bot_zombie

This entity is not in the FGD by default.
It should not be put directly in a map because it works properly only in the game mode and only if spawned by the game mode.

bot_zombie is a point entity available in Black Mesa. This is a zombie from elimination game mode which appears with waves of them to attack players and their base. This entity is not related to NPC zombie version from singleplayer campaign, they're AI behavior and navigation are completely different. They use zombie security and zombie scientist models, they never use zombie grunt and zombie HEV models, as both were introduced later in the game's development. Due to this entity is not an NPC, you cannot influence its relationship with other NPCs, and vice versa.

Bug:Just like the game mode, this entity is unfinished and have several bugs and issues:

• This entity ignores dynamic objects (prop_physics, prop_dynamic, etc). It endlessly trying to go through them (sometimes it manages to go through a physical object, literally).
• Sometimes it may get stuck standing in front of an abyss instead of ignoring it.
• This entity ignores snarks.
• No blood particles and decals if shot damage is received.
• Appears in T-pose.

Note:This entity doesn't provide some NPC zombie features:

• Never creates headcrab after death.
• Doesn't react to a shot to the knee.
• Never tries to throw a physics object at a player.
• The amount of health, damage and view push cannot be customised.
• Can't hit multiple enemies (only one target can get damage).

Represented by class CBotAI.

Navigation and spawn

It's not an NPC, so it don't use nodes. They're using navigation mesh, it is stored in .nav file, the file can be generated with nav_generate cvar. This file is required to make zombie able to spawn. If navigation mesh is not generated or generated not properly, zombies created with ent_create bot_zombie will always wove along the X axis.

Usually zombies appear in areas of a map that are not visible to the players (one zombie at one point), but sometimes something goes wrong and one or more zombies may appear in point that is visible for players.

Dedicated Console Variables

Cvar/Command	Parameters or default value	Descriptor	Effect
survival_nextwavetime	15	Integer	The amount of seconds before next wave.
survival_wavecount	15	Integer	The amount waves.
survival_sceneselectionfile	survival_scenes.txt	String	Unknown scene selection file. This file is not in the game files. Todo: Find out if this file is present in older versions of the game.

Note:Cvars that affect NPC zombie versions do not affect this entity.

Elimination_zombies.txt

This file is placed in bms_misc_dir.vpk/scripts/scenes, this is a script file that configures some parameters for the waves. The comments explain what each line does.

"Scene"
{
	"SceneId" "Elimination" //Scene ID. Should not be changed.
	"SceneData"
	{
		"TotalCount"	"32"         //Total count of zombies per wave.
		"MaxActive"		"8"  //Maximum amount of alive zombies at the same time.
		"SpawnRate"		"1"  //Spawn rate value. Small values will make zombie spawn faster.
		
		"AIBot"
		{
			"Class"	"bot_zombie" //Classname to use. Should not be changed, other classes will cause Wave Failed! message bug and no one will spawn.
		}
	}
}