L4D2 - Entity Group Mutation Tool

What is it? A mutation based tool for placing entity groups in maps for mutations.


As there aren't enough buttons to get nice control, you'll need to bind a few keys. I use a standard WASD setup.

You'll need to bind two keys, "+lookspin" and "alt2", I have +lookspin bound to "q", and "alt2" bound to right ALT.
"q" = "+lookspin"
"RALT" = "+alt2"


The default method
map mapname groupspawner
This will load the default entity groups (groupspawn_defaults.nut) and custom entity groups (groupspawn_user.nut), if it exists.

Some maps will crash due to EDICT limits, if that's the case, you can load the lite method which ONLY loads your custom file (groupspawn_user.nut), of course you need to create it first.
map mapname groupspawner_lite

Using the tool

The first thing you'll be presented with is a prompt to enter the mutation name via chat (holdout/dash/etc).

Once you enter that, the tool will attempt to load any existing file if it exists under the ems directory.

You'll then be presented with the entity group menu and you'll see the 3D cursor with the current group spawned. To help placement and selecting(especially for groups with no visible items), there is an "EntityGroup" model added to each group. Also for info_item_positions with no script group, a sprite.

The default group is NONE, which will place an info_item_position with no script group.

You can navigate this menu by pressing fwd/back. Pressing "use" will select a group (as well as pressing right). Selecting a group will close the menu. The menu can be open and closed pressing zoom (normally MOUSE3).

By default targetnames are unique, the default target name is "prop". You can change this via chat commands which will be detailed later.

Spawn Mode versus Edit Mode
When no existing item is selected, you're in Spawn mode, when an existing group is selected, you're in Edit Mode.

In Spawn Mode, pressing RELOAD will spawn the current group at the cursor location, inheriting the current cursor's angles. By default, spawning an item will automatically select it and enter Edit Mode. Pressing RELOAD with a group selected (ie Edit Mode) will delete the selected group.

Selecting an existing group

To select a group (which enters EDIT Mode), look at it as you were going to shoot it and press +Use. Some groups may be hard to select depending on their contents, usually looking at the "Entity Group" model will let you select it. If it's particularly hard to select for whatever reason, walk very close to it (within 128 units), make sure you have nothing selected and press Melee/Shove and that should select it. Pressing +Use again will deselect the currently selected group.

The 3D Cursor and Manipulation

The cursor works similar in both both spawn and edit modes.

Holding walk will enter manipulation mode. While holding +Walk, you can manipulate the pitch,yaw and roll of the cursor or currently selected item.

  • Forward/Back modifies the Pitch
  • Left/Right modifies the Yaw
  • +Lookspin/+Use modifies the Roll

Translation Mode Translation mode only works on selected groups (EDIT Mode) as the cursor will always be where you're looking in Spawn Mode.

To enter translation mode, press +ALT2 while still holding +Walk, and the 3D cursor will change to a translation cursor.

Translate X/Y/Z
  • Forward/Back moves the object forward and back relative to your view
  • Left/Right moves the object left and right relative to your view
  • +Lookspin/+Use moves the group up/down

Chat commands

Some chat commands do different things depending on whether you've in Spawn Mode or Edit Mode (an item is selected)
  • !save This saves the current file to the ems directory
  • !run Saves the entities file and runs your mutation.
  • !load This deletes all placed entity groups and loads the file from ems (if it exists)
  • !removeall This deletes all placed entity groups.
  • !name value
    • Edit Mode: This will rename the currently selected group
    • Spawn Mode: This will set the default name for spawned groups
  • !rarity integer
    • Edit Mode: This will set the rarity for the currently selected group
    • Spawn Mode: This will set the default rarity for spawned groups
  • !group integer
    • Edit Mode: This will set the group value for the currently selected group
    • Spawn Mode: This will set the default group value for spawned groups

Saving and testing

To save your placements, chat the command !save, this will save the file under the ems subfolder (usually C:\Program Files (x86)\Steam\steamapps\common\left 4 dead 2\left4dead2\ems

Update 2013.9.10 The tool now saves the files under ems/maps and you can simply run your mutation by chatting !run.

@ Steam Workshop

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