Linear interpolation with one point

You can use linear interpolation for points to annotate a moving object:

1. Before you start, select the Points.

2. Linear interpolation works only with one point, so you need to set Number of points to 1.

3. After that select the Track.

4. Click Track to enter the drawing mode left-click to create a point and after that shape will be automatically completed.

5. Move forward a few frames and move the point to the desired position, this way you will create a keyframe and intermediate frames will be drawn automatically. You can work with this object as with an interpolated track: you can hide it using the Outside, move around keyframes, etc.

6. This way you'll get linear interpolation using the Points.