Wednesday, March 16, 2011

Case Study: 3D Imaging Brings Dinosaur Bones to Life

At Direct Dimensions, we love to 3D laser scan important historical treasures. Perhaps one of the oldest items we've gotten our scanners on is a Pterosaur we scanned for Johns Hopkins University.

Pterosaurs, known more commonly as pterodactyls, lived in the late Triassic to the end of the Cretaceous period. Pterosaurs are particularly notable because they are the first known vertebrate creatures to have evolved winged flight and could grow quite large—the largest known pterosaur had a wingspan of about 33 feet. However, because their bones were hollow bones, the skeletons preserved very poorly, as they are often crushed by the weight of sediment. So when you find a good skeleton, there is much to study about these great creatures.

This is what Julia Molnar, a graduate student at Johns Hopkins University department of Art as Applied to Medicine, brought to Direct Dimensions – a set of bone castings from a well preserved pterosaur skeleton. For her masters thesis project, Ms. Molnar was studying the way in which pterosaurs would have taken flight. Very little is known about their launch sequence, and how such an enormous creature could vault into the sky without dragging its giant wings along the ground.

Thus the challenges – digitize the cast pieces, assemble correctly into a complete skeleton, and help formulate the 3D motion sequence for the ancient creature within the computer.

Step 1: Direct Dimensions scanned the castings of the 8-foot pterosaur skeleton with a FARO Arm equipped with the FARO laser line scanner. The FARO laser scanner also collects precise data without ever having to physically contact its target. The fragments were each scanned in two positions—one with the limbs folded inward, as they would have been when the pterosaur was grounded or at rest, and the other with the wings fully extended, as they would have been in flight.

Though there were some difficulties during the scanning process, they did not prove insurmountable. Ms. Molnar described the process: “The scanning was challenging because there were many undercuts, particularly around the ribcage, and the casting is very fragile. I was really impressed with the way they handled the challenges.”

With Molnar helping explain how the components go together, technician Jon Wood created two 3D digital models of the entire pterosaur skeleton - one for each of the two positions: on ground and in flight.

With these completed digital 3D models, Ms. Molnar then created a 3D animation to show the launch movement. Working in a software program called 3D Studio Max, she applied the constraints that paleontologists had previously discovered about pterosaur flight to animate the transition between the closed, resting position and the open flight position. She discovered that pterosaurs very likely had a quadrupedal launch—a two-phase motion that pressed upwards with the hind legs and then followed that with a forward vault motion using its forelimbs. This technique enabled the pterosaur to clear the surface without dragging its wing tips along the ground.

At Direct Dimensions we were thrilled to have used our 3D laser scanning and digital modeling skills to advance the research of this prehistoric creature. We hope to have more projects like this in the future. There are no limits to how we can use our innovative 3D technologies to uncover our world’s most ancient secrets.