# PlayableBehaviour > PlayableBehaviour is the base class from which every custom playable script derives. ## Definition * **Type:** Class * **Namespace:** [UnityEngine.Playables](/engine/6000.0/script-reference/unityengine/playables.md) * **Assembly:** UnityEngine.CoreModule * **Implements:** [IPlayableBehaviour](/engine/6000.0/script-reference/unityengine/playables/iplayablebehaviour.md), [ICloneable](https://learn.microsoft.com/dotnet/api/system.icloneable) ```csharp public abstract class PlayableBehaviour : IPlayableBehaviour, ICloneable ``` ## Remarks A PlayableBehaviour can be used to add user-defined behaviour to a [PlayableGraph](/engine/6000.0/script-reference/unityengine/playables/playablegraph.md). A PlayableBehaviour must be part of a branch of a [PlayableGraph](/engine/6000.0/script-reference/unityengine/playables/playablegraph.md) that is connected to an output to be active. In the following example, two [AnimationClip](/engine/6000.0/script-reference/unityengine/animationclip.md) are controlled by two [AnimationClipPlayable](/engine/6000.0/script-reference/unityengine/animations/animationclipplayable.md), which are blended by a [AnimationMixerPlayable](/engine/6000.0/script-reference/unityengine/animations/animationmixerplayable.md). A custom BlenderPlayableBehaviour is modifying the inputs weigth of the [AnimationMixerPlayable](/engine/6000.0/script-reference/unityengine/animations/animationmixerplayable.md) every frame. ## Examples ```csharp using UnityEngine; using UnityEngine.Animations; using UnityEngine.Playables; public class BlenderPlayableBehaviour : PlayableBehaviour { public AnimationMixerPlayable mixerPlayable; public override void PrepareFrame(Playable playable, FrameData info) { float blend = Mathf.PingPong((float)playable.GetTime(), 1.0f); mixerPlayable.SetInputWeight(0, blend); mixerPlayable.SetInputWeight(1, 1.0f - blend); base.PrepareFrame(playable, info); } } public class PlayableBehaviourSample : MonoBehaviour { PlayableGraph m_Graph; public AnimationClip clipA; public AnimationClip clipB; // Use this for initialization void Start() { // Create the PlayableGraph. m_Graph = PlayableGraph.Create(); // Add an AnimationPlayableOutput to the graph. var animOutput = AnimationPlayableOutput.Create(m_Graph, "AnimationOutput", GetComponent()); // Add an AnimationMixerPlayable to the graph. var mixerPlayable = AnimationMixerPlayable.Create(m_Graph, 2); // Add two AnimationClipPlayable to the graph. var clipPlayableA = AnimationClipPlayable.Create(m_Graph, clipA); var clipPlayableB = AnimationClipPlayable.Create(m_Graph, clipB); // Add a custom PlayableBehaviour to the graph. // This behavior will change the weights of the mixer dynamically. var blenderPlayable = ScriptPlayable.Create(m_Graph, 1); blenderPlayable.GetBehaviour().mixerPlayable = mixerPlayable; // Create the topology, connect the AnimationClipPlayable to the // AnimationMixerPlayable. Also add the BlenderPlayableBehaviour. m_Graph.Connect(clipPlayableA, 0, mixerPlayable, 0); m_Graph.Connect(clipPlayableB, 0, mixerPlayable, 1); m_Graph.Connect(mixerPlayable, 0, blenderPlayable, 0); // Use the ScriptPlayable as the source for the AnimationPlayableOutput. // Since it's a ScriptPlayable, also set the source input port to make the // passthrough to the AnimationMixerPlayable. animOutput.SetSourcePlayable(blenderPlayable); animOutput.SetSourceInputPort(0); // Play the graph. m_Graph.Play(); } private void OnDestroy() { // Destroy the graph once done with it. m_Graph.Destroy(); } } ``` ## Methods | Method | Description | | ----------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [OnBehaviourPause](/engine/6000.0/script-reference/unityengine/playables/playablebehaviour/onbehaviourpause.md) | This method is invoked when one of the following situations occurs: The effective play state during traversal is changed to [PlayState.Paused](/engine/6000.0/script-reference/unityengine/playables/playstate/paused.md). This state is indicated by [FrameData.effectivePlayState](/engine/6000.0/script-reference/unityengine/playables/framedata/effectiveplaystate.md). The [PlayableGraph](/engine/6000.0/script-reference/unityengine/playables/playablegraph.md) is stopped while the playable play state is Playing. This state is indicated by [PlayableGraph.IsPlaying](/engine/6000.0/script-reference/unityengine/playables/playablegraph/isplaying.md) returning true. | | [OnBehaviourPlay](/engine/6000.0/script-reference/unityengine/playables/playablebehaviour/onbehaviourplay.md) | This function is called when the [Playable](/engine/6000.0/script-reference/unityengine/playables/playable.md) play state is changed to [PlayState.Playing](/engine/6000.0/script-reference/unityengine/playables/playstate/playing.md). | | [OnGraphStart](/engine/6000.0/script-reference/unityengine/playables/playablebehaviour/ongraphstart.md) | This function is called when the [PlayableGraph](/engine/6000.0/script-reference/unityengine/playables/playablegraph.md) that owns this PlayableBehaviour starts. | | [OnGraphStop](/engine/6000.0/script-reference/unityengine/playables/playablebehaviour/ongraphstop.md) | This function is called when the [PlayableGraph](/engine/6000.0/script-reference/unityengine/playables/playablegraph.md) that owns this PlayableBehaviour stops. | | [OnPlayableCreate](/engine/6000.0/script-reference/unityengine/playables/playablebehaviour/onplayablecreate.md) | This function is called when the [Playable](/engine/6000.0/script-reference/unityengine/playables/playable.md) that owns the PlayableBehaviour is created. | | [OnPlayableDestroy](/engine/6000.0/script-reference/unityengine/playables/playablebehaviour/onplayabledestroy.md) | This function is called when the [Playable](/engine/6000.0/script-reference/unityengine/playables/playable.md) that owns the PlayableBehaviour is destroyed. | | [PrepareData](/engine/6000.0/script-reference/unityengine/playables/playablebehaviour/preparedata.md) | This function is called during the PrepareData phase of the [PlayableGraph](/engine/6000.0/script-reference/unityengine/playables/playablegraph.md). | | [PrepareFrame](/engine/6000.0/script-reference/unityengine/playables/playablebehaviour/prepareframe.md) | This function is called during the PrepareFrame phase of the [PlayableGraph](/engine/6000.0/script-reference/unityengine/playables/playablegraph.md). | | [ProcessFrame](/engine/6000.0/script-reference/unityengine/playables/playablebehaviour/processframe.md) | This function is called during the ProcessFrame phase of the [PlayableGraph](/engine/6000.0/script-reference/unityengine/playables/playablegraph.md). |