Back in 1988 while using Sculpt-3D on the Amiga I wondered if I could digitize 3D objects with a custom hardware device. I constructed this little monster, the DigiPen using hiresolution potentiometers and an analog to digital converter. There were originally four joints in the arm of the pen (I’ve since scavenged some for parts on other projects). You held the pen in your hand and touched the object being digitized. It could “trace” an object in real time into a 3D model using bezier curves or polygons. I used the pots and built a multiplexer to allow me to use only one A/D because I couldn’t afford to have four A/D converters….and pots were a lot cheaper than optical encoders at the time. I learned a lot about multiplexing hardware with this project as well as serial communications and matrix mathematics for 3D.
It worked amazingly well. Originally it had a standalone user interface that I wrote for the Amiga. Later I interfaced it into “Vertex”, the 3D modeling application that I wrote whose source code was subsequently stolen.
Today there are several devices available commercially that perform the same task in higher resolutions.