View on GitHub

ezEngine Documentation

The documentation for ezEngine

PhysX Trigger Component

The PhysX trigger component is a special kind of actor that determines whether other actors overlap with its volume. If so, it sends a trigger event message. Other components or script code can react to this message to implement their game logic.

Triggers are often used to open and close doors, to check whether a character walked over a pickup item and to detect when the player reached some location.

A trigger is set up the same way as a static actor or a dynamic actor, by attaching collision shapes to it. Which other physics objects activate the trigger is determined through the collision layers on the attached shapes.

Since triggers are not simulated like rigid bodies, they don’t require much configuration.

Triggers can be moved around at runtime and they will fire, if an object enters a trigger because the trigger moved into the object.

When a trigger fires, it sends the event message ezMsgTriggerTriggered. The message states which other object was involved, and whether it entered or left the trigger volume. It will also contain the hash value of the TriggerMessage string. This can be used to identify which (kind of) trigger was just triggered. Simply compare the hash value, against the hash value of some known trigger message.


Physics triggers only detect overlaps with other physics objects. For such scenarios they are an efficient solution. If, however, you need to query overlaps with other kinds of objects, you should take a look at the spatial system.

Component Properties

See Also