And also it enables players to spawn any NPC on maps that have a nodegraph (or an .ain file for those fancy people). So basically it's used to spawn zombies on zombie maps that don't actually spawn zombies on their own, like they should. ZINV lets you set spawning distances, maximum number of living NPCs, and some more neat options that I'll be going over below in this guide. You can get ZINV+ HERE, which adds some nice fixes and such.

Let's start with the 3 tick box options a the top. The "Exploded On Death" setting will only take effect on NPCs spawned AFTER you tick it. All of them are pretty simple so feel free to skip this part.

• Enabled? Should it spawn NPCs?
  
• Exploded On Death? Whether or not killed NPCs should go boom when they die
  
• Chase Players? Should spawned NPCs will go to a player's position (so you can't hide)

Note: I think the "d" at the end of "exploded" should be removed :)

The 3 slider options are the second most important, right under the actual configuration for the addon to read. Like the tick boxes, these are also quite self explanatory, but I'll go over them anyway.

• Minimum Spawn Distance Number of hU away that an NPC must be from any player to spawn
  
• Maximum Spawn Distance Number of hU away an NPC can be spawned, NPCs beyond this number will be de-spawned
  
• Maximum NPCs Allowed How many living NPCs can be present at any given time

Note: hU are Hammer Units, which are hard to measure with unless you open the map in the Hammer Editor

For starters, let me explain what a nodegraph is. When a mapper creates their map, they have the ability to place in info_node entities, that will be baked into the map and connected to each other, which then, NPCs can use these info_node entities for navigating the map based on their connections. Effectively, info_nodes are entities that say "You can go here!".

Using the Nodegraph Editor Tool, you can easily check for, and view a map's nodegraph without having to decompile and load maps to Hammer. This is the easiest way to check if a map is able to spawn NPCs using ZINV/ZINV+.

ZINV configs are what the addon reads when it's active (I don't know exactly how it works though). For beginners, I'll be going through all of the settings in the Spawn Editor.

• Health How many hit points the NPC has
  
• Chance The percent chance of the NPC spawning (should be 100 or under)
  
• Scale How B I G the NPC is when they spawn
  
• Override Spawn Flags If ticked, the default flags an NPC spawns with will be ignored
  
• Spawn Flags What flags the NPC will spawn with (NPC specific!)
  
• Squad What squad the spawned NPC will belong to (they communicate information and use tactics)
  
• Proficiency Determines the NPC's aim and ability with their weapon
  
• Damage Multiplier Multiplies the damage dealt by the spawned NPC
  
• Model The model used for the spawned NPC (I haven't gotten this to work)
  
• NPC What type of NPC to spawn
  
• Weapon What weapon the NPC should be spawned with

Shotgun Boi Squad





Note: Tactics apply to Combine NPCs, and their tactics aren't very tactical (rush enemy, rush enemy and then retreat, be annoying and shoot a bunch)

Hopefully this guide was helpful enough for anyone who want's to learn to use ZINV. Also I'd like to add that if you've updated the config but ZINV/ZINV+ is still spawning a different or older version of the current config, then cleaning up the map somehow resets it and should fix this issue.
Also I don't know if there is already a guide on this prior to making this one, I just felt like writing a guide on ZINV. 'cause it's fun
If you find any spelling errors that I missed, please tell me in the comments so that I can correct them.