From Valve Developer Community
A hub for articles about creating fighting and combat in Source maps and mods.
- ai_relationship - sets which NPCs will fight or ally with which others
- Standoffs - controls how NPCs behave during combat
- Assaults - organized attacks along a path
- Squads - getting NPCs to act as a team
- Rappelling (see external link)
- Door kicks (through the use of scripted sequences)
- ai_goal_police - station a guard at a door (non-lethal)
- path_corner - used to create patrol routes (see external links for tutorial)
- Turrets - fixed, movable, and usable varieties
- Hint nodes and Nodegraph for NPC navigation.
Most NPCs can fight, but some require special set-up:
- Dropships: npc_combinedropship; see external link
- Gunships and helicopters (npc_combinegunship and npc_helicopter) (see external link)
- Striders (npc_strider)
- headcrab cannisters
- NPCs will not move far, if at all, unless they have info_nodes. See Node graph.
- All types of Combine soldier are placed with npc_combine_s entities; see the model property.
- Human rebels are placed with npc_citizen entities.