🎬 Lesson 9.4: Timeline — Building a Cutscene (Mini-Project)

What Timeline Is

Timeline is Unity's track-based sequencing tool. Where the Animator picks one clip based on game state, Timeline lays out many things on a shared clock — animations, camera cuts, audio, particle activations, and code callbacks — and plays them in perfect sync. It's how you author intros, scripted moments, victory sequences, and cutscenes.

Two pieces work together: a Timeline asset (the reusable sequence, saved in your project) and a PlayableDirector component (the thing in the scene that plays a Timeline asset and binds its tracks to real objects).

Creating a Timeline

1. Install Timeline and Cinemachine from the Package Manager if they aren't already (Cinemachine is what we'll use for cameras).
2. Create an empty GameObject named CutsceneDirector.
3. Open Window ▸ Sequencing ▸ Timeline. With CutsceneDirector selected, click Create — Unity adds a PlayableDirector and saves a new .playable Timeline asset (put it in an Assets/Cutscenes folder).
4. You now have an empty timeline ready for tracks.

Reading the Timeline Window

The Timeline window is a horizontal time ruler with stacked tracks. Each track holds clips you drag along the ruler; the white playhead marks the current time. Add a track with the + button (or right-click the track list). Here is the cutscene we're about to build, drawn exactly as the Timeline window lays it out:

The common tracks:

• Animation Track — bind a GameObject and record or drop Animation clips (e.g. a door swinging open).
• Activation Track — turns a GameObject on for the clip's duration (great for switching a particle effect on at the right beat).
• Audio Track — plays an AudioClip in sync.
• Cinemachine Track — sequences and blends virtual cameras (next section).
• Signal Track — emits Signals your code reacts to.

Cinemachine Camera Blends

The magic of a cutscene is the camera. Rather than hand-animate the Main Camera, you place Cinemachine cameras (lightweight "virtual cameras" that describe a shot) and let Timeline cut and blend between them.

1. Add a Cinemachine Camera for each shot (e.g. vcam_Wide aimed at the whole room, vcam_CloseUp framing the reward). Make sure your Main Camera has a CinemachineBrain.
2. On the timeline, add a Cinemachine Track and bind it to the Main Camera's brain.
3. Drag each virtual camera onto the track as a clip. Order them along the ruler.
4. Overlap two clips and Timeline automatically blends from one shot to the next over the overlap — a smooth push-in instead of a hard cut (see the shaded overlap in Figure 1).

💡 Cut vs. blend: no overlap = an instant cut; overlap = a blend whose length equals the overlap. Drag the clip edges to tune exactly how fast the camera moves between shots.

Signals: Running Code on Cue

Sometimes the timeline needs to talk to your game — "now spawn the boss," "now re-enable input." That's a Signal: a marker on a Signal Track that fires a UnityEvent the instant the playhead crosses it, handled by a Signal Receiver component.

1. Add a Signal Track. Right-click it at the end of the sequence ▸ Add Signal Emitter, and create a new Signal Asset named OnCutsceneEnd.
2. Unity adds a Signal Receiver to the director. Wire its reaction like any UnityEvent — call a method on your cutscene manager.

using UnityEngine;
using UnityEngine.Playables;

// Plays a cutscene and restores player control when it ends.
public class CutsceneManager : MonoBehaviour
{
    [SerializeField] PlayableDirector director;
    [SerializeField] MonoBehaviour playerController; // disabled during the cutscene

    public void PlayCutscene()
    {
        playerController.enabled = false;
        director.stopped += OnDirectorStopped; // fires when the timeline finishes
        director.Play();
    }

    // Called by the OnCutsceneEnd Signal (wire this in the Signal Receiver).
    public void OnCutsceneEnd()
    {
        Debug.Log("Cutscene beat reached: revealing reward.");
    }

    void OnDirectorStopped(PlayableDirector d)
    {
        director.stopped -= OnDirectorStopped;
        playerController.enabled = true; // hand control back to the player
    }
}

Triggering It from Gameplay

Turn Play On Awake OFF on the PlayableDirector so the cutscene waits for a cue. Then trigger PlayCutscene() from whatever gameplay moment you like — walking into a trigger volume, defeating the last enemy, or pressing a switch:

Figure 2: The cutscene lifecycle, from trigger to handing control back.

Mini-Project: The Reveal

Summary

🚀 What's Next?

That wraps the Graphics tracks — lighting, shaders, VFX, and cinematics. Next we switch dimensions entirely. Module 10: 2D Essentials starts the 2D track: sprites, sorting, tilemaps, and 2D physics, beginning with Lesson 10.1: The 2D Setup — Sprites & Sorting.