3. PRODUCING 3D FIGURES USING ABRASION OPTICS
Here in figure 6 is a simple cube-image. It was scribed into a piece of black acrylic one point at a time. The plastic is colored black only for contrast. Reflection-mode illumination with a dark plastic background gives images that are very easy to view. The abrasion pattern is composed of several hundred curved scratches that reconstruct several hundred glowing points. Each scratch has a different radius and each glowing point has a different depth. It took about 30 minutes of work to create. Commonly available acrylic plastic was used here, but softer polycarbonate or styrene seems to work better. The scriber point cannot be excessively sharp, since ideally it should create a round-bottomed scratch having a mirrorlike inner surface.
When lit by an extended source, the overall result looks like the plastic was abraded by sandpaper. A point source illuminator is required. In this photo the sun is used as the light source, but a 200-watt spotlight in a ceiling fixture will also work. The entire collection of hologram-generation equipment is visible in the photograph: a simple drafting compass with the graphite pencil point replaced with a small iron nail.