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Museum scientists use 3D scanning to discover secrets of rare Stegosaurus
Posted by 3DP4E

By Staff | 3Ders

In 2013, London's Natural History Museum managed to purchase a rare Stegosaurus skeleton. Nicknamed Sophie, the Stegosaurus is one of the most well-preserved skeleton known. Discovered in 2005, in Wyoming, America, the skeleton is 5.6 meter (18 feet) long and 2.9 meter (9.5 feet) tall. It is the most complete skeleton of a single Stegosaurus ever found, with only a few bones (the left arm and base of the tail) missing.

"Although Stegosaurus has been known about for more than 130 years, not much is known about its biology." explained Natural History Museum dinosaur researcher Professor Paul Barrett. "Because the new skeleton is almost complete, and three-dimensional, we can do a lot of things that have not been possible until now, such as looking at how the leg muscles work or how the skull functions during biting."

"Thanks to this fossil, we can begin to uncover the secrets behind the evolution and behaviour of this iconic but poorly understood dinosaur species."

The research led the Natural History Museum to commission Propshop, voxeljet's modelling subsidiary, to laser-scan the Stegosaurus and create a 3D digital template of the entire skeleton. The Stegosaurus skeleton were scanned and specific pieces were 3D printed to preserve the form in case of possible future loss or damage of the original.

Digitising the Stegosaurus specimen. Stegosaurus tail vertebra (A). Photogrammetry software created a point cloud - millions of floating points representing the bone (B). These points were joined together to create a 3D representation (C).

James Enright, Propshop's Managing Director of voxeljet UK said it was an honour to have been asked to help. "We were able to use our experience in digitally scanning rare, large or one-off objects to good effect," Enright says. "The skeleton was scanned using Lidar technology, and the data gathered from the noncontact, handheld, high-res Laser scanner was then digitally manipulated to create a highly accurate computerized model."

Once a computer model of the Stegosaurus skeleton had been built, the next step was to use it to estimate its body mass and therefore its weight. "I wanted to do this because an animal's weight affects how fast it can move, how much food it must eat and how it interacts with other species, so it's an important basic characteristic to determine." explained the Museum's Dr Charlotte Brassey.

"First of all I scanned lots of skeletons of modern mammals, including elephants, rhinoceroses and deer, and generated a 3D computer model of each animal's shape based on their skeleton. This technique is called convex hulling and it is like stretching a rubber sheet around the skeleton. I analysed the volume of these 3D shapes and found it correlated with the body mass of living examples of the animals. So I knew the same 3D modelling approach could be applied to a dinosaur skeleton and used to predict the body mass of the dinosaur when it was alive." said Brassey.

Propshop then 3D printed the skull, the radial plates and tail bones using one of voxeljet's larger printers, the VX1000, and then fabricated and finished the parts using traditional modelling craftsmanship.

Using Propshop's digital and real-world models, the museum will be able assess the strength and bone density of different parts of the skeleton, discover how the pieces are fitted together and how they may have moved in relation to various functions – chewing, for example. So palaeontologists can gain a much better idea of the Stegosaurus's diet, it's size, and whether its plates were used as means of defence or a giant self-cooling system.

"Finding one as complete as this, where the only major parts missing are the left arm and base of the tail, is exceptional and it's the only Stegosaurus in the world that's anywhere near this complete," saidBarrett. "So it's an amazing find and a really nice acquisition for the Museum."

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