MotionPlayer

A lightweight AnimationClip playback system for Unity 6000.3 and later, built on the Playables API.

MotionPlayer is intended for cases where an AnimatorController and state machine are more than you need. It plays clips directly, supports cross-fades and optional layers, and keeps the non-layered player as small as possible.

Components

MotionPlayerSingle

The smallest player for a single AnimationClip.

• One clip only
• Direct AnimationClipPlayable -> AnimationPlayableOutput connection
• No mixer or state collection
• Best suited to simple props, effects, and characters that only need one clip

MotionPlayer

The standard lightweight player for multiple clips.

• Play / Pause / Resume / Stop / Rewind
• CrossFade and Blend
• Normalized-time playback
• Reverse playback with negative speed
• End callbacks
• Foot IK / Playable IK options
• Normal, UnscaledTime, and Fixed update modes
• Inactive states are paused instead of continuing to evaluate in the background

MotionPlayerLayered

Use this only when animation layers are required. The normal MotionPlayer does not include layer-mixer overhead.

• Base layer plus optional additional layers
• Override and Additive layers
• AvatarMask support
• Independent layer weights
• Layer-local Play / CrossFade / Blend controls
• Layers at weight 0 pause their active states

Layer structure is intended to be configured in the Editor rather than added and removed repeatedly at runtime.

Installation

Copy this repository into your Unity project. A typical location is:

Assets/Plugins/MotionPlayer

MotionPlayer does not depend on that exact path.

If the target GameObject already has an Animator, leave its Controller set to None when MotionPlayer is responsible for animation playback.

Basic usage

using UnityEngine;

public class CharacterMotion : MonoBehaviour
{
    [SerializeField] MotionPlayer motionPlayer;

    void Start()
    {
        motionPlayer.Play("Idle");
    }

    public void Run()
    {
        motionPlayer.CrossFade("Run", 0.2f);
    }

    public void StopRunning()
    {
        motionPlayer.CrossFade("Idle", 0.2f);
    }
}

Pause, resume, stop, and rewind

motionPlayer.Pause("Run");       // Keep the current time.
motionPlayer.Resume("Run");      // Continue from the current time.
motionPlayer.Stop("Run");        // Stop and return to the start.
motionPlayer.Rewind("Run");      // Return to the playback start position.

Play() restarts the state by default. Use Resume() when you want to continue from its current position.

Start from normalized time

motionPlayer.Play("Run", 0.5f);
motionPlayer.CrossFade("Attack", 0.15f, 0.25f);

Reverse playback

MotionPlayer.AnimationState state = motionPlayer.GetState("Door");
state.speed = -1.0f;
motionPlayer.Play("Door");

A negative speed starts from the end of the clip and uses time 0 as the playback end.

Layered usage

using UnityEngine;

public class LayeredCharacterMotion : MonoBehaviour
{
    [SerializeField] MotionPlayerLayered motionPlayer;

    int upperBodyLayer;

    void Awake()
    {
        upperBodyLayer = motionPlayer.GetLayerIndex("UpperBody");
    }

    public void Run()
    {
        motionPlayer.CrossFade("Run", 0.2f); // Base layer
    }

    public void Reload()
    {
        motionPlayer.SetLayerWeight(upperBodyLayer, 1.0f);
        motionPlayer.CrossFade(upperBodyLayer, "Reload", 0.15f);
    }

    public void DisableUpperBodyLayer()
    {
        motionPlayer.SetLayerWeight(upperBodyLayer, 0.0f);
    }
}

Layer 0 is always the Base layer and has weight 1. Additional layers can use an AvatarMask and can be configured as Override or Additive.

Runtime state lookup

String lookup is convenient for occasional calls:

motionPlayer.CrossFade("Run", 0.2f);

For hot paths, cache the state index once and use the integer overloads:

int runState;

void Awake()
{
    runState = motionPlayer.GetStateIndex("Run");
}

void Run()
{
    motionPlayer.CrossFade(runState, 0.2f);
}

Requirements

• Unity 6000.3 or later
• Unity Playables / Animation Playables APIs

Design goals

• Keep direct clip playback lightweight
• Avoid Animator Controller state-machine overhead when it is not needed
• Avoid per-frame managed allocations in normal playback paths
• Keep layers optional rather than imposing their cost on every player
• Keep the public API small and explicit

MotionPlayer is not intended to replace every Animator feature. If you need complex Animator Controller state machines, Blend Trees, parameter-driven transitions, or other Animator-specific workflows, Unity's Animator may still be the better fit.

License

MIT License. See LICENSE.