From Valve Developer Community
The notorious Director. Required entity in every Left 4 Dead map. Also used to force survivors to their respective info_suvivor_position at the start of a campaign for camera intro sequences.
Note:Using the changelevel console command to restart the map will always cause the info_director to ignore forcesurvivorpositions input. If you are restarting the map after a fresh compile using changelevel and you need to test out your intro sequence, use the kill console command afterwards to have the mission fail, this will cause the map to restart in a way that allows the info_director to use forcesurvivorpositions input, which will also allow your cameras to function.
Bug: When called by a logic_auto's onmapspawn input, the info_director will ignore forcesurvivorpositions input unless the map was freshly loaded from the game menu as a campaign, or the map has restarted after mission failure. To get around this, it is much more reliable to have the info_director call forcesurvivorpositions and releasesurvivorpositions on itself using its ongamestart input. This will allow the forcesurvivorpositions to function properly even when the map is automatically loaded after a compile, or by using the map "yourmapname" console command. When your campaign is ready for release, you can safely change it back to using a logic_auto before final compilation if you wish, since players will be loading your campaign from the game menu.
- Entity Scripts (vscripts)
<scriptlist>(New with Left 4 Dead 2)
- Space delimited list of VScript files (without file extension) that are executed after all entities have spawned. The scripts are all executed in the same script scope, later ones overwriting any identical variables and functions.
- Script think function (thinkfunction)
<string>(New with Left 4 Dead 2)
- Name of a function in this entity's script which will be called automatically every 100 milliseconds (ten times a second) for the duration of the script. It can be used to create timers or to simulate autonomous behavior. The return value (if present) will set the time until the next call. Note:Try to avoid expensive operations in this function, as it may cause performance problems.
- Origin (X Y Z) (origin)
- The position of this entity's center in the world. Rotating entities typically rotate around their origin.
- Players are immune to damage while this is active. No mobs or SI will spawn. Use when starting an intro.
- Players will now take damage. Mobs and SI can spawn given that the player is no longer standing in a nav square marked as PLAYER_START and/or CHECKPOINT. Use when an intro is finished.
- Force the survivors to their starting positions and disable movement.
- Release the survivors from their starting positions and enable movement.
- Force a panic event.
- Allows survivor dialogue to be fired from entities such as trigger_once (For example, in No Mercy's elevator with parameter hospital04_path4)
- Fired when a map loads, all players join and gameplay begins.
- Fired when a panic event is finished.