Most of my posts so far have been about experiments or challenges in 3-dimensional design for 3D printing. However, it’s possible to get into 3D printing without knowing much about design software, if you have a 3D scanner. In theory, to create an object suitable for 3D printing you can just sculpt it by traditional methods (e.g. carve wood, chisel stone, build up clay, etc.), and scan it.
Unfortunately, in my experience this is often much harder than it sounds. The cheapest scanners are easy to use, but often do not capture enough detail. Slightly better scanners are not as user-friendly and professional grade scanners are out of my price range (they’re often over $10K). Here I’ll post my experience with the scanners I’ve used, and some tips I’ve picked up along the way for successful scanning.
The first scanner I tried was the Sense, by 3D Systems. It’s about $400, and is available for both Mac and PC. There is a newer model now than the one I used, and I don’t know how many improvements they’ve made since then. Basically, the one I used looks like an industrial stapler, and must be tethered to a computer. You aim it at an object, and walk around it. The software tracks the object in real-time, and tries to reconstruct its shape in 3D.
The best thing about the Sense is its cost. It’s cheap, and does a reasonable job with human-sized objects. However, it’s hard to walk around an object with the unit while you are tethered to your computer. It also loses its tracking about 60% of the time, and every time that happens you have to start over. There are probably tricks to avoid this, but I never found anything that worked great.
With that all said, I did some fun projects with it. The one I like the best was when I scanned all of my family members and turned us into a chess set. I’m the king, my wife the queen, my two boys are the rook and bishop, my dog is the knight, and the Roomba that scurries around our house is the pawn (my son’s idea). With the exception of the Roomba, each was scanned, and accessories (stands, crowns, glasses, and a little dog house) were added afterwards on the computer. The Roomba was modeled from scratch in Rhino.
An even cheaper low-end 3D scanner isn’t really a scanner at all. 123D Catch, by Autodesk, is a fantastic free smartphone app that often does the job quite nicely. At the time I made the above chess set this program was still giving fairly crude results. Since then it’s improved so much that it is now my go-to solution for quick, cheap scans of relatively large objects. The way it works is that you walk around your object and take lots of pictures. Those pictures get uploaded to Autodesk’s servers, which grind them through some presumably very sophisticated image processing software. After a relatively short wait, they then provide you with a 3D file of your image. The cool thing is that scale is not an issue. You can scan things as big as a building, or as small as a person. However, very small items are tricky, as they will try to reconstruct everything that your camera has taken a photo of. This instructable has some great information on how to deal with this, although I’ve never personally had much success with using 123D catch to scan small objects.
In the last few years I’ve gotten a lot more serious about my design work, and have at times needed a professional quality scanner. As I mentioned above, most of those are well over $10K, which I just can’t afford. The first thing I tried was an ultra-cheap solution: the Ciclop scanner, a diy open source laser scanner by bq which can supposedly capture very fine details. It uses two cheap lasers pointed at a small object on a turntable, and a webcam to capture the resulting pattern on the object. I spent hours getting it all put together and set up, but was never able to get a decent scan, so eventually I just gave up in frustration.
Finally, I decided I should bite the bullet and spend more than a few hundred bucks, but I still didn’t have near enough for a high-end machine. The best compromise I found is the Einscan-S, which sells for about $1000. This machine projects a changing white-light pattern on an object, and captures the result in stereo with two cameras. The model I bought came with a turntable, but I never found that very useful.
The Einscan software allows for a turntable mode and a free-scan mode. What I normally do is place an object on the turntable from the Ciclop scanner, and use free-scan mode to capture lots of images of it in different positions. Each time an image is captured, the software reconstructs more of its 3-dimensional form. It rarely loses tracking from one image to the next, and when it does you can just discard the last image. Here’s a scan I did recently of a bronze statue of Alice (from Alice in Wonderland), by the artist Karen Mortillaro. (More on my collaboration with her in a later post!).
Notice the white powder on the original bronze statue in the photo. That’s a standard trick in 3D scanning, where you evenly coat your object with baby powder so it gets picked up by the scanner’s cameras better.
You can see in the picture that the smallest details, like the texture of the hair, are not present in the scan. That may be the difference between a professional quality scanner and an almost-professional quality one, although those particular details may be too small even for the best scanners.
The Einscan-S is not as easy to use as, say, 123D catch. However, it definitely picks up a lot more detail. It does not detect color information, which is fine if you are like me, and only interested in 3D printing the resulting objects. The biggest drawback is the size limitations. I have only been able to get it to capture objects less than 12″ tall.
Einscan now has a “pro” version that looks a lot like the Sense. They claim it will capture even more detail than the “S” version, larger sizes, and color. I don’t know how many of their claims are accurate, and it costs about three times as much. If I ever get to play with one, I’ll post those results here!