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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