The Geometry Cache Track enables you to scrub through a Geometry Cache and render it out with frame accuracy. Once you have imported your Alembic file into Unreal Engine and added it to a Level, you can add it to a Level Sequence and add the Geometry Cache Track to play your content.
Steps
For this How-to guide, we are using the Blueprint Third Person template project. You will also need an Alembic file to import into the Engine. If you do not have your own asset, download this Sample File.
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Import your Alembic file(s) into Unreal Engine as a Geometry Cache and define your desired settings.
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Place your Geometry Cache in the Level, then create a Level Sequence and add it to Sequencer with the + Track button.
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Click the + Track button for the newly created Track and select Geometry Cache from the Tracks menu.
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Scrub the Timeline to view a playback.
You can also set the Level Sequence to Auto Play before selecting Play in the Level.
End Result
With the Geometry Cache Track set, you can scrub through your content or it will play back automatically when your Level Sequence plays.
You can access the properties of the Geometry Cache by right-clicking on the Track in the Tracks Window. From the properties menu, you can change which Geometry Cache asset is being used, add a Start or End Offset, or adjust the Play Rate. There are also options for the Section itself and whether to play the animation in Reverse.
The following properties are available for Geometry Cache tracks from the right-click context menu, under Properties:
| Property | Description |
|---|---|
| Geometry Cache | Specifies the Geometry Cache asset to play. |
| Start Offset | Number of frames to offset into the beginning of the animation clip. |
| End Offset | Number of frames to offset into the end of the animation clip. |
| Play Rate | Defines the playback rate of the animation clip (lower to slow down, increase to speed up). |