Oldest known T. rex and Artec 3D meet again for a Japanese museum installation

04/08/2021

By Svetlana Golubeva

After the successful initial reconstruction of Trix back in 2014-2016, the team at Naturalis Biodiversity Center decided they needed a 3D scanner of their own.

Considering their options through research and conversations with Dutch suppliers, the team settled on Artec Space Spider as the best and most suitable for their various tasks, in terms of accuracy, performance, and ease of use. And like the last time, the scanner was supplied by Artec’s long-time partner and Ambassador – 4C Creative CAD CAM Consultants.

“For us, it was most important that we could reproduce dinosaurs with the Space Spider. We discussed which scanner would be best and most convenient for us, and chose Space Spider because it covered most of our needs,” said Hanneke Jacobs, Project Manager of Dinosaurs at Naturalis.

“The largest predator who ever lived on Earth demands the ultimate scanning technology: Artec delivers again!” said Edwin Rappard, director of 4C. “We are proud that Naturalis has chosen the Artec Space Spider to finish the job that started with Artec Eva years ago. Artec makes it possible even to combine the 2016 Eva data with current Space Spider data: the ultimate solution.”

Lightweight yet powerful, Artec Space Spider is an ideal choice when it comes to capturing small parts with intricate geometrical elements such as bones and various types of fossils in high resolution and with steadfast accuracy. It was good timing too – not long before, the Center signed an agreement with the Japanese Dinosaur Museum in Nagasaki to build the first copy of Trix, quite simply named “3D Trix.” It meant that the famous Tyrannosaurus rex and Artec scanners would meet once again.

3D Trix: from 3D scan to assembled skeleton

Following a brief training session on Space Spider and Artec Studio software, 3D modeler and Naturalis anatomist Pasha van Bijlert, responsible for the second digital reconstruction of the T. rex skeleton, got down to work.

Following a brief training session on Space Spider and Artec Studio software, 3D modeler van Bijlert got down to work (Source: Hanneke Jacobs)

The Trix skeleton consists of about 320 bones. Most of these were already scanned with Artec Eva, including the older ribs, the tail, and the vertebrae. This meant that Pasha wouldn’t have to rescan the entire skeleton again – just the bones that didn’t have enough details and needed to be rescanned in better quality. For instance, the foot bones, the jaw, as well as the skull. This saved the modeler lots of time, allowing him to focus more on the modeling and mounting of the missing elements into the final 3D skeleton.

Using Autodesk Maya, what Pasha did first was to position all the scanned 3D models already available into a realistic and intimidating pose for a T. rex, as if ready to devour its imaginary prey. After that, he began working on particular bones that needed to be rescanned and restored.

A 3D-printed part of 3D Trix’s upper skull next to the real Tyrannosaurus rex skeleton in Naturalis Biodiversity Center (Source: Hanneke Jacobs)

Overall, it took Pasha just a couple of days in total to complete all the missing scans, and another couple of weeks to process and combine them into one complete 3D model.

The post-processing workflow varied from bone to bone. “If I was able to scan a bone from all sides, it was simply a process of aligning the scans, perhaps removing the ground or surrounding objects, and then doing a fusion in Artec Studio,” said Pasha, adding that he didn’t need texture for this task. Speaking about his workflow in Artec Studio, he continued, “I particularly like the alignment tool, because apart from individual scans, you can also align ‘finished’ models to different positions.”

For some of the scans that were not of sufficient quality – for instance, if a bone had been scanned before it was fully restored, or if it had been scanned while already mounted in the frame – some extensive post-processing was required using a combination of Artec Studio, Geomagic Wrap, and Zbrush, to remedy the missing data.

“Where possible, I mirrored or transplanted sections from different bones to fill out the flat areas,” he said. “In some cases, I had to hand-sculpt the missing areas based on photos of Trix and other T. rex specimens.”

Tail “trixifixation” and a new pose

To make sure the new 3D Trix looked as realistic and authentic as possible, several steps were taken, including replacing some cast bones in poor condition that Trix had inherited from other specimens – these included a tailbone from the now-auctioned T. rex Stan. At the request of the Nagasaki museum, Pasha also needed 3D Trix in an attacking position.

The new reconstruction of Naturalis’ T. rex, 3D Trix features an attacking pose (Source: Hanneke Jacobs)

Aiming for a more true-to-life version, the 3D modeler also brought 3D Trix’s knees closer together. By looking at the fossilized dinosaur footprints, Pasha figured out that the wide-set legs of the original Trix and other T. rexes were simply not correct. He also moved the bones of the spinal column closer together than in the original, because by design, the new model didn’t have to be disassembled like the original skeleton.

Ready to 3D print

After processing and post-processing, Pasha imported the full skeleton into Rhino, where he modeled the internal armature (steel frame) that would support the mounted skeleton from the inside.

3D printing a lower part of 3D Trix’s jaw (Source: Hanneke Jacobs)

After slicing the completed model for printing with Simplify3D and Cura, it was finally time to 3D print and color all the bones! The smaller parts like nails and teeth were printed on a few small Ultimaker printers using recycled PLA (polylactic acid) bioplastic, a strong and durable material which can be biologically degraded under special conditions. The larger bones were printed via two large-scale Builder Extreme 1500 3D printers.

Fully assembled skeleton of 3D Trix displayed in Naturalis Biodiversity Center (Source: Hanneke Jacobs)

The last step was to color the bones and then thread them one by one onto a previously designed frame of rods using the 3D model as a reference.

After almost a year of 3D printing and painting using nearly 45 million square mm of acrylic paint, the special reconstruction of 3D Trix was completed at the end of 2020. The actual printing and assembling of the bones was done in the “Live Science” exhibition hall of Naturalis, so all visitors could witness the entire process from start to finish. The new T. rex would soon be shipped off to its new home in Japan.

Assembling 3D Trix in Naturalis

Bringing Leo into the game

Right after the new reconstruction was completed, the team at Naturalis decided to add one more Artec scanner to their reconstruction toolbox, and given the size of dinosaurs, this decision made perfect sense – Artec Leo.

“Leo can scan bigger bones very easily, so it saves us a lot of time,” said Hanneke. “It makes scanning so much easier. Plus, it also feels very futuristic when you’re using it!”

Working with these two scanners has created an ideal solution for the team. “Now for the smaller bones we use Space Spider, and for the big ones we use the Leo. It’s a perfect combo.”

With both scanners on hand, Hanneke and her team get scanning requests from other departments at the center as well: “The other day I made a scan of a big mammoth hip bone that has [now] been printed and mounted in a skeleton. Now that they know it’s here, more people know how to find us. It’s part of our toolkit now.”

Exploring areas so rich in bones, the researchers say they’ll likely be kept busy for the next 20 years at least. In fact, the team already has plans to go everywhere from Wyoming to Angola.

We can’t wait to see what the Naturalis team does next!

The Naturalis Dream Team (from left to right): Mickel van Leeuwen, Pasha van Bijlert, Donald vd Burg, Hanneke Jacobs, Ashwin van Grevenhof, Wilco de Pineda (Source: Hanneke Jacobs)