---
title: Actions and triggers
framework: usd
role: collectionGroup
path: usd/actions-and-triggers
---

# Actions and triggers

Enable visual and audible responses to programmatic or environmental events.

## Overview

Overview Create a Preliminary_Behavior to uniquely pair triggers with actions. You can configure some of the triggers and actions, like the settings for a proximity trigger, the velocity of an impulse action, and the audio file for background music or sound effects. The runtime implements the concrete triggers and actions the schemas define. The exception is NotificationAction, which refers to custom effects that an app implements.

## Topics

### Essentials

- [Preliminary_Behavior](usd/preliminary-behavior.md)

### Triggers

- [Preliminary_Trigger](usd/preliminary-trigger.md)
- [CollideTrigger](usd/collidetrigger.md)
- [ProximityToCameraTrigger](usd/proximitytocameratrigger.md)
- [SceneTransitionTrigger](usd/scenetransitiontrigger.md)
- [TapGestureTrigger](usd/tapgesturetrigger.md)
- [NotificationTrigger](usd/notificationtrigger.md)

### Actions

- [Preliminary_Action](usd/preliminary-action.md)
- [AudioAction](usd/audioaction.md)
- [ChangeSceneAction](usd/changesceneaction.md)
- [EmphasizeAction](usd/emphasizeaction.md)
- [GroupAction](usd/groupaction.md)
- [ImpulseAction](usd/impulseaction.md)
- [LookAtCameraAction](usd/lookatcameraaction.md)
- [OrbitAction](usd/orbitaction.md)
- [SpinAction](usd/spinaction.md)
- [StartAnimationAction](usd/startanimationaction.md)
- [TransformAction](usd/transformaction.md)
- [TransformAnimationAction](usd/transformanimationaction.md)
- [VisibilityAction](usd/visibilityaction.md)
- [WaitAction](usd/waitaction.md)
- [NotificationAction](usd/notificationaction.md)