Vixel: exploring projection onto a rotating helix

The idea and the physical setup

We explored three-dimensional model projection, with potential applications in advertising, education and medical visualisation.

Our setup placed a projector above a motor-driven helical surface. A speed controller adjusted the motor. The initial plan was to align the rotation speed manually with the projector’s frame rate, before exploring sensing and automatic adjustment.

What the early experiments showed

In early experiments with static two-dimensional images, projecting a circle onto the rotating helix produced a frustum-like form; a square produced a cut-pyramid form.

The next challenge was to turn a three-dimensional model into the appropriate image slices for a curved, moving surface. Ordinary flat cross-sections were not sufficient: the projected image needed to account for the shape of the helix and its rotational phase.

Modelling and the next engineering questions

We modelled the helical surface in MATLAB to understand its geometry and began exploring Unity and other slicing tools. We were also considering how to synchronise the motor speed, frame rate and projection phase so the resulting image would remain stable.