Computer Graphics World

July 2009 36 ■ ■ ■ ■ Digital Imaging Larson agrees. "We can see textures of wrinkles in the skin, and there appears to be some muscle preservation, as well. You can see areas on the shoulder that look like they were preserved in the shape of the original muscles. Maybe there is still some soft tissue left; maybe, though we do not know for sure yet," he says. "But certainly what is left there is something left by the soft tissue, whether it is bacteria that cre- ated chemicals that made those muscle shapes or muscle tissue itself. We do not know because we have not done any de- structive tests on him." Additionally, the RP model enables other museums to exhibit the rare fi nd, augment- ing their display with perhaps CG anima- tions and information about the beast's prehistoric past and the scientifi c procedures it has un- dergone in more recent times. And this is something that Lar- son is especially interested in. At the Black Hills Institute, Larson and his colleagues not only discover, collect, and clean fossils, but they also prepare them, make replicas through the usual molding and casting process, and mount them for museums world- wide. Research also plays a vital role in what they do. "When kids see the prototyped Leonardo and scientists study it, they basically see the same thing as they would by looking at the original bones, at least as far as the surface detail goes," Larson says. In fact, scanning and RP have been used before to "complete" a dinosaur skeletal mount in which the left side of a jaw may be present but the right side is not, for instance. e process will accurately duplicate the part; presenting the beast whole gives people a better understanding of what it looked like, a shape. In fact, Larson and his group are cur- rently doing just this to produce a com- pleted skull of a new species of dinosaur. "We don't have a complete skull, but we do have enough parts, such as rights and lefts. If we prototype the missing pieces, it will give us a whole skeleton to articulate properly, to off er a better visualization of what it looked like," he explains. Presently, the prototyped model of Leon- ardo is on exhibit at the Phillips County Museum in Malta. Casts made from the prototype are at the Judith River Dinosaur Foundation and the Black Hills Institute. Smaller-sized versions of these precise models also have been made for various purposes. "We live in a wonderful age where we can take what we know about electron- ics and use it on animals that have been dead for 70 million years or more. Using all these wonderful advances in medi- cal technology and computer technology, and other technological advances, we can do some things with fossils that we never thought possible," Larson says. "In fact, we are fi nding out that the fossilization process preserved a lot more than just the bones of that animal. Originally, we didn't even think they were bones, but that they were replaced with something else—until we did X-ray refraction and found they re- ally were bones. We are discovering more A crew at the Black Hills Institute preps the rapid-proto- typed model of the prehistoric beast. Perfectly Preserved Leonardo offi cially has been deemed the best-preserved di- nosaur remains in the world by Guinness World Records, with ap- proximately 90 percent of his body covered in fossilized soft tissue. Most dinosaur fossils contain only bone fragments of these long- ago beasts. That's because in this period where every creature fought for survival, hungry scavengers of- ten ran away with chunks of a fallen creature in their mouth and belly. Even more rare is fi nding a dinosaur that is mummifi ed, since bacteria and other decomposers would fur- ther break down the carcass. So how did Leonardo survive the tests of time? Scientists theorize that immediately upon his death, the dinosaur's fresh corpse be- came submerged and covered in silt, staving off the decomposition process. Eventually, the corpse became mummifi ed and fossilized, with tiny pieces of sand replacing preserved tissue. Images © Black Hills Institute of Geological Research.

• Cover