In addition to creating “born digital” objects, you can digitize existing real-world objects to make them printable. Of the various methods of 3D scanning, as it's usually called, I’ll cover my favorite three possibilities at the moment. Like much of 3D printing, the technology for scanning is changing quickly.
Still a rough art, no capture method in 3D scanning reproduces exactly the object. Some types of scanning technology have issues with separating the background from object or even factors like going from a very dark to a very light surface. Most 3D scans will require some finessing in order to get good results from the resultant print. With a bit of work, though, you can get really interesting and useful objects from a scanner.
Makerbot Industries has released a desktop 3D scanner called the Digitizer. Roughly the size of a turntable, it scans objects up to 8 inches in diameter. It uses a camera and lasers to “draw” the edges of an object as it is slowly turned around a single point. The Digitizer is also linked to the Makerbot Desktop software. If you have a Makerbot printer, you can set up the Digitizer + Replicator to act like a copy machine, placing an object on the Digitizer platform and then feeding the file directly to the Replicator.
The Digitizer is limited in that it only collects volumetric information and can’t capture surface colors. Other scanners can, and while the most common FDM printers available now can’t do full color, higher end printers can. It may be a situation where scanning things and expecting them to be archival quality will become more realistic as the scanners get better. The Digitizer now sells for $799.
3D Systems Sense
Sense by 3D systems is a handheld scanner that uses proprietary methods (but include at least camera and IR sensors) to create 3D scans of objects from 8 inches to 118 inches. It’s a far more interesting and overall more powerful scanner than the Digitizer in that it allows you to scan absolutely arbitrary objects, rather than being limited to things that will fit onto a turntable. You can scan freestanding objects, people, parts of rooms, nearly anything.
The software for the system originally ran only on Windows PCs, but they recently released a version for Macintosh systems. They also showed off a version of the Sense that worked with the iPad at CES 2014, which would be an excellent truly portable solution.
Sense also has price going for it. It’s only $399 for the basic Sense unit, and for the power that it affords you, it’s a very good deal.
The last of the 3D scanning gadgets that I’ll cover actually isn’t a gadget at all. The 123D Catch is one of the coolest options for capturing a physical object. The software and app-based option uses standard photographs to recreate objects through the use of very clever and complicated math. You simply take a series of photos around the object, changing the position each time, until you circumscribe the object in roughly 15 degree arcs. The software then interpolates the object from the photos, using the shadows and highlights to get depth from the series of photos.
The 123D Catch is available in three forms: free as a universal iOS app that allows you to take pics in the app itself; as a Windows app that allows you to load photos into it directly from another source (a DSLR or other digital camera); or as a web app that does many of the same things as the PC app, allowing you to upload photos taken elsewhere and convert them to a 3D model.
All of these are free to use, in limited ways. The free version is licensed only for noncommercial uses of the models. It’s borderline magic, especially as a freely available service, what 123D Catch can do with static 2D photographs. The key advantage of this is that you can use it in places that would look at you oddly if you brought in a dedicated 3D scanner, but don’t blink if you take a series of photographs. Think about 123D Catch at next museum or art gallery you visit, and take a few extra shots and give it a try.