UnityGame/Library/PackageCache/com.unity.timeline/Documentation~/wf-subtimeline.md

Create a Sub-Timeline instance

This workflow demonstrates how to create a single cut-scene by nesting a Timeline instance within another Timeline instance.

This workflow uses the Gameplay Sequence sample. Consult Timeline Samples for information on the samples available from the Timeline package and how to import these samples into your projects.

To demonstrate how to combine two Timeline instances, this workflow is divided into the following main tasks:

1. Set up the main Timeline instance.
2. Add a Control track and create a Sub-Timeline instance.
3. Adjust the Control clip.
4. Play the result.

Set up the main Timeline instance

This workflow demonstrates how to combine two Timeline instances to create a single cut-scene. By default, in the Gameplay Sequence Demo scene, the CanSubTimeline Sub-Timeline instance is already combined with the GameplaySequence Timeline instance.

Before demonstrating how to combine two Timeline instances, remove the Sub-Timeline instance. To do this, follow these steps:

1. Load the GameplaySequence scene and open the GameplaySequence Timeline instance in the Timeline window.

   Consult Gameplay Sequence Demo for the steps on how to load the GameplaySequence scene and display the GameplaySequence Timeline instance.

2. In the Timeline window, expand the Props Track group.

   The Props Track group contains tracks that activate and animate the Table and Can GameObjects. The Props Track group also contains the Can Sub-Timeline Control track that nests the CanSubTimeline Timeline instance. This Timeline instance animates the Can GameObject as it bounces and falls off the table.

   The Props Track group expanded in the Timeline window with the Can Sub-Timeline track selected

   Since this workflow demonstrates how to combine two Timeline instances, you should remove the nested CanSubTimeline Timeline instance.

3. To remove the nested CanSubTimeline Timeline instance, delete the Can Sub-Timeline Control track.

   To delete the Can Sub-Timeline Control track, select the More (⋮) menu from its Track Header and choose Delete. This is one way to delete a track from a Timeline instance. The Timeline window includes other ways to delete a track.

Add a Control track and create a Sub-Timeline instance

To nest the CanSubTimeline Timeline instance within the GameplaySequence Timeline instance, do the following:

1. In the scene, select the GameObject associated with the Timeline instance that will be the main Timeline instance.

   In this workflow, the GameplaySequence is the main Timeline instance. It is associated with the Timeline GameObject.

   

   Select the Timeline GameObject to display the GameplaySequence Timeline instance in the Timeline window

2. When the Timeline window displays the GameplaySequence Timeline instance, enable the Lock icon.

   When locked, the Timeline window does not change when you select GameObjects. This makes it easier to set up or modify a Timeline instance.

3. Add a Control track to the Props Track group.

   To do this, click the Add (+) button beside the Prop Track group name, and choose Control Track.

   

   The Add button (A) beside the Prop Track group name.

   A new Control Track is added at the end of the Prop Track. You may have to scroll the Timeline window to view the new Control track.

   A Control track is a special track for adding a Particle System, a Prefab instance, a ITimeControl Script, or a nested Timeline instance.

4. In the Scene Hierarchy, find the GameObject that is associated with the Timeline instance to be nested.

   In this workflow, you want to nest the CanSubTimeline Timeline instance which is associated with the CanSubTimeline GameObject. This GameObject is within the Table hierarchy.

   

   The CanSubTimeline is associated with CanSubTimeline GameObject

5. Select and drag the CanSubTimeline GameObject into the Control track that you added to the Props Track group.

   The Timeline window places a Control clip where you release the CanSubTimeline GameObject. The Control clip is set to the same size as the CanSubTimeline Timeline instance.

   When a Timeline instance is nested within another Timeline instance, the nested instance is referred to as a Sub-Timeline instance.

   

   (A) Control track with a Control clip.
   (B) Downward arrow in the Control clip indicates that the Control clip contains a Sub-Timeline instance.
   

6. To view and Sub-Timeline instance, double-click its Control clip.

   The Local or Global button indicates whether the Timeline ruler displays the time local to the Sub-Timeline instance or the time global to the main Timeline instance.

   When you edit a Sub-Timeline instance, the Timeline title displays a breadcrumb list of Timeline and Sub-Timeline instances. There can be many nested Sub-Timeline instances.

   

   (A) Local or Global button.
   (B) Sub-Timeline instance with breadcrumb list or nested Sub-Timeline instances.
   

   You cannot change the duration of the Sub-Timeline instance. You must return to the main Timeline instance and change the duration of the Control clip to change the duration of the Sub-Timeline instance.

7. Click the name of the main Timeline instance, in the breadcrumb list beside the Timeline selector, to return to the main Timeline instance.

Adjust the Control clip

After you create a Sub-Timeline instance, you may have to reposition its Control clip to ensure a smooth transition between the animation in the main Timeline instance and the Sub-Timeline instance.

For example, in this workflow, when the character bumps into the table, the TableBase Animation track animates the table before the Sub-Timeline takes control and animates the can.

To ensure a smooth transition between these two animations, the Control clip must be repositioned to when the table begins to move. To do this, follow these steps:

1. In the Timeline instance, select the Control clip for the Can Sub-Timeline.

   

   The properties for the CanSubTimeline Control clip display in the Inspector window

2. Set the Start for the Control clip to frame 833.

   This is the last frame when the StaticCan Activation clip is active. This is also the frame when the TableBase keyframe animation begins.

Play the result

To properly preview the entire cut-scene, including the Player character with the looping jog animation, click Play in the Game View.

If you attempt to preview this animation in the Timeline window, the Player character is shown in a T-Stance for most of the cut-scene because the jog Animator state is only available during runtime.