One example of how 3D printing and rapid prototyping has changed how the laboratory functions can be found with these 3D printed Radiolucent OptoTrak marker holders. Previous versions were made of metal, which interfered with obtaining perfect fluoroscopic video. These new markers are not only invisible to x-rays, they are fully articulating, incorporating a ball-and-socket design which was tested, refined, and printed, right here in the laboratory. Deformation characteristics of this particular resin allow the section contacting the spine to be heat molded to contour perfectly to each unique motion segment.