This is a (soon-to-be) parametric sprocketed roller for 16mm film. Modeled after the rollers on the JK optical printer gate, it's designed for actively moving film. It requires a high-detail printer to make in a useful form.
Something that's being tried, with the [elmo_cl_sprocketed_roller_sprocket_disc](../elmo_cl_sprocketed_roller_sprocket_disc) model, is creating a two-material design.