Interface overview
The timeline sits below the 3D canvas and includes:
- Playhead — Shows the current time position. Drag it to scrub through the scene.
- Ruler — Displays time markers for reference.
- Tracks — Rows for animation clips, audio files, and shot ranges.
Playback
Use the play, pause, and scrub controls to preview your scene. Playback runs all active animation clips and audio tracks simultaneously.
Keyboard shortcuts
| Shortcut | Action |
|---|
| Spacebar | Play and pause. |
| Shift+Up | Jump the playhead to the start of the timeline. |
| Left / Right arrows | Step the playhead backward and forward. |
| Ctrl+scroll (hover over timeline) | Zoom in or out on the time span. |
| Shift+scroll (hover over timeline) | Pan left or right when only part of the timeline is visible. |
Animation clips
Animation clips contain keyframed movement for objects and cameras. Each clip appears as a bar on the timeline that you can move, trim, or extend.
Pre-animated USD assets
If you import a USD asset that already contains animation (a rigged character, for example):
- Open the Outliner panel.
- Expand the Object group, then expand the asset.
- Expand its Animation node.
- Click and drag the animation clip down onto the timeline, placing it at the spot where the object’s row lives. The clip displays its duration (e.g., “20.8s”) so you can place it precisely.
- Toggle Keyframes on for that object.
Without Keyframes enabled, pre-animated USD assets may render correctly in the browser but sit frozen on playback in Lightcraft Spark on iPhone or iPad.
Audio tracks
Add audio files to the timeline for reference during shot planning. Audio tracks display waveforms so you can visually sync camera movement or scene events to sound cues.
Shot ranges
Shot ranges appear on the timeline as highlighted sections, each corresponding to a shot in the scene. Adjusting a shot range changes the shot’s start and end time.
