func_trigger
An invisible brush volume that detects entities entering, staying inside, or exiting its bounds. The foundation of almost all map logic involving the player or moving entities.
Properties
Name Type Description
Filter Name String Target name of a LogicFilter entity (e.g. LogicClassFilter) to restrict which entity types can activate this trigger. If left blank, any entity activates it. Outputs
Name Pass Variables Description
OnTriggerEnter
!from_class Fires once when an entity enters the volume. OnTriggerStay
!from_class Fires every update frame for each entity currently inside the volume. OnTriggerExit
!from_class Fires once when an entity leaves the volume. Pass variable details:
!from_class The full class name of the entity that entered (e.g. Player, GruntEnemy). !from_class The full class name of the entity that is staying inside. !from_class The full class name of the entity that exited. Notes
Apply the tool_trigger texture to all faces. The brush will not render in-game but will be visible in the editor shaded in a distinct color.
For most uses you will want to attach a LogicClassFilter and set it as the Filter Name, otherwise every entity that walks through — including enemies and physics props — will fire the outputs. See the Advanced Outputs page for practical wiring examples.
func_trigger is also the entity used as the transition volume for level transitions. See Level Transitions.