3D scanning at La Brea Tar Pits with Artec Space Spider
Dire wolf skeleton unearthed from La Brea Tar Pits
12,000 years ago, the very heart of Los Angeles, California had large reserves of natural asphalt (aka ‘tar’) deposits lurking beneath the surface of the ground. Not to mention at the bottom of streams and ponds. When animals such as mammoths, bison, horses, ground sloths, and camels ventured down to the water to quench their thirst, they would occasionally get stuck in the extremely sticky asphalt that had seeped up to the surface. As little as 1.5 inches (4 cm) of liquid asphalt was enough to entrap a bison or even a mammoth.
Recreation of a mammoth and sabre-toothed cat trapped in asphalt, from Titans of the Ice Age
Predators, including dire wolves (Canus dirus), sabre-toothed cats (Smilodon fatalis), and American lions (Panthera leo atrox), saw them helplessly struggling in place and closed in for what they thought would be an easy meal. Soon both predator and prey were mired in the unforgiving asphalt, where they would both die of starvation and slowly decay on the surface, with some of their remains eventually buried over time in asphalt-saturated sediments.
Sabre-toothed cat skeleton in the museum at La Brea Tar Pits
The museum at La Brea Tar Pits is home to a collection of fossils that have been unearthed from those same still-bubbling asphalt deposits since scientists first began studying them in 1906. All in all, more than 3.5 million specimens have been discovered at La Brea Tar Pits over the years. These fossils have been radiocarbon dated to as much as 50,000 years old.
The museum at La Brea Tar Pits
The Tar Pits have been a literal treasure trove for paleontologists the world over, with massive numbers of well-preserved specimens discovered. To give one example, they’ve unearthed the remains of more than 3,600 dire wolves alone, in addition to the tens of thousands of other fossils the asphalt has offered up.
Pit 91 at the La Brea Tar Pits
Researchers have been conducting a number of studies on the specimens for years now, including radiocarbon dating and other molecular analyses that provide data on biotic changes over time that can be correlated to environmental changes and human impact. Radiocarbon dating allows them to put a precise date on these ancient plants, insects, birds, reptiles, amphibians, mammals, and shells, and gradually develop a much clearer view into what the local environment was like thousands of years before humans arrived and settled.
This is crucial not merely for the sake of understanding the past, but also to help scientists interpret more accurately the changes taking place in today’s environment, as well as to better predict what may be to come in the decades and centuries ahead, and to assist with conservation planning.
Fossils found in Pit 91, one of more than 100 pits at La Brea Tar Pits
Prior to the radiocarbon dating, which is a type of destructive testing, the museum would make plaster casts of fossils, so as to preserve the originals for study. Photogrammetry with a DSLR camera was also briefly employed for each specimen, which entailed lengthy processing times and a huge backlog of fossils waiting in shelves and boxes.
Shelves of fossils in storage at The La Brea Tar Pits Museum
Then they learned about 3D scanning being used in paleontology, how it significantly accelerates workflows while at the same time heightening accuracy and opening up a range of possibilities using 3D printing and visualization, in addition to it unlatching the doors to digital archival.
American lion skeleton in the museum at La Brea Tar Pits
The 3D scanning specialists at Artec Certified Reseller Rapid Scan 3D introduced them to the Artec Space Spider, a professional handheld structured-light scanner that quickly creates metrology-grade 3D models of objects, even those with complex organic shapes, such as fossils. Boasting an accuracy of up to .05mm, in mere minutes Space Spider does what used to take up to an hour or more per fossil.
Chris Strong of Rapid Scan 3D said, “When we looked at the levels of detail that La Brea Tar Pits needed for 3D scanning fossils and bones, it was apparent that the Artec Space Spider was the right choice. The Space Spider is portable and easy to use, for everyone from beginners to advanced users. We're able to capture high-resolution data with color information within minutes. We have been implanting the Artec scanners in the aerospace and medical industry for years with great success as well. The same technology can be used for heritage preservation as well as scanning bones and fossils.”
Carrie Howard holding a camel’s 6th cervical vertebra unearthed from the asphalt
In the words of La Brea’s Imaging Specialist Carrie Howard, “Space Spider accurately captures the complex geometries of bones. Some of these shapes and surface characteristics are challenging to capture, from the sweeping curves of a bison’s rib, to the long maxillary canine teeth of a sabre-toothed cat, as well as the short-faced bear’s metatarsals, and so many more examples I could name...Space Spider lets us capture it all in perfectly lifelike, high-resolution color 3D.”
Howard went on, “one of our initial projects included 400 specimens. We scanned and processed those quickly, and then continued on with others. Now we’re able to handle so many more specimens than we ever used to in the past, whereas with photogrammetry, the time it took for this quantity of specimens was more than three times as long.”
Dire wolf vertebra discovered during the Museum’s excavation Project 23
Howard’s process for 3D scanning with Space Spider takes a few minutes in most cases: she simply places a specimen onto a small turntable, picks up Space Spider, then slowly rotates the turntable as she moves the scanner up and down, thereby capturing every facet and surface. During the process, the scanner’s software, Artec Studio, displays the scan in real time as it takes place. If any spots are missed, it is immediately visible, and the area can easily be scanned once again. The specimen is then turned over and the process is repeated.
3D scanning a dire wolf jawbone with Artec Space Spider
Post-processing takes place in Artec Studio, which entails aligning and registering the scans into a unified, “perfect digital replica” 3D model, which is then exported as an OBJ file and archived.
3D model of Dire wolf jawbone, scanned by Artec Space Spider
Recently the Museum tested the Artec Micro, an automated metrology-grade desktop 3D scanner designed for scanning small objects at up to 10 microns’ accuracy. The Museum has an extensive collection of small specimens, from a variety of plants and animals including bird bones, freshwater snails, and a wide range of seeds. The scanning workflow is easy: they simply mount a specimen on Micro’s scanning platform, and after a few mouse clicks, the scanner takes care of the rest. The platform swings and rotates while Micro’s structured blue light and twin cameras capture every characteristic of the specimen’s surfaces from all possible angles.
As seen in the above photo, Museum visitors are welcome to observe Space Spider in action from the other side of the glass, alongside a screen displaying the 3D scan of the fossil in real time (via Artec Studio). Across from the 3D scanning window is the Museum’s Fossil Lab, playfully nicknamed, the “Fishbowl,” a semi-circular, glass-enclosed lab where children and adults alike can watch paleontologists up close as they sift through, clean, and catalog a wide variety of fossil finds.
Considerations and talks about an online 3D-model specimen database for researchers near and far, as well as various types of local and virtual public outreach, including for schools and universities, have been points of focus for the Museum, and will continue.
Two additional projects, currently in the exploration and development stage, will utilize AR (augmented reality) to heighten public engagement with La Brea Tar Pits’ paleontological resources via interactive and immersive exhibits. Such projects would greatly benefit from the 3D models created with the Museum’s Space Spider, together with other digital technologies, for increasing the public’s knowledge of science and reducing scientific misconceptions at all levels of society.