What is extrapolation in Timeline, and how do we use it? This article will answer those questions, so let’s get to it!
Extrapolation deals with the space between animation clips, and telling Timeline what to do with that space. The main purpose of extrapolation is to fix animation issues, such as a game object snapping to a new transform position. Post-extrapolation deals with the space after an animation, while pre-extrapolation handles the space before the clip plays. If you select an animation clip in the timeline editor, you should see the Post-extrapolation option available in the inspector. By default, this is set to Hold. The zero indicates the amount of seconds the clip will hold for once it’s done playing.
This is because these two clips do not currently have any space between them. Let’s add some space now by dragging the last clip (dash), to the right.
Now you can see the infinity symbol, which represents the Hold assignment.
Now the post-extrapolation seconds are set to 4.1 automatically, because that’s the time between clips after moving the last one over.
Here I select the final animation in the timeline.
Notice that the Hold value here is Infinity. There aren’t any more animations after this one, so the final frame will Hold for well, infinity seconds!
If you don’t see an option for pre-extrapolation in the inspector, that’s because you most likely have animation tracks with no space between them. Here I move the Dash animation clip into space, and now there are icons before and after the clip, showing that there is pre and post-extrapolation.
The inspector will now also display both extrapolation options.
Each extrapolation setting has an icon for easy visual reference in Timeline. The Hold option is represented as an infinity symbol.
The Loop option has this oval shaped looping icon with a single arrow.
The Continue option has an arrow icon pointing right.
The Ping Pong option has an oval with two arrows moving in a circular direction.