I’ve finished two sculptures made from 3D scans of the Antarctic landscape so far. This latest one is of a ventifact — wind-eroded boulder — that I photographed in the McMurdo Dry Valleys, a trip I recounted in an earlier blog post. I call it the “Bird” Ventifact because from certain angles, it looks like a giant beaked bird with a crest.
In addition to its lively, birdlike presence, part of what attracted me to this form was its concavities and holes, worn by the abrasive action of volcanic gravel carried by fierce Antarctic winds. If a successful sculpture is judged by how it transforms as one walks around it and takes it in from different vantage points, this ventifact certainly works as sculpture. By capturing it in 3D, I’ve “brought it home” for others to experience as an object and not just as a series of flat photographs. Looking at one side hardly predicts what you’ll find on other sides:
Ventifacts and figures: granite boulders at the top of the ridge above Lake Bonney have been sculpted into strange shapes.The “Bird” ventifact looks completely different from another angle. I took 31 photographs from different angles to make the 3D file.
In order to capture the complexity of the form, with all its undercuts and hollows, I chose 3D printing over CNC routing, because the router bit only moves up and down in one direction, and does not tilt to get other angles. 3D printing, by contrast, is additive, and builds the form in layers, preventing the undercuts from collapsing during the printing process with temporary supports that can be broken off once the print is finished. Since the 3D printers that I have access to only have a capacity of about 8 x 8 x 11 inches, and my finished sculpture is 16 x 29.25 x 29.25 inches, I had to print it in sections, epoxy it together, and smooth the joints between the pieces before painting it. However, I was able to assemble the 25-odd pieces into a seamless whole. I’ve made this short video of the process. Watch it full screen and see it come together:
The “Bird” Ventifact from another side. The finished sculpture is 16 x 29.25 x 29.25 inches.Bird Ventifact Sculpture, alternate view.Bird Ventifact Sculpture, alternate view.
One of 162 photos I took while walking around an iceberg stuck in the sea ice near the Dellbridge Islands.
Screenshot of PhotoScan 3D file, with the “texture layer” (the colors from the original photos).Close-up of the left half, just showing the form without the texture layer. Gaps will be filled in later in Modo, the 3D editing program I use. Gaps are areas the software can’t resolve. I think that some may not have been visible from the angles I photographed, while others were rather flat and didn’t offer enough cues for the software to match points between photos. But those are minor issues to fix.
Part of my project here involves capturing forms in 3D. There have been plenty of photographs taken in Antarctica, within and outside the Antarctic Artists and Writers Program, but relatively little sculpture, and the sculpture that has been done has been more inspired by the landscape than an attempt to capture the specifics of the marvelous forms and textures produced by the interaction of wind and water in this unusual environment. My method for doing so involves taking a series of overlapping still photos of an object or scene from different angles and processing them with photogrammetry software into a 3D file. I edit that file in 3D design software and then fabricate it as a sculpture generally using a CNC router at Fab Lab Baltimore, though they can also be 3D printed. The three photos above show stages in processing my most ambitious capture thus far completed: 162 photos of a large iceberg stuck in the sea ice near Inaccessible Island in McMurdo Sound that I shot on December 1st. I blogged about that day in an earlier post — Evan and I went out there in a Haagland tractor and this iceberg was our first stop. There’s no way it would be possible to make a 3D capture like this with an iceberg floating in the water. Also when you’re in a zodiac boat near a floating iceberg, you have to keep your distance because it can flip without notice, causing dangerous waves. This photo gives you an idea of the scale:
Me and my iceberg. It’s stuck in the sea ice near Inaccessible Island (my favorite island name in Antarctica — sounds so…remote). When the ice around it melts, it probably will start floating again eventually. See the diagonal lines, especially noticeable on the left side? Those are earlier float lines. As icebergs melt in open water they shift position, sometimes tilting, sometimes doing an abrupt flip. You wouldn’t want to be this close to it if that happened. But stuck in six feet of sea ice this one wasn’t going anywhere!
Up until recently I used Autodesk 123D Catch to create the 3D files, which is very good free software. Right before leaving for Antarctica, I purchased Agisoft PhotoScan Standard, which can handle larger files, and, I hoped, the larger number of images and greater detail I intended to throw at it with my Antarctic images.
The largest object I’d ever processed a 3D file of before was the Liberty Cap at Yellowstone. One of the source photos is in the center, with two views of the 3D file in Modo on either side.
Turns out PhotoScan is up to the task, although it takes several hours of cranking away in the background for the 3D captures to process. That’s why I haven’t processed that many yet. But I wanted to try a few to make sure it would work. Up until now, the largest natural object I’ve made a capture of is the Liberty Cap, a rock formation called a hot spring cone in Yellowstone National Park that’s 37 feet high. I made that file with 123D Catch and it came out so well I was reasonably confident that the formations would, too.
I started with this pressure ridge by the Double Curtain Glacier, which I also talked about in an earlier post. It wasn’t a huge number of photos, but extraordinarily complex. I was excited to get this result:
PhotoScan was able to process the elaborate quasi-Baroque facade of this pressure ridge.This Modo screenshot shows a detail of the center of the above 3D file. You can see how photogrammetry software makes a polygon mesh, breaking the form into little triangles. These triangles can be moved, deleted, or otherwise edited.
Before tackling the iceberg at the top of this post, I tried processing a portion of an enormous iceberg stuck in the sea ice that Laura Von Rosk and I traveled by snowmobile to see. I wasn’t sure if anything that large could be processed, so although I spent a half hour taking about 170 photos of it from every angle, I only processed 44 of the photos of one side and a bit of its adjacent sides. Here are some screenshots from that experiment. Check out the amazing detail captured from this huge object:
This is an iceberg stuck in the sea ice between New Harbor and Cape Bernacchi. The snowmobile in the foreground gives you an idea of how enormous this iceberg is.PhotoScan processed 44 of the photos into an excellent 3D version of this portion of the iceberg. No gaps!Another side of the iceberg, shown without the texture layer.This is a Modo screenshot of a detail of the mesh of the above 3D file. Check out the detail!
I have many captures ready to process as 3D files, including the Scott Base pressure ridge, the Canada Glacier, Blood Falls, ventifacts, even a penguin subcolony (we’ll see if the penguins moved around too much to process). I’ll share them on this blog as I complete them, though it will be some time before I get to them all because it takes a few to several hours for PhotoScan to go through its paces. But I’m positive I’ll be bringing back many pieces of 3D Antarctica from this trip.
