Basic Principles



  • To start making Alien Swarm maps, do the following:
    • Go to your UT2004\System folder
    • Right click on the UnrealEd.exe and choose Create Shortcut
    • Right click on the shortcut and choose properties
    • In the Target box, add " -mod=AlienSwarm" to the end
    • Double click the shortcut to load UnrealED with the AlienSwarm packages and suchlike loaded.

    Maps should be named AO-Mapname.ut2.

  • The camera will always be pointing down from above on the player's marines. You have to leave space above all the rooms for the camera. If the camera goes inside geometry, then no sound effects will be heard and certain areas of the screen will get HOM effects. so always leave room. The camera is just over 510 units above the marine. I recommend making the ceiling even higher than this, if it's too close you may experience some network or sound problems.

  • It is best to leave space above ALL of your level, not just above the rooms. This is so the player can easily scroll the camera about. I typically carve a huge cube out above the level, with texture Engine.BlackTexture selected, giving this effect:

  • You will also need to place a BlockingVolume in the space above the rooms, so the player can't jump his marines out the top of the rooms and run about on top of the walls. To place a BlockingVolume, position your red builder brush and click the Volume button on the left. Set the BlockingVolume to bClassBlocker=true and add AoMarine to the BlockedClasses list. This way the volume will just block the marines and not the camera.

  • Be careful of hanging wires or other decoration that might get in the way of camera, you don't want to obscure the player's view too much. Also, make sure they are non-solid, else the cursor will aim at them if the player clicks there, which would cause the marine to shoot up in the air.


  • You should place 8 playerstarts in the map. By default the players are just allowed 4 marines, but more human players join, this number increases.