NPC Door Navigation
Valve's AI does not yet contain any door-specific combat code. NPCs will stand in doorways when others from their squad attempt to pass through, and do not understand the principle of clearing a room from a door entry. For these reasons, combat in or around doorways should be either avoided, or semi-scripted with assaults.
It is quite possible to have NPCs enter a combat area through a door, but without custom AI code the door itself should not be a point of interaction.
Optimal node pattern
- Main movement targets
- Guarantee a nodegraph link by presenting a straight line through the doorframe.
- Placed slightly ahead to decrease the likelihood of NPCs stopping too close to the door and causing congestion.
- Flank nodes
- Create alternate exit points, and are a solid choice for FIND_COVER routines.
- Entrance / Exit Pinch
Entrance / Exit Pinch.
- Ensures that NPCs travelling through the doorway do so one at a time.
- Limitation: NPCs that are not using the node (i.e. are not travelling through the door) may still choose to stand on it! This is a bug that should be fixed.