This was the first picture of the working VVD. You can see 2 Nema motors, and the oscillating arm on the left. How I got it to work?
I can share this image since I started submitting for a patent, but in the end, I gave up. The project, which I developed all by myself from scratch, was still a prototype and not yet commercially viable product, I did not have marketing power to push it, or to involve some big companies, so I stopped working on it.
Back to the picture, my solution was to have a rectangle of film for rear-projection, inside a thin plexiglass frame (100). It was suspended with 4 rubber bands on each angle (101). They were connected to two oscillating arms (102) moved up and down by 2 (or 4) stepper motors (103). By sweeping up and down the film, a volume was created (143), and by projecting a different image when the film is in a different vertical position, a volumetric image is created!