3D Scanning Bones and Artifacts

Airwolf 3D Creative Director Tyler Caros shares his latest project and offers up tips for 3D scanning objects on a budget and preparing them for 3D printing.

Why use 3D scanning for 3D printing?

3D scanning and 3D printing really go hand in hand. There are many ways to create 3D models, but using 3D scanning technology not only can replicate things that already exist in a real physical form, but the files also can be stored for years to come and can be reproduced a countless number of times.

3D Photoscanning on a budget

We have all seen the handheld laser scanners on the market or maybe the large scanning booths. Those systems are either very expensive or the quality is not good enough to produce a great-looking replica. How can we bring this technology down to a price range that is obtainable to the everyday person without sacrificing quality? This is where photogrammetry comes in. Using an average DSLR camera, anyone can scan objects, almost anywhere.

A few weeks ago, our purchasing manager brought in a real Mammoth leg bone. As soon as he displayed it in his office, I knew I had to borrow it for a few days because I just had to have one of my own. For a couple of weeks, I kept my eye on the mammoth bone — and then the day came when I finally had a few hours to scan it. I will not go into too much detail, but for those of you looking to try 3D scanning on a budget, this will give you good insight on the workflow and how to get a basic scan with little work by using an affordable DSLR camera and some low-cost software.

How to set up for 3D scanning with photogrammetry

For this scan, I set up the photo room with even lighting. You don’t want harsh lighting on your subject. I simply used my normal room lights for this. If the lights are too harsh, you can diffuse them with some tracing paper.

I set the bone on a small box I had laying around. You want to have the least amount of surface area touching the box as possible because this will have to be patched later after scanning. I am not using any fancy turntables, green screens, or other sophisticated equipment for this project because I want to show that great results can still be had on a budget. I also wanted this to be as simple as possible.

I usually walk around my subject three times, taking each picture with about a 60% overlap. This ensures that all of the details have been captured and that the software can properly “stitch” the model. In most cases, I take my photos at three levels: a shot from below that captures the bottom details while angled up at the subject, a straight-forward shot, and a down-angle shot that looks over the top of the subject. After my three rounds of photos are complete, I go back in and capture small details. This is especially important if you have more intricate elements like holes or cutouts. Try to capture as much detail as you can.

Import photos into 3D scanning software

After the photos are taken, we must import them into 3D scanning software. I use the standard version of Agisoft Photoscan because it is a great software package and is easy to use. Another program you can use is Autodesk’s new ReMake software, which also works well.

Once the photos are imported, the software uses them to create a 3D model. It does this by using an algorithm which compares similar patterns and points in the photos and then stitches them together, creating the 3D model. For a large number of photographs (I usually take an average of 120-140 photos per scan), processing can take some time — but it is well worth the wait.

Preparing a 3D scan for 3D printing

The process has a couple more steps, which will help clean up the model and prepare it for 3D printing. Using a 3D mesh editor, I removed the box from under the bone. I also patched the hole and decimated the mesh. You can use many different software packages to do this, including Blender, Meshmixer, and ZBrush. I used ZBrush, which is a paid software, but is also very powerful. Blender and Meshmixer are both free and work great for cleaning up scans as well.

After the model was cleaned up, I uploaded it to the Netfabb cloud service to make sure everything is watertight. Once the file was repaired, it was ready for 3D printing. Next Step: Preparing for 3D Printing and Painting. Stay Tuned…