A Bouncing Ball

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A Bouncing Ball

It's possible to track a bouncing ball in full 3D from a single camera with this setup. It relies on the fact that the ball bounces in a straight line, only in a vertical plane.

- Start with the ground plane set up properly, either from a moving-camera solve or maybe using single-frame alignment.

- Create a single supervised tracker that tracks the ball.

- Create an initial GeoH object at the location of the first bounce on the floor, ie by scrubbing to that frame.

- Scrub to the last bounce, and rotate the GeoH object so that it's X axis lines up with the location of the last bounce. This will set a rotation key on this frame, copy or drag the key around (or the value itself) so that that is the orientation for the entire shot.

- Add a second GeoH object, unlocked for motion along the X axis and the vertical axis (Z or Y), reparent the supervised tracker to it, and lock it at 0,0,0.

- Track through the shot.

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