My Homebrew 3D Scanner

Imagine a camera that captures the shapes of things, and a printer that prints out those shapes. We live in a world where paper is flat and computer displays are flat, but pretty much everything else is 3D. So how about taking photography into the third dimension? Not just as a visual illusion, but as a way to record three-dimensional shapes and then print them out as actual objects.

Years ago, friends and I got excited about this and built 3D scanners and 3D printers. We started a company called Z Corp. to make 3D printers, and these days there’s a printer in every major town. 3D scanners are not so common, however, which is strange because you can build one in a few minutes.

This is Kenny Jensen, sitting on a stool that slowly rotates at a constant speed. It has an electric, motorized antenna rotor bolted to the seat post.

A bubble level ensures that the axis of rotation is vertical. A laser pointer shines through the stem of a wineglass, which spreads the beam into a vertical line on his face. The wineglass stem is a cylindrical lens that spreads the beam in only one axis.

A camcorder looks at this green line from an angle and sees a wiggly, green line silhouette. The computer records the video frames of this wiggly green line. (The nylon sock holds his hair down. Hair is too fine for the beam, and shows up as spikes.)

How do we turn all those video frames of squiggly lines into a 3D model? Jensen wrote a MATLAB script that does it. (You can see the step-by-step instructions on Instructables at makezine.com/go/3Dscanner, including the script.) The software does some simple trigonometry to calculate the distance to each point on the surface of the face, then assembles the 3D model. There’s commercial software that does the same thing, as well as a rapidly growing collection of free utilities.

Once I had 3D models of myself, I proceeded to 3D-print them and then cast those parts in metal. I made some titanium toy soldiers of myself. I also made self-portrait cremation urn bookends of my head. I thought they were pretty creepy, but my mom loved them. She’s still got them on her mantel.

Video of the scanner in action: makezine.com/go/3Dscannervid