crescendo Events.

For pure survival maps, it is possible to control which areas infected can spawn in by either marking all areas with both "Finale" and "Battlefield" and then removing the "Finale" attribute from areas to disable spawning there. Note that this will break navigation for other game modes.

Note.png Note: This behavior may be a bug rather than an intentional feature.

Multi-Gamemode Maps

Existing crescendo or finale events that use the "Battlefield'" or "Finale" nav attributes can often be used without any changes to the nav mesh.

If your map adds survival sections to a coop map, add a func_nav_attribute_region encasing the area you want to play Survival in, as well as areas where infected should spawn for survival.
Call it "survival_nav_battlefield" and enable the Flag "Battlefield". You may also add additional "func_nav_attribute_region" entities of same names for more attributes like "Battlestation", where Survivor bots tend to stay.

Note.png Note: Using both the "Player_start" and "Finale" attributes in the same area does not work in multi-mode maps.

To enable the nav attributes, you need a info_gamemode entity which force spawns a point_template entity with the output OnSurvivalPostIO.

  My Output Target Entity Target Input Parameter Delay Only Once
Io11.png OnSurvivalPostIO Point_template ForceSpawn <none> 0.0 No

This very same point_template can be used to spawn all other entities required by survival, such as all weapons and props to block paths.

info_survivor_position

Survivors spawn at info_survivor_position entities.
Unfortunately finale maps use the same entity to "teleport" the survivors away when approaching the escape vehicle. If your survival map is also the finale of a campaign, or if your map uses the info_survivor_position for anything but the survival spawnpoint, you will need to delete those. Else your players might spawn at the wrong place.
Delete the extra info_survivor_position entities via the Info_gamemode entity, using the following outputs

  My Output Target Entity Target Input Parameter Delay Only Once
Io11.png OnSurvival info_survivor_position used by finale kill <none> 0.0 No

Items

In L4D, all placed items in the map will spawn in survival mode regardless of the normal densities allowed in other modes. If you wish to change the item placement or numbers, you can use the info_gamemode to spawn or kill items.

In L4D2, all item spawns are removed in survival mode.
In order to spawn items, you must give every intended survival item a name. You may give all of them the same name to make it easier.

Note.png Note: Director controlled entities such as weapon_spawn and weapon_item_spawn do not work.


Add a point_template, give it a unique name which lists all survival item names in its "Template" lines.
Add a info_gamemode entity with the following outputs

  My Output Target Entity Target Input Parameter Delay Only Once
Io11.png OnSurvivalPostIO Point_template ForceSpawn <none> 0.0 No
Warning.png Warning: Using "OnSurvival" instead of "OnSurvivalPostIO" will cause ammo and ammo upgrades not to be spawned.

info_gamemode - other uses

Maps are able to load different entities, depending on which gamemode the map is run in. As mentioned in the previous section, survival gamemodes in L4D2 require a info_gamemode and point_template to spawn any items in survival gamemode at all.
The same two entities can be used to load func_brush walls, clip brushes, prop_dynamic, items, or any other sort of entity into your map for survival gamemodes. Like adding barricade props to stop players from reaching the end map saferoom.
Alternatively, you could use info_gamemode along with a logic_relay to delete items you do not wish to have in survival, like Alarm cars which when shot would start the survival round prematurely.

Mission file and testing

Before you can test your map in survival mode, you must add your map to the mission files "survival" mode section.

Example:

"modes"
{
 	"survival"
 	{
 		"1"
 		{
 		"Map" "mymap"
 		"DisplayName" "My survival Map"
 		"Image" "maps/preview_01"	
 		}
 	}
}

The map can be loaded into survival either through the main menu, or using the console via the Command "map mapname_here survival". The latter allows you to use sv_cheats 1 while on survival mode.

See also