A well preserved dinosaur trackway that includes footprints from both sauropods (the group that diplodocus belongs to) and theropods (the grroup that T.rex belongs to) in the same place was discovered 70 years ago in Texas.
At the time it was common to excavate tracks and then remove them in blocks from the surrounding rock, these blocks have disappeared off to many different parts of the world. However new research has shown that it's possible to reconstruct the trackways as a whole and in 3D, using the photographs originally taken at the scene.
The technique has a similar result to the method used to scan and reconstruct the ancient human footprints that were recently found and then washed away on a beach in Norfolk, England. It's a great example of how new technology can help us find out much more from a fossil, even years after it's original discovery.
The BBC article has a little video as well - http://www.bbc.com/news/science-environment-26851338
Scientists digitally reconstructed a model of a dinosaur chase using photos of theropod and sauropod footprints excavated 70 years ago